Evaluation of Physicochemical and Antioxidant Property of Dehydrated Hibiscus (Hibiscus rosa-sinensis) Flower Petals and Its Stability in Product Preparation

Abstract

The study was conducted to analyze the physico-chemical and antioxidant property of fresh and dehydrated Hibiscus powder petals and its stability in product preparation. The proximate analysis of fresh hibiscus flower petals showed the moisture 89.34%, fat 2.76%, protein 4.12%, total ash 7.23%, fiber 10.75% and anthocyanin content 877.04 mg/100g. Different drying methods were evaluated such as sun drying, solar drying, drying after freezing (Freeze for one hour followed by drying mechanical drying at 55°C), vacuum drying (50°C) and drying using lab scale air oven (55°C) on physiochemical and retention of antioxidants in powder of dehydrated hibiscus flower petals. Higher concentration of protein (4.05) and anthocyanin (107.5 mg/100g) were recorded in vacuum dried sample and it significantly different (α= 0.05) from other treatments. The data on change in physico chemical characteristics of different treatments (jelly powder mix) upon storage of 60 days; the lower moisture content (4.031 %) and fat content (0.31 %) was recorded by T4 at the end of storage. It was given a significant loss of anthocyanin content during storage and the highest composition was given by T3 (10.47 mg/100g). The colour intensity (L* value) indicated that the product was brighter in appearance and the maximum was recorded by T1 followed by T2 and the higher a* value was recorded by T4 followed by T2. A slight reduction of DPPH radical scavenging activity was observed among dry powder mix vs. the prepared product and it depends upon the composition of hibiscus powder incorporated.