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K. A. CLEARY, Dept. of Food Science, North Carolina State Univ., Schaub Hall, Box 7624, Raleigh, NC 27695-7624 and R. F. McFeeters, USDA-ARS-South Atlantic Area-Food Science Research Unit, North Carolina State Univ., Dept. of Food Science, Box 7624, Raleigh, NC 27695-7624. Oxidative off-flavors can develop in pickle products after exposure to oxygen. Plastic containers, which are becoming more common in the pickle industry, can allow oxygen to migrate into the containers during storage. Pickle products have been colored for many years using the spice turmeric. The color in turmeric is a result of the presence of the phenolic compound curcumin, which is also a natural antioxidant. Our objective was to determine if turmeric, at levels suitable for use in pickle products, would be effective in inhibiting the formation of oxidative aldehydes in pickles after exposure to oxygen. Fresh-pack dill pickles were made from pickling cucumbers (32-38 mm diameter) and packed in glass containers. Oxygen and different concentrations of turmeric were added to the pickles, and volatile aldehydes were later analyzed as a function of time using purge and trap, and gas chromatography-mass spectrometry (GC-MS). Commercial pickle products were also analyzed. Hexanal was the major oxidative aldehyde compound formed, and was used as an indicator of oxidative off-flavor formation. Hexanal formation increased as the amount of oxygen in the container increased. Turmeric was found to retard formation of hexanal and other aldehydes, specifically pentanal, 2-hexenal, and heptanal, with greater effectiveness as turmeric concentration increased from 16 to 250 ppm. Dill spices were also found to reduce formation of aldehydes. Turmeric was determined to be an effective antioxidant at concentrations appropriate for coloring in pickles. With a level of oxygen comparable to that which would enter a plastic container during a one-year storage period, turmeric maintained hexanal levels near concentrations found in commercial fresh-pack pickles packaged in glass containers. As the trend towards plastic containers continues, it is important to understand how to reduce the development of oxidative off-flavors in pickles that may develop due to the oxygen permeability of plastic containers.
Session 29, Food Chemistry: Antioxidants and bioactive agents
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