title: Modification of the health-promoting value of potato tubers field grown under drought stress: emphasis on dietary antioxidant and glycoalkaloid contents in five native andean cultivars (Solanum tuberosum L.).
abstract: The effects of drought stress on dietary antioxidant and glycoalkaloid contents in potato tubers were investigated using a selection of five native Andean cultivars. Both freshly harvested and 4 month-stored tubers were analyzed. Responses to drought stress were highly cultivar-specific. The antioxidant contents of the yellow tuber-bearing cultivars (Sipancachi and SS-2613) were weakly affected by the drought treatment, whereas the pigmented cultivars demonstrated highly cultivar-dependent variations. A drastic reduction of anthocyanins and other polyphenols was revealed in the red- (Sullu) and purple-fleshed (Guincho Negra) cultivars, whereas an increase was shown in the purple-skinned and yellow-fleshed cultivar (Huata Colorada). The hydrophilic antioxidant capacity (evaluated by Folin-Ciocalteu and H-oxygen radical absorbance capacity assays) was highly correlated with the polyphenol content and followed, therefore, the same behavior upon drought. Carotenoid contents, including beta-carotene, as well as vitamin E, tended to increase or remain stable following drought exposure, except for the cultivar Sullu, in which the level of these lipophilic antioxidants was decreased. Vitamin C contents were not affected by drought with the exception of Guincho Negra, in which the level was increased. These variations of health-promoting compounds were associated with increased or stable levels of the toxic glycoalkaloids, alpha-solanine and alpha-chaconine. Storage at 10 degrees C for 4 months tended to decrease the concentrations of all dietary antioxidants, except those of vitamin E. This storage also reduced the drought-induced variations observed in freshly harvested tubers. These results were discussed in terms of their implications for human diet and health as well as in plant stress defense mechanisms.
authors.affiliation: Institut des Sciences de la Vie, Universite Catholique de Louvain, Louvain-La-Neuve, Belgium.
authors.forename: Christelle M
authors.initials: CM
authors.lastname: Andre
authors.forename: Roland
authors.initials: R
authors.lastname: Schafleitner
authors.forename: Cédric
authors.initials: C
authors.lastname: Guignard
authors.forename: Mouhssin
authors.initials: M
authors.lastname: Oufir
authors.forename: Carlos Alberto Alvarado
authors.initials: CA
authors.lastname: Aliaga
authors.forename: Giannina
authors.initials: G
authors.lastname: Nomberto
authors.forename: Lucien
authors.initials: L
authors.lastname: Hoffmann
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Hausman
authors.forename: Danièle
authors.initials: D
authors.lastname: Evers
authors.forename: Yvan
authors.initials: Y
authors.lastname: Larondelle
mesh_terms: D000470:Alkaloids / Q000032:analysis*; D000975:Antioxidants / Q000032:analysis*; D001205:Ascorbic Acid / Q000032:analysis; D002338:Carotenoids / Q000032:analysis; D055864:Droughts; D005419:Flavonoids / Q000032:analysis; D009753:Nutritive Value; D010636:Phenols / Q000032:analysis; D035281:Plant Tubers / Q000737:chemistry* / Q000254:growth & development*; D059808:Polyphenols; D011198:Solanum tuberosum / Q000737:chemistry* / Q000254:growth & development*
chemical_list: D000470:Alkaloids; D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D002338:Carotenoids; D001205:Ascorbic Acid