Yellow pea germination impact on protein isolation - protein digestibility and quality

Enhancing the amino acid composition and nutritional quality of plant-based protein ingredients is essential for sustainable food development. This study investigated the effects of germination on yellow pea ( Pisum sativum L.) protein isolates using the micellar precipitation method. The results indicate that short-term germination induces compositional and structural modifications in yellow pea proteins, which persist through micellar precipitation and influence the amino acid profile of the resulting isolates. Germination activated endogenous proteolytic systems, leading to partial hydrolysis of storage globulins and a shift toward lower-molecular-weight peptides. Germinated isolates exhibited a lower loss of essential and non-essential amino acids during digestion, resulting in higher non-essential amino acid bioaccessibility (23%) compared with non-germinated isolates (17%). After digestion, germinated isolates showed reduced histidine and phenylalanine levels, reflecting increased digestive release of these amino acids. Glutamic acid content increased in germinated isolates compared to non-germinated ones, while glycine levels rose post-digestion in germinated samples, indicating improved bioaccessibility. These findings underscore the value of germination as a strategy to improve the amino acid composition and digestive bioaccessibility of pea protein isolates, reinforcing their nutritional relevance for plant-based protein applications. • Germination enhances the bioavailability of essential amino acids in pea isolates • Micellar precipitation yields high-purity pea protein isolates • SDS-PAGE shows increased hydrolysis and soluble protein fractions • Process optimisation lowers water and saline use without reducing yield extraction • Germinated isolates increased amino acid bioaccessibility after digestion