Gelation behaviour of Auricularia polytricha polysaccharides-whey protein isolate

The thermal gelling behaviour and formation mechanism of Auricularia polytricha polysaccharides-whey protein isolate (APP-WPI) gel was studied by moisture migration, conformation transformation and microstructure. Electrostatic repulsion between APP and WPI limited the rapid or random aggregation of WPI aggregate, leading to establishment of a more ordered structure. The conformation transformation from α-helix to β-sheet and strong hydrophobic interaction in WPI gelation process promoted the formation of stable three-dimension (3D) gel network, as proved by the increase in crystallinity and thermal stability. The composite gel had decreased T23 and PT23 values which indicated restricted water mobility within the gel resulting in dense water cavity via APP's high-water absorption. Furthermore, 0.25–1.00% APP concentration improved gel hardness, water holding capability, storage modulus (G′) and loss modulus (G″) of WPI gel. This study demonstrated that APP played a vital role in regulating ideal physicochemical and structural characteristics of WPI-based gel products.