フィッシュミールの油脂について-I

Abstract

It is well known that the oxidation of oil in fish meal results in not only accumulation of toxic peroxidual oxygen deterimental to animal or fish but also the reduction protein digestibility of the meal. However, about such deteriorative changes of the meal, especially peroxide value of fish meal oil which is possible to procceed in the manufacturing process and also in the storage period, a reliable information have scarcely been presented as yet. In addition, even though several investigations suggested the protection of fish meal from these deterioration with the aid of some chemical antioxidants, none of them did not distinctly point out the merit or behavior of these additives. To throw light on these problems, the authors tentatively prepared brown fish meal samples in the laboratory under the conditions described in Table 1, and investigated the stability of oil in the presence or absence of antioxidant added there to. The results shown in Tables 2-4 indicate that the oxidation of oil in fish meal advances most readily in the drying process, the products proving just after the completion of drying to have peroxide values 90-120meq/kg even when prepared from comparatively fresh raw fish. These undesirable changes, however, could be inhibited to a satisfactory extent by adding BHA to the boiling water in 0.10% concentration (samples No. 2 and 4), although in a lower concentration, 0.01% (No. 6), the result was rather negative. Since the results of estimation of BHA (Table 5) indicate that the amount of BHA found in the meal and in pressed oil were equal to 1% and 10%, respectively, referred to the total amount of BHA applied, a large amount of BHA may certainly remained in boiling water and be discarded. So, to save the loss of BHA, it may be better that an antioxidant is applied to the fish cake rather than to boiling water.