History of the Development and Application of Whey Protein Products

CHAPTER 2

History of the Development and Application of Whey Protein Products Julian Price Milk Specialties Global, Eden Prairie, MN, United States

2.1

INTRODUCTION

Whey is produced during the manufacture of cheese or casein. It is the liquid that remains after the casein is removed by coagulation with either rennet or acid. It contains about half of the total solids (B6.5% by weight) of milk, including around 20% of the total milk protein. Of the solids in whey, lactose accounts for B75% and crude protein B13%. The nitrogen-containing components include soluble proteins, collectively known as the whey proteins, which are mostly denatured by heat treatments greater than B65 C, and nonprotein nitrogen such as small peptides, ammonia, and urea. The major whey proteins in both their native and heated forms are highly valued for both their physical and physiological functionalities. The other solids in whey are minerals, organic acids, milk fat (rich in phospholipids), and several interesting minor components. Cheese was originally produced on a small local scale as a way of preserving milk; the whey was largely considered a waste product. It was mostly used as an animal feed but also for producing some food products such as fermented whey drinks. Its nutritional and health-giving properties were also recognized in some cultures. However, when large-scale production of cheese commenced, utilization of the large quantities of whey became a problem. For this book it is instructive to recall the origins of industrial modern whey processing, and to appreciate what has driven the development of products and processes in the intervening years. One technology that completely transformed industrial processing of whey in general, and whey protein in particular, was cross-flow membrane filtration. Developed in the early 1970s, it is now used in some form in almost every whey processing operation. The drivers for the development of whey protein products differed significantly in the United States, Europe, and New Zealand (NZ), the regions Whey Proteins. DOI: https://doi.org/10.1016/B978-0-12-812124-5.00002-3 © 2019 Elsevier Inc. All rights reserved.

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where most of the development occurred. In the mid-western United States, in the late 1960s, the primary driver was concern over environmental pollution from the dumping of huge volumes of whey. For example, in Wisconsin in 1950 there were around 150 cheese plants, mostly collecting around 25,000 100,000 L of milk per day, and a large number of these disposed of their whey directly into their local river. Subsequently, many of these cheese plants amalgamated into larger factories, resulting in a reduction of the number of individual plants by about half by 1975. This exacerbated the pollution problems with some rivers becoming akin to open sewers. This prompted the authorities in many states to place a maximum biochemical oxygen demand (BOD) of 20 ppm on dairy wastewater, regardless of where it was disposed. This meant it was no longer possible to dispose of whey without treatment; this provided the first real driver to establish a whey processing industry. One response adopted by many small cheese plants was to dry the whey using roller dryers to produce what became known as “popcorn whey.” This was a very inefficient process for drying whey which contains only 6.5% solids. Furthermore, the product was of low value, being sold for pig feed at around US$250 per tonne in the 1960s. In the early 1970s the cost of natural gas rose, resulting in production of “popcorn whey” becoming uneconomic; however, it continued for some time as it enabled cheese manufacturing to continue. It was recognized that much of the cost of producing the dried whey could be saved if an economical means of preconcentrating whey before roller drying, other than by thermal evaporation, could be developed. This was the trigger for the introduction of membrane filtration into the dairy industry. Between 1975 and 1985 approximately 100 reverse osmosis (RO) plants were installed in the United States, and treated over 50% of all cheese whey production. Through the 1980s with continued consolidation of cheese manufacturing, roller dryers were replaced by evaporators and spray dryers. However, RO systems were commonly used for preconcentrating whey before evaporation, or to reduce volumes of whey and hence the cost of transporting the whey from small plants to factories with evaporators and dryers. In the early 1970s a second fundamental membrane process, ultrafiltration (UF), was introduced. Toward the end of the 20th century, the other two fundamental membrane processes, nanofiltration (NF) and microfiltration (MF), began to be used for whey processing. Concomitantly, the trend to develop added-value products intensified. The drivers for the introduction of membrane filtration into the European dairy industry were somewhat different from those in the United States. Initially, there was less pressure to reduce BOD in the wastewater although the industry was aware this could happen in the future. This provided the European industry time to focus more on added-value products. This resulted

2.2 Membrane Development—1960s to 1980s

in less emphasis on RO and more on UF. Denmark was the first European country to use UF on cheese whey; a major incentive for this was an agreement with a German pharmaceutical company to produce a lactose-rich product as a fermentation substrate. In New Zealand, the development of whey processing was driven by an unusual combination of political changes on the other side of the world and an approach by a global beverage company (MacGibbon, 2014) (see Section 2.3.2.3). From its beginnings in the 1970s, membrane processing has become an integral part of virtually all industrial whey processing. The rest of this chapter covers the development of the key processes used, and how and why they have become so important in developing added-value whey protein ingredients, together with some of the challenges involved. The chapter concludes with a discussion of further developments of whey protein-based ingredients and products, as well as some of the challenges yet to be met.

2.2 2.2.1

MEMBRANE DEVELOPMENT—1960S TO 1980S Cellulose Acetate

In the mid 20th century, the availability of water, especially to increasing populations in arid regions, became a major concern. Water which was unsuitable for drinking became the focus of the attention. This led to consideration of seawater, which until then could be converted to drinking water only by costly and high energy-consuming thermal evaporation processes. Research on using membranes to desalinate seawater commenced in the 1950s. The early research on the newly named RO process focused on the use of cellulose acetate (CA) membranes. CA was used for photographic film and the process of converting it into an asymmetric filtration membrane involved a chemical modification using magnesium perchlorate and acetone. One advantage of CA was that it was possible to make a membrane with fairly controlled pore size in the 10,000 to 100,000 molecular weight range. In the late 1960s, it was recognized that filtration in this UF range could be of interest to the dairy industry for concentration or separation of macromolecules such as proteins. Other advantages of CA were that it was a low-cost material and that it was hydrophilic, making it relatively resistant to fouling, an important consideration in dairy applications. While CA membranes proved suitable for purifying brackish and surface water, there were difficulties in their application in the dairy industry. They were found to have pressure, temperature, and pH limitations, and to be

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susceptible to attack by microorganisms. For example, their pH range is 3 8, and their maximum operating/cleaning temperature is 40 C. Their introduction was a very important milestone in membrane technology but their widespread application was relatively short lived.

2.2.2

Polysulfone and Polyethersulfone

Polysulfones (PS) are thermoplastic polymers with the following chemical structure:

PS membranes were introduced by Union Carbide in 1965 and showed extremely high thermal and chemical stability. PS was found to be a more suitable membrane material than CA for desalination of seawater. PS membranes could be manufactured with reproducible properties and controllable pore size down to 40 nm; the first US patent was issued in 1971. PS membranes dominated this market for more than a decade in several formats, e.g., the DuPont fine hollow fiber concept. UF-PS membranes were invented after it was observed that some experiments with PS produced “leaky” membranes. These membranes were introduced into the dairy industry by several companies but principally by Rhone Poulenc in France. They were well suited to food and dairy applications where their high chemical and thermal stabilities were more important than for desalination applications because of the regular cleaning required. With a normal operating pH range of 2 11 and temperatures of up to 55 C, PS therefore displaced CA as the preferred membrane material. Interestingly, PS is stable beyond 55 C, but this limit was set for the applications for which the membrane was used. The robust characteristics of PS contributed considerably to the rapid adoption of PS, although it was largely superseded a few years later by polyethersulfone (PES), a chemically similar material, as the preferred material for membranes used for separation of whey proteins. A major reason for this was that PES is more hydrophilic than PS, and so more resistant to fouling in dairy applications. PES has the structure:

2.3 Systems and Applications Development

2.2.3

Polyamide

In the mid 1970s, John Cadotte of North Star Research in St Paul, Minnesota, invented a new RO membrane made of polyamide (PA). PA has characteristics superior to those of CA and aryl compounds such as PS for RO applications. The main advantages of PA membranes were a relatively high capacity, very high salt rejection, and good temperature- and pHresistance. However, they are not resistant to oxidizing agents such as chlorine, which makes them more difficult and expensive to clean than PS membranes. PA is used in thin-film composite (TFC) membranes constructed in two-layer designs, although three-layer designs have also been developed. These membranes consist of a PS membrane as support for a very thin layer of PA, which is polymerized in situ on the PS membrane. TFC membranes quickly became the RO membrane of choice in virtually all applications, including whey processing.

2.3

SYSTEMS AND APPLICATIONS DEVELOPMENT

In today’s dairy industry almost every cheese plant has an RO or UF system using the very familiar spiral-wound format. The following discussion shows how the industry evolved to this position.

2.3.1

Reverse Osmosis

In addition to RO (and UF) membranes being extremely thin, and hence having to be supported, RO presents the additional challenge of operating at much higher pressure compared to UF. The early pilot work on RO membranes in food applications used a plate-and-frame or tubular format which could accommodate such pressures. The first publication relating to the application of RO in food systems, including whey, was carried out on a plate-and-frame device, known as the Wurstack, by a group at the USDA’s Western Regional Laboratory at Albany, California, in 1965. Although several companies investigated the plate-and-frame assembly, only one (De Danske Sukkerfabrikker, DDS—see below) successfully commercialized it in dairy applications. At the end of the 1960s, another configuration, the tubular design, was generally considered to be a superior format for RO in food applications, as it was relatively simple from an engineering point of view and conducive to hygienic design. Several companies had been developing tubular systems, most notably American Standard and the Havens Company of San Diego, California, whose owner Glenn G. Havens is generally considered the

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inventor of tubular glass-fiber RO systems. In the United Kingdom, Babcock & Wilcox and Patterson Candy International (PCI) were two main players developing RO food applications. Babcock & Wilcox used porous glass fiber to support the membrane, whereas PCI used a polyester-backed membrane supported in perforated stainless steel tubes. In the 1970s the only two successful suppliers of commercial RO systems using CA membranes into the dairy industry were the Danish Sugar Company, or DDS, using a plate-and-frame system with circular membrane sheets, and PCI, using their tubular design. Both companies supplied over 40 systems into the United States between 1975 and 1985. However, both systems were relatively expensive and had unique problems. The plates in the DDS system began to fail after a few years and were prohibitively expensive to replace, leaving many dairies that had bought these systems in financial stress. The tubular membranes were very expensive to replace and had an extremely high energy consumption. FilmTec, which introduced the TFC RO membrane to the dairy industry around 1980, was already a manufacturer of spiral membranes for the water industry. As spiral membranes were being introduced to dairies for UF applications, they were tried for RO as well. The capital cost of systems was greatly reduced, replacement membrane costs and energy consumption were significantly lower compared with the plate-and-frame, and tubular systems. Spiral RO quickly became the standard and tubular and plate-and-frame designs changed from being the only options to being obsolete in a few years.

2.3.2

Ultrafiltration

2.3.2.1 In the United States—1970 85 The company Abcor Inc. commenced work on UF in the late 1960s and in 1970 manufactured a system for a project in New Zealand (see Section 2.3.2.3). Abcor’s initial design involved a CA membrane supported on a porous plastic tube, similar in concept to the RO tubular designs but operating at lower pressure. A truly remarkable development occurred in 1971 which was largely due to the efforts of one individual. It began at the unlikely place of Pollock, South Dakota, where a former dairy farmer called Frank Thomas, originally from Ontario, Wisconsin, born in 1923, had purchased the former Dakota Cheese Company. After attending a seminar at the University of Wisconsin on the potential for UF in the dairy industry, he came up with the idea of processing whey by UF to make calf milk replacer in which the protein level would be increased from 12% to 35% by removing the small-molecular-weight components, lactose, and minerals.

2.3 Systems and Applications Development

Thomas developed his process using spiral UF membranes housed in 4-in. (100 mm) dairy tubing for protein recovery. The first plant was commissioned in 1972 and had an output of around 90 kg of protein per day; a photograph, from the local news, of this plant appears in Fig. 2.1. A second system followed at Lynn Dairies at Granton in central Wisconsin, with a plant being about three-times the size of the first plant at Pollock. Thomas’s early UF plants were built by Ladish Tri-Clover, a name still familiar to many in today’s dairy industry. The plants were difficult to run and because the membranes were made of CA they proved even more difficult to clean. As mentioned in Section 2.2.1, the pH range for CA membranes is 3 8 and the highest allowable temperature is 40 C. Thomas used his success at Lynn Dairy to start Thomas Technical Services Inc. (TTS) which sold UF systems for whey protein concentrate (WPC) production. Several other larger companies became aware of the potential of UF for separating whey protein and began entering the market. Abcor changed

FIGURE 2.1 Frank Thomas’ first UF system in Pollock; Rushmore Ads/News, June 28th, 1972. Courtesy of Thomas Technical Services Inc., Neillsville, WI.

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its default design from tubular to spiral-wound as they realized the cost advantage. They supplied their customers with highly engineered spiralwound systems and soon passed TTS as the dominant spiral system supplier. Nevertheless, Thomas’s design was the basis for most UF systems now used in the dairy industry. The introduction of PS-, and particularly PES-, UF membranes allowed spiral systems to be easily cleaned at pH in the range 2 11 and at temperatures up to 55 C. This was a critical event which enabled spiral-wound technology to become successful. DDS marketed their system toward difficult applications such as 75% and 80% WPCs and for UF of milk for cheese making. They were very successful in these markets through to the mid to late 1980s, when the lower-cost spiral systems had developed sufficiently to displace their plate-and-frame format as the preferred technology. An alternative system was the “leaf” UF system marketed by competitor Dorr Oliver which was basically similar to the DDS plate-and-frame system, except that with the Dorr Oliver system membrane cartridges were replaced while with the DDS system individual flat membrane sheets were replaced. While the cost of the membranes was relatively low with the DDS system, the labor cost to change possibly hundreds of membrane sheets was very high; with the Dorr Oliver system the membrane cost was higher but replacing the membranes was cheaper as it involved simply sliding in new cartridges. Romicon introduced a hollow-fiber UF design to the dairy industry and installed several systems. Their big advantage was their ability to be cleaned by running the cleaning solution in the reverse direction though the membranes to easily remove the fouling. If this was tried on the other system designs, the membranes would be destroyed. In the United States in the 1970s, there was a relatively slow uptake of UF compared to RO. Apart from the difficulties of operating and cleaning these plants, UF, unlike RO left another liquid by-product in the form of UF permeate, which contained the majority of the solids of the original whey. Therefore UF contributed very little toward solving the whey pollution problem, and small dairies tended to dispose of their UF permeate in the same way as they had disposed of their whey. This restricted the uptake of UF by the larger dairies, where this option was not available, until other solutions were found.

2.3.2.2 In Europe—1975 85 UF in Europe started later than in the United States but quickly took the lead in terms of producing high-protein WPCs; for instance WPC80 1 was produced in Denmark as early as 1978, which was several years earlier than similar products were routinely produced in the United States. It is also the

2.3 Systems and Applications Development

main reason why the adoption of spirals as the dominant technology happened later in Europe than in the United States. DDS was among the first to use PS-UF membranes, which were readily applicable to their plate-and-frame equipment. The initial research and development effort took place in a tight cooperation with Mejeriselskabet Danmark (MD Foods, now Arla) in Denmark. After a few years of research and development, a “pilot plant,” but of full commercial size, was installed in the MD cheese operation in Holstebro, Denmark. This UF plant was in operation in early 1974. Pasilac (then owned by DDS) designed and installed DDS plate-and-frame UF systems using their M35 membrane and was prominent in the market in Europe, as well as dominating the market in Australia and New Zealand for around a decade from the mid 1970s. The DDS/Pasilac systems delivered most of the high-protein WPC plants built over this period. They were certainly ahead of their competitive rivals in this regard. Fig. 2.2 shows a WPC75 plant at Danmark Protein from approximately 1980. In Ireland, Abcor’s tubular design employing CA membranes first appeared in the mid-1970s. The first whey UF installation to run commercially was the Carbery plant at Ballineen in County Cork, which ran from 1975. The UF permeate from this installation was successfully utilized for fermentation into alcohol. WPC and alcohol production have run continuously since

FIGURE 2.2 Multistage high-protein UF system comprising many M35 DDS plate-and-frame modules at Danmark Protein (now Arla) at Nr. Vium Mejeri, Videbæk, Jutland. Photograph courtesy of Bjarne Nicolaisen/Arla Food Ingredients.

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1975, making the site one of the longest continuous commercial producers of WPC in the world. They added whey protein isolate (WPI) and protein hydrolysates to their manufacturing portfolio from the late 1990s. Another Abcor plant, which actually predated the Carbery plant, was installed in Ireland at Avonmore’s Ballyragget site. This installation was used to manufacture WPC35, WPC50, and WPC75 for a limited period. However, the installation was never a commercial success. It was probably Carbery’s innovative utilization of the lactose-rich UF permeate stream that allowed them to make a commercial success of their UF installation, whereas Avonmore did not have any added-value use for its permeate at this time. Avonmore did not use membrane processes again commercially in dairy applications until 1989 and did not use UF again commercially until 1995. Also playing a minor but significant role in this period in Europe was Rhone Poulenc from France, who introduced a plate-and-frame system with a design similar to a plate heat exchanger. Another player was the UK company, PCI, which has the distinction of installing the first whey UF plant in the United Kingdom, at the Milk Marketing Board site at Aspatria in the county of Cumberland (now Cumbria). This was a UF system in which the membrane was deployed in tubular format as shown in Fig. 2.3. The plant was commissioned in

FIGURE 2.3 A PCI tubular UF system, similar to that installed at MMB in Aspatria, processing whey in Northern France. Photograph courtesy of PCI Membranes, Filtration Group.

2.3 Systems and Applications Development

1979, and was designed to make WPC76 for the Japanese market. The significance of 76 was that the protein level needed to be .75% for import into Japan to be classified as an ingredient rather than final product and thus benefit from greatly preferential import tariffs. The brand name for this ingredient was “Lacteen.” This project was only made possible by the pioneering work carried out over the preceding 10 years in New Zealand; this is covered in some detail in the following section.

2.3.2.3 In New Zealand—1960 90 In the late 1960s in NZ, two events combined, with the result that, within a few years, the NZ dairy industry was undoubtedly the world leader in the technology and knowledge to produce added-value whey protein products. During the 1960s, whey utilization in NZ was reasonably advanced for that time, as there was already large-scale casein production. Lactose, whey powder, demineralized whey powder, and lactalbumin (a whey protein extract, produced via heat denaturation and precipitation) were being produced but a significant proportion of whey was still being fed to pigs, irrigated on pasture or discharged to waterways, the last causing environmental damage as in other countries. However, in NZ this was not the main driver for change, due to the sparsely populated nature of the country. The advent of refrigerated shipping had enabled NZ to develop a substantial dairy export trade to the former “Mother Country” of the United Kingdom, which remained their largest export market until the 1970s, when Britain joined the Common Market, now known as the European Union (EU). The United Kingdom had first applied to join the Common Market in 1961 and it was clear that the NZ reliance on the UK market needed to be reduced. This prompted a large government commitment to research and development in the NZ dairy industry. Coincidentally, in 1969 the New Zealand Dairy Board (NZDB) was approached by a large multinational beverage company, now known to be Coca Cola, seeking to source a supply of soluble protein to fortify an acidic beverage product they were trying to develop. The company had a clear set of requirements for the ingredient, in that it needed to be clear in solution at pH 3.5 in the presence of phosphate or citrate in a carbonated beverage and not have any adverse effect on the overall flavor. The company had identified that whey protein had potentially the characteristics they were seeking. This was immensely challenging, as it represented the perfect storm of innovation as we recognize it today, in that this was a request for a brand new product, for a brand new application, using a technology or technologies that had not yet been identified for the purpose.

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Following a screening of alternative technologies considered to have the potential for extracting the whey protein from acid casein whey in a soluble form, the team fairly rapidly identified UF as the one with the greatest potential to form the basis of the extraction process. A tubular plant using CA membranes was acquired from Abcor in 1970, designated the Abcor UF300S, the 300 being the active filtration area in square feet (approximately 27 m2). This was installed at the NZ Dairy Research Institute (NZDRI) in Palmerston North, a full 2 years earlier than Frank Thomas commissioned his first spiral system in Pollock, USA. Work on this plant proved invaluable, not only to the NZDRI but also to Abcor, in that many technical challenges associated with system design were met and applied to future systems. This system proved capable of producing the degree of protein concentration required for the application, but UF alone could not produce a clear protein extract from whey. Consequently, development effort was also required to clarify the whey. In conjunction with centrifugation, diatomaceous earth filtration was found to provide the clarity required in the UF concentrate prior to spray drying and a product meeting the requirements requested by Coca Cola was successfully produced on a pilot scale. In order to scale up production, a much larger plant was acquired from Abcor and installed at the NZ Co-operative Dairy Co. in Waitakaruru, Waikato. The team learned to make the product successfully on a potentially commercial scale, incorporating discoveries and overcoming technical problems that are now taken for granted, e.g., the effect of silicon-based antifoams and the development of cleaning regimes involving proteolytic enzymes. During the early 1970s, NZDRI also evaluated alternative UF formats, with pilot plants purchased in plate-and-frame, flat leaf, and hollow-fiber formats, though spirals followed considerably later. The advantages of PS over CA were also evaluated. So, when whey UF was in its infancy in the United States and Europe, NZDRI had successfully developed a potential “gamechanger” for nutritional beverage applications, along with possessing the most comprehensive knowledge of whey UF in the world at that time. The potential for the whey protein required by Coca Cola was considered to potentially outstrip the ability of the NZ dairy industry to supply it, which may have contributed to what happened next, as before any commercial product launch, the corporation changed direction in that it took an alternative approach to delivering nutritional beverages and it took another 30 years before clear low-pH beverages fortified with whey protein would be commercially available (see Chapter 9: Whey Protein Ingredient Applications). Thus, despite the technical superiority of the NZ dairy industry, it had no market for its novel whey protein products at that time. The commitment to

2.3 Systems and Applications Development

development continued from the mid 1970s, to find new uses and customers for WPC. At the leading edge of the technology was the WPC product at .75% protein, mainly for the emerging market for functional proteins in Japan. Acid casein whey, the main starting material, happened to be particularly suitable for these applications and eventually the NZDB sales team found a successful application in the pumping of hams, as an alternative to egg white. The development activity that followed the original product development largely revolved around developing an understanding of the functional properties of whey proteins, such as solubility, foaming, whipping, emulsification, and gelation—the understanding in New Zealand of these aspects led the world at this time. In addition to the Abcor system whey UF plant there was another large commercial WPC operation in New Zealand at that time. In March 1970, The Lactose Company of NZ Ltd commenced commercial production of a WPC with a protein level of 53% 58%, named Prolac, which was spray-dried and marketed as an egg white replacer for bakery applications. The plant was in Edendale, Southland in the remote south of New Zealand’s South Island, more than 600 miles southwest of Palmerston North where the development work with Abcor took place. The Lactose Company had evaluated three US technologies for ultrafiltration, namely Havens, Abcor, and Door Oliver. The initial commercial plant utilized Havens modules, but by 1972 Door Oliver became the preferred design and the Havens modules were systematically replaced as new Door Oliver modules were acquired. Prolac production continued in Edendale until the operation was relocated and expanded to a purpose built facility at Kapuni, Taranaki in the North Island in 1977. In 1979, DDS supplied a large, seven-stage system for this operation to add capacity to the relocated Door Oliver system. Pasilac/DDS became the dominant supplier of commercial UF equipment for the next few years from the late 1970s. Their first installation in New Zealand was in 1978, processing whey at the sulfuric acid casein plant at Te Aroha Thames Valley, Waikato, making WPC55. This was the first of at least a dozen similar plants supplied by Pasilac to Australia and New Zealand over the next few years. These included a three-line DDS plant at Rangitaiki Plains Dairy Company (later Bay Milk Products) at Edgecumbe, Bay of Plenty, in around 1979, also making WPC55 from B1 ML/day of sulfuric acid casein whey, followed by a similar installation at Longburn, near Palmerston North in 1980/81 processing lactic acid casein whey. These operations at this time were not commercially successful, as there was insufficient market for the WPC, so the NZDB acquired the assets, paid the dairies to operate the plants and took responsibility for the sale of the product. Over a number of years as markets developed so did the processes, with an incremental increase from WPC55 to WPC75, WPC80, and finally WPC82.

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The next plant built in the early 1980s was at Hautapu, Waikato, processing sweet whey from both cheese and rennet casein. This was the last significant installation before the first big spiral system was built at Kiwi Dairies’ factory in Hawera, Taranaki around 1990. The Hawera installation was capable of processing around 2 ML/day of cheese whey, as well as 1.5 ML/day of lactic casein whey. Further large spiral systems followed at Clandeboye, Canterbury in 1996 and Lichfield, Waikato in 1998. As an interesting aside, the Kiwi Dairies installation was not the first major spiral UF owned by the NZ dairy industry. A large spiral system designed by Abcor and built by APV Crawley in the United Kingdom, with about 2500 m2 of membrane area, was ordered for the Tirau site in Waikato at the start of the 1980s. However the Tirau dairy was actually built and commissioned as a lactalbumin plant rather than a WPC operation and the spiral plant remained in storage until it was finally scrapped about 10 years later. The decision to produce lactalbumin rather than WPC certainly appears to have been related to lack of market demand for WPC. However, it is interesting that the plant was never installed anywhere else rather than being scrapped.

2.3.2.4 Domination of the Spiral-Wound Membrane—From the Mid 1980s By the early 1980s, most new whey UF systems deployed PS or PES membranes and RO systems were moving toward the new TFC membrane. However, there were many formats of membrane equipment in use, and each had its own advantages and disadvantages. The DDS plate-and-frame UF system introduced in the 1970s focused on engineering to achieve the absolute highest membrane performance per unit of applied area through supplying a very high shear rate over the membrane surface. The result was the need for much less membrane surface to achieve the same or better results than spiral-wound systems were capable of delivering but the capital cost of the plate-and-frame system was very high. DDS marketed their system toward difficult applications such as 75% and 80% WPC and for UF of milk for cheese making. They were very successful in these markets, as at the time they had relatively little real competition in these technically more challenging applications. Abcor/KMS may claim to have been close to DDS in technical capability but out-sold by DDS; however, what is beyond doubt is that DDS was dominant by the end of the 1970s. Of the other plate-and-frame formats, Dorr Oliver and Rhone Poulenc had failed to gain a significant foothold, while the Romicon hollow-fiber design faded after a short time as individual membrane fibers frequently broke, resulting in protein losses. The membrane cartridges were expensive and it became common to glue a toothpick or similar into the ends of the damaged

2.3 Systems and Applications Development

fiber to allow the cartridge to continue to be used. The damaged fibers were found by running water into the permeate side and seeing which fiber was allowing a high volume of water passage. There were obvious limitations with the early spiral systems as pioneered by Thomas Technical Services. They were difficult to clean, as alluded to earlier, due to the restrictive processing and cleaning conditions associated with CA membranes. The fairly basic engineering of the systems meant that the hydraulic conditions within the plant also made cleaning inefficient, with flow rate across the membrane surface being below that required for efficient cleaning. This, together with the inherent characteristics of whey compared to water, from which the technology was borrowed, meant that those early systems could make products like WPC35 reasonably reliably, but higher protein levels could not be achieved. It became obvious that the spiral format was by far the most economical for filtration membranes, so that, if certain challenges could be overcome, it could compete with and displace the other formats in more challenging applications. The first of these, already mentioned, was the availability of PS/ PES membranes in the spiral-wound format. Desalination Systems Inc. (Desal) in California was among the pioneers. They had previous success with spiral-wound elements in other applications, such as water purification, and when they decided to enter the dairy industry, this was their membrane configuration of choice. There were several challenges of adapting water elements for dairy use, which mainly centered around utilizing more robust materials to enable the elements to stand up to the repeated operation and cleaning cycles required of a dairy application. They also needed to accommodate the higher and varied viscosities, as whey protein was increased to higher levels, required to compete with the plate-and-frame and other more highly engineered formats. Other innovations followed to fulfill the requirements of the hygiene standards required of membrane elements used, to make the new WPCs acceptable in food applications. In the case of Desal, this was their patented Durasan outer wrap, which they used to promote the use of spiral-wound elements in the dairy industry. As well as these innovations in the manufacture of spiral-wound elements, there was scope for improving the engineering of the membrane systems. Abcor/KMS had built their early tubular systems to run in batch mode, but hygiene problems were common and they realized the need to reduce product time-in-process. By the time they built their tubular plants in Ireland, they had already designed and incorporated features that are taken for granted in today’s spiral systems, such as a single feed pump feeding multiple (typically five) stages in series, each with their own circulation pump (without interstage valving) and a “floating” baseline pressure, as well as the use of a volume ratio

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controller to control the process, rather than using a refractometer. These revolutionary features were adopted on Abcor/KMS’s early spiral systems, greatly enhancing the hydraulics for both production and cleaning when compared to systems built by TTS. They continued to improve engineering and system designs to facilitate the building and operation of larger, more sophisticated, systems. For example, they had worked out how to make WPC at .75% protein through the incorporation of diafiltration by the time the ill-fated APVbuilt system was delivered into New Zealand (B1980). All other membrane filtration formats succumbed to the spiral design, with the exception of certain niche applications, as the frontiers of what spiralwound membranes could achieve were pushed back. From a purely technical aspect, the spiral design remains, relatively speaking, low-tech. It still requires much higher membrane areas for the same processes when compared to the other systems but the capital and operating costs are so much lower that a spiral system can be delivered at a much lower cost and the replacement membranes are also much less expensive. It is important to remember that, at that time, virtually all applications ran on hot (unchilled) whey, typically at 40 50 C. The advantages of running hot were that the cost of cooling the whey was avoided and the lower viscosity of the hot feed streams meant that permeate fluxes were much higher, so reducing the size of the system and minimizing the capital cost. However, as system and process complexity increased, the downsides of hot processing became more and more apparent. These were rapid fouling of the membranes in certain applications, the realization that membrane life was much shorter and the growing appreciation of the microbial risks involved. Nevertheless, this was such an important step in the evolution of dairy processing that spiral-wound membrane systems now feature in virtually all significant whey processing operations worldwide.

2.3.3

Nanofiltration

From the early 1980s there was a growing appreciation that the salt content of certain whey streams was limiting their utilization in added-value applications, either for reasons of taste or nutrition. For demineralized whey powders for infant formula, ion exchange (IE) and electrodialysis (ED) were already being used but these technologies were prohibitively expensive for other applications. Hence a more economic way to remove minerals, particularly sodium, potassium, and chloride, from dairy streams such as acid whey, delactosed whey, or salt whey, was sought. At least two technologies were trialled in industrial-scale plants, one of which endured while the other did not. The one that did not last was a membrane

2.3 Systems and Applications Development

process called “Counter Diffusion,” first applied for demineralizing cane molasses in the Australian sugar industry in the early 1980s. It involved a membrane consisting of immobilized organic crystals providing a porous but highly selective barrier held within hollow fiber modules, with the feed material on one side of the membrane and water on the other, so that salt diffused across the membrane from feed to water. At least one plant was installed for whey in Australia, and another in Avonmore’s Ballyragget site in Ireland in 1989, the technology being applied to the desalting of delactosed whey. The Australian plant operated for about 3 years, before the equipment supplier went out of business. By this time the alternative new technology for salt reduction was gaining critical mass. In 1984 the first of a new type of membrane was tested for the first time to complete the family of pressure driven membrane separations as we know them today. This NF membrane application was piloted at the Mid-American Dairymen’s plant in Winsted, Minnesota—shown in Fig. 2.4. The application was to demineralize Cheddar cheese salt whey by removing the sodium chloride with a reduction of the normal sweet whey limits. The membrane was the first attempt by FilmTec to develop a TFC RO membrane for desalination of seawater but the problem was it did not reject salt! It was called the FT 40. A subsequent conversation ensued between FilmTec’s Director of

FIGURE 2.4 The first NF/UO for salt whey, at Mid-American Dairymen’s plant in Winsted MN in 1985. Photograph courtesy of George Hutson.

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Research, Bob Peterson, and George Hutson, the owner of a growing Minneapolis-based company specializing in building spiral membrane systems for the dairy industry called Filtration Engineering Inc. (now part of Tetra Pak). Hutson was asked by Peterson whether such a membrane could have any useful application, to which he replied “Will it reject lactose?” The response was along the lines of “I have no idea, let’s try it.” It did reject lactose and a new application was born, based on a membrane that showed repeatable characteristics that were not those intended when it was originally manufactured. There was disagreement as to what to call the membrane and its application; the industry in general adopted “nanofiltration” (from the original “leaky RO”) whereas Hutson and Filtration Engineering registered the name “Ultra Osmosis” (UO) and continued to use that name for many years before finally accepting the term nanofiltration following FE’s acquisition by Tetra Pak. The first system was installed in Winsted in 1985 with six FilmTec 3838 NF membranes. The process successfully removed monovalent ions such as sodium, potassium, and chloride, while leaving lactose, polyvalent ions, such as calcium, and of course protein in the concentrate. Shortly after this Gene Sorenson, then President of FilmTec, said they did not want to continue manufacturing the membrane and Hutson took the idea to Desalination Systems, as the patent for manufacture was publicly owned. Don Bray, the president of Desal agreed to manufacture it. Desal achieved the desired characteristics at the first attempt and the membrane was termed the DK, a term which was still recognized 30 years later (The D stood for Don (Bray) and the K for his lab assistant Karen). The first major installation was sold in 1988 to Avonmore Dairies in Ireland to demineralize hydrochloric acid (HCl) casein whey. The research was led by Paddy O’Donovan with the objective of removing the majority of the chlorides and neutralizing the whey to pH 5.6 to make a product analogous to sweet whey. The application was a success, and Filtration Engineering installed the first system at Carrick-on-Suir in 1989 with the second system at Shannonside the same year. Hence the UO/NF process changed the entire HCl casein whey process in Ireland, and many applications subsequently incorporated UF as well, to turn acid casein whey into high-value WPC. NF has since been widely adopted in desalting of salt whey, as well as in several other applications where total solids concentration with partial demineralization is beneficial to the application. The Carrick-on-Suir plant was eventually relocated to Avonmore’s Ballyragget site, where it was converted to run as a UF system making WPC35 in 1995. This was replaced by a new UF system commissioned in 1996, supplied by Separation Technology Inc. (SeparaTech), a small Minnesota company supplying membrane filtration systems for food and dairy applications.

2.3 Systems and Applications Development

2.3.4 Ion Exchange Technology and Microfiltration—in the Development of Whey Protein Isolate The development of WPI can be traced back to some IE resin work at Bath University in South West England in the 1970s. This included resin development work and utilizing whey as a substrate from which to extract proteins. The Bio-Isolates group from Swansea built a pilot scale plant in South Wales, before a larger plant was installed at Mitchelstown Co-operative Creamery, Ireland (which became part of DairyGold Co-op in 1989), in the late 1970s to scale up the work that was being done at Bath in conjunction with BioIsolates. Mark Davis of Davisco Cheese, Le Sueur, Minnesota, became aware of this work at about this time and the first commercial plant specifically designed to extract whey proteins via IE was built as a joint venture in Le Sueur in 1982 83. The process involved a cation exchange process on acidified whey, in a stirred reaction tank, at a pH value below the isoelectric point of the major whey proteins, so that these proteins were positively charged. This was followed by washing to remove lactose and other nonprotein materials then elution from the resin by raising the pH with an alkali, e.g., NaOH, to release the protein. The process created a new dairy ingredient category, as the product eluted from the resin was essentially free of fat and lactose and so was close to pure whey protein. Following concentration (using UF, which also removed any excess ions), the product was spray-dried to a powder with typically around 95% protein on a dry basis. The new ingredient was called BiPRO, and it opened up new added-value applications for whey protein ingredients, initially due largely to its unique functionality, which was attributed to a combination of various aspects of its composition. BiPRO was a commercial success; the factory was expanded in the late 1980s and Davisco continued to develop a range of WPIs and derivatives over the subsequent decades, through to the company’s acquisition by the Canadian cooperative Agropur in 2014. Bio-Isolates went public as a publicly listed company, after which Davisco took over the company in about 1992, acquiring all the associated technology and patents and adding further manufacturing capacity in the late 1990s. Soon after the introduction of BiPRO, work was progressing, mainly in Europe, to manufacture an analogous product using membrane filtration. This required the development of another filtration process that was new to the dairy industry and was capable of removing the residual milk fat and other colloidal material from whey. This enabled UF to be used on the clarified whey stream to give a composition similar to that achieved in BiPRO. This process was, of course, MF. All the initial work was done with ceramic membranes, which were available with proven tightly controlled pore sizes in the region of 0.1 0.5 μm. This

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included development work at the Institut National de la Recherche Agronomique (INRA) in France, as well at Avonmore Foods (now Glanbia) at Moorepark in Ireland, in conjunction with Tetra Pak in a project led by Paddy O’Donovan. At the successful conclusion of this project, a commercial system was built at Avonmore’s plant at Richfield, Idaho, in 1989 90 using Pall membranes and this remains the only ceramic MF system for commercial production of WPI in the United States. For several years ceramic microfiltration remained the only filtration technique available for the defatting of whey but as with the previous examples of RO and UF, the high capital cost of ceramic systems was all the incentive required to induce the pioneers of spiral system designs to find a more costeffective alternative. At SeparaTech Inc., the decision was made by the owner Randy Willardsen to investigate the use of polymeric membranes in a spiral configuration for comparison with ceramic MF for WPI production. An initial screening of different membrane types indicated that polyvinylidene difluoride (PVDF) MF membranes with a nominal pore size of 0.2 μm, which were at the time being used for clarification of corn syrup, could successfully be used to clarify whey or preconcentrated WPC ahead of a final UF step in the production of WPI. The initial supplier of membranes for this application was Advanced Membrane Technologies Inc. (AMT) of San Diego, California, closely followed by Synder Filtration of Vacaville, California. SeparaTech sold the first plant using this design to Land O Lakes in Perham, Minnesota, in 1995. This first plant needed expansion and some reengineering to meet process guarantees but did produce a high quality WPI; the plant became the prototype for essentially all spiral MF-WPI produced to the present day. Two further installations followed in 1996 at the Protient sites in Juda, Wisconsin, and Mountain Lake, Minnesota, followed by a fourth plant installed at Volac International Ltd. in Wales in 1997. This was Europe’s first WPI system, built before there was any market for WPI in nutritional applications other than perhaps infant formula in that continent. The pore size of the PVDF membranes adopted for MF of whey proteins was, and remains, of the same order as with the ceramic membranes they were competing against, though the size distribution was far less precise. Consequently, one of the main challenges was to achieve an acceptable rate of protein passage through the membrane without allowing the smallest of the fat globules present to either pass into the permeate or to lodge in the pores, thereby fouling the membrane. Related to this issue was the limitation on the maximum feed pressure that could be applied to the membrane, which is in the region of 0.15 MPa (1.5 bar, 22 psi). As a pressure drop of around 0.1 MPa is required across each spiral element to achieve adequate cross-flow velocity, such systems were limited to one membrane element per

2.3 Systems and Applications Development

housing and also the trans-membrane pressure was very variable across the membrane. This meant that even with a great degree of control of the hydraulic flow within a spiral MF system making WPI, the resultant performance was much less efficient or consistent than the ceramic systems they were competing against. Nevertheless, the spiral MF system utilizing PVDF membranes was a fraction of the capital cost of the ceramic systems, which more than compensated for the much greater membrane area required for the same duty, so once again the development of spiral applications had displaced other more capitalintensive filtration alternatives. Two other ceramic systems were built for WPI manufacture, one in New Zealand and another at Carbery in Ireland in 1997 98 but these proved to be the last and the Carbery system was replaced with a spiral system built by Complete Filtration Resources (CFR) of Marshfield, Wisconsin, in 2010 11.

2.3.4.1 Optimizing Spiral MF Conditions for WPI Production Initially the spiral MF applications were generally run at around 50 C. However, as this author learned at a very early stage in 1998, the initial high flux was extremely short lived on this process. PVDF MF fouling tends to be prohibitively rapid at these temperatures, so reengineering of systems to run at ,20 C quickly followed. The trend toward cold processing continued through the 1990s, such that today most whey protein membrane filtration systems are run cold. The balance between high temperature, high flux rate, rapid fouling and cold processing, low flux, long run time, better microbial quality is just one example of the frequently occurring issues relating to the processing of whey and whey protein products. There are invariably multiple theoretical ways to achieve the same goal and the art of achieving the desired goal effectively is the successful management of the compromises and trade-offs that need to be made.

2.3.4.2 By-Products of WPI Production Another issue typical of whey protein processing which becomes a little more complex in the manufacturing of WPI using MF is the issue of byproducts (or coproducts). This is a perennial issue in cheese and whey processing, going back to the early days where finding a whey solution became paramount for cheese manufacturers. Then, when UF became established, the majority of the solids again ended up in the by-product, i.e., the UF permeate. Thus solutions had to be found to accommodate this before WPC could really be commercialized. MF used in production of WPI extends this even further, as it generates yet another coproduct, which in this case is the MF retentate, a very interesting but challenging

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product, containing all the residual milk fat, colloidal material, and an elevated proportion of the larger whey proteins such as the immunoglobulins. This retentate is now available as a commercial product. It is marketed as Whey Protein Phospholipid Concentrate or High-Fat Whey Protein Concentrate. It typically contains about 65% protein, 20% fat, and 8% ash (American Dairy Products Institute, https://www.adpi.org/Portals/ 0/Standards/WheyProteinPhospholipidConcentrate_book.pdf).

2.4

KEY DEVELOPMENTS SINCE 1990

The following section is by no means a tour de force of all developments in whey protein processing and applications in the last 27 years, but rather it is intended to give a flavor of the most significant developments of recent years.

2.4.1 Agglomeration/Instantization and Whey Protein in Sports Nutrition Until the early 1990s most WPC manufactured was WPC34/35 produced on relatively simple spray dryers, typically as a fine powder and utilized as animal feed or in industrial food applications. With a low-fat, relatively lowprotein product such as this, reconstitution characteristics in water tended to be reasonable and end-use requirements were not particularly demanding. However, from the late 1980s, there was a growing understanding of the potential role proteins could perform in recovery after arduous exercise, as in sports. At this time the proteins that were already in this embryonic market were egg white and caseinate. Whey protein began to attract a lot of attention in this regard for a number of reasons including the growing body of research regarding not only its nutritional properties but also its bioactive properties. The principal pioneer of this work at this time was David Jenkins, who was able to combine seeing and understanding the need with engineering experience to turn the whey protein into an easy-to-use form and the business acumen to make a success of the enterprise. That company, and the product it produced, was Designer Protein.

2.4.1.1 Designer Protein—The First Instantized Whey Protein Powder As a chemical engineer, three-time UK Olympian and Olympic Silver medallist at Munich in 1972, David Jenkins had long been fascinated with all manner of performance enhancement for sport and life. By the late 1980s his focus was how to best improve recovery in sport. An extensive paper based on the multiyear research done by Professor Saris on the Tour de France

2.4 Key Developments Since 1990

competitors was highly influential. His recovery formula proposals included protein, and not just “carbs” (carbohydrates), common sense today—but a game-changer 40 years ago. Also influential were postoperative surgery formulae, all of which had combinations of proteins, carbohydrates, fats, vitamins, and minerals. Adopting this approach, Jenkins developed a formula and prototype for an instantized product in 1987, called ProOptibol, the first recovery optimizer, which began selling in health food stores in Southern California and Hawaii in early 1988 and became very popular among cyclists and triathletes (see Fig. 2.5). ProOptibol contained 33% protein, 60% carbohydrate, MCT (medium-chain triglyceride) oil, vitamins, and minerals and was made at Owatonna Riverbrands of Owatonna MN, a subsidiary of Innovative Food Processors owned and founded by the late Dr. Gene Sanders. Sanders had been a professor of food engineering at the University of Minnesota. He had set up his own instantizing/agglomeration plant south of Minneapolis and had started by agglomerating maltodextrins for Grain Processing Inc. This was a batch process involving the use of hot air to fluidize a quantity of powder and raising the moisture level by spraying in water to make the powder particles stick together via collisions into agglomerates, followed by redrying. This process is known as rewet agglomeration. Through careful management of process parameters, it is possible to accurately control the particle size profile of the final product, and it is also possible to incorporate surfactants such as lecithin with the spray, such that almost any soluble but difficult-to-mix powder can be transformed into an easy mixing version. The original whey protein source was WPC75 from Golden Cheese in Corona, which made product primarily for the Japanese market. In 1991 this changed to WPC80 to align with changes in the Japanese import tariffs. This proved a significant benefit as the increase in protein level resulted in much lower lactose levels that would be better tolerated by lactose intolerant individuals when ingested. Working with Gene Sanders and his research and development team in late 1992, Jenkins was eventually successful making small (5 kg) batches of instantized whey protein. Without any added carbohydrates this proved quite a challenge, as the protein powders behaved very differently from the carbohydrates that Sanders had become used to agglomerating. The process was then successfully scaled up to run in Sanders’ larger fluid-bed agglomerators, processing .300 kg at a time. Once they had established the ideal agglomerated particle size distribution and specifications for optimal dissolution in cold water or milk, they had developed the first instantized protein powder in the United States—it was easily mixed with a spoon with no blender required. The first flavor was vanilla praline; chocolate and strawberry

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FIGURE 2.5 Advertisement for ProOptibol 1991, endorsed by elite triathlete Paula Newby-Fraser. Courtesy of David Jenkins.

2.4 Key Developments Since 1990

followed. The products were branded Designer Protein. The commercial launch was in July 1993 at the National Health Food Show in Las Vegas. An advertising campaign in bodybuilding magazines followed. By 1994 it was the number one selling protein brand in America and grew at 100% a year through 1998 (Fig. 2.6). As the 1990s progressed, the demand for high-protein powders was fuelled by changes in the sports nutrition market, particularly by those, such as bodybuilders and weightlifters, wanting to rapidly build their muscle mass, coinciding with the period when the use of anabolic steroids was becoming unacceptable (see also Chapter 3: Manufacture of Whey Protein Products: Concentrates, Isolate, Whey Protein Fractions and Microparticulated and Chapter 16: Sports and Exercise Supplements).

2.4.1.2 The Growth of Instantized Whey Protein Powders Thus the demand for high-protein powders was dramatically increasing, accompanied by the new requirement for powders to be easy mixing, as the users would be simply mixing the powders into water, milk, or juice. At the same time, the higher-protein whey powders, especially fat-free WPIs, were inherently more difficult to mix as fine powders than the lower-protein versions. This led to an explosion in demand for agglomerated protein powders, first applied in the United States, and around 5 years ahead of the situation in Europe. This demand is still increasing as the understanding of the nutritional benefits of protein in general and whey protein in particular reaches a wider audience. More academic studies were showing the benefits of whey protein, not only in promoting the gain of muscle mass but even more favorable evidence was emerging regarding the importance of protein in maintaining general health (see also Chapter 15: Nutritive and Therapeutic Aspects of Whey Proteins). As the demand for agglomeration of whey protein powders took off, an opportunity emerged for a more efficient, higher-capacity (i.e., lower cost) method of agglomeration to expand the availability of instant whey protein powders. As it happened, this technology already existed and was conveniently concentrated in the Midwestern United States. This technology was analogous to the batch rewet agglomeration system used by Gene Sanders in Owatonna, but was a continuous version. The following Wisconsin companies were all involved in the instantizing of WPC or WPI from around the late 1990s: I I I I I

Main Street Ingredients, La Crosse Maple Island, Medford Lake Country Foods, Oconomowoc Century Foods, Sparta Marron Foods, Durand

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FIGURE 2.6 Designer Protein—the only five-times winner of the American Taste Award—hence the Gold Medal and Splash from 1998. Courtesy of David Jenkins.

2.4 Key Developments Since 1990

The process of continuous rewet agglomeration started with the pioneering research of David Peebles at the beginning of the 1950s, and instantized nonfat dry milk was first marketed in 1954. Soon it replaced the existing spray-dried products on the retail market. The basic Peebles instantizer is shown in Fig. 2.7; commercial rewet agglomeration processes for highprotein WPC and WPI were based on this technology, commencing commercially around 1997. Even though these continuous agglomeration processes dominated the agglomeration market for several years, and many thousands of tonnes of protein powders are still instantized in this way, the batch system was never entirely displaced. Vision Process started a batch agglomeration business in 2003 in Litchfield MN, and subsequently expanded and moved to Owatonna. The tolling costs were higher than the continuous alternative, but the greater control possible in a batch system allowed them to compete in terms of quality and consistency. This business is now part of Kerry Foods. As recently as 2014, Marron Foods also added a batch system to their existing continuous facility.

FIGURE 2.7 Peebles instantizer, as first marketed in 1954. rGEA Group 2018.

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2.4.1.3 Continued Development—Removing the Need for Rewet Agglomeration One obvious disadvantages of rewet agglomeration was the cost associated with shipping the product to the contract processor, the cost of the agglomeration (including 1% 2% processing losses), and the cost of financing the additional time and inventory to permit the agglomeration to take place. Consequently, the designers and manufacturers of spray dryers started working in earnest to find a way to spray dry, agglomerate, and instantize in a continuous process. Spray dryers with integral agglomeration and instantization for WPC80 and WPI began to appear in the early 2000s, the designs being variations on a theme. The agglomeration was achieved by the use of multiple atomization nozzles with overlapping sprays, with fines return to the wet zone below the nozzles, giving some flexibility to vary the particle size and density via manipulation of variables such as lance position and spray cone angle. The fines would be recovered from chamber and fluid bed exhaust air, with lecithin sprayed at the base of the chamber or in the first section of the fluid bed, prior to final drying and cooling, as illustrated in Fig. 2.8. An example of the microstructure of such a powder is shown in Fig. 2.9. Depending on the design and adjustment of the system, particularly the location of the introduction of the fines in relation to the atomization nozzles, different agglomerate structures can result. These can influence final powder properties, primarily wetting and dispersing characteristics, but also bulk density and mechanical stability.

2.4.2 Whey Protein Fractionation and Whey Protein Hydrolysates for Infant Formula The history of infant formula development goes back to the 19th century but our specific interest starts in 1962, with the first products brought to market reflecting the realization that the casein to whey protein ratio in bovine milk was very different to that in human milk; also, the total protein content in breast milk is much lower than in bovine milk (see also Chapter 12: Whey Proteins in Infant Formula). These newly developed formula milks contained demineralized whey added to the skim milk to standardize the protein content and bring the casein to whey ratio essentially to the 40:60 found in human milk. The production of whey powders demineralized by up to 90% by a combination of IE and ED developed as a result of this from the late 1970s, with Euroserum in France producing around one-third of the world’s demineralized whey powders. However, as the science developed, it became apparent that the whey protein

FIGURE 2.8 Schematic diagram of an agglomerating spray dryer. rGEA Group 2018.

FIGURE 2.9 A photomicrograph of an agglomerated dairy powder. rGEA Group 2018.

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component in breast milk and that in formula milk were very different. For instance β-lactoglobulin (β-Lg), a protein making up around half of the protein present in demineralized whey, is not present in human milk. Further to this, β-Lg has been shown to be an inducer of allergy in early infancy, due to the presence of antigenic sites on the peptide sequence of the protein. The majority of the proteins in human milk are contributed by α-lactalbumin (α-La) and lactoferrin. As a consequence, with the quantity of infant formula manufactured worldwide increasing rapidly, not only has the overall quantity of whey protein being used in infant formula increased greatly but also so has the desire to “humanize” infant formula made from bovine milk and to address the allergenicity issue. This has driven several technological developments in whey protein processing, primarily whey protein fractionation and protein hydrolysis.

2.4.2.1 Whey Protein Fractionation Pure (or at least highly concentrated) whey protein fractions including α-La have been produced commercially via IE chromatography for over 20 years, e.g., by Davisco. These separations utilize charge affinity characteristics of the different whey proteins for particular ligands within a resin matrix. Essentially, any whey protein separation is possible using this technology but, as is so frequently the case in whey protein processing, the tail tends to wag the dog in that the production of a new (potentially) high-value derivative results in the majority of the (in this case already valuable) starting material as a by-product needing to be found a market. With α-La only comprising about 20% of total bovine whey protein, the value needed to be derived from the added-value component must be great enough to cover the cost of extraction, assuming that the value of the by-product is at least the same as the starting material. Of the minor whey proteins, lactoferrin has received the main attention, together with lactoperoxidase. They tend to be grouped together because they have similar isoelectric points, and very much higher than those of the major whey proteins. Hence they tend to be extracted together in chromatographic processes as, at a pH close to neutral, they both carry a net positive charge while the remainder of the proteins present are all negatively charged (see Chapter 1 for further information on lactoperoxidase and lactoferrin). Lactoferrin is currently manufactured in New Zealand by Fonterra, Synlait, and Tatua, in Australia by Murray Goulburn, Bega Bioingredients, Warrnambool Cheese & Butter, and Beston Global, as well as in Europe by Friesland Campina and in the United States by Glanbia. Lactoferrin is considered a bioactive component in milk. In the EU, bioactive components come under the novel foods legislation and may therefore only

2.4 Key Developments Since 1990

be marketed once safety has been demonstrated. In November 2012, the European Commission published its decision approving lactoferrin produced by Friesland Campina as a novel food, meaning that lactoferrin can now be used in a variety of foods throughout the EU, including infant formula. For the economics to work for the production of purified minor whey components, the minor premium component has to command a very high price, to cover both the cost of extraction and potentially some reduction in the value of the coproduct, which is often produced in great excess of the target compound. The ideal situation, of course, is where all the components produced have a premium value in relation to the starting material. To this end, there have been attempts to market a “whey protein refinery” capable of splitting the whey protein into its major constituent components, e.g., high purity α-La, β-Lg-depleted WPI, high purity β-Lg, immunoglobulin-enriched WPI, glycomacropeptide (GMP), lactoferrin, and lactoperoxidase. Upfront Chromatography in Denmark sold a system into Dairy Farmers Co-op in Queensland, Australia, in 2002 based on their “Rhobust” expanded bed adsorption technology but this does not appear to have been followed up with any further major systems. The original system was relocated to Adelaide in South Australia, but is not believed to be heavily utilized at the present time. Another example is “Continuous SEParation” (CSEP) Technology, a so-called system approach to continuous simulated moving bed chromatography. This technology was intended to provide the benefits of conventional chromatography (specificity, reproducibility, and mildness) while addressing some of the perceived shortcomings, e.g., cost, throughput, flexibility, productivity, and complexity. A commercial system was installed at Murray Goulburn’s plant at Leongatha in Australia in around 2004. It was reported to still be in use as recently as 2017, but the technology was not adopted elsewhere. There have been attempts to separate α-La from β-Lg via membrane filtration, though the similarity in molecular size makes this difficult and no such process has yet been commercialized. There are other commercial processes by which the concentration of α-La relative to the other whey proteins has been altered to make the whey protein more attractive to manufacturers of infant formula. One such product has been manufactured in California by Hilmar Ingredients. Their α-La enrichment process (for which they have a patent) involves pH and mineral manipulation, followed by centrifugal separation and concentration of the α-La-enriched fraction by UF. The other fraction can be returned for incorporation in WPI or WPC80. While the technology exists to produce whey protein ingredients capable of making infant formula which more closely resemble human milk, e.g., by increasing proteins such as α-La and lactoferrin while depleting levels of

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β-Lg, the adoption of such ingredients appears to have been retarded by the economics of using them. However, not surprisingly, they do seem to have found their way into the “high end” formulae for preterm infants and for normal term infants for the first 4 6 months; this is where their use is likely to grow (see also Chapter 12).

2.4.2.2 Whey Protein Hydrolysis One hundred percent whey-protein partially hydrolyzed formulae (PHF-W) became available in the late 1980s. Whereas greater (or less well controlled) hydrolysis tended to result in a bitter flavor from short-chain peptides, this type of formula had a taste comparable to standard intact protein formulae, which led to better acceptance than other hydrolysates. In addition, PHF-W are commercialized in the United States as routine infant formulas, at prices broadly comparable to other routine formulae. The following statement has been approved by the Food and Drug Administration in the United States: For infants who are not exclusively breastfed, emerging clinical research in healthy infants with family history of allergy shows that feeding a 100% Whey-Protein Partially Hydrolysed formula may reduce the risk of common food allergy symptoms, particularly allergic skin rash, when used instead of whole-protein cow’s-milk formula from the initiation of formula feeding.

Several infant formula manufacturers have developed their own proprietary enzymes and processes for producing their hydrolyzed whey protein products. Whey protein hydrolysates have also found niche applications in other areas, e.g., sports nutrition and some clinical applications, where products are used for both their claimed nutritional and functional attributes compared to their nonhydrolyzed analogues. Therefore many producers of high-protein whey products also offer hydrolysates for such applications as well as for infant formula. In the United States, they are produced by Davisco, Hilmar, Leprino Foods, and Milk Specialties Global, while in Europe the producers would include Carbery in Ireland, Arla in Denmark, and Kerry Foods in The Netherlands and Ireland (see also Chapter 14: Bioactive peptides for information on whey protein hydrolysis and bioactive peptides).

2.5 WHEY PROTEINS AND ADVANCES IN CHEESE MAKING TECHNOLOGY Over the last 25 years, considerable effort has gone into finding ways to increase the efficiency of cheese making without adversely affecting quality.

2.5 Whey Proteins and Advances in Cheese Making Technology

This can generally be divided into two areas, which to a degree overlap. These are: I I

making more cheese per vat of milk processed (increased output); and making more cheese for a given volume of milk processed (increasing yield).

2.5.1

Increasing Cheese Output

From the 1980s, developments in milk UF paralleling those for WPC production have led to the use of this technique to increase the total milk protein concentration (typically standardized to a constant protein-to-fat ratio) being increasingly widely adopted for increasing the productivity of existing and newly built cheese making operations. This is beyond the scope of this review, other than as a background to a potentially superior alternative that has implications for the arrival of a new type of WPC or WPI. UF of cheese milk has been predicted to become widely, if not universally, adopted but it is actually limited by what happens to the whey proteins. As UF concentrates the casein, it also concentrates the whey proteins, resulting in a greater proportion of those proteins ending up in the cheese. This does increase cheese yield, but, above a certain level, the native whey proteins adversely affect the cheese quality, with both textural and flavor changes becoming increasingly noticeable. Increasing levels of calcium associated with the reduced whey drainage also plays a role in adversely affecting the cheese texture. Therefore, UF of cheese milk has tended to be limited to a very modest level, particularly to eliminate seasonal variations in milk composition, so that the composition of the milk going into the vat is consistently around the highest “naturally occurring” level all year (or season) round. As the understanding of the limitations of UF in this application became more widely understood from the late 1990s onwards, research shifted to MF as a potential alternative. The likes of Jean-Louis Maubois at INRA in France and David Barbano at Cornell University in Ithaca, NY, in the United States demonstrated that these limitations on protein standardization could be overcome by using MF instead of UF, as the native whey proteins passed into the permeate so that the cheese milk could be standardized to a casein-to-fat ratio rather than protein-to-fat. This technique was slow to gain traction for a combination of reasons: ceramic MF was very expensive and not widely understood in the dairy industry, plus there are some legislative restrictions in the United States. The ability to make more cheese per vat is indisputable and most of the arguments over cheese quality seem to have been won. However, the situation over yield

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is much less clear-cut than with UF as no, or very little, whey protein is captured in the cheese and around 1% 2% of the casein is lost into the permeate as free casein not trapped into micelles. As with whey UF and MF, further work has reduced the cost, largely by working out how to use cold spiral rather than hot ceramic MF to effect an efficient separation and the number of plants microfiltering milk is increasing. Lloyd Metzger at the University of South Dakota has been prominent in this work. The principal reason to include MF of milk in this discussion is that the coproduct of the casein concentrate is the MF milk permeate, containing the whey proteins. This whey stream is very interesting, in that it differs considerably from typical cheese or acid whey streams. The industry has not yet adopted a universal name for the product, and those which have been put forward include “milk serum,” “ideal whey,” “native whey,” and “virgin whey.” Its interesting characteristics compared to more traditional wheys include: I

I I

I

It is free from all additives associated with the cheese making process, such as annatto, rennet, and cultures, and its pH is essentially the same as that of fresh milk. It is fat free. It is free from GMP, the portion of κ-casein that is cleaved during the renneting process, which makes up  20% of the protein in cheese whey. The reported casein loss into this fraction also implies that around 4% 8% of the protein would be made up of monomeric αs- and β-casein. These proteins do appear in electrophoretograms of one commercially available product analyzed by the author.

These attributes make milk MF permeate suitable for the production of protein isolates with significantly different attributes to traditional WPIs made by either IE, MF, or UF processes. For instance, the absence of cheese making “debris” (particularly annatto in some countries), together with the relatively higher concentration of α-La, enhances its suitability for use in infant formula. Such ingredients are becoming commercially available, e.g., from Sachsenmilch in Germany, Ingredia and Lactalis in France, as well as Leprino Foods in the United States. These products are generally being marketed as nutritionally superior to WPI, which is not without its challenge with WPI having been promoted as “the ideal protein for human nutrition.” For example, Lactalis has been marketing their version under the brand name Pronativ, with the emphasis on improved recovery times after strenuous exercise.

2.5 Whey Proteins and Advances in Cheese Making Technology

2.5.2

Increasing Cheese Yield

As indicated earlier, there is an obvious desire to capture some or all of the whey proteins in cheese without adversely affecting quality, which has not proven possible to a great degree to date through membrane filtration on its own. Limited success has been achieved through steps such as pasteurizing the milk at a temperature high enough to denature the whey protein, often with salts such as calcium chloride to decrease whey protein solubility at elevated temperatures. UF of cheese milk has had success in some particular areas. The most spectacular example was undoubtedly in the manufacture of Feta cheese, with the UF process taking the retentate up to the dry matter level of the final cheese curd, thereby capturing 100% of the whey proteins in the cheese. This technique was pioneered by Arla in Denmark using bovine milk, and was commercially very successful, with production in Denmark peaking at an estimated 100,000 tonnes per year. However, since 2002, when the EU awarded Feta PDO (protected designation of origin) status, this product can no longer be marketed within the EU as Feta. Another technique which has found widespread application, especially in the manufacture of pizza cheese, is microparticulation (further information on microparticulation appears in Chapter 3: Manufacture of Whey Protein Products: Concentrates, Isolate, Whey Protein Fractions and Microparticulated). The generally used process is to take a WPC at around 60% protein and subject it to a combination of a heat, to denature and precipitate the protein, and a mechanical process to break the protein particles into a fairly tight size distribution in the 1 10 μm range. These particles are similar in size to fat globules in milk and so when the microparticulated WPC is added back into the cheese milk, the particles become trapped in the cheese curd. SPX (formerly APV) of Silkeborg in Denmark produces equipment which uses scraped surface heat exchangers to do the heating and provide the shearing action Fig. 2.10. Other equipment manufacturers such as GEA, Tetra Pak, and Alpma produce equipment along broadly similar lines. The use of such “recycled” whey protein streams does have some legislative restrictions, but these have largely been overcome via classification as “secondary starter.” Such cheese yield extension techniques have generally been applied to relatively high-moisture cheeses. So far it has not proven possible to incorporate a significant amount of whey protein into hard cheeses, such as cheddar, without adversely affecting the sensory characteristics.

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FIGURE 2.10 Microparticulation plant, for producing LeanCreme, from liquid WPC. Courtesy of SPX Flow.

2.6 CURRENT WHEY PROTEIN PRODUCTS AND THEIR APPLICATIONS The spectrum of whey protein products that have emerged over the last 40 years are, more or less in their time order of appearance and increasing value, as follows: I I I I I I I I I I

whole whey powder demineralized whey powder delactosed whey powder WPC34/35 WPC60/65 WPC75/80/85 WPI whey protein hydrolysates individual protein fractions native WPI

However, within the above categories the properties of the product depend on the type of whey being processed and also on the specifics of the process used to make the product, which can influence the functionality to make the product work in specific applications. As far as the range of applications is concerned, these are divided into five broad categories: 1. Filler. 2. Cheese yield extender (as discussed earlier).

2.6 Current Whey Protein Products and Their Applications

3. Functional ingredient in food applications (gelling, water binding, emulsification, foaming, heat stability. and fat replacement). 4. Nutritional applications (animal feed, sports, lifestyle, clinical. and infant) 5. Applications using the bioactivity of whey proteins.

2.6.1

Filler

The “Filler” classification includes some long-standing relatively low-value applications for whey powder such as biscuits, bakery, bread, and confectionery. For many of these applications, the whey protein portion of the ingredient serves little function, so these will not be dwelt upon, other than to say that over time more of these of applications have moved to using whey permeate powder, possibly with a degree of demineralization if there is any sensitivity over salt levels. This change has contributed to the freeing up of the protein fraction for higher value applications. Another example of the use of whey powder as a filler is processed cheese, where it is mixed with “real” cheese and emulsifiers, to create a “cheese product” from which the fat does not separate when it is heated.

2.6.2

Physically Functional Applications

The most obvious example of where whey type and/or differences in manufacturing process are crucial is in delivering a specific physical functionality in the WPC or WPI. The functional properties typically of interest to food manufacturers would be required in conjunction with some heating or cooking process. The attributes which may be varied to influence functionality would typically be the mineral profile and the pH to produce a WPC or WPI with good gelation and water-binding characteristics, e.g., to hold water in a cooked meat product. In this case one would look to produce a product with a low level of calcium, a pH above 7, and possibly the addition of a mineral-sequestering agent such as disodium phosphate or sodium polyphosphate. For such a product, acid casein whey is a better starting material than sweet whey, as it is free from GMP; the latter is particularly heat stable and forms  20% of the total protein in sweet whey WPC and reduces the functionality. Acid whey is high in calcium in comparison to sweet whey but at pH 4.4 very little is bound to the protein so essentially it is all removed in the UF permeate when a high-protein WPC is produced. Then the final step would be to neutralize the WPC to the desired pH with NaOH or KOH. There is so much more sweet whey produced than acid whey, so manufacturers have tried to recreate this functionality starting from sweet whey, some with more success than others. This is incidentally why (apart from the fact that it appeared first) BiPRO is much more widely used for its functional attributes than MF-WPI. BiPRO does not contain GMP, and is also naturally

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very low in calcium, whereas MF-WPI would typically contain  0.4% calcium. The absence of fat in a WPI compared to a WPC also generally aids the functionality. Before the market in sports nutrition developed, the largest market for BiPRO was in applications utilizing its physical functionality, e.g., in products such as surimi in Japan. The distinction between physically functional and nutritionally functional applications is obviously blurred, and all the more so with high-protein WPCs. The most obvious example is dairy products, where there is a useful distinction between generally more “traditional” uses of whey protein ingredients where the primary driver for their use is to cheapen a formulation, e.g., whey powder, WPC, or demineralized delactosed whey replacing milk protein in an ice cream or yoghurt, to where the objective is protein fortification, with whey protein being the protein of choice.

2.6.3

Nutritionally Functional Applications

WPCs developed specifically for nutritional purposes and to replace other protein sources were used in animal nutrition before human nutrition, with the arguable exception of infant formula, which has already been discussed. Volac International in the United Kingdom pioneered the use of low-heat-processed WPC in calf milk replacer from 1990, with feeding trials consistently showing enhanced performance in comparison to skim milk-based formulations. However, the lamb milk formula remained a skim-based formula, as it was deemed to be the most sensitive and to carry the highest perceived risk to change. This formulation changed to WPC for the 1993 season; it again outperformed the skim-based formulation and it has remained the UK brand leader ever since. As Volac’s WPI business developed from the late 1990s, the whey protein source for their milk replacers gradually became more fortified by Procream, the whey MF retentate by-product of WPI manufacture. This synergy further benefited the nutritional quality of the milk replacers Volac produces, with the Procream disproportionately rich in immunoglobulins (among the larger whey proteins) and phospholipids from milk fat globule membrane and skim milk membrane material, which are concentrated with the small fat globules remaining after whey separation in the MF process. Undoubtedly the biggest growth area for whey proteins in nutritional applications over the past decade and more is in a market that barely existed when Volac was launching their whey protein-based calf milk replacer. It was not until the 1990s that significant quantities of WPC80 were finding their way into high protein powders for bodybuilders and power athletes in the United States, with WPI later in the decade. Nutrition bars containing whey protein appeared just before the millennium, which typically incorporate a blend of dairy proteins (see Chapter 13: Whey Protein-Based Nutrition Bars

2.6 Current Whey Protein Products and Their Applications

for further information on high-protein bars and Chapter 16 on sports nutrition). Market development in Europe was around 5 years behind the United States but with the sector expanding from the “hard-core” to elite athletes through to recreational athletes, supply has struggled to keep up with demand, with over 30,000 tonnes per year of whey protein currently used in these applications in Europe. A large majority of this is consumed by males under the age of 35, whose motivation has been to consume whey protein in a convenient form and, to a certain extent, have not been too bothered about the sensory experience of consuming the product, in the belief that it is delivering tangible results, i.e., increased muscle mass. As the market for whey protein-based or fortified products expands beyond the recreational athlete to the general health and wellness sectors, the marketing message has needed to evolve, and the taste and convenience of the products needed to improve. Success in these markets will only be achieved by high quality ready-toconsume products. These will most likely be beverages, but could also include products such as snack bars or extruded products. Euromonitor reported global RTD (ready-to-drink) launches with a “high source of protein” claim grew 24% a year from 2010 to 2015, with whey protein being the dominant source of protein. Whey protein-fortified RTDs tend to fall into two categories: those formulated at a pH of ,3.5 and those at a more neutral pH. The more acidic drinks tend to be clear fruit flavors, where the high net positive charge results in the protein remaining soluble following a high heat treatment. This general type of formulation has been around commercially for approximately 15 years, but the high astringency of the protein at low pH was a big challenge to mass market appeal. However, the palatability of such drinks has improved dramatically in recent times, together with the application of novel formats. The most interesting of these is probably Fizzique, a carbonated version with 20 g of protein in a 12-oz (350 mL) slim-line can, launched in 2017 (Fig. 2.11). The technical challenge for the low-acid/neutral whey protein-based RTDs is very different from that of the high-acid examples. Applying the heat treatment required for food safety will render the whey protein insoluble, so the developer has to develop a formulation and a process which can cope with the fouling effects of denaturing whey protein, as well as a product which is both stable and has the desired sensory characteristics. These products tend to be similar to drinking yogurts or smoothies, and another widely seen example is whey protein-fortified coffees. One example of a technique already mentioned to modify whey protein for use in such products is microparticulation, where the whey protein is “predenatured” but in a controlled manner that is tailored to meet the requirements of the end product. Arla in Denmark has launched a number of ingredients and retail products in this

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FIGURE 2.11 Fizzique carbonated protein water. Courtesy of David Jenkins.

2.7 Further Developments

space, and Volac in the United Kingdom launched a retail brand to market its Upbeat product, a whey protein smoothie containing fruit and fruit juice which won the Best Dairy Drink at the 2014 World Dairy Innovation Awards. The market for clinical nutrition is much smaller though developing, with applications such as WPI-based preparations for postoperative recovery, or more highly specialized applications such as preparations based on purified GMP for patients suffering from phenylketonuria, as GMP is the only known dietary protein that in its pure form contains no phenylalanine (see also Chapter 15: Nutritive and Therapeutic Aspects of Whey Proteins for further information on nutritive and therapeutic aspects and Chapter 17 on functional foods).

2.6.4

Bioactivity of Whey Proteins

All the proteins and peptides in whey demonstrate biological activity in their native form, which is not surprising given the millions of years of evolutionary development of mammalian milk. Whey has been used in certain medical treatments over several centuries, but obviously without the understanding of the physiology involved. The multitude of physiological effects of the different components has been widely studied over the past 20 years or so, and some high-value niche applications are developing. Bioactivity is too wide a subject to cover in detail in this chapter. For a review of the bioactivity of the major whey proteins, as well as minor components present at levels down to parts per billion, see the review by Smithers (2008) (see also Chapter 14: Bioactive Peptides, Chapter 15: Nutritive and Therapeutic Aspects of Whey Proteins, and Chapter 17 for information on bioactive peptides, nutritive and therapeutic aspects, and the use of whey proteins in functional foods, respectively).

2.7

FURTHER DEVELOPMENTS

Today the technology exists to make WPCs, isolates, hydrolysates, and fractions that find their way into a wide spectrum of applications. This concluding section is an attempt to predict where the likely growth areas will be, as far as the uses of whey protein products over the next 5 10 years and where market developments, technological developments, or other primary factors may be the essential drivers for these developments. For instance, the use of whey protein for infant formula will continue to grow but it will be technologically and compositionally “more of the same” unless novel ways are found to enable the incorporation of the components which will further “humanize” the products more economically than is currently the case.

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2.7.1

New Markets

Scientific research continues to reinforce our knowledge relating to the benefits in a healthy diet of protein in general and whey protein in particular. When aligned with the realization that the average diet is deficient in protein compared to the other macronutrients, i.e., carbohydrates and fats, comes the belief that there is massive potential to expand the marketing of whey protein products for their nutritional benefits, from the under 35 male to the wider population. As well as postexercise recovery, whey protein can help to maintain a healthy lifestyle in areas such as weight management, minimizing sarcopenia (the tendency to lose muscle mass and function as we age), and the maintenance of bone density through aiding calcium absorption (see also Chapter 15: Nutritive and Therapeutic Aspects of Whey Proteins). This will really be a continuation of the developments outlined in Section 2.6.3, with more and more whey protein-fortified analogues of common food and beverage groups with which we are familiar today. Alongside the introduction of high-quality retail products rich in whey protein, we can also expect to see the introduction of ingredients specifically developed to enable protein fortification of prepared foods at the expense of the other macronutrients, e.g., in soups, sauces, breakfast cereals, or analogue creams with the fat partially or completely replaced by whey protein. These ingredients will be delivering both a functional and nutritional benefit, and so will add cost to the final products, so there will inevitably be the question of affordability.

2.7.2

New Technologies or Processes

The technologies already exist to essentially take whey apart into its constituent components, so it is difficult to see a revolution or eureka development in the next decade in this area. There may be incremental improvements to existing processes—one example could be that if minor whey proteins such as lactoferrin were to find wider application in infant formula then a hybrid between IE and membrane processing might emerge. Affinity microfiltration membranes could combine a traditional MF separation process with the charge on the membrane simultaneously and reversibly bind the target protein. Such a process could potentially make the isolation of lactoferrin more economical, which would make it easier to include it at meaningful levels in infant formula. Novel applications of existing technologies may be applied to target the minor proteins found in milk. Osteopontin is a good example. An ingredient recently commercialized by Arla Food Ingredients contains osteopontin at nearly 90% purity (Lacprodan OPN-10). Osteopontin occurs at far higher concentrations in human milk than in bovine milk, and it has become highly

2.7 Further Developments

valued as another ingredient to humanize infant formula. The Arla process involves a combination of ultrafiltration and microfiltration, together with managing the solubility of the target and other proteins to allow its effective purification. This example is likely to be repeated with the isolation and commercialization of other minor proteins/peptides, as well as other components such as milk fat globule membrane (MFGM) material and milk oligosaccharides such as sialyllactose. There is an area where, if the appropriate technology can be developed and introduced, there would be a massive impact on whey protein processing worldwide. This is the “holy grail” of cold pasteurization. Whey processing is dominated by the continual need to make compromises between process temperature, the wonderful medium for bacterial growth which is WPC, and the heat-sensitive nature of the product, making pasteurization difficult and higher heat treatments all but impossible. Work is going on in several areas, e.g., high pressure, pulsed electric fields, and various frequencies in the electromagnetic spectrum, but to date, these technologies have found limited commercial application in the dairy industry.

2.7.3

Novel Products

There has been some interesting work done over the past decade and more on using whey proteins to form edible films and coatings, and as novel biodegradable packaging materials with tailored barrier properties. However, industrial implementation of this new technology remains reliant on further research before we see significant commercial adoption (see Chapter 11: Whey Protein-Based Packaging Films and Coatings for information of the use of whey proteins in films and coatings). Another promising area of research is aimed at the controlled production of whey protein nanoparticles—submicron-sized structures capable of encapsulation of sensitive compounds such as aroma and bioactive ingredients for delivery within beverages or other food systems.

2.7.4

New Areas of Application

The final area for new development concerns the application of the bioactivity of whey proteins in specific nutritional, therapeutic, or pharmaceutical applications. The production techniques generally exist to isolate all the characterized components, so continuing science-led advances in the understanding of the bioactivity should produce market-led demand for some extremely high-value (though low-volume) products for new applications based on whey protein fractions. The burdens of regulatory acceptance of functional claims are obviously a challenge, which will probably mean

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that novel applications in this area are fairly slow to develop. Nevertheless there appears to be some very compelling evidence of potential to develop products in this area and once again Smithers (2008) provides a good summary in his review (see also Chapter 17 on functional food products). One example not covered in the Smithers (2008) paper that also demonstrates the issues around claims and their regulation is some remarkable wound-healing effects attributed to the antimicrobial effects of lactoferrin, in the treatment of chronic open wounds with biofilms by Randall Wolcott at the Southwest Regional Wound Care Center in Lubbock, Texas. In a study by Sun, Scot, Smith, Rhoads, and Wolcott (2008), a group of 190 patients (over a period from 2002 to 2006) classified with a high risk of amputation was treated with lactoferrin mixed with xylitol applied to the wound site. This treatment had a far higher success rate, in terms of wound closure and saving of the limb, than had been reported in similar studies elsewhere. However, despite more than a decade of (apparently) greatly increased success in the treatment of this debilitating chronic problem, particularly of the elderly, the Center is very restricted in the claims it can make for the treatment. (Therapeutic and nutritive aspects of whey proteins are covered in Chapter 16).

2.8

CONCLUSIONS

This chapter is not intended to be a definitive account of all the significant events in whey protein processing over the past 40 years or so but to give a flavor of the events over this time and link many of the developments within the context of when, why, and how they came about. It is also intended as a tribute to the scientists, engineers, and entrepreneurs who made it happen.

Acknowledgments There are a number of people who were “there at the time” and played very significant roles in the development of whey processing on an industrial scale, who gave generously of their time, their recollections, and their archive materials. I take full responsibility for any mistakes, but those errors and omissions would have been far greater without the valuable contributions from the following people: Ken Burgess, Mark Chilton, Mitch Davis, Bill Eykamp, George Hutson, David Jenkins, Kevin Marshall, Bjarne Nicolaisen, John Joe O’Flynn, Dan O’Shea, Randy Thomas, Dan Twomey, Dave van der Werff, Jorgen Wagner, Randy Willardsen. Also acknowledged is the Society of Dairy Technology in the United Kingdom (www.sdt.org) who published an article by the author in 2013 which formed the basis of this chapter.

References MacGibbon, J. (Ed.), (2014). Whey to go. Whey protein concentrate: A New Zealand success story. Martinborough: Ngaio Press.

Further Reading

SDT. (2012). Dairy technology handbook. Society of Dairy Technology. Available from www. sdt.org. Smithers, G. W. (2008). Whey and whey proteins 2 From ‘gutter-to-gold’. International Dairy Journal, 18, 695 704. Sun, Y., Scot, E. D., Smith, E., Rhoads, D. D., & Wolcott, R. (2008). Biofilms in chronic wounds. Wound Repair and Regeneration, 16, 805 813.

Further Reading Bylund, G. (Ed.), (2003). Dairy processing handbook (2nd ed.). Lund: Tetra Pak Processing Systems. Cheryan, M. (1997). Ultrafiltration and microfiltration handbook (2nd ed). Lancaster PA: Technomic Publishing Co. Deeth, H. C., Datta, N., & Versteeg, C. (2013). Non thermal technologies. In G. Smithers, & M. A. Augustin (Eds.), Advances in dairy ingredients. Chichester: Wiley-Blackwell Publishing. Grandison, A. S., & Lewis, M. J. (1996). Separation processes in the food and biotechnology industries: Principles and applications. Cambridge: Woodhead Publishing. Law, B. A., & Tamime, A. Y. (Eds.), (2010). Technology of cheesemaking (2nd ed.). Oxford: WileyBlackwell. (Society of Dairy Technology Series). Tamime, A. Y. (Ed.), (2013). Membrane processing: Dairy and beverage applications. Oxford: WileyBlackwell. (Society of Dairy Technology Series). Wong, W. K. (Ed.), (2001). Membrane separations in biotechnology (2nd ed.). New York: Marcel Dekker.

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