Comparação entre os métodos de determinação de índice de iodo para gordura de soja parcialmente hidrogenada

Abstract

The hydrogenation process is very important in the manufacture of by-products of soybean oil, and is intended to reduce the degree of unsaturation to increase oxidative stability and melt temperature. The control of the hydrogenation process is done by measuring the melting point, the iodine value. In this research the instrumental (gas chromatography with flame ionization detector) and volumetric methods (Wijs method) were compared for the determination of iodine value in partially hydrogenated soybean fat. For this, thirty eight soybean fat samples were collected in an industrial reactor and at different times of the hydrogenation reaction. Analyzing the results obtained by twoway ANOVA and Tukey's test, it was concluded that the instrumental method was more accurate in determining the iodine value in hydrogenated fats with different degrees of saturation. The use of the volumetric method, although presenting a lower cost, requires a greater training of the analyst to obtain results similar to those obtained by the chromatography.