Determination of Trace Protein in Oils and Fats by Fluorescence Spectrophotometer

Abstract

The sensitive analytical method by fluorescence spectrophotometer was developed for determination of trace amount of protein in oils and fats. Recoveries of spiked soybean protein powder into refined salad oils were 54 and 58% at the level of 1 and 5 ppm, respectively, and these coefficients of variation were 12 and 5%, respectively. The determination limit was 1ppm. Then residual proteins in fish oil and lard during the oil refining process were examined using this method. The protein concentrations were 6 ppm in crude fish oil and 22 ppm in lard. The amounts of protein markedly decreased at alkali refining and were lowered less than the determination limit at bleaching. Amounts of protein in 8 hydrogenated fish oils, 9 refined lard, 8 refined beef tallows, 3 refined soybean oils and 11 hydrogenated soybean oils, which are used for oils and fats products, were all less than the determination limit. © 2004, Japan Oil Chemists' Society. All rights reserved.