Changes in bioactive compounds and health-promoting activities in adzuki bean: Effect of cooking conditions and in vitro simulated gastrointestinal digestion

• Cooking condition affects microstructure, bioactive compounds, biological activity. • Autoclaving caused a higher release of bioactive compounds and leaching effect. • Recommended to autoclave for 10 min and consume both cooked bean and cooking water. • Digestible fraction from autoclaving showed higher health promoting activities. • Type and amount of phenolics in digestible fraction depended on cooking condition. Cooking conditions influenced the microstructure, bioactive compounds, and biological activities of adzuki beans. In comparison to boiling, saturated steam under pressure in an autoclave caused more potential bioactive substances in beans to be released. Potential bioactive compound content and antioxidant activities of cooked beans and cooking water from autoclaving for 60 min and 10 min (A60 and A10) were higher than boiling for 60 min (B60). In vitro simulated gastrointestinal digestion revealed that the digestible fractions from A10 and A60 had higher antioxidant, ACE-I inhibitory, and DPP-IV inhibitory activities than B60 in the digestible fraction of adzuki beans paste. Cooking conditions and digestive enzyme cleavage influenced the exposure of specific antioxidant functional groups and hydrophobic groups. Catechin and vitexin were found to be the most abundant phenolics in all digestible fractions, whereas p -courmaric acid, sinapic acid, and syringic acid were found in digestible fractions from A10 but not B60 or A60. According to these findings, A10 could be recommended for cooking adzuki bean since it not only provides health-promoting actions of bean paste after in vitro digestion but it also reduces cooking time.