Phytochemical changes in phenolics, anthocyanins, ascorbic acid, and carotenoids associated with sweetpotato storage and impacts on bioactive properties

•Purple sweetpotato; NCPuR02-020, contained highest levels of all phenolic components.•A decrease in phenolic components was observed after curing and storage.•Covington contained the highest level of beta-carotene and total carotenoids.•Levels of carotenoids were significantly increased over curing and storage times.•Antioxidant activity and ascorbic acid gradually decreased with storage. Sweetpotato phytochemical content was evaluated in four genotypes (NCPUR06-020, Covington, Yellow Covington, and NC07-847) at harvest and after curing/storage for 4 or 8months. Curing and storage for up to 8months did not significantly affect total phenolic content in Covington, Yellow Covington, and NC07-847, however for NCPUR06-020, a purple-fleshed selection, total phenolic content declined mainly due to anthocyanin degradation during storage. Covington had the highest carotenoid content at harvest time (281.9μg/g DM), followed by NC07-847 (26.2μg/g DM), and after 8months, total carotenoids had increased by 25% and 50%, respectively. Antioxidant activity gradually declined during storage, and freshly harvested sweetpotatoes also demonstrated higher anti-inflammatory capacity as gauged by inhibition of lipopolysaccharide-induced reactive oxygen species (ROS) in SH-SY5Y cells. Gradual changes in sweetpotato phytochemical content and antioxidant and anti-inflammatory capacity were noted during normal long-term storage, but the specific effects were genotype-dependent.