ARS | Publication request: HPLC profiling of phenolics in diverse potato genotypes

Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 16, 2010
Publication Date: July 1, 2011
Citation: Navarre, D.A., Kumar, S., Shakya, R., Holden, M. 2011. HPLC profiling of phenolics in diverse potato genotypes. Food Chemistry. 127:34-41.

Interpretive Summary: Because potatoes are the most consumed vegetables in the United States, potatoes with higher amounts of vitamins and phytonutrients could significantly boost the amounts of phytonutrients consumed in the diet. We hypothesized that the quickest way to bring high-phytonutrient potatoes to the market would be to utilize the existing genetic diversity of potatoes and screen numerous genotypes to hopefully identify lines with higher amounts. We evaluated over 50 genotypes selected on the basis of our previous work, and identified several lines that have much higher than average amounts of phytonutrients. To determine how the amounts of phytonutrients in these potatoes compared to other vegetables, we analyzed phenolics and antioxidants in 15 other vegetables, including tomatoes, spinach and broccoli. Some of the color-flesh genotypes had amounts of antioxidants that compare favorably with other vegetables and on a fresh weight basis we found that some purple potato genotypes had the highest amounts of antioxidants among the vegetables surveyed.

Technical Abstract: Methanolic extracts of potatoes from over fifty genotypes representing cultivars, breeding lines, primitive germplasm and wild species were analyzed for phenolic content and hydrophilic antioxidant capacity. Total phenolics were measured using the Folin-Ciocalteau method, antioxidant capacity using the ORAC assay and individual compounds by LCMS. Total phenolics ranged from 1.8 to 11 mg g-1 DW and antioxidant capacity from 27 to 219 µmol TE g-1 DW. Chlorogenic acid was the most abundant phenolic compound and ranged from 22 to 473 mg 100g-1 DW. Rutin and kaempferol-3-rutinose were the most abundant flavonols detected. Total phenolics and antioxidants were compared between potatoes and 15 other vegetables, with broccoli having the most antioxidant capacity (271 µmol TE g-1 ) on a dry weight basis, while a purple-flesh potato had the most on a fresh-weight basis (34 µmol TE g-1). These data show that high-phytonutrient potatoes compare favorably to other vegetables and suggest that biofortified potatoes would positively impact dietary consumption of phytonutrients.