Apple juice clarification using fungal pectinolytic enzyme and gelatin

Clarity in fruit juices, particularly from apples and grapes, is desirable to maintain aesthetically pleasing quality and international standards. For this mainly fungal pectinases are used in industrial processes. In present study, effect of gelatin on efficacy of a fungal pectinolytic enzyme preparation from Aspergillus niger van Tieghem was analyzed for clarification of a commercial apple juice (himcu, sweetened apple juice, Deptartment of Horticulture, Govt of Himachal Pradesh). Juice containing both gelatin and enzyme was about 1.5- to 2-times more clarified in same time of incubation as compared to that containing enzyme alone. The most effective clarification (%T650, 85%; p<0.001) was achieved with 15 IU/ml of enzyme preparation, in presence of 0.01% gelatin, at 45°C in 6 hrs of holding time. Juice treatment, scaled-up to 200-times, resulted in about 143% more transmittance as compared to control. On complete clarification, a viscosity drop of 35.5% was observed in the juice. The clarified juice stored at room temperature (∼25°C) did not show any significant haze development after two months of storage.