RESUMO: O metil jasmonato (MeJA) é reconhecido como um hormônio vegetal que induz várias alterações bioquímicas relacionadas à qualidade dos frutos, mas é evidente que o efeito do MeJA durante a pós-colheita é muito variável quanto à concentração, espécies de plantas e até mesmo cultivares. O objetivo deste trabalho foi relacionar a aplicação deste regulador em baixa concentração (10 µmol L-1 por 24 h) às mudanças na fisiologia pós-colheita, na incidência de antracnose e na qualidade do mamão ‘Golden’ durante o armazenamento a 24 ± 1 ° C. A partir do sétimo dia de armazenamento, a incidência de antracnose foi reduzida em mais de 50% com o tratamento com MeJA. Incidência da doença também foi reduzida. Embora o MeJA tenha reduzido a acidez dos frutos, os teores de ácido ascórbico e sólidos solúveis não foram alterados durante o armazenamento com o tratamento hormonal. A cor da casca e a firmeza da polpa apresentaram ligeira retenção. A redução na produção de etileno foi acompanhada pela redução da respiração nos frutos tratados. MeJa aumentou a atividade da CAT apenas na casca, enquanto a atividade da SOD não foi induzida por MeJA na casca e na polpa. Embora o aumento da CAT a partir do terceiro dia de armazenamento possa ter contribuído para a redução da peroxidação lipídica na casca, a redução do MDA na polpa não pode ser explicada apenas pela atividade da CAT. Em resumo, a aplicação de MeJA em mamão ‘Golden’ reduziu a incidência e severidade da antracnose, diminuiu a respiração, a produção de etileno e a peroxidação lipídica. Conclui-se que a aplicação de MeJA em baixa concentração (10 µmol L-1) pode contribuir para o controle da antracnose em mamão ´Golden` e retardar o amadurecimento dos frutos.

ABSTRACT: Methyl jasmonate (MeJA) is recognized as a plant hormone that induces several biochemical changes related to improving fruit quality, but it is evident that the effect of MeJA during postharvest is very variable upon concentration, plant species, and even cultivars. The objective of this research was to relate the application of this regulator at low concentration (10 µmol L-1 for 24 h) to changes in postharvest physiology, on the incidence of anthracnose and quality of ‘Golden’ papaya fruit during storage at 24 ± 1°C. From the seventh day of storage, anthracnose incidence was reduced by more than 50% with MeJA treatment. The lesion area after infection was also reduced. Although, MeJA reduced fruit acidity, the ascorbic acid and soluble solids content were not altered during storage with the hormonal treatment. The skin color and pulp firmness showed slight retention. The reduction in ethylene production was accompanied by a reduction of respiration in treated fruits. MeJa increased CAT activity only in the skin whereas SOD activity was not induced by MeJA in both skin and pulp. Although, the increase of CAT from the third day of storage may have contributed to the reduction of lipid peroxidation in the skin, the MDA reduction in the pulp cannot be explained only by CAT activity. In summary, the application of MeJA in ‘Golden’ papaya reduced the incidence and severity of anthracnose, decreased respiration, ethylene production and lipid peroxidation. It is concluded that the application of MeJA at a low concentration (10 µmol L-1) may contribute to anthracnose control in ´Golden`papaya and slows the ripening of fruits.

ABSTRACT The aim of this study was to test the hypothesis that lemongrass and thyme essential oils (EOs) reduce Botrytis cinerea development and control gray mold in ‘Italia’ grapes. The fungitoxicity evaluation was performed by EOs direct contact with the pathogen, in culture medium, and by exposure to the EOs volatile phase. Individualized rachis berries were inoculated by subcuticular injection of a conidia suspension and after 4 hours sprayed with the EOs of lemongrass and thyme (100 to 1,000 mg·L-1), or oils blend (500 mg·L-1 thyme + 100 mg·L-1 lemongrass), and then stored at 25 °C / 75% relative humidity. To verify the possibility that the EOs protect the fruit against B. cinerea, the berries were sprayed with 400 mg·L-1 of each EOs or with the blend (200 mg·L-1 thyme + 200 mg·L-1 lemongrass), and after 24 hours inoculated with B. cinerea. On clusters, thyme (800 mg·L-1) and the blend (500 mg·L-1 thyme + 100 mg·L-1 lemongrass) were sprayed 4 hours after inoculation and then stored at 25 and 1 °C. The disease incidence and severity were analyzed, as well as the fruit quality attributes. EOs had antimicrobial effect, in-vitro, incorporated into the culture medium or by volatilization against B. cinerea. On detached berries, the thyme and oil blend reduced the gray mold severity when inoculated 4 hours before spraying. In clusters, thyme at 800 mg·L-1 significantly reduced the gray mold development only in fruits kept at 1 °C, without impairing the clusters quality, which could be an alternative for the disease management in postharvest.

RESUMO: Apesar das técnicas de armazenamento refrigerado e atmosfera modificada já terem sido estudadas para carambolas processadas, pouco foi feito considerando a fruta inteira. Além disso, cada cultivar possui peculiaridades, dessa forma a eficiência dos tratamentos pós-colheita combinados deve ser estudada. O objetivo deste trabalho foi avaliar o efeito do cloreto de polivinila (PVC), 8,5 µm de espessura e polietileno de baixa densidade (PEBD), 33 µm de espessura associados ao armazenamento refrigerado (10 ± 1 °C e 5 ± 1 °C / 85 ± 5% de UR) na conservação da carambola Malasia. O armazenamento a 25 °C manteve a qualidade da carambola, independentemente do tipo de filme, até quatro dias. A perda de massa foi maior nos frutos embalados em PVC, mas esta não foi percebida pela análise sensorial. As temperaturas de armazenamento de 5 e 10 °C não causaram dano de frio, mas os frutos apresentaram retenção no desenvolvimento da coloração amarela e na redução da firmeza; esses aspectos foram avaliados positivamente na análise sensorial. O tipo de filme não influenciou a conservação do fruto. O armazenamento a 5 e 10 °C, independente do filme da embalagem, prolongou a vida útil da carambola ‘Malasia’ até 16 dias, seguido por dois dias a 25 °C.

ABSTRACT: Despite the fact that cold storage and modified atmosphere techniques have already been studied for fresh cut Star fruit, little has been done considering the whole fruit. Besides that, each cultivar has its peculiarities, so the efficiency of combined postharvest treatments should be studied. The objective of this study was to evaluate the effect of polyvinyl chloride (PVC), 8.5 µm thick and low-density polyethylene (LDPE), 33 µm thick associated with cold storage (10 ± 1 °C and 5 ± 1 °C / 85 ± 5% RH) on the conservation of ‘Malasia’ Star fruit. Storage at 25 oC maintained Star fruit overall quality, regardless of the film type, up to four days. The weight loss was higher in fruit packed with PVC, but this fact was not noticed by the sensory analysis. The storage in 5 and 10 oC did not caused chilling injury but fruit presented retention of yellow color development and firmness reduction; these aspects were positively assessed by the sensory analysis. The film type did not influence the conservation of the fruit. The storage at 5 and 10 °C, regardless of the package film, prolonged ‘Malasia’ star fruit shelf life up to 16 days, followed by two days at 25 °C.