MICROBIAL, ENZYMATIC, AND CHEMICAL-CHANGES DURING STORAGE OF FRESH AND PROCESSED ORANGE JUICE

Microbial, enzymatic, and chemical comparisons were made on orange juice stored at 4-degrees-C without pasteurization, with light pasteurization (66-degrees-C, 10 sec) directed at vegetative microorganisms, and with full pasteurization (90-degrees-C, 60 sec) directed at the heat stable isozyme of pectinesterase. Effects of oxygen-barrier and nonbarrier packaging were also examined. Oxygen-barrier packaging did not benefit unpasteurized juice. However, lightly and fully pasteurized juices in barrier cartons exhibited lower microbial counts, greater ascorbic acid retention, and apparent slowing of cloud loss by the third week of storage. During the first 22 days storage, microbial, cloud, sugar, and ascorbic acid values for lightly pasteurized juice were similar to those of juice receiving full pasteurization.