NUTRITIONAL COMPOSITION, PHYTOCHEMICAL AND ANTIOXIDANT ACTIVITY OF TWO VARIETY (LIGHT RED AND DARK RED) ROSELLE (Hibiscus sabdariffa L.) JAM.

Abstract

Roselle (Hibiscus sabdariffa L.) calyces are rich in nutrient but the utilization of its calyces in the preparation of jam is not popular in Bangladesh. The study aimed to develop roselle jam from dark and light red varieties and to evaluate phytochemicals, antioxidant capacity, sensory and nutritional parameters. Roselle jam was processed using the open kettle method. One way analysis of variance (ANOVA) was performed to find out the level of significance at P <0.05. The investigation was taken place by preparing roselle jam in addition of sugar, commercial pectin, roselle seed extract as a natural pectin and citric acid. Three different formulations for single colour variety were made from roselle calyx extract and sugar (50:50) by adding seed extract, commercial pectin and no extra pectin. The sensory score of roselle jam processed with seed extract from both varieties (sample B and sample E) were found to be the best among different formulations of two varieties. The carbohydrate, fat, protein, ash and fiber were determined at the range of 59.33% to 60.78%, 1.16% to 1.76%, 1.42% to 1.76%, 0.72% to 1.34% and 1.46 to 2.33% respectively. Energy content was found ranging from 262.94-267.112 kcal/100g. Vitamin C content in roselle jams was estimated ranging (16.87- 24.55) mg/100g. Jam from light red roselle showed higher antioxidant capacity and TPC than dark red roselle. Moreover, the anthocyanin content and total flavonoid content for light red roselle jam ranged from 0.27 to 0.51 mg TA/100 ml and 62.87 to 88.33 mg QE/100 g whereas for dark red roselle jam had 0.41 to 0.51 mg TA/100 ml and 58.66 to 79.20 mg QE/100 g. Total viable count was found in acceptable limit and fungal activity was not seen after 15 days of storage at cold (8±2 0C) temperature.