Changes of phenolic compounds, antioxidant capacities, and inhibitory effects on digestive enzymes of kiwifruits (Actinidia chinensis) during maturation

Phenolic compounds are considered the main bioactive components in kiwifruit. In order to well understand the accumulation pattern of health-beneficial phenolics, and to obtain high-quality kiwifruits with health-promoting characteristics, the changes of physicochemical properties, phenolic compounds, antioxidant capacities, and inhibitory effects on digestive enzymes of Donghong kiwifruits during maturation were systematically investigated. Noticeable variations in physicochemical properties and phenolic profiles were observed throughout the maturation stages of Donghong kiwifruit. According to the HPLC analysis, phenolic compounds, including chlorogenic acid, (-)-epicatechin, procyanidin B2, quercetin-3-O-rhamnoside, gallic acid, neochlorogenic acid, and caffeic acid, were found in Donghong kiwifruit, while chlorogenic acid was the most abundant phenolic compound. Considering the accumulation patterns of both total phenolics and soluble solids content, the optimum harvest time of kiwifruit with relatively high level of health-beneficial components was determined. Furthermore, Donghong kiwifruit exerted remarkable antioxidant capacities, and inhibitory effects on pancreatic lipase and alpha-glucosidase. Indeed, the Pearson's correlation showed that chlorogenic acid, caffeic acid, (-)-epicatechin, and quercetin-3-O-rhamnoside could be major contributors to the antioxidant activity and inhibitory effects on digestive enzymes. Results are beneficial for better understanding of the accumulation patterns of health-beneficial phenolic compounds, which can aid in the targeting of specific developmental stages with an optimal phenolic profile for the production of health-beneficial products.