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Applications of low- and high-intensity ultrasound
ContentsD!~est
Enzymes as Food AnfioxJdants
Detecting Foodborne Yeasts Yeasts play an integral role in the production of t~rmented beverages and bakery goods, but yeasts and other fungi are also implicated in the spoilage of many foods, for example fruit juices. Techniques for the accurate identification of particular species cr strains of yeasts from foods are therefore important in process and quality control. On page 287, Tibor D e ~ reviews the latest approaches available for the detection, quantifi-
cation and identification of foodbome yeasts and other fungi. Historically, food mycologists have had to rely on colony counting and a battery of mo~hological and biochemical tests; however, the field of mycology is rapidly following the lead of bacteriology, adapting more rapld, easily automated and aeeurate eleetrometric and nucleic acid 'fingerprinting' techniques suitable for use in industrial quality-control laboratories.
Applications of Low- and High-intensity Ultrasound Ultrasound, which has a higher frequency than audible sound, has many applications in both food analysis and food processing. Lowintensity ultrasound does not affect the material it passes through. It is a useful non-invns~ve tool for monitoring the composition, thickness, internal physical state and flow rate of foods, either for research purposes or for on-Me monRorh~g and eon~rol in food processing plants, and a number of instrument manufacturers have recently developed suitable equipment for commercial use. It can also be used to monitor the contents of packaged foods (see article
by Gestrelius et aL, TIFS December 1994) as well as the integrity of package seals (see next month's issue). High-intensity ultrasound, on the other hand, can be used in the laboratory or processing plant to effect novel changes in the physical and ehemi¢'~l properties of foods in a variety of ways, including modifying crystallization processes, altering enzyme activities, promoting certain chemical reactions, assisting membrane filwation and destroying microorganisms. D. Julian McClements discusses the theory, applications and future of ultrasound in the food industry on page 293.
Open Processing Equipment In open food processing plants, the newly released EuropeoJa Hygienic risk of microbial contamination from Equipment Design Group (EHEDG) the environment poses ~d[fional guidelines, prepared in cooperation e~fety eon~derafions beyond those with the 3-A Steering Committee in required when all equipment is fully the USA, and addressing the rational enclosed. These are discussed on design, testing and maintenance of page 305 in the 16th in an ongoing hygienic equipment for food proseries of extended summaries of cessing.
Following last month's article by Madsen and Bertelsen on the potential applications of spices as natural food antioxidants, this month Anne S. Meyer and Anette Isaksen (page 300) review the antioxidant activity of enzymes derived from food-grade microorganisms and plant or animal tissues. Glucose oxidase and catalase are currently used commercially for the removal of oxygen, but other enzymes such as alcohol oxidase or hexose oxidase, which are currently not exploited, may also find applications in the food industry. The potential of superoxide dismutasas ia the removal of active oxygen species and of ghitathinne S-trmlsferase and glutathione peroxidase in reducing fipid hydmperoxide levels are also considered. Meyer and Isakaen briefly discuss legal issues surrounding the use of enzymes in food processing, and discuss the need for further developmental research on the more promising candidate enzymes.
7th European Nutrition
Conference The Federation of European Nutrition Societies (FENS) recently held its four-yearly meeting in Vienna, Austria. On page 311, C.E. West reports on the highlights of the many plenary sessions and workshops of this five-day event. Preceded by a satellite symposium on resistant starches, the meeting had as its main theme 'Under- and overnu~fion in Europe'. The wide range of topics addressed included iron, iodine and folate deficiencies; the links between diet and health; and the factors regulating food intake and the growing problem of obesity.
Trends in FoodScience& Technology September1995 [VoL 61
Enzymes as Food AnfioxJdants
Detecting Foodborne Yeasts Yeasts play an integral role in the production of t~rmented beverages and bakery goods, but yeasts and other fungi are also implicated in the spoilage of many foods, for example fruit juices. Techniques for the accurate identification of particular species cr strains of yeasts from foods are therefore important in process and quality control. On page 287, Tibor D e ~ reviews the latest approaches available for the detection, quantifi-
cation and identification of foodbome yeasts and other fungi. Historically, food mycologists have had to rely on colony counting and a battery of mo~hological and biochemical tests; however, the field of mycology is rapidly following the lead of bacteriology, adapting more rapld, easily automated and aeeurate eleetrometric and nucleic acid 'fingerprinting' techniques suitable for use in industrial quality-control laboratories.
Applications of Low- and High-intensity Ultrasound Ultrasound, which has a higher frequency than audible sound, has many applications in both food analysis and food processing. Lowintensity ultrasound does not affect the material it passes through. It is a useful non-invns~ve tool for monitoring the composition, thickness, internal physical state and flow rate of foods, either for research purposes or for on-Me monRorh~g and eon~rol in food processing plants, and a number of instrument manufacturers have recently developed suitable equipment for commercial use. It can also be used to monitor the contents of packaged foods (see article
by Gestrelius et aL, TIFS December 1994) as well as the integrity of package seals (see next month's issue). High-intensity ultrasound, on the other hand, can be used in the laboratory or processing plant to effect novel changes in the physical and ehemi¢'~l properties of foods in a variety of ways, including modifying crystallization processes, altering enzyme activities, promoting certain chemical reactions, assisting membrane filwation and destroying microorganisms. D. Julian McClements discusses the theory, applications and future of ultrasound in the food industry on page 293.
Open Processing Equipment In open food processing plants, the newly released EuropeoJa Hygienic risk of microbial contamination from Equipment Design Group (EHEDG) the environment poses ~d[fional guidelines, prepared in cooperation e~fety eon~derafions beyond those with the 3-A Steering Committee in required when all equipment is fully the USA, and addressing the rational enclosed. These are discussed on design, testing and maintenance of page 305 in the 16th in an ongoing hygienic equipment for food proseries of extended summaries of cessing.
Following last month's article by Madsen and Bertelsen on the potential applications of spices as natural food antioxidants, this month Anne S. Meyer and Anette Isaksen (page 300) review the antioxidant activity of enzymes derived from food-grade microorganisms and plant or animal tissues. Glucose oxidase and catalase are currently used commercially for the removal of oxygen, but other enzymes such as alcohol oxidase or hexose oxidase, which are currently not exploited, may also find applications in the food industry. The potential of superoxide dismutasas ia the removal of active oxygen species and of ghitathinne S-trmlsferase and glutathione peroxidase in reducing fipid hydmperoxide levels are also considered. Meyer and Isakaen briefly discuss legal issues surrounding the use of enzymes in food processing, and discuss the need for further developmental research on the more promising candidate enzymes.
7th European Nutrition
Conference The Federation of European Nutrition Societies (FENS) recently held its four-yearly meeting in Vienna, Austria. On page 311, C.E. West reports on the highlights of the many plenary sessions and workshops of this five-day event. Preceded by a satellite symposium on resistant starches, the meeting had as its main theme 'Under- and overnu~fion in Europe'. The wide range of topics addressed included iron, iodine and folate deficiencies; the links between diet and health; and the factors regulating food intake and the growing problem of obesity.
Trends in FoodScience& Technology September1995 [VoL 61