46C-23 |
Loss of fatty acids of Menhaden oils during extraction and purification process |
S. SATHIVEL, Fishery Industrial Technology Center, University of Alaska, Kodiak, AK 99615, W. Prinyawiwatkul, Department of Food Science, Louisiana State University Agricultural Center, Baton Rouge, LA 70803-4200, and C. C. Grimm, USDA-ARS-SRRC, New Orleans, LA 70124. Many marine fish have been studied for oil production and physicochemical properties. The purification process of fish oils includes degumming, neutralization, bleaching, and deodorization. Insoluble and soluble impurities, fatty acids, pigments, pigment-breakdown products, and residual free fatty acids, aldehydes and ketones are removed from crude fish oils during purification process. Losses of oil and fatty acids at different processing steps during purification affect production cost and final quality of fish oils. This study investigated changes in fatty acid composition and losses of fatty acids of Menhaden oils during extraction (crude oil) and purification process (degumming, neutralization, bleaching, and deodorization). Crude Menhaden oil and processed oils (degummed, neutralized, bleached, and deodorized) were thoroughly mixed with distilled water:chloroform:methanol (1:4:4 by volume). The fatty acids methyl esters (FAMEs) were prepared following the procedure 969.33 (AOAC, 1990). The fatty acids (FAs) were identified and quantified using GC/MS. The FA content was reported as mg/g oil. Three experimental replications were conducted, each with 3 batches of crude oils and 3 GC injections per batch. The loss of each fatty acid during processing was calculated based on the original quantity present in the crude Menhaden oil. To produce 763g of deodorized oil, 1000g of crude menhaden oil was required. The major weight loss (11%) occurred when crude oil was processed to degummed oil. The omega-3 fatty acids (combined C18:3 and C22:6) in the deodorized oil accounted for 23.9% of total fatty acids. The loss of omega-3 fatty acids from crude oil to deodorized oil was 7.1%, whereas 11.5% and 14.1%, respectively, for saturated and unsaturated fatty acids. Up to 4.2%, 4.9% and 1.7% loss of saturated, unsaturated, and omega-3 fatty acids, respectively, was observed from the degumming to neutralization step. This study showed that oil purification steps affect the fatty acid composition of fish oils.
Session 46C, Food Chemistry: Lipids, antioxidants and emulsifiers
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