Effects of amidated low methoxyl pectin on physiochemical and structural properties of polymerized whey proteins

This study aimed to investigate effects of amidated low methoxyl (ALM, 0.3%, w/v) pectinon physiochemical and structural properties of polymerized whey proteins (PWP, 10%, w/v) prepared by thermal aggregation at 85 degrees C for 10-30min. Particle size, zeta potential, isoelectric point(IEP), surface hydrophobicity, free sulphydryl group, rheological properties and the secondary structure of all samples were analysed. ALM pectin increased mean diameter and narrowed size distribution of PWP samples (p<0.05) regardless of heating time. Addition of ALM pectin shifted the IEP of PWPpectin complex to lower pH, which decreased with heating time increased. ALM pectin decreased the surface hydrophobicity of PWP heated for 30min pronouncedly. Whey protein(WP) complexed with ALM pectin showed decreased gelation time and rheological properties of improved elasticity. ALM pectin had no considerable effect on secondary structure of PWP. Data indicated that ALM pectin could alter physiochemical properties of heat-induced polymerized WPns.