Thom Huppertz holds an MSc in Dairy Science from Wageningen University, The Netherlands and a PhD in Dairy Science from University College Cork, Ireland. Currently, he is employed as a Principal Scientist at NIZO food research, Ede, The Netherlands. His research focusses on the physical chemistry of dairy products, with particular emphasis on the protein functionality and product-process interactions. In addition, he is an Adjunct Professor in Dairy Science and Technology at South Dakota State University and the Editor-in-Chief of the International Dairy Journal.
LinkedIn – nl.linkedin.com/pub/thom-huppertz/5/734/572/
Milk proteins are typically considered to have the highest functionality among food proteins. However, enzymatic strategies to further enhance functionality are of large interest and offer opportunities beyond those traditionally used. Enzymatic modification of milk proteins can involve (selective) hydrolysis of proteins, cross-linking of proteins or modification of the charge on proteins. For protein cross-linking, various enzymes are available, including transglutaminase and tyrosinase, both of which have specific cross-linking patterns and can be applied to enhanced firmness of acid gels or heat stability, but also create casein particles consisting of a framework of covalently cross-linked caseins, rather than non-covalently interacting caseins. Such particles react different to changes in environmental conditions and can e.g., swell rather than disrupt on pH change or calcium removal. For charge modification of proteins, deamidation using protein glutaminase offers interesting opportunities. Treatment with this enzyme converts glutamine residues into glutamic acid residues. Treatment of whey proteins showed that particularly in α-lactalbumin considerable structural changes occurred, leading to increased stability to heat and added calcium. Furthermore, deamidation also changes the iso-electric point of whey proteins, thus affecting their behavior in acidic products, such as whey beverages for sports nutrition. Careful consideration of protein structures and interactions in combination with enzymatic modification can thus create a new range of functionalities for milk proteins.