ARS | Publication request: Studies of Amylose Content in Potato Starch

Submitted to: Potato Association of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 6, 2011
Publication Date: February 1, 2012
Citation: Jansky, S.H., Fajardo, D.A. 2012. Studies of Amylose Content in Potato Starch [abstract]. Potato Association of America Proceedings. Paper. No. 37.

Technical Abstract: Potato starch is typically low in amylose (~20-25%), but high amylose starch has superior nutritional qualities. The ratio between amylose and amylopectin is the most important property influencing the physical properties of starch. There is a strong case to be made for the development of food crops that will contribute to an increase in resistant starch consumption in order to improve public health. Preliminary screenings have revealed high apparent amylose content (AAC) for the species S. commersonii and S. acaule, and a high variability among and within species. Amylose content has been determined in tuber samples from 107 accessions representing 39 Solanum species with an average AAC of 30.5%. The top five species for mean amylose percentage were S. commersonii, S. acaule, S. stenotomum, S. raphanifolium and S. circaefolium (34.9-37.7%), while the lowest three species were S. lignicaule, S. berthaultii and S. morelliforme with amylose percentages ranging from 20.2% to 24.2%. Additionally, a total of 181 clones of American and foreign potato cultivars were evaluated in 2009 and 2010 for AAC in tuber starch. A wider range of amylose content was found for both years in the foreign varieties (27.2% - 39.1% and 21.3% – 34.7%) than in the American ones (28.2% - 36.6% and 20.5% – 31.7%). A higher amylose content mean was found in the foreign (34% and 28.2%) compared to the American cultivars (31.4% and 26.8%). In another study, amylose content sometimes increased during storage, implying that the starch pathway in storage is dynamic and there might be some breakdown and resynthesis of starch. Also, AAC was determined for 11 cultivars at different tuber developmental stages. The samples were harvested weekly at Hancock, WI and Rhinelander, WI from 47 to 121 days after planting. The amylose content remained statistically stable throughout the growing season. Finally, a screen of around 200 clones from SolCAP was performed to determine AAC from tubers harvested in NY (2009), OR (2010) and WI (2010). These results plus the molecular SNP data will be used for association mapping studies, diagnostic tools and molecular breeding approaches.