Antioxidants in Fish Oil Production for Improved Quality

There is an increasing demand for fish oil containing omega-3. By-products (e.g., heads, tails, belly flaps, backbones, and viscera) from fish fillet production are currently utilized for production of fish oil and fish meal for feed but can be a valuable source of omega-3 for human consumption. However, the quality of some oil is not good enough for human consumption due to oxidation during processing. The aim of this work was to decrease oxidation during oil production by adding antioxidants to herring by-products early in the production process. Of several antioxidants the most potent were selected by a fast screening test. Butylated hydroxytoluene, propyl gallate and citric acid were further evaluated on a labaroatory scale and pilot plant production of herring oil. The selected antioxidants resulted in lower total oxidation during processing [up to 71% reduction in TOTOX (2 times the peroxide value plus the anisidine value)]. In addition, higher oil stability was achieved by adding antioxidants during processing (improved stability up to 400%).