Comparative evaluation of legume and yeast protein powder supplements: nutritional composition, protein quality, and functional characteristics

Abstract

This study evaluated the nutritional composition, lipid profile, protein quality, and functional properties of legume- (soybean, pea, and faba bean) and yeast-derived protein powder supplements as alternative ingredients for vegan foods. Legume proteins, particularly pea and soybean, exhibited higher water absorption, solubility, and gel-forming capacity, underscoring their suitability for hydration-driven applications, such as emulsion gels and meat analogues. Yeast protein powder (YPS) contained higher levels of essential amino acids, branched-chain amino acids, and dietary fibre, along with distinctive lipid and phospholipid profiles, which contributed to superior protein quality indices, including amino acid score and protein digestibility-corrected amino acid score, surpassing even casein. Although YPS showed lower digestibility and weaker gelation, its high oil absorption capacity highlights its potential for lipid-rich or emulsified formulations. These results indicate that legumes and yeast provide complementary advantages, and their combined use may support the development of nutritionally balanced and functionally versatile vegan foods.