水噴霧加熱法によるフライ油の変質について (第4報)

温度, 水噴霧量および新油添加率の影響

抄録

The object of this study is to elucidate the influences of temperature, amount of water sprayed and fat turnover rate on the deterioration of frying oils in the continuous water-spraying and heating systemr.
The influence of temperature was examined at 160±2, 180±2 and 200±2°C in the existence of air, or in the state of protected fat surface by means of metal float as wide as possible (Table-1, Fig.-1, 2). It was observed that thermal oxidative deterioration (viscosity increasing ratio, Iodine V.) was more influenced by specific surface area exposed in air than temperature, however, hydrolytic deterioration (Acid V.) was influenced by temperature very significantly. On the contrary, the increase in carbonyl value was smaller at 200°C as compared with the case of the lower temperature.
This suggests increased volatility of carbonyl compounds at 200°C.
The influences of the amount of water sprayed and fat turnover rate were also examined (Fig.-3, 4), The increase of acid value was accelerated by the increase of the amount of water sprayed, and the viscosity increasing ratio was less influenced. Fat turnover rate acted effectively as the preventing factor on any thermal oxidative or hydrolytic deterioration.