Physicochemical properties of infant formula model emulsions stabilised by different whey protein hydrolysates and characteristics of interfacial peptides
Jiecheng Li, Christian G. Hartinger, Fan Zhu
Abstract
Whey protein hydrolysate (WPH) can be an important ingredient of infant formula for improved nutritional benefits. Whey protein isolate was hydrolysed using trypsin, pepsin, bromelain, papain, and flavourzyme to obtain WPH (degree of hydrolysis ∼10%, except for pepsin). The hydrolysates were formulated into infant formula model emulsions. After homogenisation, the droplet sizes of the WPH-stabilised emulsions were smaller than that of the intact whey protein-stabilised emulsion, except for the papain-stabilised emulsion. The peptidomics of WPHs and the interfacial proteins/peptides of WPH-stabilised emulsions were investigated. A large number of unique peptide sequences from different WPHs were found to have high expression on the interfacial proteins/peptides, which significantly depended on their chain length (10–20), molecular weight, higher net charge, higher pI, and amphipathy (positive hydrophobicity). These peptide sequences played an important role in the stabilisation of emulsions. Different enzymatically hydrolysed whey proteins offered more possibilities for stabilising the infant formula emulsions.