Process-Induced Chemical Changes in Food

Ohshima, T, Yankah, V V, Ushio, H, Kiozumi, C, Ohshima, Toshiaki, Yankah, Vivienne V., Ushio, Hideki, Kiozumi, Chiaki

Raw whole fishes (Horse mackerel, Trachurus japonicus) were degutted and separately treated with antioxidants BHA, BHT, TBHQ and tocopherol before fermentation, by completely immersing the samples in 0.1% antioxidant solutions. Fish samples were then salted, fermented and dried to mark the end of processing. A portion of the control samples were packed in an oxygen absorber during storage for 2 months at room temperature to study the effect of oxygen scavenging on lipid oxidation. The moisture content and total lipid decreased with processing and storage. An inductive effect of the fish oil was observed with 2-thiobarbituric acid values and the formation of lysophos-phatidylcholine (LPC) for TBHQ and BHA treated fish during the fermentation process. Free fatty acid formation was detected in all fish samples throughout processing and storage. For samples treated with tocopherol, only *-tocopherol was detected at the end of 2 months storage. Although TBHQ showed the best antioxidative effect during processing, it was the fastest synthetic antioxidant to be depleted. However, relatively high levels of BHA were present in the sample after 2 months storage. Red color patches, suspected to be antioxidant degradative products, were observed around the operculum of TBHQ treated samples after processing.