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ARS Home » Midwest Area » Madison, Wisconsin » Vegetable Crops Research » Research » Publications at this Location » Publication #332340
Title: Rate of cooling alters chip color, sugar contents, and gene expression profiles in stored potato tubers

Author
item WIBERLY-BRADFORD, AMY - University Of Wisconsin
item Bethke, Paul

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/27/2017
Publication Date: 6/8/2017
Publication URL: http://handle.nal.usda.gov/10113/5836344
Citation: Wiberly-Bradford, A.E., Bethke, P.C. 2017. Rate of cooling alters chip color, sugar contents, and gene expression profiles in stored potato tubers. American Journal of Potato Research. 94(5):534-543. https://doi.org/10.1007/s12230-017-9591-3.

Interpretive Summary: Low temperature storage of potatoes decreases spoilage and delays sprouting. Unfortunately, low temperature storage also causes potatoes to accumulate sugars that produce dark colored pigments when potato chips or French fries are cooked. The resulting chips and fries are visually unappealing and may taste bitter. Research into this process will better enable plant breeders and those who store potatoes to deliver a quality product to consumers. In this research, responses of two chipping potato varieties to gradual or rapid cooling were compared. It was observed that the timing and extent of changes in chip color, sugar contents, and gene expression depended on cooling rate, storage duration, and potato variety. These observations highlight that care must be taken when comparing responses to the storage environment when different cooling treatments or varieties are studied.

Technical Abstract: Potatoes accumulate sucrose and the reducing sugars glucose and fructose when stored at low temperatures. This process, cold-induced sweetening, has been studied extensively because potatoes with elevated reducing sugars produce undesirable, dark-colored products and acrylamide, a suspected carcinogen, during high temperature cooking. Potatoes in commercial storages are cooled slowly, but research studies frequently use potatoes cooled rapidly. In this study, effects of cooling rate and variety on chip color, sugars and gene expression were examined. Rapidly cooled and slowly cooled tubers had similar sugar contents and produced dark chips 16 weeks after cooling to 3oC began. Sucrose and reducing sugar contents, however, were substantially less in slowly cooled than in rapidly cooled tubers for the first 13 weeks after cooling began. Differences in gene expression were observed between cooling treatments and varieties. Overall, the data show that cooling rate, time in storage and variety each influence aspects of cold-induced sweetening.