Effects of processing conditions on hydrolysates of proteins from whole whey and formation of Maillard reaction products

Abstract

Chemical modifications of proteins during food processing can lead to new functionalities and applications of products. Enzymatic hydrolysis, with Alcalase and Flavourzyme, of whole whey was carried out in different conditions, including pH (5.5, 7.0, and 8.5), temperature (42°C, 50°C, and 58°C), enzyme-substrate ratio (E/S) (1%, 2%, and 3%), and duration (60, 180, and 300 min). The hydrolysates were evaluated for the presence of intermediate and advanced Maillard Reaction Products (MRPs), surface properties, ferric reduction capacity, and content of the redox-active sulfhydryl group. A decrease in the free sulfhydryl group was also observed during whey hydrolysis with both enzymes. This suggested their depletion because of their ability to react with carbonyl compounds generated during MRPs. Of all the variables, pH had the strongest effect on the release of peptides during whey protein hydrolysis, including the enhancement of surface properties, and significantly affected the generation of MRPs and ferric reducing capacity of the hydrolysates. Practical applications Whey protein is a protein source containing all the essential amino acids. Chemical modifications of proteins during food processing can lead to new functionalities and applications of the products. This study demonstrates that processing-induced modifications can enhance the antioxidant capacity of the whey for use as natural preservatives in the food industry. The hydrolytic processes in this study could be used to valorize whole whey and to generate value-added functional ingredients comprising of peptide, Maillard Reaction Products (MRPs) and peptide-MRP adducts. This range of novel products could be applied as antioxidants in the food industry for food preservation and health promotion.