Improving mineral bioaccessibility and balancing physical stability in soymilk through bioprocessing

Abstract

Phytic acid (PA) in soy foods acts as an antinutrient through chelate minerals and proteins, yet it may also contribute to system stability. To improve mineral bioaccessibility and balancing physical stability, soymilk with varied PA levels was fabricated by modulating phytase treatment (0–15 U/g). The physical properties, mineral bioaccessibility, and microrheology of soymilk were investigated. Results showed that moderate enzymolysis (retaining 65.17 % PA) increased bioaccessible calcium content by 28.61 % without stability loss, whereas complete PA removal maximized iron and zinc bioaccessibility by 43.21 % and 74.01 % but induced instability. Furthermore, PA degradation increased particle mobility in soymilk and the soluble content of α subunits and basic peptide. Spatial distribution analysis demonstrated preferential hydrolysis of free/soluble PA promoted mineral release. Negative correlations between PA distribution and bioaccessible mineral contents were established. These findings emphasise PA's dual role in balancing mineral bioaccessibility and colloidal stability, providing formulation strategies for high nutritional plant-based products.