Effects of Harvest Date and Storage Duration on End-Product Quality of Three Processing Potato Varieties

Texture quality of French fries is an important characteristic for customer satisfaction. Determining the effects plant maturity and harvest timing on specific textural quality characteristics of French fries during raw potato (Solanum tuberosum L.) storage are needed. A two year study evaluated the effects of three harvest dates; early (prior to physiological maturity), normal (at physiological maturity), and late (after physiological maturity), on quality attributes of French fries produced from processing tubers of three varieties, Russet Burbank, Clearwater Russet, and Alpine Russet over a nine month storage season at 8.3oC. Analysis of specific textural attributes was evaluated, including crispness, external shell, mealiness, moistness, texture variation, texture defects, and internal appearance. Fry color, glucose and sucrose concentrations, and sprout development were analyzed over the nine month storage season. Yield data were evaluated using a mock contract to ascertain the economic impact of harvest timing on gross return for three varieties. Early harvest produced lower total yields and negatively affected growers� adjusted price with losses due primarily to low specific gravities. Early harvest incentives with Russet Burbank were insufficient to compensate growers for harvesting early. French fry texture quality from harvest through the nine month storage season was negatively impacted by an early harvest, especially with regard to crispness. Late harvest produced higher total yield/ha of tubers >170 grams, thereby increasing adjusted price. Clearwater Russet produced higher yields of undersized tubers when harvested early. Clearwater Russet had high specific gravities that increased the adjusted price and maintained good textural quality and fry color quality throughout the storage season. Alpine Russet experienced moderate to severe declines in textural quality and fry color quality over the storage season. Russet Burbank produced high total yields, however, it produced tubers with low specific gravity, and significantly reducing the adjusted price. Russet Burbank experienced significant declines in textural quality and fry color quality over the storage season. Overall, early harvest was detrimental to total yield, textural end-product quality and base prices of all varieties, although Clearwater Russet maintained desirable texture and fry quality throughout a nine month storage season.Thesis (Ph.D., Plant, Soil and Entomological Sciences) -- University of Idaho, 201