Nutritional quality, phenolics, and antioxidant capacity of mung bean paste obtained from seeds soaked in sodium bicarbonate

Soaking softens the texture and reduces cooking time of legumes. The study evaluate the application of sodium bicarbonate at this step of bean paste technology. An effect of this treatment on the nutritional (changes in the composition and digestibility of the carbohydrate and protein fraction) and pro-health quality (polyphenol level and antioxidant activity) of the final product was studied. For paste preparation, before cooking mung bean seeds were soaked in water (CS) and sodium bicarbonate solutions (NaHCO3) (0.5%, 1%, and 2% - 0.5SB, 1SB, and 2SB, respectively). The shortest cooking time was observed in the 2SB. The total phenolic compounds and the antioxidant activity of the chemically extractable fraction of the bean paste increased with the increasing concentration of NaHCO3. The highest content of potentially bioaccessible phenolics was determined in 2SB (8.51 mg/g d.m.), while the lowest in CS (6.94 mg/g d.m.). The process of soaking in the NaHCO3 solution increased the content of resistant starch, decreased starch digestibility, and only slightly affected protein digestibility. In conclusion, soaking the mung bean in NaHCO3 before cooking shortened the cooking time, increased the content of phenolics and the antioxidant capacity of the paste, and diversified the nutritional quality of the final products.