Effect of pasteurization, sterilization and storage conditions on quality of sweet orange (Mosambi) juice

摘要

Nutritional, sensory and microbial quality of unpasteurized (raw) and pasteurized sweet orange juice was studied. Unpasteurized and pasteurized juices were filled in sterilized and unsterilized bottles, stored at room (25+/-2degreesC) and refrigerated (10+/-2degreesC) temperatures. About 22% vitamin C was destroyed in the raw juice within 2 h at room temperature. Raw juice kept at low temperature also exhibited rapid destruction of vitamin C resulting in only 5% retention by the end of 12 h of storage. However, pasteurized juice, after an initial destruction of 7.26% could retain relatively more vitamin C. Visual appeal of all the juice samples was maintained within highly acceptable range during the entire period of storage. With the advancement of time, deterioration in taste and flavour occurred which adversely affected the overall acceptability of juice samples. The presence of total viable count (1 x 10(2) cfu/ml), yeast and mold (5 x 10(2) cfu/ml) and coliforms (2.5 x 10(2) cfu/ml) was recorded in fresh juice and Staphylococcus aureas was absent. Pasteurization of juice was not effective to kill the existing surviving microbes, but helped in delaying the growth.