Microwave drying of black rosehip (Rosa pimpinellifolia L.) fruit: optimization for enhanced anthocyanin content and analysis of physicochemical properties and bioaccessibility

Abstract

Black rosehip (Rosa pimpinellifolia L.) fruit is a rich source of anthocyanins and has been promoted for several bioactive properties. Drying this fruit can increase its shelf life and enhance its applications in functional food products. This study aimed to optimize the microwave drying process of black rosehip fruit. The process was optimized based on the effect of microwave power (300, 500, and 650 W) and the amount of sample per batch (50, 75, and 100 g) on the amount of total anthocyanins and individual anthocyanins (cyanin chloride, cyanidin-3-glucoside, cyanidin-3-rutinoside, pelargonidin-3-glucoside, and cyanidin chloride). The effect of different drying conditions on color, microstructure, and texture was also investigated. The bioaccessibility of anthocyanins from the dried food sample at optimum conditions was assessed by in vitro gastrointestinal digestion. The results showed that microwave power and the amount of sample had a significant effect on the anthocyanin content of black rosehip fruit. The optimum conditions were determined to be 350 W power and 50 g sample mass. Lower microwave power and less sample mass produced dried fruits which were slightly darker, less red and less yellow. The hardness of dried fruit was also significantly affected by the microwave drying conditions. The dried black rosehip at optimum conditions showed a high bioaccessibility of cyanidin-3-glucoside (82.6 ±4.1%) which is known for a wide range of bioactive properties.