Submitted to: Idaho Winter Commodity School Proceedings
Publication Type: Proceedings
Publication Acceptance Date: May 15, 2006
Publication Date: December 15, 2006
Citation: Brown, C.R. 2006. Anthocyanin and Carotenoid Contents in Potato: Breeding for the Specialty Market. Proceedings of the Idaho Winter Commodity Schools 39: 157-163. Interpretive Summary: Potato is perceived by the US consumer as a cheap source of carbohydrates. However, investigations into the contents of potato reveal that it is a good source of phenolic compounds and carotenoids. Among the phenolics that are of interest are the anthocyanins. Anthocyanins are the red and blue pigments that are found all over the plant kingdom. Most flowers have bright colors conferred by anthocyanins. Anthocyanins are water soluble. Among the properties that are considered very special are the roles of anthocyanins in preventing cancer, heart disease, and age related macular degeneration. Studies have shown that populations eating diets high in phenolics including anthocyanins have lower levels of all three of these conditions. The deterioration of cognitive mental abilites also seems to be slowed down by a diet high in anthocyanins. Anthocyanins help the brain stay young. Potatoes also have the very same carotenoids that are present in the human retina, lutein and zeaxanthin. Humans cannot synthesize these compounds and must obtain them from their diets. Carotenoids are particularly important in the protection of living tissues from the high-energy blue light wavelengths. This photo-protectant occurs in plants and animals. High levels of these carotenoids in the human retina reduce the severity of macular degeneration and cataracts. The breeding of potatoes high in these two classes of pigment provides a high vector for these nutrients in the human diet and opens new market niches for potatoes.
Technical Abstract: A breeding effort designed to increase the antioxidant level of potato by means of high concentrations of anthocyanins and/or carotenoids provided selected materials for analysis. Extraction methods suitable for isolating both hydrophilic and lipophilic compounds were used and measurements of total anthocyanin and total carotenoid were made. Total anthocyanin values varied between 9.5 and 38 mg per 100 g fresh weight (FW). The hydrophilic fraction ORAC measurements among anthocyanin rich clones varied between 250 and 1420 umoles Trolox equivalents per 100 g FW. These two variables were significantly correlated, r = 0.73, and with significant positive slope in linear regression. Measurement of total carotenoids revealed differing degrees of yellowness covered a range of total carotenoid extending from 35 to 795 'g per 100 g FW. Dark yellow cultivars had roughly ten times more total carotenoid than white flesh cultivars. The lipophilic fraction ORAC values ranged from 4.6 to 15.3 nmoles '-tocopherol equivalents per 100 g FW. Total carotenoid was correlated with the lipophilic ORAC values, r = 0.77, and also had a statistically significant positive regression coefficient. Clones with red and yellow pigments visible in the flesh had anthocyanins and carotenoids in elevated levels and ORAC contributions from both fractions. The introgression of high levels of carotenoid from germplasm directly extracted from the Papa Amarilla (Yellow Potato) category of cultivars of South America into long-day adapted North American materials is presented here.