Effect of Maturity & Storage on Distribution of Phosphorus Among Starch & Other Components of Potato Tuber

Abstract

The effect of maturity and post-harvest storage of potato tubers on the content of starch-bound P and other P fractions of the potato were investigated. The increase in P upon maturation appears chiefly as starch-bound P in very young tubers and mostly as trichloroacetic acid-soluble organic P (i. e. phytic acid) in older tubers. During cold storage of the tubers, the P split off from the starch appears as inorganic phosphate, whereas phytic acid P appears mainly in the trichloroacetic acid-insoluble, non-starch fraction of the tubers, consisting of nucleic acid, phosphoproteins, and phospholipids. From the observations that the starch granules increase in P content during development and decrease during post-harvest storage of OC it seems probable that P is distributed hetero- geneously within the starch granules, the outer layers containing more P than the inner layers.