Effects of Drying and Storage on Anthocyanin Content and Antioxidant Activity in Hibiscus Tea Infusions

Abstract

Hibiscus rosa-sinensis is one of the traditional flowers used in tropics for ornamental gardens and for its curative health benefits. All parts of hibiscus are reported to possess significant medicinal values and the flowers especially are rich source of anthocyanin pigments. Anthocyanins serve as natural food colourants and also contribute to health benefits as a rich source of antioxidants. The major anthocyanin present in the red flowers of Hibiscus rosa-sinensis is cyanidin-3-sophoroside (Lowry, 1976). Investigations were carried out to explore the drying method of petals, antioxidant potential and nutritional benefits of hibiscus floral tea and squash from the cv. Red single of hibiscus. The hibiscus petals were subjected to drying by three different methods such as shade, sun and oven. It was observed that highest recovery of dried petals (19.66 %) and anthocyanin content (59.05 mg/l) was attained by shade drying of petals. The dried flower petals were quantified for cyanidin-3-glucoside using HPLC. In another experiment, tea infusions prepared from Green tea, Hibiscus tea and their combination proved significance and highest anthocyanin content was registered in freshly prepared Hibiscus tea (72.13 c3g eq.mg/l). However, highest ABTS (249.19 μg/ml), DPPH radical scavenging activity (733.22 μg/ml) in terms of IC50 values, highest total phenol content (82.57 mg GAE/g) and high organoleptic scoring were recorded in freshly prepared Green tea + Hibiscus tea [1:1].  The tea samples were tested for their qualities by storing upto 90 days. The above investigation proved the potential uses and anti-oxidant benefits of hibiscus petals in the preparation of hibiscus tea infusions.