Comparisons in phytochemical components and in vitro digestion properties of corresponding peels, flesh and seeds separated from two blueberry cultivars

Abstract

Highbush blueberries (HB) and rabbiteye blueberries (RB) were separated into peels, flesh, and seeds to assess the compositions of nutriment, anthocyanins, soluble sugars and fatty acids, and the in vitro digesting abilities. Total phenolics contents (TPC) of 51–56 mg GAE/g DW were found in blueberry peels. Compared with HB peels, RB peels showed much higher TPC, but only contained 35 phenolics and lacked peonidin-3-O-rutinoside. Glucose, fructose, and sucrose were all present in HB and RB, but RB flesh had a higher acid-sugar ratio. Unsaturated fatty acid concentrations in HB and RB seeds were comparable (26.65 and 26.43 mg/g, respectively). However, HB seeds have 35 fatty acids, but RB seeds lacked cis-4,7,10,13,16,19-docosahexaenoic acid and cis-10-pentadecenoic acid. The in vitro digestion test showed that the whole fruit/peels/flesh of RB had a higher recovery and bioavailability index of phenolics and anthocyanins. Therefore, the reuse of blueberry pomace needs to be emphasized.