Process-dependent structural and functional modification of yeast protein: Alkaline extraction-acid precipitation versus high-pressure homogenization-assisted pH shifting.

Abstract

Limited redispersibility constrains commercial yeast-protein ingredients. This study compared preparation efficiency, structure, and function of yeast protein prepared by alkaline extraction-acid precipitation (ASAP) and high-pressure homogenization-assisted pH shift (HPHS). ASAP achieved higher product yield (69.23% ± 1.42%) and protein recovery (57.81% ± 2.42%) than HPHS. ASAP-YP exhibited dense sheet-like morphology, higher β-turn content (55.71%), and preserved reactive groups, whereas HPHS-YP formed porous aggregates with higher α-helix content and lower sulfhydryl availability. Under tested conditions, ASAP-YP showed higher solubility (pH 3-13), water absorption (17.99 ± 0.62 g/g), oil absorption (7.98 ± 0.12 g/g), emulsifying activity (59.88 ± 2.58 m2/g), and foaming capacity (124.00% ± 2.00%). Multivariate analysis indicated β-turn content, surface hydrophobicity, and reactive-group content were positively associated with selected functional properties. These findings support ASAP as a promising route, while validation across additional raw materials remains necessary.