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Whey and Whey Powders: Protein Concentrates and Fractions
Whey and Whey Powders: Protein Concentrates and Fractions T Tavares and FX Malcata, University of Porto, Porto, Portugal; Faculdade de Engenharia da Universidade do Porto, Porto, Portugal ã 2016 Elsevier Ltd. All rights reserved.
Cheese Whey Health is one of the major reasons that determine consumer’s choices of food; following and maintaining a healthy diet is crucial. However, the difficulty in having consumers change radically their eating habits has led to the emergence of a number of foods that have the same appearance as the conventional ones but that contain certain functional ingredients able to bring health benefits in addition to responding to the nutrition issue. The liquid portion obtained during the coagulation and syneresis process in a cheese production is a by-product called whey (the water-soluble fragment). That can be found in different sources, depending on which milk it arises, although the majority is derived from cows. The worldwide production of bovine whey is estimated as ca. 108 tons per year. Unfortunately, all over the world, a great part of whey does not undergo those downstream processing routes, so a significant portion is (1) sprayed onto fields while the resulting smell and salt levels often prove troublesome; (2) discharged into rivers, lakes, or seas, although the very high polluting power usually precludes other species to survive therein; (3) or discharged into municipal sewage systems. These discharges cause serious environmental problems, because whey is a strong organic pollutant – with particularly high biological oxygen demand (40–60 g l1) and chemical oxygen demand (50–80 g l1). An increased interest in whey protein products, owing to their nutritional role and their role upon human health, has been seen in the last decades. There are two categories of food uses for whey: as raw material for fermentation (due to its high lactose content) aiming at the production of bioproducts or through its protein components as whey protein isolates, whey protein concentrates, whey fractions, and heat-stable whey proteins to bioactive peptide production derived therefrom. These science-based nutritional solutions are perfectly formulated for the production of functional ingredients showing a variety of functional, physiological, and nutritional properties that make them potentially useful in a wide range of applications, such as healthy beverages, nutrition bars and supplements, and pharmaceutical preparations – thus providing a promising alternative for whey upgrade.
Whey Protein Composition Whey retains c.50% of the total milk nutrients; the most important components of whey are soluble proteins (0.6–0.8%, w/v) that represent 20% of total milk proteins, namely, b-lactoglobulin (b-Lg), a-lactalbumin (a-La), immunoglobulins (Igs), bovine serum albumin (BSA), lactoferrin and lactoperoxidase enzymes and caseinomacropeptide, lactose (4.5–5%, w/v), lipids (0.4–0.5%, w/v), and mineral salts (8–10%, w/w using a dry extract basis). The concentration of
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whey protein could vary depending on the source of milk, time of the year, type of feed, stage of lactation, quality of the cheese manufacture process, and the type of whey (acid or sweet). Whey proteins have unique characteristics. Beyond their great importance in nutrition (supply energy and essential amino acids), they exhibit chemical, physical (gel formation, foam stability, and water retention), physiological (useful in therapies, including antimicrobial and antiviral actions, immune system stimulation, and anticarcinogenic activity), functional (growth and cellular repair), and technological features. Based on these properties, individual proteins and protein concentrates of whey have been incorporated in food formulation by industry. The most relevant whey proteins are briefly characterized in Table 1.
Key components of whey What makes the whey proteins being so high quality in what concerns to biological activities? The amino acid content of each protein influences whey protein products’ bioactivities, being one of the reasons for such success. Whey proteins are rich in sulfur-containing amino acids (i.e., cysteine and methionine); therefore, they are susceptible to intramolecular bond formation via disulfide bridges. The high content of cysteine leads to achieve whey as an important and cheap container of dietary L-cysteine. Although this amino acid is not an essential one (can be synthesized from methionine), it appears to have some manner of deficiency syndrome associated with it, at least indirectly via glutathione. Glutathione, tripeptide in which cysteine is the limiting substrate, is an antioxidant molecule responsible for several functions, including immune-modulation mechanism, cellular defense against oxidative stress, and detoxification. Aging, cancer, and HIV patients are supplemented with whey protein in order to increase glutathione levels. A lack in glutathione is a common problem in HIV-infected individuals. Cysteine could be itself an adjuvant in diabetes type II therapy. As mentioned before, theoretically, an increase in cysteine leads to an increase of glutathione production that can relieve the risk of diabetes when this is caused by oxidative stress. Otherwise healthy persons can also benefit when taking a whey protein supplement. The increase of glutathione levels leads to the increase of resistance training. In addition to the glutathione production and its role in the defense against oxidative stress and detoxification, cysteine might also have an important role on hydrogen sulfide (H2S) cardioprotective control. H2S is produced and transported by the enzyme action, acting as a signaling molecule, promoting vasorelaxation of blood vessels. It is also characterized by antioxidative capabilities. Low levels of H2S increase homocysteine levels, which is an indicative of heart and neurovascular diseases. H2S is derived from a circulating cysteine pool that remains in storage in the body and fit to buffer a pool of H2S that preserves physiological functions.
Encyclopedia of Food and Health
http://dx.doi.org/10.1016/B978-0-12-384947-2.00748-0
Table 1
Whey protein characterization
MW (kDa)
Solubility
Structure
Source of
Properties
b-Lactoglobulin
50
18.4
Globular protein with rigid spatial structure Composed mainly of b-sheet motifs Monomer: 1. Free thiol group 2. Disulfide bridges
BCAAs (25.1%) Leucine (13.5%) Cysteine
Gelling capacity Structuring and stabilizer agent Resistant to gastric digestion Binds small hydrophobic molecules assuming their transport Stimulates glutathione synthesis (Cys content) High nutritional value (high sulfur content) – sport supplements
a-Lactalbumin
20–25
14.2
Solubility depends on pH and ionic charge pI: 5.2 Temp. >65 C, pH 6.5 Denature and aggregate formation Temp. <65 C pH 5.2–7.2 – stable dimmer pH 3.2–5.2 – octamer formation pH 3.0 and 8.0 – monomer Do not precipitate during milk acidification pI: 4.7–5.1 Low pH, high temperature, or moderate concentrations of denaturants – ‘molten globule’ Neutral pH the ‘apo’ state (partially unfolded state) pH > 6.7 Irreversible denaturation/ aggregation Temp. <75 C Reversible denaturation
Compact globular protein – highly heterogeneous, 26% a-helix, 14% b-sheet (significantly unfolded), and 60% of other motifs 4 Disulfide bonds make this protein relatively heat-stable The ‘molten globule’ presents a balance between native and unfolded states Ca2þ stabilizes the conformation of chiefly the bsheet domain
Essential amino acids BCAAs Leucine (10.6%) Isoleucine Valine Aspartic acid (10.6%) Cysteine
Structure and composition with 72% homology to human a-lactalbumin – supplements for infant formula High nutritional value (amino acid content) – sport supplements Lactose biosynthesis – acting as a coenzyme
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(Continued)
Whey and Whey Powders: Protein Concentrates and Fractions
Proteins
Concentration (% whey dry bases)
(Continued) Concentration (% whey dry bases)
MW (kDa)
Solubility
Immunoglobulins
10–15
150–1000
pI: 5.5–8.3
Caseinomacropeptide
10–15
8
pI: 4.0–5.0 pH 1–10 – soluble Temp. 80–95 C, pH 4 and 7, 15 min – soluble pH 1–5 – minimum solubility (88%) Emulsifying activity – minimum near pI Decrease in pH – decrease in CMP volume
Bovine serum albumin
5–10
69
Lactoferrin
1–2
78
pI: 4.7–4.9 Heat-induced gelation at pH 6.5 pH 4.5–8.0 – forms a heart-shaped molecule pI: 8.0–8.5
Lactoperoxidase
0.5
89
pI: 9.6 Acidic pH – more active
Structure
Small Y-shaped proteins (4 polypeptide chains) 2 Light 2 Heavy Bond by disulfide bonds Glycosylates through O-glycoside bridge Phosphorylates by phosphorylation of a Ser residue (conditions without posttranscriptional modifications)
Source of (6.5%) Tryptophan Cysteine
BCAAs Acidic and hydroxyl amino acids
Globular protein 17 Intrachain disulfide bonds 1 Free sulfhydryl group
Essential amino acids
Monomeric glycoprotein 1–4 Glycans (depending on the species)
BCAAs Leucine (9.58%) Alanine (9.72%)
Properties
Not inactivated by gastric acids Partially resistant to proteolytic enzymes
Increases absorption of Zn2þ Interactions with cellular components, for example enterotoxins, bacteria, and viruses Ingredient in diets, patients with liver diseases and phenylketonuria (amino acid content) Interactions with hormone cholecystokinin Sialic acid – regular functioning of cell membranes and membrane receptors Lactose synthesis Binds small hydrophobic molecules – assuming their transport
Iron-binding glycoprotein Iron transport and absorption in the gut
Catalyzes oxidation of thiocyanate (SCN)
Whey and Whey Powders: Protein Concentrates and Fractions
Proteins
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Table 1
Whey and Whey Powders: Protein Concentrates and Fractions
They also present a high concentration of branched-chain amino acids (BCAAs) (in some cases higher than 26%) – leucine, isoleucine, and valine, being important factors in tissue growth and repair. Leucine has been identified as the key amino acid in protein metabolism during the translation–initiation pathway of protein synthesis. In that order, leucine-rich proteins are efficient in improving muscle protein synthesis. It has been speculated that the quality of a particular protein for enhancing muscle hypertrophy and stretch is related with the content of leucine. Thus, nutritional supplements containing these proteins may be efficient in preventing sarcopenia in the elderly and would represent a safe and convenient nutritional strategy. In addition, a high leucine concentration leads to enhance the immune function through intracellular conversion to glutathione. Tryptophan is the precursor of niacin, serotonin neurotransmitter, and melatonin hormone; the last two regulate many neurobehavioral effects, for example, appetite, satiety, mood, airway sensory perception, pain sensation, and rhythm of sleep and wake. Zinc is an essential mineral involved in bone, hormone, and enzyme metabolism.
Variants of Whey The emergence of new processing technologies and more sophisticated analytical methods has permitted the production of a number of whey protein components already available in the market and used as additives. Those products comprise whey protein isolate (90–95% protein), almost pure protein; whey protein concentrate (ranging from 25 to 89% protein), most commonly available as 80%, with reduced lactose, fat, and mineral contents (as protein concentration increases, fat, lactose, and mineral contents decrease); hydrolyzed whey protein, presenting a variable protein concentration in which fat, lactose, and mineral contents also vary with protein concentration (hydrolysis used to obtain smaller peptide fractions, with an increase of bioactive peptides, reduces allergic potential and a theoretical improvement of solubility and digestibility when compared with nonhydrolyzed whey protein); and, finally, undenatured whey concentrate, presenting a variable protein concentration that usually ranges from 25 to 89%, processed to preserve native protein structures, and typically has higher amounts of immunoglobulins and lactoferrin. This variability is important when choosing whey fractions for specific nutritional applications.
Whey and Whey Protein Features Whey protein is classified as high-quality protein based on human amino acid requirements, digestibility, and their bioavailability. Besides being susceptible to catalysis, they can be hydrolyzed via gastric, pancreatic, and microbial proteases, thus generating peptides that may present biological activity. Nevertheless, advances in nutritional biochemistry and biomedical research have undergone a notable intensification in search of peptides obtained via controlled in vitro hydrolyses in order to better understand the complex relationship between nutrition and prevention and/or treatment of diseases. Accordingly, scientific evidences have shown a wide
509
range of peptides playing crucial physiological functions and modulating some regulatory processes. However, only some of such health effects, found in vitro, have eventually been confirmed in studies encompassing human volunteers. Studies showed that whey proteins appear to be resistant to gastric digestion and pass quickly to the intestinal tract. Due to the lack of hydrolysis in the stomach, there is no apparent difference between the time of digestion and absorption and subsequent plasma amino acid profile of a whey isolate and a whey hydrolyzate. It was also found that whey protein takes ca. 40–60 min to reach the blood plasma after ingestion. A number of favorable health effects have indeed been claimed for some whey protein concentrate, isolate, or its hydrolyzate. They truly open up a wide range of possibilities, within the market, for functional foods. They are able to affect the cardiovascular, nervous, digestive, or immune systems, including antimicrobial properties, and being implicated in diseases such as cancer, diabetes, osteoporosis, stress, obesity, or cardiovascular complications. The main biological activities of whey proteins related with specific diseases and its respective studies are listed in Table 2. In terms of whey powders, biological function of their proteins is not fully known. Nevertheless, there has been an effort to enhance and justify the market product claims. Whey proteins have been shown to lower plasma and liver cholesterol, as well as plasma triacylglycerol levels in model animals fed with cholesterol-containing diets. High-protein dairy products, and in particular those that contain whey proteins, may reduce fat deposition and improve insulin sensitivity. Whey hydrolyzates are characterized by a low degree of allergenicity and very rarely cause adverse reactions. Currently, a hypoallergenic, hydrolyzed formula is recommended to children nonbreast-fed or partially breast-fed with a high allergy risk. The risk for atopic dermatitis in high-risk infants can be reduced with certain whey milk hydrolyzates when breastfeeding is insufficient. b-Lactoglobulin animal studies suggest reduction of blood pressure by inhibition of angiotensin-converting enzyme and exhibition of immune-enhancing activity. In vitro studies reveal that b-lactoglobulin, chemically modified by 3-hydroxyphthalic anhydride, shows antiviral activity against human herpes simplex virus type 1 (HSV-1) and its hydrolyzate antimicrobial activity against several gram-positive bacteria and bactericidal activity. a-Lactalbumin contributes to reduce the incidence risk of some cancers, and its hydrolyzate reduces the blood pressure. This whey protein has also been associated with treatment of chronic stress-induced cognitive decline. It presents bactericidal activity against Streptococcus pneumonia and its hydrolyzate antimicrobial activity against several gram-positive bacteria. BSA has been shown in vitro to protect lipids against phenolic-induced oxidation. One important property that has been associated with this protein is the ability to inhibit breast cancer growth in vitro. b-lactoglobulin and a-lactalbumin show antiviral activity against HSV-1, when chemically modified. Lactoferrin is a bioactive protein with an ability to bind iron. In opposition to anticancer feature, the antibacterial activity has been attributed to the iron-binding property.
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Whey and Whey Powders: Protein Concentrates and Fractions
Table 2
Specific diseases/whey protein biological functions
Clinical diagnosis
Type of study
Cardiovascular disease
In vitro
Animal Human trial
Immunologic disease
Gastrointestinal disease
Sources
Results/advantages
Hydrolyzed: whey protein concentrate, a-lactalbumin, and bovine serum albumin Caseinomacropeptide Hydrolyzed whey protein (peptide concentrate), b-lactoglobulin, and a-lactalbumin Whey protein concentrate
Angiotensin-converting enzyme (ACE) inhibition ACE-inhibition activity
In vitro
a-Lactalbumin Caseinomacropeptide b-Lactoglobulin Lactoperoxidase and lactoferrin Whey protein isolated
Animal Clinical trial
Caseinomacropeptide Whey protein concentrate ProtectaminW
Animal
Whey protein concentrate Hydrolyzed whey protein (peptide concentrate)
Clinical trial
a-Lactalbumin Lactoferrin (infant formula) Hydrolyzed whey protein (infant formula)
Hydrolyzed whey protein (infant formula) Hydrolyzed whey protein Neurological disease
Microbial disease
Animal
a-Lactalbumin
Clinical trial
a-Lactalbumin
In vitro
Whey protein concentrate (enriched with Helicobacter pylori – antibodies) Hydrolyzed b-lactoglobulin a-Lactalbumin Hydrolyzed a-lactalbumin Caseinomacropeptide b-Lactoglobulin, a-lactalbumin, and bovine serum albumin (chemically modified by 3hydroxyphthalic anhydride) Lactoferrin
Clinical trial
Reduced blood pressure (ACE-inhibiting peptides) Hypertensive and obese persons (with resistance exercise): Increase of HDL and total antioxidant capacity Decrease of triglycerides, systolic blood pressure, and total cholesterol Atherosclerosis patients: Decrease in CCL5 (atherosclerosis biomarker) levels Macrophages enhance function via a tripeptide of glycine–leucine–phenylalanine Macrophages enhance function by low concentrations of caseinomacropeptide (CMP) Enhanced production of spleen and lamina propria lymphocytes Suppressive actions on lymphocyte proliferation Stimulation in the proliferation of murine spleen lymphocytes Exertion of anti-inflammatory effects in a rat model of colitis Increased lymphocyte and glutathione levels in patients with lung inflammation and cystic fibrosis Increased glutathione levels (human immunodeficiency virus (HIV)) 41% Reduction in ulcerative lesions and 73% with repeated doses Reduction of gastric injuries to 68.5% (sulfhydryl-containing moieties) Reduction in ulcerative lesions (prostaglandin production) Increased bifidobacteria proportion Increased bifidobacteria proportion improving gastrointestinal immunity Decreased potential for developing atopic diseases Decreased incidence of infantile colic Bowel resection and protective effect on the gastric mucosa (sulfhydryl component – glutathione production) Protective effects and better seizure control as assessed by myoclonus (involuntary muscle twitch) Increased plasma tryptophan (a precursor of serotonin – key for the treatment of stress-induced cognitive decline) Improved seizure control in persons with drug-resistant epilepsy; antidepressive effects and sleep quality Prevention of infections Antimicrobial against several gram-positive bacteria and bactericidal activity Bactericidal activity (S. pneumonia) Antimicrobial against several gram-positive bacteria Antimicrobial activity Exhibition of antiviral activity against human herpes simplex virus type 1 (HSV-1) Bacteriostatic and bactericidal activity against Escherichia coli, Salmonella typhimurium, Shigella dysenteriae, Listeria monocytogenes, Bacillus stearothermophilus, B. subtilis, and Micrococcus luteus Antifungal activity against Candida albicans In combination with lysozyme, immunoglobulins, or antibodies – more potent bacteriostatic agent against Pseudomonas aeruginosa, L. monocytogenes, and E. coli Decreased intracellular group A streptococci in chronic pharyngitis patients 100% Eradication of Helicobacter pylori
Whey and Whey Powders: Protein Concentrates and Fractions
Table 2
511
(Continued)
Clinical diagnosis
Type of study
Sources
Results/advantages
Cancer
In vitro
Whey protein concentrate
Increment of glutathione levels; stimulation of immunity; detoxification of potential carcinogens Mutagenic agent causing oxidative damage to tissues (ironbinding capacity) Increased glutathione levels; protection of human prostate cells against oxidant-induced cell death Protection of human hepatoma cell line Antiproliferative effects in mammalian, colon adenocarcinoma, and intestinal cell lines; delaying initiation of cell apoptosis Inhibition of growth in human breast cancer cells Induced cell death in tumor cells and exertion of cancerprotective mechanisms in melanoma cells, breast cancer cells, stomach cancer cells, lung cancer cells, lymphoma cells, colorectal cancer cells, and polyps Enhanced cytotoxicity – high rate of apoptosis Lower incidence of colon and mammary tumors and fewer aberrant crypts (colon cancer) Prevention of breast and intestinal cancers in female rats Increased glutathione concentration, leading to stimulation of immunity Depletion of tumor cells (glutathione concentration higher than normal cells) Prevention and treatment of 5-fluorouracil chemotherapyinduced oral mucositis Immune-enhancing Inhibition of metastasis of primary tumors 16/20 Survivors at 6 months Increased NK cell function, glutathione levels, hemoglobin, and hematocrit Improved quality of live Reduced risk of colon carcinogenesis 2/7 Patients had tumor regression after 6 months Increase in glutathione levels in healthy cells and decrease in glutathione levels in cancer cells Improved postprandial glucose tolerance and long-term glucose control Anti-inflammatory effect Protection against endothelial dysfunction, lowering of HbA1c, and insulin resistance Cellular glucose toxicity Reduction in parameters of oxidative stress Decrease in triglycerides and the exposure to glucose (AUC) by up to 44% Increased insulin secretion and reduced postprandial (after meal) exposure to glucose by 21% Prevention of hepatitis C virus infection in a human hepatocyte line Reduced inflammatory markers and improved liver enzymes (hepatitis C patients) Decreased serum lipid peroxidase levels and serum alanine transferase activity (hepatitis B patients) Increased IL-2, NK activity, and plasma glutathione levels Stimulation in the proliferation and differentiation of osteoblastic cells and suppression of bone resorption Increased femoral bone strength in young ovariectomized rats
Whey protein isolate Whey protein isolate (with coadjuvant baicalein) a-Lactalbumin Bovine serum albumin Lactoferrin
Animal
ImmunocalW Whey protein concentrate
Hydrolyzed whey protein
Clinical trial
b-Lactoglobulin Lactoferrin Nondenatured whey protein concentrate
Lactoferrin ImmunocalW (with coadjuvant baicalein)
Diabetes
Hepatitis
Animal
Whey protein concentrate and a-Lactalbumin
Clinical trial
Whey protein concentrate
In vitro
Lactoferrin Whey protein concentrate
Osteoporosis
Clinical trial
ImmunocalW
In vitro
Milk basic protein (lactoferrin, lactoperoxidase, and minor components) Whey protein concentrate and hydrolyzed whey protein Milk basic protein
Animal Clinical trial
Increased bone formation (osteocalcin and procollagen I carboxy-terminal propeptide levels increase), bone mineral, and radial density Inhibition of osteoclast-mediated bone resorption (Continued)
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Table 2
Whey and Whey Powders: Protein Concentrates and Fractions
(Continued)
Clinical diagnosis
Type of study
Exercise
Clinical trial
Sources
Results/advantages
Nondenatured whey protein concentrate
Increase in body mass composition and improved quality of life on HIV-positive women Improvement in one of the four muscles, lean tissues mass, and strength Significant improvements in peak power and increase of 30 s work capacity Increased lymphocyte glutathione levels Decrease in percent body fat improving body mass index Prevention and/or attenuation Reduced fat buildup in obese women with high liver fat content and reduced triglycerides and total cholesterol
Whey protein concentrate
Obesity
In vitro Clinical trial
Whey protein concentrate Whey protein concentrate
Lactoferrin develops a direct role in defending the body against pathogens. This protein possesses bactericidal power against a wide range of microorganisms. The antimicrobial effect can be taken advantage of in the treatment of enteric infections. Recent studies have demonstrated that iron-unsaturated lactoferrin is active against the fungi – which are responsible for dermatophytosis. Lactoferrin possesses antiviral effects too and plays an important role upon stimulation of the immune system.
Whey Proteins, Interaction with Different Organs Whey proteins are beneficial to the intestinal lining, especially in clinical situations where gut function is impaired. A study in rats showed that whey promotes neutrophil chemokines – GCP-2 activity in the intestines and subsequent intestinal cell growth. In a clinical study, it was found that the outcome provided by a whey protein concentrate administered to a person with Crohn’s disease was very close to the behavior of glutamine, reducing intestinal permeability. In the liver, whey proteins exhibited an important role in studies with nonalcoholic fatty liver, showing the ability to reduce liver enzyme (ALT, alanine transaminase; AST, aspartate aminotransferase; and GGT, gamma-glutamyl transpeptidase) levels and fat deposits, enhancing glutathione (due to cysteine). A reduction in weight and waist circumference has also been verified. Another study showed that high-dose supplementation in obese women with high fat content in the liver was able to reduce the accumulation of fat in the liver, reducing triglycerides and total cholesterol.
Whey Powder and Exercise After performing exercise, subjects enter into metabolic stress, requiring consumption of essential amino acids, whey proteins, minerals, or other serum-derived compounds (usable energy). From the mechanistic point of view, due to their composition in amino acids, whey proteins can provide substrates and bioactive components that are capable of extending the overall benefits of regular physical activity. Accordingly, they have been chosen by bodybuilders and elite athletes, in addition to people whose health is compromised. Whey protein can help to improve muscle strength and reduce the likelihood of bone fracture; these
characteristics are directly related to their unique amino acid composition, as mentioned earlier, which are quite similar to those of skeletal muscle proteins. However, the improvement seen in increased skeletal muscle protein occurs through mechanisms that are definitely beyond those assigned to the said content of essential amino acids. When it comes to a moderate exercise, there is an improvement in immunity. On the other hand, when the training is heavy, there is stress in the immune system, leading to the production of free radicals and increased inflammatory activity. It is thought that those factors can harm the immunobiological activity of athletes who train heavily, in which muscle performance and recovery may be affected by oxidative stress. The availability of glutathione can be used to combat this problem. Other studies have shown that whey proteins have helped to achieve more easily the desirable weight and shape body, being more effective than caseins in what concerns to satiety.
Acknowledgment This work received partial financial support from author T. Tavares, provided via postdoctoral fellowship (Refs. SFRH/ BPD/89360/2012), supervised by author F. Xavier Malcata, under the auspices of ESF (III Quadro Comunita´rio de Apoio) and the Portuguese state.
See also: Cheese: Composition and Health Effects; Dairy Products: Dietary and Medical Importance; Milk: Sources and Composition; Whey and Whey Powders: Fermentation of Whey; Whey and Whey Powders, Principles and Applications of Dialysis; Whey and Whey Powders: Production and Uses.
Further Reading Chatterton DEW, Smithers G, Roupas P, and Brodkorb A (2006) Bioactivity of b-lactoglobulin and a-lactalbumin – technological implications for processing. International Dairy Journal 16: 1229–1240. Gauthier SF, Pouliot Y, and Saint-Sauveur D (2006) Immunomodulatory peptides obtained by the enzymatic hydrolysis of whey proteins. International Dairy Journal 16: 1315–1323.
Whey and Whey Powders: Protein Concentrates and Fractions
Ha E and Zemel MB (2003) Functional properties of whey, whey components, and essential amino acids: mechanisms underlying health benefits for active people (review). Journal of Nutritional Biochemistry 14: 251–258. Jain SK (2012) L-Cysteine supplementation as an adjuvant therapy for type-2 diabetes. Canadian Journal of Physiology and Pharmacology 90: 1061–1064. Korhonen H (2009) Milk-derived bioactive peptides: from science to applications. Journal of Functional Foods 1: 177–187. Korhonen H and Pihlanto A (2006) Bioactive peptides: production and functionality. International Dairy Journal 16: 945–960. Korhonen H and Pihlanto A (2003) Food-derived bioactive peptides – opportunities for designing future foods. Current Pharmaceutical Design 9: 1297–1308. Krissansen GW (2007) Emerging health properties of whey proteins and their clinical implications. The Journal of the American College of Nutrition 26: 713S–723S. Madureira AR, Tavares T, Gomes AMP, Pintado ME, and Malcata FX (2010) Invited review: physiological properties of bioactive peptides obtained from whey proteins. Journal of Dairy Science 93: 437–455. McGregor RA and Poppitt SD (2013) Milk protein for improved metabolic health: a review of the evidence. Nutrition and Metabolism 10: 46–58. Meisel H (2005) Biochemical properties of peptides encrypted in bovine milk proteins. Current Medicinal Chemistry 12: 1905–1919.
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Saito T (2008) Antihypertensive peptides derived from bovine casein and whey proteins. In: Bo¨sze Z (ed.) Advances in experimental medicine and biology: bioactive components of milk, vol. 606, pp. 295–317. New York: Springer. Smithers GW (2008) Whey and whey proteins – from ‘gutter-to-gold’. International Dairy Journal 18: 695–704.
Relevant Websites http://www.bythewhey.com/ – By the whey. http://www.dairyglobalnutrition.org/NutrInfo/content.cfm? ItemNumber¼88387&navItemNumber¼88574 – Dairy for Global Nutrition. http://www.innovatewithdairy.com/Pages/FactsAboutWhey.aspx – Think USA Dairy (U.S. Dairy Export Counsil). http://www.leanitup.com/review-protein-powder-buyers-guide-150-popular-proteinpowders-shaken-graded/ – Lean it up. http://www.milkfacts.info/Milk%20Composition/Protein.htm – The Milk Quality Improvement Program (Cornell University).
Cheese Whey Health is one of the major reasons that determine consumer’s choices of food; following and maintaining a healthy diet is crucial. However, the difficulty in having consumers change radically their eating habits has led to the emergence of a number of foods that have the same appearance as the conventional ones but that contain certain functional ingredients able to bring health benefits in addition to responding to the nutrition issue. The liquid portion obtained during the coagulation and syneresis process in a cheese production is a by-product called whey (the water-soluble fragment). That can be found in different sources, depending on which milk it arises, although the majority is derived from cows. The worldwide production of bovine whey is estimated as ca. 108 tons per year. Unfortunately, all over the world, a great part of whey does not undergo those downstream processing routes, so a significant portion is (1) sprayed onto fields while the resulting smell and salt levels often prove troublesome; (2) discharged into rivers, lakes, or seas, although the very high polluting power usually precludes other species to survive therein; (3) or discharged into municipal sewage systems. These discharges cause serious environmental problems, because whey is a strong organic pollutant – with particularly high biological oxygen demand (40–60 g l1) and chemical oxygen demand (50–80 g l1). An increased interest in whey protein products, owing to their nutritional role and their role upon human health, has been seen in the last decades. There are two categories of food uses for whey: as raw material for fermentation (due to its high lactose content) aiming at the production of bioproducts or through its protein components as whey protein isolates, whey protein concentrates, whey fractions, and heat-stable whey proteins to bioactive peptide production derived therefrom. These science-based nutritional solutions are perfectly formulated for the production of functional ingredients showing a variety of functional, physiological, and nutritional properties that make them potentially useful in a wide range of applications, such as healthy beverages, nutrition bars and supplements, and pharmaceutical preparations – thus providing a promising alternative for whey upgrade.
Whey Protein Composition Whey retains c.50% of the total milk nutrients; the most important components of whey are soluble proteins (0.6–0.8%, w/v) that represent 20% of total milk proteins, namely, b-lactoglobulin (b-Lg), a-lactalbumin (a-La), immunoglobulins (Igs), bovine serum albumin (BSA), lactoferrin and lactoperoxidase enzymes and caseinomacropeptide, lactose (4.5–5%, w/v), lipids (0.4–0.5%, w/v), and mineral salts (8–10%, w/w using a dry extract basis). The concentration of
506
whey protein could vary depending on the source of milk, time of the year, type of feed, stage of lactation, quality of the cheese manufacture process, and the type of whey (acid or sweet). Whey proteins have unique characteristics. Beyond their great importance in nutrition (supply energy and essential amino acids), they exhibit chemical, physical (gel formation, foam stability, and water retention), physiological (useful in therapies, including antimicrobial and antiviral actions, immune system stimulation, and anticarcinogenic activity), functional (growth and cellular repair), and technological features. Based on these properties, individual proteins and protein concentrates of whey have been incorporated in food formulation by industry. The most relevant whey proteins are briefly characterized in Table 1.
Key components of whey What makes the whey proteins being so high quality in what concerns to biological activities? The amino acid content of each protein influences whey protein products’ bioactivities, being one of the reasons for such success. Whey proteins are rich in sulfur-containing amino acids (i.e., cysteine and methionine); therefore, they are susceptible to intramolecular bond formation via disulfide bridges. The high content of cysteine leads to achieve whey as an important and cheap container of dietary L-cysteine. Although this amino acid is not an essential one (can be synthesized from methionine), it appears to have some manner of deficiency syndrome associated with it, at least indirectly via glutathione. Glutathione, tripeptide in which cysteine is the limiting substrate, is an antioxidant molecule responsible for several functions, including immune-modulation mechanism, cellular defense against oxidative stress, and detoxification. Aging, cancer, and HIV patients are supplemented with whey protein in order to increase glutathione levels. A lack in glutathione is a common problem in HIV-infected individuals. Cysteine could be itself an adjuvant in diabetes type II therapy. As mentioned before, theoretically, an increase in cysteine leads to an increase of glutathione production that can relieve the risk of diabetes when this is caused by oxidative stress. Otherwise healthy persons can also benefit when taking a whey protein supplement. The increase of glutathione levels leads to the increase of resistance training. In addition to the glutathione production and its role in the defense against oxidative stress and detoxification, cysteine might also have an important role on hydrogen sulfide (H2S) cardioprotective control. H2S is produced and transported by the enzyme action, acting as a signaling molecule, promoting vasorelaxation of blood vessels. It is also characterized by antioxidative capabilities. Low levels of H2S increase homocysteine levels, which is an indicative of heart and neurovascular diseases. H2S is derived from a circulating cysteine pool that remains in storage in the body and fit to buffer a pool of H2S that preserves physiological functions.
Encyclopedia of Food and Health
http://dx.doi.org/10.1016/B978-0-12-384947-2.00748-0
Table 1
Whey protein characterization
MW (kDa)
Solubility
Structure
Source of
Properties
b-Lactoglobulin
50
18.4
Globular protein with rigid spatial structure Composed mainly of b-sheet motifs Monomer: 1. Free thiol group 2. Disulfide bridges
BCAAs (25.1%) Leucine (13.5%) Cysteine
Gelling capacity Structuring and stabilizer agent Resistant to gastric digestion Binds small hydrophobic molecules assuming their transport Stimulates glutathione synthesis (Cys content) High nutritional value (high sulfur content) – sport supplements
a-Lactalbumin
20–25
14.2
Solubility depends on pH and ionic charge pI: 5.2 Temp. >65 C, pH 6.5 Denature and aggregate formation Temp. <65 C pH 5.2–7.2 – stable dimmer pH 3.2–5.2 – octamer formation pH 3.0 and 8.0 – monomer Do not precipitate during milk acidification pI: 4.7–5.1 Low pH, high temperature, or moderate concentrations of denaturants – ‘molten globule’ Neutral pH the ‘apo’ state (partially unfolded state) pH > 6.7 Irreversible denaturation/ aggregation Temp. <75 C Reversible denaturation
Compact globular protein – highly heterogeneous, 26% a-helix, 14% b-sheet (significantly unfolded), and 60% of other motifs 4 Disulfide bonds make this protein relatively heat-stable The ‘molten globule’ presents a balance between native and unfolded states Ca2þ stabilizes the conformation of chiefly the bsheet domain
Essential amino acids BCAAs Leucine (10.6%) Isoleucine Valine Aspartic acid (10.6%) Cysteine
Structure and composition with 72% homology to human a-lactalbumin – supplements for infant formula High nutritional value (amino acid content) – sport supplements Lactose biosynthesis – acting as a coenzyme
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(Continued)
Whey and Whey Powders: Protein Concentrates and Fractions
Proteins
Concentration (% whey dry bases)
(Continued) Concentration (% whey dry bases)
MW (kDa)
Solubility
Immunoglobulins
10–15
150–1000
pI: 5.5–8.3
Caseinomacropeptide
10–15
8
pI: 4.0–5.0 pH 1–10 – soluble Temp. 80–95 C, pH 4 and 7, 15 min – soluble pH 1–5 – minimum solubility (88%) Emulsifying activity – minimum near pI Decrease in pH – decrease in CMP volume
Bovine serum albumin
5–10
69
Lactoferrin
1–2
78
pI: 4.7–4.9 Heat-induced gelation at pH 6.5 pH 4.5–8.0 – forms a heart-shaped molecule pI: 8.0–8.5
Lactoperoxidase
0.5
89
pI: 9.6 Acidic pH – more active
Structure
Small Y-shaped proteins (4 polypeptide chains) 2 Light 2 Heavy Bond by disulfide bonds Glycosylates through O-glycoside bridge Phosphorylates by phosphorylation of a Ser residue (conditions without posttranscriptional modifications)
Source of (6.5%) Tryptophan Cysteine
BCAAs Acidic and hydroxyl amino acids
Globular protein 17 Intrachain disulfide bonds 1 Free sulfhydryl group
Essential amino acids
Monomeric glycoprotein 1–4 Glycans (depending on the species)
BCAAs Leucine (9.58%) Alanine (9.72%)
Properties
Not inactivated by gastric acids Partially resistant to proteolytic enzymes
Increases absorption of Zn2þ Interactions with cellular components, for example enterotoxins, bacteria, and viruses Ingredient in diets, patients with liver diseases and phenylketonuria (amino acid content) Interactions with hormone cholecystokinin Sialic acid – regular functioning of cell membranes and membrane receptors Lactose synthesis Binds small hydrophobic molecules – assuming their transport
Iron-binding glycoprotein Iron transport and absorption in the gut
Catalyzes oxidation of thiocyanate (SCN)
Whey and Whey Powders: Protein Concentrates and Fractions
Proteins
508
Table 1
Whey and Whey Powders: Protein Concentrates and Fractions
They also present a high concentration of branched-chain amino acids (BCAAs) (in some cases higher than 26%) – leucine, isoleucine, and valine, being important factors in tissue growth and repair. Leucine has been identified as the key amino acid in protein metabolism during the translation–initiation pathway of protein synthesis. In that order, leucine-rich proteins are efficient in improving muscle protein synthesis. It has been speculated that the quality of a particular protein for enhancing muscle hypertrophy and stretch is related with the content of leucine. Thus, nutritional supplements containing these proteins may be efficient in preventing sarcopenia in the elderly and would represent a safe and convenient nutritional strategy. In addition, a high leucine concentration leads to enhance the immune function through intracellular conversion to glutathione. Tryptophan is the precursor of niacin, serotonin neurotransmitter, and melatonin hormone; the last two regulate many neurobehavioral effects, for example, appetite, satiety, mood, airway sensory perception, pain sensation, and rhythm of sleep and wake. Zinc is an essential mineral involved in bone, hormone, and enzyme metabolism.
Variants of Whey The emergence of new processing technologies and more sophisticated analytical methods has permitted the production of a number of whey protein components already available in the market and used as additives. Those products comprise whey protein isolate (90–95% protein), almost pure protein; whey protein concentrate (ranging from 25 to 89% protein), most commonly available as 80%, with reduced lactose, fat, and mineral contents (as protein concentration increases, fat, lactose, and mineral contents decrease); hydrolyzed whey protein, presenting a variable protein concentration in which fat, lactose, and mineral contents also vary with protein concentration (hydrolysis used to obtain smaller peptide fractions, with an increase of bioactive peptides, reduces allergic potential and a theoretical improvement of solubility and digestibility when compared with nonhydrolyzed whey protein); and, finally, undenatured whey concentrate, presenting a variable protein concentration that usually ranges from 25 to 89%, processed to preserve native protein structures, and typically has higher amounts of immunoglobulins and lactoferrin. This variability is important when choosing whey fractions for specific nutritional applications.
Whey and Whey Protein Features Whey protein is classified as high-quality protein based on human amino acid requirements, digestibility, and their bioavailability. Besides being susceptible to catalysis, they can be hydrolyzed via gastric, pancreatic, and microbial proteases, thus generating peptides that may present biological activity. Nevertheless, advances in nutritional biochemistry and biomedical research have undergone a notable intensification in search of peptides obtained via controlled in vitro hydrolyses in order to better understand the complex relationship between nutrition and prevention and/or treatment of diseases. Accordingly, scientific evidences have shown a wide
509
range of peptides playing crucial physiological functions and modulating some regulatory processes. However, only some of such health effects, found in vitro, have eventually been confirmed in studies encompassing human volunteers. Studies showed that whey proteins appear to be resistant to gastric digestion and pass quickly to the intestinal tract. Due to the lack of hydrolysis in the stomach, there is no apparent difference between the time of digestion and absorption and subsequent plasma amino acid profile of a whey isolate and a whey hydrolyzate. It was also found that whey protein takes ca. 40–60 min to reach the blood plasma after ingestion. A number of favorable health effects have indeed been claimed for some whey protein concentrate, isolate, or its hydrolyzate. They truly open up a wide range of possibilities, within the market, for functional foods. They are able to affect the cardiovascular, nervous, digestive, or immune systems, including antimicrobial properties, and being implicated in diseases such as cancer, diabetes, osteoporosis, stress, obesity, or cardiovascular complications. The main biological activities of whey proteins related with specific diseases and its respective studies are listed in Table 2. In terms of whey powders, biological function of their proteins is not fully known. Nevertheless, there has been an effort to enhance and justify the market product claims. Whey proteins have been shown to lower plasma and liver cholesterol, as well as plasma triacylglycerol levels in model animals fed with cholesterol-containing diets. High-protein dairy products, and in particular those that contain whey proteins, may reduce fat deposition and improve insulin sensitivity. Whey hydrolyzates are characterized by a low degree of allergenicity and very rarely cause adverse reactions. Currently, a hypoallergenic, hydrolyzed formula is recommended to children nonbreast-fed or partially breast-fed with a high allergy risk. The risk for atopic dermatitis in high-risk infants can be reduced with certain whey milk hydrolyzates when breastfeeding is insufficient. b-Lactoglobulin animal studies suggest reduction of blood pressure by inhibition of angiotensin-converting enzyme and exhibition of immune-enhancing activity. In vitro studies reveal that b-lactoglobulin, chemically modified by 3-hydroxyphthalic anhydride, shows antiviral activity against human herpes simplex virus type 1 (HSV-1) and its hydrolyzate antimicrobial activity against several gram-positive bacteria and bactericidal activity. a-Lactalbumin contributes to reduce the incidence risk of some cancers, and its hydrolyzate reduces the blood pressure. This whey protein has also been associated with treatment of chronic stress-induced cognitive decline. It presents bactericidal activity against Streptococcus pneumonia and its hydrolyzate antimicrobial activity against several gram-positive bacteria. BSA has been shown in vitro to protect lipids against phenolic-induced oxidation. One important property that has been associated with this protein is the ability to inhibit breast cancer growth in vitro. b-lactoglobulin and a-lactalbumin show antiviral activity against HSV-1, when chemically modified. Lactoferrin is a bioactive protein with an ability to bind iron. In opposition to anticancer feature, the antibacterial activity has been attributed to the iron-binding property.
510
Whey and Whey Powders: Protein Concentrates and Fractions
Table 2
Specific diseases/whey protein biological functions
Clinical diagnosis
Type of study
Cardiovascular disease
In vitro
Animal Human trial
Immunologic disease
Gastrointestinal disease
Sources
Results/advantages
Hydrolyzed: whey protein concentrate, a-lactalbumin, and bovine serum albumin Caseinomacropeptide Hydrolyzed whey protein (peptide concentrate), b-lactoglobulin, and a-lactalbumin Whey protein concentrate
Angiotensin-converting enzyme (ACE) inhibition ACE-inhibition activity
In vitro
a-Lactalbumin Caseinomacropeptide b-Lactoglobulin Lactoperoxidase and lactoferrin Whey protein isolated
Animal Clinical trial
Caseinomacropeptide Whey protein concentrate ProtectaminW
Animal
Whey protein concentrate Hydrolyzed whey protein (peptide concentrate)
Clinical trial
a-Lactalbumin Lactoferrin (infant formula) Hydrolyzed whey protein (infant formula)
Hydrolyzed whey protein (infant formula) Hydrolyzed whey protein Neurological disease
Microbial disease
Animal
a-Lactalbumin
Clinical trial
a-Lactalbumin
In vitro
Whey protein concentrate (enriched with Helicobacter pylori – antibodies) Hydrolyzed b-lactoglobulin a-Lactalbumin Hydrolyzed a-lactalbumin Caseinomacropeptide b-Lactoglobulin, a-lactalbumin, and bovine serum albumin (chemically modified by 3hydroxyphthalic anhydride) Lactoferrin
Clinical trial
Reduced blood pressure (ACE-inhibiting peptides) Hypertensive and obese persons (with resistance exercise): Increase of HDL and total antioxidant capacity Decrease of triglycerides, systolic blood pressure, and total cholesterol Atherosclerosis patients: Decrease in CCL5 (atherosclerosis biomarker) levels Macrophages enhance function via a tripeptide of glycine–leucine–phenylalanine Macrophages enhance function by low concentrations of caseinomacropeptide (CMP) Enhanced production of spleen and lamina propria lymphocytes Suppressive actions on lymphocyte proliferation Stimulation in the proliferation of murine spleen lymphocytes Exertion of anti-inflammatory effects in a rat model of colitis Increased lymphocyte and glutathione levels in patients with lung inflammation and cystic fibrosis Increased glutathione levels (human immunodeficiency virus (HIV)) 41% Reduction in ulcerative lesions and 73% with repeated doses Reduction of gastric injuries to 68.5% (sulfhydryl-containing moieties) Reduction in ulcerative lesions (prostaglandin production) Increased bifidobacteria proportion Increased bifidobacteria proportion improving gastrointestinal immunity Decreased potential for developing atopic diseases Decreased incidence of infantile colic Bowel resection and protective effect on the gastric mucosa (sulfhydryl component – glutathione production) Protective effects and better seizure control as assessed by myoclonus (involuntary muscle twitch) Increased plasma tryptophan (a precursor of serotonin – key for the treatment of stress-induced cognitive decline) Improved seizure control in persons with drug-resistant epilepsy; antidepressive effects and sleep quality Prevention of infections Antimicrobial against several gram-positive bacteria and bactericidal activity Bactericidal activity (S. pneumonia) Antimicrobial against several gram-positive bacteria Antimicrobial activity Exhibition of antiviral activity against human herpes simplex virus type 1 (HSV-1) Bacteriostatic and bactericidal activity against Escherichia coli, Salmonella typhimurium, Shigella dysenteriae, Listeria monocytogenes, Bacillus stearothermophilus, B. subtilis, and Micrococcus luteus Antifungal activity against Candida albicans In combination with lysozyme, immunoglobulins, or antibodies – more potent bacteriostatic agent against Pseudomonas aeruginosa, L. monocytogenes, and E. coli Decreased intracellular group A streptococci in chronic pharyngitis patients 100% Eradication of Helicobacter pylori
Whey and Whey Powders: Protein Concentrates and Fractions
Table 2
511
(Continued)
Clinical diagnosis
Type of study
Sources
Results/advantages
Cancer
In vitro
Whey protein concentrate
Increment of glutathione levels; stimulation of immunity; detoxification of potential carcinogens Mutagenic agent causing oxidative damage to tissues (ironbinding capacity) Increased glutathione levels; protection of human prostate cells against oxidant-induced cell death Protection of human hepatoma cell line Antiproliferative effects in mammalian, colon adenocarcinoma, and intestinal cell lines; delaying initiation of cell apoptosis Inhibition of growth in human breast cancer cells Induced cell death in tumor cells and exertion of cancerprotective mechanisms in melanoma cells, breast cancer cells, stomach cancer cells, lung cancer cells, lymphoma cells, colorectal cancer cells, and polyps Enhanced cytotoxicity – high rate of apoptosis Lower incidence of colon and mammary tumors and fewer aberrant crypts (colon cancer) Prevention of breast and intestinal cancers in female rats Increased glutathione concentration, leading to stimulation of immunity Depletion of tumor cells (glutathione concentration higher than normal cells) Prevention and treatment of 5-fluorouracil chemotherapyinduced oral mucositis Immune-enhancing Inhibition of metastasis of primary tumors 16/20 Survivors at 6 months Increased NK cell function, glutathione levels, hemoglobin, and hematocrit Improved quality of live Reduced risk of colon carcinogenesis 2/7 Patients had tumor regression after 6 months Increase in glutathione levels in healthy cells and decrease in glutathione levels in cancer cells Improved postprandial glucose tolerance and long-term glucose control Anti-inflammatory effect Protection against endothelial dysfunction, lowering of HbA1c, and insulin resistance Cellular glucose toxicity Reduction in parameters of oxidative stress Decrease in triglycerides and the exposure to glucose (AUC) by up to 44% Increased insulin secretion and reduced postprandial (after meal) exposure to glucose by 21% Prevention of hepatitis C virus infection in a human hepatocyte line Reduced inflammatory markers and improved liver enzymes (hepatitis C patients) Decreased serum lipid peroxidase levels and serum alanine transferase activity (hepatitis B patients) Increased IL-2, NK activity, and plasma glutathione levels Stimulation in the proliferation and differentiation of osteoblastic cells and suppression of bone resorption Increased femoral bone strength in young ovariectomized rats
Whey protein isolate Whey protein isolate (with coadjuvant baicalein) a-Lactalbumin Bovine serum albumin Lactoferrin
Animal
ImmunocalW Whey protein concentrate
Hydrolyzed whey protein
Clinical trial
b-Lactoglobulin Lactoferrin Nondenatured whey protein concentrate
Lactoferrin ImmunocalW (with coadjuvant baicalein)
Diabetes
Hepatitis
Animal
Whey protein concentrate and a-Lactalbumin
Clinical trial
Whey protein concentrate
In vitro
Lactoferrin Whey protein concentrate
Osteoporosis
Clinical trial
ImmunocalW
In vitro
Milk basic protein (lactoferrin, lactoperoxidase, and minor components) Whey protein concentrate and hydrolyzed whey protein Milk basic protein
Animal Clinical trial
Increased bone formation (osteocalcin and procollagen I carboxy-terminal propeptide levels increase), bone mineral, and radial density Inhibition of osteoclast-mediated bone resorption (Continued)
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Table 2
Whey and Whey Powders: Protein Concentrates and Fractions
(Continued)
Clinical diagnosis
Type of study
Exercise
Clinical trial
Sources
Results/advantages
Nondenatured whey protein concentrate
Increase in body mass composition and improved quality of life on HIV-positive women Improvement in one of the four muscles, lean tissues mass, and strength Significant improvements in peak power and increase of 30 s work capacity Increased lymphocyte glutathione levels Decrease in percent body fat improving body mass index Prevention and/or attenuation Reduced fat buildup in obese women with high liver fat content and reduced triglycerides and total cholesterol
Whey protein concentrate
Obesity
In vitro Clinical trial
Whey protein concentrate Whey protein concentrate
Lactoferrin develops a direct role in defending the body against pathogens. This protein possesses bactericidal power against a wide range of microorganisms. The antimicrobial effect can be taken advantage of in the treatment of enteric infections. Recent studies have demonstrated that iron-unsaturated lactoferrin is active against the fungi – which are responsible for dermatophytosis. Lactoferrin possesses antiviral effects too and plays an important role upon stimulation of the immune system.
Whey Proteins, Interaction with Different Organs Whey proteins are beneficial to the intestinal lining, especially in clinical situations where gut function is impaired. A study in rats showed that whey promotes neutrophil chemokines – GCP-2 activity in the intestines and subsequent intestinal cell growth. In a clinical study, it was found that the outcome provided by a whey protein concentrate administered to a person with Crohn’s disease was very close to the behavior of glutamine, reducing intestinal permeability. In the liver, whey proteins exhibited an important role in studies with nonalcoholic fatty liver, showing the ability to reduce liver enzyme (ALT, alanine transaminase; AST, aspartate aminotransferase; and GGT, gamma-glutamyl transpeptidase) levels and fat deposits, enhancing glutathione (due to cysteine). A reduction in weight and waist circumference has also been verified. Another study showed that high-dose supplementation in obese women with high fat content in the liver was able to reduce the accumulation of fat in the liver, reducing triglycerides and total cholesterol.
Whey Powder and Exercise After performing exercise, subjects enter into metabolic stress, requiring consumption of essential amino acids, whey proteins, minerals, or other serum-derived compounds (usable energy). From the mechanistic point of view, due to their composition in amino acids, whey proteins can provide substrates and bioactive components that are capable of extending the overall benefits of regular physical activity. Accordingly, they have been chosen by bodybuilders and elite athletes, in addition to people whose health is compromised. Whey protein can help to improve muscle strength and reduce the likelihood of bone fracture; these
characteristics are directly related to their unique amino acid composition, as mentioned earlier, which are quite similar to those of skeletal muscle proteins. However, the improvement seen in increased skeletal muscle protein occurs through mechanisms that are definitely beyond those assigned to the said content of essential amino acids. When it comes to a moderate exercise, there is an improvement in immunity. On the other hand, when the training is heavy, there is stress in the immune system, leading to the production of free radicals and increased inflammatory activity. It is thought that those factors can harm the immunobiological activity of athletes who train heavily, in which muscle performance and recovery may be affected by oxidative stress. The availability of glutathione can be used to combat this problem. Other studies have shown that whey proteins have helped to achieve more easily the desirable weight and shape body, being more effective than caseins in what concerns to satiety.
Acknowledgment This work received partial financial support from author T. Tavares, provided via postdoctoral fellowship (Refs. SFRH/ BPD/89360/2012), supervised by author F. Xavier Malcata, under the auspices of ESF (III Quadro Comunita´rio de Apoio) and the Portuguese state.
See also: Cheese: Composition and Health Effects; Dairy Products: Dietary and Medical Importance; Milk: Sources and Composition; Whey and Whey Powders: Fermentation of Whey; Whey and Whey Powders, Principles and Applications of Dialysis; Whey and Whey Powders: Production and Uses.
Further Reading Chatterton DEW, Smithers G, Roupas P, and Brodkorb A (2006) Bioactivity of b-lactoglobulin and a-lactalbumin – technological implications for processing. International Dairy Journal 16: 1229–1240. Gauthier SF, Pouliot Y, and Saint-Sauveur D (2006) Immunomodulatory peptides obtained by the enzymatic hydrolysis of whey proteins. International Dairy Journal 16: 1315–1323.
Whey and Whey Powders: Protein Concentrates and Fractions
Ha E and Zemel MB (2003) Functional properties of whey, whey components, and essential amino acids: mechanisms underlying health benefits for active people (review). Journal of Nutritional Biochemistry 14: 251–258. Jain SK (2012) L-Cysteine supplementation as an adjuvant therapy for type-2 diabetes. Canadian Journal of Physiology and Pharmacology 90: 1061–1064. Korhonen H (2009) Milk-derived bioactive peptides: from science to applications. Journal of Functional Foods 1: 177–187. Korhonen H and Pihlanto A (2006) Bioactive peptides: production and functionality. International Dairy Journal 16: 945–960. Korhonen H and Pihlanto A (2003) Food-derived bioactive peptides – opportunities for designing future foods. Current Pharmaceutical Design 9: 1297–1308. Krissansen GW (2007) Emerging health properties of whey proteins and their clinical implications. The Journal of the American College of Nutrition 26: 713S–723S. Madureira AR, Tavares T, Gomes AMP, Pintado ME, and Malcata FX (2010) Invited review: physiological properties of bioactive peptides obtained from whey proteins. Journal of Dairy Science 93: 437–455. McGregor RA and Poppitt SD (2013) Milk protein for improved metabolic health: a review of the evidence. Nutrition and Metabolism 10: 46–58. Meisel H (2005) Biochemical properties of peptides encrypted in bovine milk proteins. Current Medicinal Chemistry 12: 1905–1919.
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Saito T (2008) Antihypertensive peptides derived from bovine casein and whey proteins. In: Bo¨sze Z (ed.) Advances in experimental medicine and biology: bioactive components of milk, vol. 606, pp. 295–317. New York: Springer. Smithers GW (2008) Whey and whey proteins – from ‘gutter-to-gold’. International Dairy Journal 18: 695–704.
Relevant Websites http://www.bythewhey.com/ – By the whey. http://www.dairyglobalnutrition.org/NutrInfo/content.cfm? ItemNumber¼88387&navItemNumber¼88574 – Dairy for Global Nutrition. http://www.innovatewithdairy.com/Pages/FactsAboutWhey.aspx – Think USA Dairy (U.S. Dairy Export Counsil). http://www.leanitup.com/review-protein-powder-buyers-guide-150-popular-proteinpowders-shaken-graded/ – Lean it up. http://www.milkfacts.info/Milk%20Composition/Protein.htm – The Milk Quality Improvement Program (Cornell University).