PHYSICAL AND CHEMICAL ASPECTS RELATED TO MEALINESS IN THE POTATO

Abstract

An investigation was undertaken to determine chemical and physical properties of potatoes which would explain the non-correlation of specific gravity with mealiness which has been encountered in some cases. It was shown that mealiness is not necessarily positively correlated with specific gravity of tubers but it was possible to correlate mealiness as determined by organoleptic methods with such factors as resistance to shear of boiled tubers and viscosity of suspensions of lyophilized tissue as measured by a Brabender Amylograph. Dry matter, starch content and amylose content were positively, sugar content negatively, correlated with mealiness. Crude protein content and starch granule size did not appear to be associated with mealiness. A negative correlation between polysaccharide content and mealiness was evident. The nature of the non-starch polysaccharide apparently present in the potato tuber and the molecular structure of the two starch components, amylose and amylopectin, deserve more extensive investigation.