In vitro gastrointestinal digestion studies on total phenols, flavonoids, anti-oxidant activity and vitamin C in freeze-dried vegetable powders.

In the present research study, the impact of digestion process on the levels of total phenols, flavonoids, vitamin C as well as anti-oxidant activity in freeze dried powders of mustard greens (MG) and roselle leaves (RL) was investigated. In addition, physicochemical and functional properties of MG and RL samples also evaluated. The digestion of freeze-dried vegetable powders was achieved through in vitro digestive procedure using various enzymes. From the study, it was observed that the digestion process increased the availability of phenols in both powders, where the digested vegetable powders possessed higher levels of total phenols and flavonoids. In contrast, the levels of vitamin C and anti-oxidant activity of vegetable powders (MG & RL) was found to be decreased minimally. Our research study suggests that in vitro digestion could enhance the TPC and TFC in mustard greens and roselle leaves. Therefore, MG and RL can be considered as a functional ingredient in the development of new products with better nutritional and functional characteristics. Further, the data on the physicochemical, functional and bioactive compounds in MG and RL may be used as reference for the enhancement of quality of products developed from MG and RL. © Association of Food Scientists & Technologists (India) 2022.