Measurement of color in potatoes

Reproducible, objective methods which conformed closely to visual appraisal were developed for measuring color differences in either cooked or raw potatoes. Experimental samples, selected from lots stored at various temperatures for different periods of time, differed in extent of graying and yellowing. Ricing was found to be preferable to mashing as a method of cooked sample preparation. A comparison of methods of sample presentation using the Gardner Color Difference Meter showed thin-layer measurement was most successful in separating cooked samples differing in amount of yellow pigment; deep-layer measurement was most successful in separating grayed samples. A simple method for measurement of color differences in raw tubers successfully separated the samples. All three methods of sample presentation were significantly correlated with visual ranking.