2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center

The determination of free soluble starch was investigated as a potential means for predicting potato end-use, which is dependent upon the textural characteristics of the cooked tissue. Cooked tissue is typically categorized as waxy (cohesive, sticky, moist) or mealy (crumbly, particulate, dry) with respect to texture and appearance. As textural characteristics are dictated by the structure and composition of the cellular constituents within the tissue, it has been hypothesized that the cells of waxy and mealy cultivars differ in their tendency to rupture and release soluble starch upon cooking. Thus, the amount of free soluble starch released from cooked tissue may serve as a predictor of potato textural characteristics. Fresh potatoes representing two cultivar extremes (Russet Burbank/mealy texture; Red Chiefton/ waxy texture) were cored to produce standardized tissue cylinders, which were boiled in d. d. water (15, 20, or 25 min.) and subjected to mechanical shear (2.0 or 7.5 minutes). For each treatment, the resulting mash was suspended in d. d. water, after which the diluted mash was centrifuged and the supernatant filtered, treated with iodine, diluted to volume, and analyzed spectrophotometrically at 660 nm to yield a Blue Value (BV). Statistical analysis indicated that BV was significantly impacted by cultivar, cook, and mash treatments. Further, a differential response of the waxy and mealy tissue to both cook and shear treatments facilitated differentiation of the cultivars on the basis of BV. Thus, the soluble starch leached from cooked tissue may represent a reliable indicator of potato quality.