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Efeito do estádio de maturação dos frutos nas características físico-químicas de acerola(1)Rejane Jurema Mansur Custódio Nogueira (2) , José Antônio Proença Vieira de Moraes, Hélio Almeida Burity (4) e Josué Francisco da Silva JuniorResumo Este trabalho teve por objetivo avaliar características físico-químicas dos frutos de acerola, em três estádios de maturação. Foram usadas acerolas oriundas de duas matrizes (UFRPE 7 e UFRPE 8), durante as estações seca e chuvosa, num pomar comercial. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 2 x 3 (plantas matrizes x estádios de maturação dos frutos), e três repetições. Foram avaliados os teores de vitamina C e sólidos solúveis totais (SST), além do pH, do peso e tamanho dos frutos. As aceroleiras UFRPE 7 e UFRPE 8 produziram frutos com teores de vitamina C adequados tanto para o mercado interno como para o externo. Os frutos verdes apresentaram teores de vitamina C significativamente maiores que os maduros e semimaduros, podendo ser utilizados pela indústria farmacêutica. Houve influência sazonal nos teores de vitamina C nas características físicas (peso e diâmetros dos frutos) e físico-químicas (SST) das matrizes estudadas. O conteúdo de vitamina C foi mais elevado durante a estação seca, e decresceu com a maturação do fruto. A UFRPE 7 produziu frutos de melhor qualidade, apresentando também maior estabilidade nas características avaliadas do que a UFRPE 8.Termos para indexação: Malpighia emarginata, fruto, qualidade, ácido ascórbico. Physicochemical characteristics of Barbados cherry influenced by fruit maturation stageAbstract This work aimed at evaluating changes in physical and chemical characteristics of Barbados cherry fruits in three maturation stages. Fruits from two genetic sources (UFRPE 7 and UFRPE 8) were used during the dry and wet seasons in a commercial orchard. The experimental design was a completely randomized block with factorial scheme 2 x 3 (source plants x fruit maturation stages) and three replicates. Levels of vitamin C and of total soluble solids (TSS) besides pH and fruit weight and diameters were evaluated. Genotypes UFRPE 7 and UFRPE 8 produced fruits containing levels of vitamin C appropriated to the internal and external markets. Immature fruits showed levels of vitamin C significantly higher than mature and semi-mature ones. Those fruits could be used in the pharmaceutic industry. Seasonal influence on levels of vitamin C, physical (fruit weight and diameter) and physicochemical (TSS) characteristics were found. Higher levels of vitamin C were observed during the dry season. These contents decreased during the fruit ripening. UFRPE 7 produced the best quality fruits and presented higher stability in most of the characteristics evaluated.

Young sexually and assexually propagated Barbados cherry plants were submitted to water deficit (20 days without irrigation). During this period the accumulation of proline, water potential of branches, osmotic potential, the relative water content of leaves, the leaf diffusive resistance, the transpiration rate and leaf temperature in the cuvette were determined. In addition, photosynthetically active radiation (PAR) and vapor pressure deficit (VPD) were measured in the porometer cuvette. The concentration of proline for both types of plants began to increase on the fifth day without watering, and reached 38.1 times the concentration in the control plants grown from seeds and 26.4 times the concentration in grafted plants on the tenth day without watering. The lowest levels of leaf water potential in the plants suffering from severe water stress varied from -4.5 to -5.7 MPa, the lowest values being observed in the sexually propagated plants. These plants also showed the highest values for transpiration (0.9 mmol.m-2.s-1) and proline concentration (20.42 mg.g-1 DM), the lowest for relative water content of the leaves (38.4%) and diffusive resistance (940 s.m-1) at the end of the experiment. The Barbados cherry plants developed strategies for surviving drought, with differences between various characteristics, resulting from prolonged stress, which significantly influenced the parameters evaluated, with the exception of leaf temperature.

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