Effects of sugar, salt and water on soybean oil quality during deep-frying

Abstract

The effects of flour dough components (water, sugar and salt) on soybean oil deterioration during deep-fat frying have been investigated. Flour dough sheets made from flour and water were used as the carrier of salt and sugar. Several analyses, including acid value, carbonyl value,p-anisidine value, color, dielectric constant, Fritest, total polar compounds and polymer content, were used to evaluate deterioration of oil quality during deep-fat frying. The relationship between frying time and analytical data was analyzed by Duncan's multiple range test. Oil quality after frying simple flour dough sheets without additives was inferior to that after frying dough sheets with added sugar or salt. The sugar and salt in the flour dough sheets may play a role as water-binding substances during frying. Among the effects of water, salt and sugar, the rate of oil deterioration was found to be highest for water, followed by salt and sugar. The combined addition of salt and sugar had no enhancing effect on the oil deterioration during deep-fat frying.