Foaming properties of the complex of whey protein isolate fibrils and octenyl succinate starch and the application in angel cake

Exploring the functional properties of protein fibrils/polysaccharide complexes has recently attracted significant attention, but their foaming characteristics and potential food applications are still far from being fully understood. This work aimed to enhance the foaming properties of whey protein isolate fibrils (WPIF) through their complexation with amphiphilic octenyl succinate starch (OSS) and assessed the feasibility of utilizing this complex as an egg white alternative in angel cake production. The results showed that at pH 6.0, WPIF/OSS complexes with ratios (r) of 2.0, 4.0, and 10.0 demonstrated equal or superior foaming capacity (up to 1.2) compared to WPIF alone. Low-temperature treatment further augmented both the foaming capacity and foam half-life of the WPIF/OSS complexes. For food application, the complex at pH 6.0 and r = 2.0 was selected. Substituting 12.5 % of the egg white with this complex resulted in cakes with the largest foam volume, lowest foam and batter densities, and reduced cohesiveness and hardness. This was attributed to enlarged pore size, which enhanced product elasticity and resilience. This study used OSS to enhance the WPIF's foaming performance, expanding its applications to the food industry. The improved quality of angel cake with WPIF/OSS highlights its potential as a food formulation ingredient.