| Abstract Detail
Physiology LeRiche, Etienne [1], Wang-Pruski, Gefu [1], Jeliazkov, Valtcho [2], Coffin, Robert [3]. The Role of Tuber Phosphorus Content in Controlling the Severity of After-Cooking Darkening in Solanum tuberosum var. Shepody and Russet Burbank. AFTER-COOKING DARKENING is caused by a non-enzymatic oxidation reaction between iron and chlorogenic acid. Sodium acid pyrophosphate is currently used to reduce the severity of after-cooking darkening by chelating iron and making it unavailable to bind chlorogenic acid. It has been suggested that internal tuber phosphate may act similarly to sodium acid pyrophosphate in controling the severity of after-cooking darkening, although this theory has never been validated. For this study, triplicate core sample of Solanum tuberosum var. Shepody and Russet Burbank tubers from fertilized and non-fertilized plots (Summerside, Prince Edward Island, Canada) were used to measure internal tuber P and determine if P plays a role in controlling the severity of after-cooking darkening. Raw tubers were halved longitudinally and half of each tuber was steam-cooked and used to assess the degree of after-cooking darkening by digital photo-imaging; the other tuber halves were divided into 8 segments along the pith and dried. The concentration of P was then measured in each segment using scanning electron microscopy equipped with an energy dispersive X-ray microanalyzer. Shepody and Russet Burbank had less after-cooking darkening and a higher concentration of tuber P in the fertilized plots (176N, 165P, 198K kg/hectare for Shepody; 198N, 198P and 220K kg/hectare for Russet Burbank) compared to non-fertilized plots. Accordingly, when X-ray mapping the concentration of P from one end of the tuber to the other, P content was negatively correlated with the severity of after-cooking darkening in Shepody (r = -0.684) and Russet Burbank (r = -0.503) tubers from both treatments. The observed trend in P concentration in tubers may reflect the trend in phosphate, a strong iron chelator. These finding further strengthen the theory that P and, more specifically, phosphate plays a role in reducing the severity of after-cooking darkening.
Log in to add this item to your schedule
1 - Nova Scotia Agricultural College, Department of Plant and Animal Sciences, PO Box 550, Truro, Nova Scotia, B2N 5E3, Canada
2 - Mississippi State University, Department of Plant and Soil Sciences, PO Box 1690, Verona, Mississippi, 38879, USA
3 - Cavendish Farms, PO Box 3500, Summerside, Prince Edward Island, C1N 5J5, Canada
Keywords:
After-cooking darkening
Potato
P
X-ray microanalysis.
Session: PAA04a-8
Location: Hall of Ideas Room F/Monona Terrace
Date: Monday, July 24th, 2006
Time: 3:45 PM
Abstract ID:99 |
