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The aim of this work was to estimate the intestinal bioaccessibility of polyphenols and antioxidant capacity of cactus pear using an in vitro gastrointestinal model. The amount of polyphenols released from the food matrix by the action of digestive enzymes was about 69-83% in pulp and 0-14% in seeds. The rest of polyphenols was associated with indigestible compounds conferring antioxidant capacity. The results suggest that these compounds could reach the colon and induce healthy effects. [ABSTRACT FROM AUTHOR]

The contents of vitamin C (ascorbic and dehydroascorbic acids) and other organic acids such as citric, oxalic, fumaric, malic and glutamic, were determined by HPLC in 54 samples of tomato, white onion, cucumber, pepper, garlic, and 'gazpacho' elaborated using the previous vegetables. Tomato and garlic had the highest amounts of organic acids, while cucumber presented the lowest content. Citric and glutamic acids presented the highest mean concentrations. The bulb vegetables presented higher concentrations of glutamic and citric acids than the fruit vegetables. Pepper was the vegetable with the highest content of vitamin C, followed by tomato and 'gazpacho'. Mean value of ascorbic acid/dehydroascorbic acid ratio varied between 0.29 and 2.53 for cucumber and tomato, respectively. 'Gazpacho' samples had a lower ascorbic acid/dehydroascorbic acid ratio than the vegetables used in its elaboration, which suggests that some amount of ascorbic acid may be enzymatically oxidized to dehydroascorbic during the elaboration. Se determinaron los contenidos de vitamina C (acidos ascorbico y deshidroascorbico) y otros acidos organicos como citrico, oxalico, fumarico, malico y glutamico, por HPLC, en 54 muestras de tomate, cebolla blanca, pepino, pimiento, ajo y 'gazpacho' elaborado a partir de estos vegetales. Tomate y ajo fueron los que presentaron mayores contenidos de acidos organicos, mientras que en pepino se encontro el menor contenido. Los acidos organicos mayoritarios fueron citrico y glutamico. Los bulbos presentaron las mayores concentraciones de acidos glutamico y acido citrico de los frutos. El pimiento fue el vegetal que presento los mayores contenidos de vitamina C, seguido de tomate y 'Gazpacho'. La relacion entre acido ascorbico/acido dehidroascorbico oscilo entre 0,29 y 2,53 para pepino y tomate, respectivamente. Las muestras de 'gazpacho' mostraron una relacion acido ascorbico/acido dehidroascorbico inferior al de los vegetales usados en su elaboracion, lo que sugiere que una cierta cantidad de acido ascorbico se oxida enzimaticamente a dehidroascorbico durante su elaboracion. [ABSTRACT FROM AUTHOR]