Blueberries (Vaccinium sp.) were reported to possess bariatric and antioxidant activity, which is related to the high phenolics content, especially anthocyanins (ACNs). Purified ACNs were more effective than whole berries in inhibiting digestive enzymes, increasing plasma antioxidants and reducing hyperlipidemia. However, anthocyanins are inherently labile and require stabilization by encapsulation, such as by spray drying. Different solvent systems and encapsulants have been compared to optimize health-related properties of ACNs, but in vitro digestion data are lacking. We thus investigated the effects of these factors on the phenolics content and antioxidant capacity of encapsulated ACNs in vitro. ACNs were extracted from blueberries using three solvent systems (acetonic, ethanolic, methanolic), fractionated, mixed with aqueous solutions of either whey protein isolate (WH) or gum arabic (GU) and spray-dried. A static model was used to simulate gastric and intestinal digestion. Microcapsules (3.5 g) were sequentially digested in vitro at 37 �C by stirring in prepared formulations of 6 mL saliva (5 min), 12 mL gastric juice (2 h), and 18 mL intestinal juice (12 mL duodenal and 6 mL bile juices, 2 h). Physicochemical properties of rehydrated microcapsules and supernatant from digesta were analyzed. Relative to WH, GU microcapsules retained more total ACNs but less ferric reducing power. Ethanolic extracts retained the most ACNs, methanolic extracts had highest antioxidant activity and acetonic extracts recorded the least. After in vitro digestion, GU microcapsules rapidly released phenolics with high antioxidant capacity within 2 h of (gastric) digestion. Antioxidant activity was reduced in the last 2 h of (intestinal) digestion. WH microcapsules gradually released phenolics with sustained antioxidant activity throughout gastrointestinal digestion. Food products with GU and WH microcapsules can be developed to mitigate gastric and intestinal oxidative stress, respectively.

<i>In vitro</i> phenolics content and antioxidant activity of microencapsulated blueberry anthocyanins: Effects of solvent-based extracts and encapsulant types

247th National Meeting (2014)

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In vitro phenolics content and antioxidant activity of microencapsulated blueberry anthocyanins: Effects of solvent-based extracts and encapsulant types