45C-3 |
Analysis of volatile oxidized compounds in DHA-enriched fish oil using headspace solid phase microextraction method |
H. LEE1, R. Taylor1, Y. Lee2, C. I. Wei3, and H. An1. (1) Dept. of Nutrition & Food Science, Auburn Univ., 328 Spidle Hall, Auburn, AL 36849-5605, (2) Dept. of Food Science & Technology, Pukyoung National Univ., Daeyun-3-Dong, Nam-Gu, 608-737, South Korea, (3) Dept. of Nutritional Sciences, Oklahoma State Univ., 139 Human Environmental Sciences Bldg., Stillwater, OK 74078-6141 Polyunsaturated fatty acids (PUFA), including docosahexaenoic acid (22:6¥ø3, DHA) and eicosapentaenoic acid (20:5¥ø-3, EPA) are known to have certain nutraceutical functions, such as, antitumor, anti-inflammatory and antiviral activities. Fish oil is used as the main commercial resource of DHA. However, DHA is easily oxidized, producing strong off-flavors, and adversely affecting consumer's acceptability. Because of the problem, the application of fish oil to food products has been limited. Objectives of this study were to (1) identify oxidized compounds using solid phase microextraction (SPME) and (2) determine DHA degradation pathway to form the oxidized volatile compounds. Volatile compounds were isolated from two types of DHA-enriched fish oil, triacylglycerol (TG) and ethyl ester (EE) and identified by solid phase microextraction (SPME) extraction, gas chromatography (GC), and gas chromatography-mass spectrometer (GC/MS). The contents of DHA in TG and EE were monitored during the 10-day accelerated oxidative storage at 80 oC. Totally, 22 compounds were identified from TG and 30 compounds from EE. The relative contents of DHA in TG and EE were decreased to 65.1 and 29.5 %(w/w) during the 10-day accelerated oxidative storage at 80 oC. (E)-2-Pentenal, 1-penten-3-ol, 2-(1- pentenyl) furan, (E)-2-penten-1-ol, 4-hexenoic acid, and (E,E)-2,4-heptadienal were detected as oxidized volatile compounds from TG, while ethanol, (E)-2-pentenal, 1- penten-3-ol, (E,E)-2,4-heptadienal, 2-(1-pentenyl) furan, and propanoic acid were the main compounds identified from EE. (E)-2-Pentenal, 1-penten-3-ol, 2-(1-pentenyl) furan, (E)-2-penten-1-ol, 4-hexenoic acid, and (E,E)-2,4-heptadienal are identified as oxidized volatile compounds generated by the autoxidation of DHA and/or EPA. The obtained data should be helpful in application of DHA-enriched fish oil in actual food systems and to control off-flavor formation during extended storage.
Session 45C, Food Chemistry: Flavor and aroma chemistry
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