Combination of crude pectolytic and cellulolytic enzymes (both prepared from Aspergillus foetidus) was used as pretreatment for extraction of carrot juice since pectinases and cellulases contribute to the breakdown of pectin and cellulose, respectively, hence enhance the juice yield and clarity. Juice yield was increased by 11.38% due to enzyme action. Juice samples along with control were stored at room (30 ± 5°C) and refrigeration temperature (5 ± 1°C) for 3 months. Evaluation of physicochemical and sensory changes was done on 0, 15, 30, 45, 60, 90th day of storage. Initially, due to enzymatic treatment, acidity, total soluble solids and β-carotene content was significantly higher as compared to control, whereas pH, viscosity and pectin content for enzymatically treated juice samples was lower than that of the control samples. β-Carotene, pectin content and total acidity decreased, whereas pH and reducing sugar content increased during storage. Colour parameters L- and a- decreased while b- increased slightly which resulted in increased browning index (BI) and total colour difference. Zero- and first-order kinetic models was used to describe the L-, a-, b-value, BI and β- carotene at both temperatures. Sensory analysis revealed that enzymatically treated juice was more acceptable at refrigeration temperature (5 ± 1°C) for 3 months.
Key words: Carrot juice, enzyme pretreatment, storage, physicochemical properties, sensory evaluation.
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