Changes in Antioxidant Activity Regularity in Brown Rice，Rice Bran and Polished Rice During In Vitro Simulated Digestion Process

Abstract:

The simulated gastrointestinal digestive experiments were studied by the method of simulated digestion in vitro for brown rice，rice bran and polished rice，Regularity of antioxidant active substances（expressed in polyphenols） and flavonoids，as well as antioxidant activity were determined by Folin-ciocalteu method，aluminum chloride sodium nitrite and oxygen radical absorption capacity（ORAC） during in vitro simulated digestion process. The results showed that the maximum release of polyphenols for brown rice，rice bran and polished rice were 3.499-，1.753-，6.595- and 4.704-，1.828-，9.113- folder higher than that at the simulated gastric digestive time point 0 h during the simulated gastric digestion process and during simulated gastrointestinal digestion respectivly；the biggest release of flavonoids were 1.522，1.961，1.653 and 3.359，5.958，3.242 times more than that at 0 h as well as the maximum ORAC values raised 3.459，4.849，12.93 and 5.659，5.112，19.65 times respectivly. The results show that the grains bound polyphenols could transfer to free polyphenols during hydrochloric acid and enzymes hydolysis digestion and be available in the upper gastrointestinal tract.