Exceptional colloidal stability of acidified whey protein beverages stabilized by soybean soluble polysaccharide

Protein‐rich beverages have gained significant attention in recent years. It is a challenge to produce whey protein beverages with high stability, good transparency, and a smooth mouthfeel. The polysaccharide (PS)–protein complex might help the food industry overcome these obstacles. In this study, soybean soluble polysaccharide (SSPS) and high methoxylated pectin (HMP, a traditional PS) are used, at different ratios to the protein, to improve the colloidal stability of the acidified whey protein solution. Both heated and unheated complexes were studied. SSPS–whey protein complexes have shown exceptional stabilities in all ratios while HMP–whey protein complexes revealed coacervation after 72 hr of storage. The prepared complexes exhibited comparable sizes and ζ‐potentials. The SSPS–whey protein complexes were less turbid than HMP–whey protein complexes at similar PS to protein ratios. Results also show that greater repulsive interactions occurred in SSPS–whey protein complexes when compared to HMP–whey protein complexes, as examined by free thiol content and intrinsic fluorescence intensity measurements. Practical Application It is a challenge to produce whey protein isolate (WPI) beverages with high stability, good transparency, and smooth mouthfeel. The polysaccharide (PS)–protein complex might help the food industry overcome these obstacles. We have demonstrated that soybean soluble polysaccharide (SSPS), at [SSPS]:[acWPI] ratios of 1:2 to 1:30, can significantly improve the colloidal stability of the acidified whey protein beverages. This SSPS–whey protein system could be used as a stable beverage base for a variety of beverages.