Changes in Total Phenols, Total Flavonoids, and Antioxidant Activities of Common Beans and Pinto Beans after Soaking, Cooking, and in vitro Digestion Process

Even though bean varieties are widely consumed all over the world, data related to how cooking methods and in vitro digestion affect bioactive compounds they contain and data related to bioavailability of polyphenols are limited. The aim of the present study was to investigate how some cooking methods and in vitro digestion influence antioxidant activity, total phenols (TP), and total flavonoids (TF) of widely consumed beans in Turkey. Soaking caused a significant decrease (25.61-38.63%) in the bioavailability of TP of dry common beans (CB). Soaking in cold water resulted in a significant decrease in TP bioavailability of dry pinto beans (PB). TF content was well retained in PB cooked without soaking but was not detected in CB after in vitro digestion. CB soaked in hot water and cooked with the addition of NaHCO3 showed the greatest inhibition effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical (p<0.05). In vitro digestion caused increase in the antioxidant activity of both CB and PB.