International Society for Tropical Root Crops (ISTRC) 41 Concentration of ascorbic acid, carotenoids, total phenolics and total anthocyanins in cooked potatoes

Potatoes are referred to as a good source of antioxidants like ascorbic acid (AA), carotenoids and polyphenols, however there is scarce information regarding the antioxidant concentration in cooked potatoes. In this study, the effect of cooking on the concentrations of ascorbic acid, carotenoids, total phenolic and total anthocyanins of diverse varieties were evaluated by spectrophotometry and HPLC. Cooking significantly reduced the AA concentration of all the varieties with boiling reducing the AA concentration to a lesser degree than either baking or microwaving. One hundred g of boiled potatoes of the variety 704393 could provide between 17 and 20 % of the RDA of AA. Comparison of the carotenoid compositions of raw and cooked tubers of some varieties revealed that cooking significantly reduced the violaxanthin and antheraxanthin concentration of all the varieties. However the lutein and zeaxanthin concentration of cooked tubers of some of the varieties evaluated was higher than in raw tubers. One hundred grams of the cooked yellow fleshed varieties provide a significant amount of zeaxanthin (above 500 ug) to the human diet. The total phenolic and total anthoacyanin concentrations of the pink and purple fleshed varieties evaluated were higher in cooked than raw potatoes. It seems that cooking has no a negative effect on the lutein, zeaxanthin, total phenolic and total anthocyanin concentration of potatoes. Cooked potatoes have a significant amount of vitamin C cooked yellow fleshed potatoes are a good source of zeaxathin, and cooked red and purple fleshed potatoes are a good source of anthocyanins