Current enzymatic milk fermentation procedures

Abstract

Aside from bacteria, yeasts and moulds, enzymes from animal, vegetal and microbial sources are increasingly utilized for milk fermentation providing a broad spectrum of innovative product conceptions. In order to alter texture and flavour or to improve the nutritional value of milk-based products from different animal milks, microbial and enzymatic fermentation procedures are traditionally established worldwide. To date, genomic and proteomic approaches enable new selection strategies for precise enzymes for modern product applications. Hereby, generating beneficial health ingredients from milk is a main aspect. New insights into the biochemical mechanisms of enzymatic digestion and genetic engineering lead to enzymes with exact defined functions for explicit ripening flavour development or the improvement of texture of fermented milk products. The ability to synthesize complex exo-polysaccharides or to release bioactive peptides by accurate proteolytic activities of enzymes or to enzymatically cross-link the protein matrix in order to modify the texture characteristics of fermented milk products is a raising facet, especially for specific pharma-or nutraceutical applications. This review aimed at discussing the recent research activities on milk fermentative enzymes, with focus on the broad spectrum of enzyme origins and current aspects of genetic engineering. New approaches on proteolytic, lipolytic, glycolytic as well as milk clotting and protein cross-linking enzymatic activities are examined and associated with possible product applications. From technical prospective, advantages and disadvantages of immobilized enzymes within milk fermentation processes are critically discussed.

Effects of Pasteurization and High-Pressure Processing of Camel and Bovine Cheese Quality, and Proteolysis Contribution to Camel Cheese Softness

“…It reported that cheese coagulation by chymosin is slower and weaker in camel compared to bovine milk ( 3 ) but the mechanisms behind these differences are still not known. In bovine milk, chymosin hydrolysis of κ-casein is the most important proteolytic reaction during cheese making ( 78 ). Of the rennet used in bovine milk coagulation, about 6–10% is retained in the bovine cheese curd ( 79 ) but the residues chymosin retained in camel cheese curd to further hydrolyze other caseins requires further investigation.…”

Quality attributes of the set-style yoghurt from whole bovine milk as affected by an enzymatic oxidative cross-linking

“…Some novel technologies have been developed or applied to improve yoghurt quality at molecular level of milk proteins, for example, by forming covalent bonds between or within the molecules with enzymes (Faegemand, Sørenson, Jørgensen, Budolfsen, & Qvist, 1999). Transglutaminase (TGase, EC 2.3.2.13) is one of typical enzymes capable of forming isopeptide bonds between the γ-carboxyamide groups and the amino groups and thus can be used to induce cross-linking of food proteins (Beermann & Hartung, 2012;Lorenzen, Neve, Mautner, & Schlimme, 2002) or glycosylation plus cross-linking of casein or soybean proteins (Jiang & Zhao, 2010. The influences of TGase treatment on functional properties of milk proteins had been widely studied (Faegemand & Qvist, 1997;Hiller & Lorenzen, 2009), while the impacts of TGase treatment on the textural and other attributes of yoghurt products were also well characterized (Bönisch, Huss, Weitl, & Kulozik, 2007;Lorenzen et al, 2002).…”

The Texture of Camel Milk Cheese: Effects of Milk Composition, Coagulants, and Processing Conditions

“…The rennet enzymes are aspartic peptidase, and the most used are the combinations of chymosin A, B, C, and pepsin extracted from the stomach of calves and other ruminants ( 131 ). Renins disrupt the milk emulsion and separate caseins from the whey, causing them to coagulate into cheese by cleaving κ-casein into para-κ-casein and casein macropeptide ( 132 , 133 ). Many studies have consistently found that the coagulation of CM proceeds at much lower rates and produces a more fragile coagulum compared to BM when using bovine chymosin ( 125 , 134 – 137 ).…”