Enhanced solubility of yeast protein via high-pressure homogenization-assisted limited enzymatic hydrolysis: mechanisms of structural modification and implications for functionality and nutrition.

Abstract

Yeast protein (YP) is recognized as a sustainable and hypoallergenic microbial protein source, yet its low solubility (typically <22%) severely restricts its utilization in food formulations. Improving solubility is therefore a key step toward broader industrial application of YP. This study investigated a synergistic treatment combining high-pressure homogenization and restriction enzymatic hydrolysis (HPH-neu) to improve the solubility of yeast protein (YP). The HPH-neu treatment significantly enhanced solubility to 81.58 ± 0.29%. In contrast, the individual application of either high-pressure homogenization (HPH) or restriction enzymatic hydrolysis (neu) was less effective in improving solubility than the combined approach. Structural analysis indicated that HPH-neu processing notably increased the contents of α-helix and random coil, and scanning electron microscopy (SEM) revealed a corresponding looser and more disordered microstructure. Furthermore, the combined treatment significantly reduced particle size (242.8 ± 5.59 nm), free sulfhydryl group content (2.20 ± 0.01 μ mol/g), and surface hydrophobicity (H0, 14123.67 ± 257.85).At the same time, it improved functional properties including the emulsifying activity index (40.51 ± 2.86 m2/g), foaming capacity (146.67 ± 2.89%), and in vitro digestibility (90.64 ± 0.33%). The HPH-neu process also yielded high scores for PDCAAS and SRC, reaching 65.96 and 73.11, respectively. In summary, the integrated HPH-neu strategy not only effectively enhanced the solubility of YP but also improved its multifaceted functional properties and digestibility. This strategy offers a promising route for protein valorization and the development of high-quality, nutritious protein ingredients.