Quality improvement of soymilk as influenced by anaerobic grinding method and calcium addition

Abstract

Soymilk is one of the plant-based milk products containing great nutritional content and has an unpleasant beany flavour and low calcium content. In this study, different grinding methods and calcium salts fortification were applied to improve the flavour, calcium content, and stability of soymilk upon calcium addition. According to the results, preparing soymilk using the anaerobic grinding method significantly reduced the lipid oxidation (0.4781 meq peroxide/kg) and increased the sulfhydryl group content (24.25 μmol/g), compared to preparing soymilk using the conventional grinding method (0.7668 meq peroxide/kg and 15.68 μmol/g). As the results of different grinding methods, oxygen-free soymilk (OFS) has a lower amount of volatile compounds (75.04 μg/mL) than regular soymilk (RS; 966.65 μg/mL). The addition of calcium salts increased the particle diameter and viscosity of soymilk, where the significant increase was shown in calcium-enriched soymilk prepared using conventional grinding. The addition of calcium lactate reduced soymilk pH while calcium carbonate addition showed the opposite results. Soymilks enriched with calcium lactate have equivalent calcium bioavailability (28.99 and 31.21%) with cow's milk (29.47%) and significantly higher than soymilks enriched with calcium carbonate (23.73 and 22.35%). Thus, this study suggests the preparation of soymilk using the anaerobic grinding method with the addition calcium lactate as the calcium source. This combination can produce calcium-enriched soymilk with high acceptability without altering the initial sensory properties.