Browsing by Author "Gomez, Maritza"
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- ItemCu(I)-glutathione complex: A potential source of superoxide radicals generation(2008) Speisky, Hernán; Gomez, Maritza; Carrasco-Pozo, Catalina; Pastene, Edgar; López Alarcón, Camilo Ignacio; Olea-Azar, Claudio
- ItemFirst Web-Based Database on Total Phenolics and Oxygen Radical Absorbance Capacity (ORAC) of Fruits Produced and Consumed within the South Andes Region of South America(2012) Speisky, Hernán; López Alarcón, Camilo Ignacio; Gomez, Maritza; Fuentes, Jocelyn; Sandoval-Acuna, Cristian
- ItemGeneration of superoxide radicals by copper-glutathione complexes: Redox-consequences associated with their interaction with reduced glutathione(2009) Speisky, Hernán; Gomez, Maritza; Burgos-Bravo, Francesca; López Alarcón, Camilo Ignacio; Jullian, Carolina; Olea-Azar, Claudio; Aliaga Miranda, Margarita Elly
- ItemTime-dependence of Ferric Reducing Antioxidant Power (FRAP) index in Chilean apples and berries(ARCHIVOS LATINOAMERICANOS NUTRICION, 2011) Henriquez, Carolina; Lopez Alarcon, Camilo; Gomez, Maritza; Lutz, Mariane; Speisky, HernanWe hypothesize that the Ferric Reducing Antioxidant Power (FRAP) assay that follows the reaction of Fe3+-TPTZ at 593 nm underestimates the antioxidant capacity of fruits, since the standardized time of the reaction (4 min) is not enough to titrate all the reducing compounds available. We measured FRAP, total phenolics and anthocyanins content in a variety of Chilean berry fruits (blueberries, blackberries, raspberries and strawberries) and apples (cv. Fuji, Granny Smith, Pink Lady, Red Delicious and Royal Gala). Taking into account the dependence of FRAP on the time course of the reaction, we propose to measure FRAP indexes after 1 min (FRAP-1), 30 min (FRAP-30) and 120 min (FRAP-120) of incubation. Most fruit extracts showed significant correlations between the antioxidant capacity and the incubation time, although in some cases the FRAP indexes did not correlate with the total phenolics and/or anthocyanins content. In fact, in apples and berries the correlation between anthocyanins content and FRAP indexes decreased with the incubation time. It is concluded that the fruit extracts analyzed require an incubation period higher than the established in the original experimental protocol to reach the equilibrium, due to the presence of a complex mixture of antioxidant compounds. In addition, a kinetic profile should be realized in each sample studied to establish the most suitable incubation period to titrate all the reactive antioxidant species.