Abstract
In the previous papers, the authors observed that the amount of copper adduct to casein increased with the storage days in system of aqueous solution and oil.
In this paper, the influence of metal-protein complex which obtained from frying oil with whale meat, or copper-casein complex on the rancidification of oil was investigated.
Then the non-fat casein, copper sulfate and copper-casein complex were admixed with soybean oil, respectively, and the peroxide value and percentage of residual tocopherol were measured during the autoxidation period at 60°C.
From the experimental results, it was found that the copper seriously affected on the rancidity of oil, but in the case of casein and copper-casein complex, the peroxide value remained in low. It was also concluded that the casein and copper-casein complex did not promote the decomposition of tocopherol.
The stability of non-filter oil of frying oil after frying whale meat were found to be higher than those of the filtered oil.
