36E-65 |
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R. YORUK, Biology Dept., Mersin Univ., Ciftlik Koyu Kampusu, Mersin, 33342, Turkey and M. R. Marshall, Jr., Dept. of Food Science and Human Nutrition, Univ. of Florida, Food and Environmental Toxicology Lab., PO Box 110720, Gainesville, FL 32611-0720. Fresh apple juice has increasing market value due to its sensory and nutritional qualities. In the juice industry, control of unpleasant browning discoloration during processing is of great importance to maintain qualities of apple products. There is interest in controlling discoloration with natural compounds. The objective was to investigate antibrowning potency of oxalic acid, a natural component of certain foods, for the inhibition of browning in the apple juice and compare its effectiveness to other carboxylic acids. The carboxylic acids tested include citric, fumaric, glutaric, malonic and succinic acids. Granny Smith apples were juiced with an ordinary domestic food processor. Juice samples were mixed with carboxylic acids and incubated at room and refrigerated temperatures for up to 21 h and 7 days, respectively. Samples were evaluated for browning by visual examination and by measurement of tristimulus color coordinates in the CIE Lab scale. The lab analysis of the juice measured pH and soluble solids content in ° Brix. Antibrowning potency of mixtures of oxalic and ascorbic acids also was studied. Oxalic acid was the most effective agent among the carboxylic acids tested for the inhibition of browning discoloration in the fresh apple juice. Oxalic acid showed effective browning inhibition for up to 24 hr incubation at room temperature. However, a combination of ascorbic and oxalic acids was found to be more effective than ascorbic or oxalic acid alone. Ascorbic acid showed a synergistic effect with oxalic acid. At refrigerated temperatures, synergistic effect was observed for up to 2 days. The mixtures of oxalic and ascorbic acids may have potential to increase acceptability of fresh apple juice by consumers. However, additional nutritional studies are required to address the issue of mineral availability if such treatments are to have application in the juice industry.
Session 36E, Fruit & Vegetable Products: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |