61B-2 |
Analysis of volatile compounds and headspace oxygen and carbon dioxide in full fat soy flour |
J. Y. LEE1, J. H. Lee1, D. B. Min1, and E. O. Choe2. (1) Department of Food Science and Technology, The Ohio State University, 2015 Fyffe Court, Columbus, OH 43210-1007, (2) Department of Food and Nutrition, Inha University, 253 Yonghyundong, Namku, Incheon, Korea, 402-751 Soy flour can be a good protein source and used to improve the color, texture and water binding capacity in baked products. The flavor quality of soy flour very often determines the quality of final products. A sensitive and reproducible method is thus necessary to monitor the off-odor in soy flour. The objective of this study was to analyze the changes of headspace oxygen and carbon dioxide and the headspace volatile compounds from full fat soy flour stored at -20°C dark, 60°C dark and light. Seven g of full fat soy flour were put in 50-mL serum bottles and sealed air-tightly with Teflon-coated rubber septa and aluminum caps. Samples were kept at -20°C dark, 60°C dark or 60°C light for 10 days. Volatile compounds were isolated by solid phase microextraction(SPME)-gas chromatography(GC) and SPME-GC-mass selective detector(MS). The headspace oxygen and carbon dioxide were determined every other day for 10 days by GC with a thermal conductivity detector. The coefficient of variation for the headspace volatile compounds from soy flour by SPME was 4.8% in total peak area. As storage time increased from 0 to 10 days, total volatile compounds of samples stored at 60°C under dark or light increased by 2.2 and 2.5 times, respectively. Headspace oxygen of samples at 60°C under dark or light for 10 days decreased by 4 and 5%, respectively, due to lipid oxidation and headspace carbon dioxide increased by 1.7 and 2.2%, respectively, due to the non-enzymatic browning reaction. Forty eight volatile compounds including 9 furan and pyrazine compounds were identified and detected in 60°C dark and light samples. However, these compounds were not detected in the samples stored -20°C. Lipid oxidation and non-enzymatic browning reaction are responsible for the formation of volatile compounds and the changes of headspace oxygen and carbon dioxide in soy flour.
Session 61B, Food Chemistry: Flavor and aroma chemistry
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