Blanching and Vacuum Drying of Jamun Leaves: A Study on Nutritional Preservation and Quality Enhancement

Abstract

This study investigates the effects of blanching and vacuum drying on the physico-chemical and nutritional properties of Paras variety jamun (Syzygium cumini L.) leaves. Blanching treatments, including hot water and steam blanching at various temperatures and durations, were evaluated for residual enzymatic activity. Optimal enzyme inactivation was achieved with hot water blanching at 70°C for 1 minute, effectively preserving enzymatic activity. The vacuum drying process was evaluated across temperatures (50-70°C) and pressures (300, 400 and 500 mm Hg). Vacuum drying at 70°C and 300 mm Hg for 245 minutes yielded leaves with 6.50 % moisture content, 0.363 water activity, 25.782 % carbohydrate content, 37.646 mg/100 g phenolic concentration, and 5.95 % antioxidant content. Higher drying temperatures reduced moisture content and increased color values, while phenolic content and antioxidant activity peaked at higher temperatures. These findings underscore the potential of vacuum-dried jamun leaves as a valuable ingredient in nutraceutical and pharmaceutical applications.