Abstract
Thermostability of the natural tocopherol mixture was compared with that of Butylated hydroxyanisole by using the continuous water-spraying and heating system. In the frying conditions, thermostability mainly depends on the stability to the volatilization by steaming and this is a very important property of antioxidants which are used in frying oils.
The test was carried out under condition that the fat surface in the system was protected from the air by means of metal float and the thermal oxidative deterioration was thus prevented as far as possible. As a result, tocopherol showed a better stability, that is, the rates of decrease of its content and of the induction period of heated oils were very small as compared with that of butylated hydroxyanisole.
On the other hand, as shown in Fig.-2, rapid decrease of tocopherol content which might be mainly caused by thermal oxidation, was observed in parallel with the decrease of the induction period of heated oils when the fat surface was kept to be exposed to air.
As mentioned above, it was recognized that when thermal oxidative deterioration during frying was maintained as minimal as possible, natural tocopherol mixture was a suitable antioxidant for frying oils.
