Aqueous micellar two-phase system as an alternative method to selectively remove soy antinutritional factors

In this work, different antinutritional factors (trypsin inhibitors, isoflavones and raffinose family oligosaccharides) were selectively removed from soy flour by using aqueous micellar two-phase systems (AMTPS). The effects of independent variables including temperature (30-60 °C), time (10-40 min) and solid to liquid ratio (0.025-0.050 g/L) on the extraction of each antinutritional factor were analyzed using a full factorial design. As general tendency, temperature and time were the most significant parameters (p < 0.05). The best condition for the selective recovery (97% of isoflavones at top phase, and more than 50% of the rest of ANFs at bottom phase) were 5 g/L of Genapol X-080, 0.2 moL/L of sodium citrate pH 5.00, 30 °C, 40 min and 0.050 g/L. Besides, in vitro gastrointestinal digestions assays demonstrated that the treated soy flour improved its protein digestibility. The findings of this work represent the introduction of a novel methodology to selectively remove soy antinutritional factors.