A spectrophotometric method for the evaluation of vegetable oil colors

Summary

A means for evaluating oil color on the basis of an optical density measurement at 500 millimicrons has been proposed. The amount of chlorophyll would be taken into account by present methods or an adaptation of these methods.

The advantages of the proposed means of evaluating oil color are that it expresses more exactly the amount of color in the oil, provides a more accurate estimate of color removal during bleaching, and makes possible more exact evaluation of bleaching earth.

Data have been presented on the color value (Optical Density × 100) of refined and bleached oils, possible variation in value obtained from different laboratories, estimation of color removed during bleaching, evaluation of bleaching earth, and relationship between color of refined and bleached oils prepared in the laboratory by the Official Method.