67C-8 |
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A. KWAKWA1, A. Prakash2, C. Hughey3, and F. Caporaso1. (1) Food Science and Nutrition, Chapman University, Hashinger Science Center, Room 219, 1 University Drive, Orange, CA 92866, (2) Dept. of Food Science & Nutrition, Chapman Univ., 1 University Dr., Orange, CA 92866, (3) Physical Sciences, Chapman University, Hashinger Science Center, Room 219, 1 University Drive, Orange, CA 92866 Irradiating almonds can control pest infestation and microbial contamination. However, almonds contain about 45% unsaturated fatty acids and may become more susceptible to lipid peroxidation when irradiated. The objective of this research was to investigate the effect of irradiation on lipid peroxidation in non pareil almonds. Almonds were irradiated up to 16 kGy. Sensory analysis was done using a trained sensory panel. Peroxide Value (PV) was measured. Gas Chromatography – Mass Spectrophotometry (GC-MS) was used to measure hexanal and nonanal, known markers of rancidity and identify sulfur compounds produced by protein radiolysis. Sensory panelists detected a slight increase in the cardboard box/ waxy off-flavor typical of rancid almonds, and a slight decrease in the typical woody odor. They detected a stronger occurrence and increase in non-rancid off-flavors, described as stale/ musty and metallic. PV of the irradiated samples were all less than the control. GC-MS showed an overall increase in hexanal and nonanal. Sulfides were detected in all irradiated samples. Pungent sulfides produced by protein radiolysis may be responsible for the non-rancid off-flavors detected by the panelists. Although GC-MS revealed an overall increase in hexanal and nonanal, the rancid off-flavor may have been less intense or overshadowed by the more pungent sulfides. The increase in hexanal and nonanal and the sensory detection of rancid flavor suggests that lipid peroxidation had occurred, despite the lower PV values. Irradiating almonds appears to induce a slightly rancid off flavor by lipid peroxidation, and a stronger off flavor probably due to protein radiolysis. Thus irradiation almonds does induce rancidity in almonds; further research is suggested to quantify sulfur compounds as these may be the key off-flavor compounds in irradiated almonds. PV may also not be an accurate analytical tool for detecting rancidity in almonds.
Session 67C, Food Chemistry: Food analysis, irradiation and toxicology
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