The antioxidant capacities of 11 commercial and non-commercial samples of Euterpe oleracea Mart. (açaí) fruit pulp were studied with the total oxidant scavenging capacity assay in a modified and automated version against three reactive oxygen species. The antioxidant capacities of all purple açaí samples were found to be excellent against peroxyl radicals, good against peroxynitrite and poor against hydroxyl radicals compared with common European fruit and vegetable juices recently analysed. In all cases the correlation between sample concentration and antioxidant capacities was non-linear. The antioxidant capacities against all three reactive oxygen species of the fruit pulp from one white açaí variety were very low. The phenolic compounds in purple açaí fruit pulp were identified by high-performance liquid chromatography-mass spectrometry, and the two major anthocyanins, cyanidin-3-glucoside and cyanidin-3-rutinoside, were quantified by high-performance liquid chromatography-visible spectrometry. The contributions of the anthocyanins to the overall antioxidant capacities of the fruit were estimated to be only approximately 10%. Obviously, compounds not yet identified are responsible for the major part of the antioxidant capacities of the açaí fruit pulp.
The antioxidant capacity of methanol and ethanol seed extracts from Euterpe oleracea Mart. (açaí) against the reactive oxygen species (ROS) peroxyl radicals, peroxynitrite, and hydroxyl radicals was studied with the total oxidant scavenging capacity (TOSC) assay in a modified and automated version. Cold methanol digestion was the most efficient extraction method with respect to the antioxidant capacity. The extracts exhibit good antioxidant capacity against peroxyl radicals, similar to the capacity of the pulp. The antioxidant capacity against peroxynitrite and hydroxyl radicals is even higher. The main antioxidants identified by HPLC-MS and HPLC-CEAD are five different procyanidins (di- through pentamers); furthermore, protocatechuic acid and epicatechin were identified as minor compounds. Determination of TOSC values of HPLC seed extract fractions indicates that the procyanidins contribute substantially to the overall antioxidant capacity. In addition, however, other compounds that have not yet been identified are responsible for a large part of the observed antioxidant capacity.
An Amazonian fruit with a high potential as a natural source of vitamin C: the camu-camu (Myrciaria dubia).Abstract -The plant. The camu-camu [Myrciaria dubia (H.B.K.) Mc. Vaugh] is a shrub from the Myrtaceae family. It grows naturally in floodable and swampy areas of the Amazonian basin. This plant is cultivated in Peru and Brazil with fruit yields ranging from (12 to 20) t × ha -1 × year -1 . The fruit. The fruit, from (1 to 3) cm in diameter, is pink to dark purple; it is the highest known source of natural vitamin C, providing (850 to 5,000) mg × 100 g -1 edible portion. The market. In the last few years, both national and international demand for the camu-camu fruit has drastically increased for the production of health food or of natural vitamin C. The current fruit production is not sufficient to satisfy the market. Conclusion. M. dubia stands out amongst other Amazonian fruit species as having a high economic and social potential. Little information is available on its processing, showing the need for research in this area. Amazonia / Brazil / Peru / Myrciaria dubia / taxonomy / botany / geographical distribution / cultivation / chemical composition / ascorbic acid / markets / processingUn fruit amazonien à fort potentiel en tant que source naturelle de vitamine C : le camu-camu (Myrciaria dubia). Résumé-La plante. Le camu-camu [Myrciaria dubia (H.B.K.) Mc. Vaugh] appartient à la famille des myrtacées. Cet arbuste pousse naturellement dans les zones inondables et marécageuses du bassin amazonien. Il est actuellement cultivé au Pérou et au Brésil avec des rendements compris entre (12 et 20) t × ha -1 × an -1 . Le fruit.Le fruit du camu-camu est une baie de couleur rose à violet et de 1 à 3 cm de diamètre ; il présente des teneurs en vitamine C extrêmement élevées, comprises entre (850 et 5 000) mg × 100 g -1 de partie comestible. Le marché. La demande internationale pour le camu-camu a considérablement augmenté au cours de ces dernières années. Le fruit est essentiellement utilisé comme source naturelle de vitamine C et pour la formulation d'aliments diététiques. Néanmoins, la production ne parvient pas à faire face à la demande. Conclusion. Parmi les fruits secondaires amazoniens, le camu-camu présente un potentiel socio-économique considérable. L'étude de voies de transformation du fruit respectueuses de sa qualité nutritionnelle est aujourd'hui nécessaire. Amazonie / Brésil / Pérou / Myrciaria dubia / taxonomie / botanique / distribution geographique / pratique culturale / composition chimique /acide ascorbique / marché / traitementThe camu-camu (Myrciaria dubia) 345
Polymers with high molecular weight and worm-like micelles are drag-reducing agents under turbulent flow. However, in contrast to the polymeric systems, the worm-like micelles do not undergo mechanical degradation due to the turbulence, because their macromolecular structure can be spontaneously restored. This very favorable property, together with their drag-reduction capability, offer the possibility to use such worm-like micelles in heating and cooling systems to recirculate water while expending less energy. The formation, growth, and stability of worm-like micelles formed by cetyltrimethylammonium bromide (CTAB) and sodium salicylate (NaSal) were investigated using the self-fluorescence of salicylate ions and the ability of the giant micelles to promote hydrodynamic drag reduction under turbulent flow. The turbulence in solutions of CTAB-Sal was produced within the double-gap cell of a rotational rheometer. Detailed diagrams were obtained for different ratios of Sal and CTAB, which revealed transitions associated with the thermal stability of giant micelles under turbulent flow.
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