A novel seafood paste was developed by the fermentation of scallop ovary using rice malt (koji) and yeast culture. Chemical analysis of the product showed the formation of high level of free amino acids and organic acids during the fermentation. The product color and flavor resembled to Japanese traditional soybean miso. The contents of total lipids (TLs) extracted from the fermented products were ranged from 9.18% to 11.59% or 11.38% to 13.57%/dry sample weight. Although the TL was rich in oxidatively unstable polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), little decrease was found in these PUFAs during the fermentation, showing the high oxidative stability of the TL from the fermented scallop ovary. Moreover, the oxidative stability of the TL extracted from the fermented products increased with increasing the fermentation time. This would be mainly due to the formation of lipid soluble antioxidants such as tocopherols, which might be derived from yeast used for fermentation.
Although scallop ovary contains relatively high level of lipids rich in EPA and DHA, its application to food material has not been succeeded. The present study showed the development of soybean miso-type food from scallop ovary using koji fermentation under the presence of yeast culture. The product color, flavor, and texture were very similar to soybean miso. Moreover, lipids of the fermented products were oxidatively stable to show the successful application of the fermented scallop ovary to commercial marine products rich in EPA and DHA.