Studies on Keeping Quality of Shelled Japanese Oyster

点击翻译按钮获取中文摘要

1. Japanese oyster Crassostrea gigas were treated with either BHA (antioxidant), tocopherols, or deoxigenizer and stored at -20^ﾟC for 12months. Untreated oysters were also stored at -20^ﾟC and -35^ﾟC. As a result, both samples stored at -35^ﾟ and treated with deoxygenizer were kept good in quality for 12 months (Koizumi and Akazawa). 2. Oyster treated by the modified amino preservative agent have better scores in organoleptic test and less values in K-value. The samples packed by laminated-Ag-zeolite polyethylene bags showed lower bacterial counts (Kayama). 3. Aldehydes, hydroxy fatty acids and free fatty acids interacted synergetically so as to cause the unacceptable taste of frozen oyster. It was speculated that dimethylsulfide also plays a subordinate part (Hatano). 4. Although free polyunsaturated fatty acids in oyster homogenate, which were mainly generated by enzymatic hydrolysis of phospholipids during cold storage, were most susceptible to oxidation, these oxidation and hydrolysis were substantially depressed below -25^ﾟC without air (Kouch). 5. POV, determined by newly designed method, of the lipids from prebrowning portion of oyster was much higher than that from the normal portion, and decreased as browning proceeded with heating. The discoloration occurred during boiling of the oyster should be prevented by inhibition of lipid peroxidation (Nakamura). 6. Oysters were treated with far infrared rays or high pressure and stored in a refrigerator. Both oyster samples were superior to the untreated sample in keeping quality (Akazawa).