76C-2 |
Effect of ozone treatment on quality of orange juice |
P. D. ANGELINO, D. A. Golden, and J. R. Mount. Dept. of Food Science & Technology, Univ. of Tennessee, 2605 River Dr., Knoxville, TN 37996-4591 Foodborne disease outbreaks associated with fruit juices have brought about regulations requiring juice processors to implement a Hazard Analysis and Critical Control Point program, with a 5-log reduction of pertinent pathogens. Small juice producers seek a method less expensive than pasteurization to provide the required 5-log reduction. Ozone treatment has been shown to be an effective method for achieving a 5-log reduction of E. coli O157:H7 in apple cider and Salmonella in orange juice. The objective of this study was to determine the effect of ozone treatment on ascorbic acid, color, and survival of Saccharomyces cerevisiae in orange juice and orange juice fractions. Samples were treated with ozone (0.9 g/hr) and analyzed for ascorbic acid (HPLC), color (L*, a*, and b*), and yeast counts. Ascorbic acid in orange juice and in water + 25mg ascorbic acid/100ml was almost fully degraded after 90 min of ozone treatment (0.9 g/hr). Ozone treatment resulted in a significant (P<0.05) decrease in redness (a* value) in orange juice, although the difference was not visibly noticeable. Orange juice samples, inoculated with S. cerevisiae and lacking or containing very low levels of ascorbic acid, showed a significant decrease in yeast populations, with yeast being undetectable within 5 to 60 min of ozone treatment. S. cerevisiae populations were not significantly reduced in samples containing at least 6 mg ascorbic acid/100ml solution. Survival of S. cerevisiae was not significantly different between ozone- and air-treated orange juice samples after a 5-day storage period at 10 C. Although ozone treatment has been shown to reduce pathogens in fruit juices, it is not recommended as an alternative to pasteurization of orange juice because ozone reduces ascorbic acid levels, alters typical orange juice color, and is ineffective at reducing numbers of spoilage yeasts.
Session 76C, Citrus: General
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