The flavor problem of soybean oil. V. Some considerations in the use of metal scavengers in commercial operations

Abstract

Summary: Citric acid and sorbitol were tested on a commercial scale and their use was found to improve the oxidative and flavor stability of soybean oil.The optimal concentration for the addition of citric acid and sorbitol is of the order of 0.01%, 0.001% being insufficient, and 0.1% giving no significant increase in flavor stability over 0.01%.Heating is not necessary for the activation of citric acid; however, it is advantageous to add the citric acid at the beginning of the deodorization in commercial operations because of the protection imparted to the oils during deodorization. Since citric acid is destroyed during deodorization, it appears desirable, on the basis of laboratory experiments, to introduce additional citric acid during the cooling phase of deodorization.Phosphatides added to the deodorizer increase the oxidative and flavor stability of soybean oil and counteract the pro‐oxidant effect of added iron. Phosphatides are thus considered to comprise a fat‐soluble form of phosphoric acid and to perform the function of a metal scavenger. The value of the second degumming step of the German process is dubious. In neither the laboratory experiments nor in a commercial run were the differences due to this operation found to be significant.