Effect of convective drying on phenolic acid, flavonoid and anthocyanin content, texture and microstructure of black rosehip fruit

Abstract

Black rosehip (Rosa pimpinellifolia) fruit is rich in nutrients that could be valorised and used as a functional food ingredient. Drying can be applied to increase the applications of this fruit. Drying can influence the composition of heat-sensitive phytochemicals and the matrix in terms of the texture and microstructure of the fruit. This study aimed to evaluate the effect of convective drying in terms of drying temperature (50–80 °C) and airflow (0.5–1.5 m/s) on phenolic acids, flavonoids, and anthocyanins content, texture, and microstructure of dried black rosehip fruit. Catechin and epicatechin, as the two main flavonoids, were in their highest concentration in fruits dried at 70 °C. The highest levels of cyanidin-3-glucoside, cyanine chloride, cyanidin-3-rutinoside, and pelargonidin-3-glucoside were determined at 70 °C and 1.5 m/s. The sample dried at 50 °C exhibited the highest concentrations of chlorogenic acid, fumaric acid, gallic acid, protocatechuic acid, quercetin, and quercetin-3-glucoside. The hardness, cohesiveness, and resilience were among the key texture parameters that were affected by drying temperature. The applied drying temperatures and air velocities induced substantial effects on the fruit microstructure. Considering these changes, it is important to assess the bioaccessibility and bioavailability of nutrients from dried black rosehip fruit in future research.