RESUMO

Although blueberries are widely studied, little information exists on their composition and content of flavonol glycosides. Most studies identify only a few flavonols in blueberries due to separation and identification issues. In the present study, we identified 44 flavonols and chlorogenic acid in 30 samples of Highbush and Rabbiteye blueberry, using HPLC-DAD-ESI-MSn. Highbush group fruits presented mainly quercetin-3-galactoside in their composition, while Rabbiteye group fruits exhibited higher levels of quercetin-3-rhamnoside and quercetin-3-glucuronide. Among the identified flavonols, 8 acylates (acetyl and hydroxymethylglutaroyl) were found, of which quercetin-3-O-[4″-(3-hydroxy-3-methylglutaroyl)]-α-rhamnoside was found for the first time in blueberries. This compound is exclusive to the cultivars Florida and Powderblue, where it is present in high quantities. Glucuronides of syringetin and laricitrin, and rhamnosyl-galactosides of myricetin, quercetin and isorhamnetin were also found for the first time in blueberries. The Principal Component Analysis showed that blueberry groups can be distinguished based on their phenolic compound profile.

Assuntos

RESUMO

The fruits and vegetables are recommended for human feeding due to the richness of antioxidant compounds. The bioactive compounds from the diet, such as vitamins C and E are important to reduce the speed of initiation or prevent the spread of free radicals. The objective of the work was to evaluate the ascorbic acid and tocopherol content of selections of Pitanga (Eugenia uniflora L.), butiá (Butiá capitata), blackberry (Rubus spp), blueberry (Vaccium Reade ashei), loquat (Eribrotia japônica), jambolan (Eugenia jambolana), purple araçá (Psidium rufum), physalis (Physalis peruviana), pear (Pyrus communis) and peaches (Prunus persica). The fruits were from 2006/2007/2008 harvest, which were obtained in Pelotas (RS) region. The tocopherol analyses were performed according Rodrigues-Amaya (1999), and ascorbic acid according Vinci, Botre e Ruggieri (1995). The tocopherol and ascorbic acid identification and quantification was performed by high-efficiency liquid chromatography system (HPLC), using a fluorescent detector for tocopherol (excitation of 290 nm and emission of 330 nm) and a UV-Visible (254 nm) for ascorbic acid. The blackberry cv. Tupy showed the highest tocopherols content (8,251 ?g.g-1 fruit) when compared with the other fruit content. The tocopherol was not found in pears and peaches of cv. Sensação and cv. Granada. The ascorbic acid content ranged from 9,291 mg.g-1 fr

As frutas e as hortaliças são recomendadas na alimentação humana pela riqueza em compostos nutritivos e também pela presença de compostos que apresentam efeito antioxidante. Os compostos bioativos adquiridos através da dieta, como a vitamina C e a vitamina E, além do aspecto nutritivo, são importantes para reduzir a velocidade de iniciação ou prevenir a propagação de radicais livres. O objetivo deste estudo foi avaliar os teores de ácido ascórbico e de tocoferóis, de seleções de pitanga (Eugenia uniflora L.), butiá (Butiá capitata), amora-preta (Rubus spp), mirtilo (Vaccium ashei Reade), nêspera (Eribrotia japônica), jambolão (Eugenia jambolana), araçá roxo (Psidium rufum), physalis (Physalis peruviana), pêra (Pyrus communis) e pêssegos (Prunus persica). As frutas utilizadas foram das safras 2006/2007/2008, obtidas na região de Pelotas/RS. A análise dos tocoferóis foi realizada segundo Rodrigues-Amaya (1999), e do ácido ascórbico segundo Vinci, Botre e Ruggieri (1995). A identificação e quantificação dos tocoferóis e do ácido ascórbico foi realizada em um sistema de cromatografia liquída de alta eficiência (CLAE), utilizando detector de fluorescência para os tocoferóis (excitação em 290 nm e emissão em 330 nm) e detector de UV-Visível para o ácido ascórbico (254 nm). A amora-preta cv. Tupy apresentou maior teor de tocoferóis (8,251 µg.g-1 de fruta) quando comparado ao conteúdo