Effect of enzymatic degradation of proteins on technological properties of whey powdered products

Abstract

Whey protein hydrolysates (WPH) possess unique functional properties, including bioactivity, improved solubility and enhanced heat stability. These characteristics make them valuable for food applications. While it is known that enzymatic hydrolysis and heat denaturation influence the technological properties of WPH, their impact on functional characteristics has not been fully explored. This study aimed to comprehensively evaluate the technological properties of WPH obtained through enzymatic hydrolysis of native and heat-denatured whey protein concentrates (WPC). WPC was hydrolysed using a protease complex (subtilisin, chymotrypsin) under varying conditions. The study assessed particle size, wettability, solubility, hygroscopicity and heat stability of the produced WPH. The influence of hydrolysis time, pH conditions and preliminary heat denaturation of proteins on these properties was analysed. Enzymatic hydrolysis improved WPH wettability and solubility but increased hygroscopicity at 65% and 85% relative humidity. The highest heat stability was observed after 90–180 min of hydrolysis at neutral pH, allowing WPH to withstand 95°C for 60 min and 137°C for 10 min. Lowering pH to 4.5 reduced heat stability. Preliminary heat denaturation of proteins before hydrolysis enhanced peptide bond accessibility but promoted protein aggregation, leading to decreased solubility, increased hydrophobicity and alterations in heat stability and water interactions. These findings suggest that both enzymatic hydrolysis and heat denaturation play an important role in modulating the functional properties of WPH. Optimising the balance between these processes could help tailor WPH properties for specific food applications, such as heat-stable protein formulations. Further research is needed to refine processing conditions and enhance the functional performance of WPH in industrial applications.