Inhibition of Cholesterol and Polyunsaturated Fatty Acids Oxidation through the Use of Annatto and Bixin in High-Pressure Processed Fish

Annatto and bixin, the main carotenoid of annatto seeds, were both found to inhibit cholesterol oxidation in minced herring (Clupea harengus) and minced mackerel (Scomber scombrus) during high pressure processing (600 MPa for 10 min) and subsequent chilled storage for 2 wk, a treatment which otherwise increased the content of cholesterol oxidation products above a critical limit for human consumption. Annatto but not bixin reduced the loss of docosahexaenoic acid caused by high pressure processing of herring from 12% to 7%, an effect assigned to antioxidative effects of phenolic compounds in annatto, while bixin as a carotenoid binds to membranes protecting membrane cholesterol. Practical Application Fish is a highly nutritive food due to the content of essential amino acids and polyunsaturated lipids. However, during processing and storage, fish meat undergoes rapid oxidative deterioration leading to rancidity adversely affecting their acceptance. Therefore, precautions are needed to stabilize the lipids in fish products. This study shows that annatto and bixin protect cholesterol against oxidation in pressurized fish, while only annatto protects the polyunsaturated fatty acids. The loss of eating quality of fish products can be prevented by a combined use of natural antioxidants and the nonthermal high pressure technology. This solution can be used in the development of new fish products processed with high-pressure treatment to improve product quality and avoid waste. (AU)