Effect of extraction methods and simulated in vitro gastrointestinal digestion on phenolic compound profile, bio-accessibility, and antioxidant activity of Meghalayan cherry (Prunus nepalensis) pomace extracts

Abstract

In the present study, phenolic compounds were extracted from Meghalayan cherry (Prunus nepalensis) pomace by conventional solvent extraction (CSE) and microwave-assisted extraction (MAE) methods, and their bio-accessibility, phenolic compound profile, and antioxidant activity were studied after in vitro gastrointestinal digestion. Response surface methodology was applied to optimize the extraction conditions, i.e., solvent concentration (40–80%), solvent-solid ratio (10–30 mL/g), extraction time (90–240 s), and microwave power (300–600W). The extract obtained at optimized MAE conditions had a high yield (44.15 ± 2.06%), total phenolic content (TPC) (155.27 ± 2.76 mgGAE/g), DPPH (92.23 ± 2.19%), and FRAP (0.64 ± 0.01 mgAAE/g) activity. These results indicated high antioxidant activity in MAE compared to CSE with reduced time and energy consumption. The HPLC profile analysis of in vitro digestion of the extracts indicated a higher bio-accessibility of phenolic acids compared to flavonoids. Of the total 11 compounds identified in MAE, hydroxybenzoic acid (128.48%), chlorogenic acid (75.18%), and rutin (50.37%) were the most bio-accessible phenolics and flavonoids in the pomace extract. Even after in vitro digestion, the phenolic compounds of MAE presented adequate antioxidant activity. These findings indicated that the health-promoting properties of pomace phenolics could be modified after gastrointestinal digestion.