Pressões hiperbáricas no controle de mofo cinzento e de mancha de Alternaria na pós-colheita de tomate Débora
Carregando...
Data
2018-05-04
Autores
Palaretti, Vanessa Voigt
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
As doenças fúngicas são as principais causas de perdas na pós-colheita do tomate, e são controladas por manejo cultural e fungicidas aplicados na pré-colheita. O tratamento hiperbárico na pós-colheita é um métodos físico, com potencial uso comercial na redução da deteriorização por fungos. Neste trabalho, a eficiência das pressões hiperbáricas para controlar o desenvolvimento das podridões de Botrytis cinerea e Alternaria sp. in vitro e em tomates ‘Débora’ foram avaliadas, bem como a atividade das enzimas antioxidantes e as relacionadas a defesa do vegetal. Os experimentos foram realizados em um sistema de pressão hiperbárica do Laboratório de Tecnologia Pós-colheita da FCAV-UNESP, Câmpus de Jaboticabal, utilizando as pressões de 100 (controle), 200, 400, 600 e 800 kPa à temperatura de 23±1°C, durante 3 e 6 dias. No ensaio in vitro as placas com os fungos permaneceram nas pressões e depois foram incubadas até que a colônia do controle atingisse a borda. No experimento in vivo, tomates inoculados com os fungos foram mantidos por 3 e 6 dias sob o tratamento nas pressões, com posterior armazenamento por mais 2 e 4 dias em condição de ambiente (23 °C, 50% UR, 100 kPa) para simular a comercialização. Avaliou-se o crescimento micelial, a taxa de germinação dos conídios dos fungos, incidência e severidade das podridões nos frutos, o metabolismo antioxidante (teor de licopeno e polifenóis totais) e a atividade das enzimas relacionadas à defesa dos tomates (peroxidase (POD), fenilalanina-amônia-liase (PAL), β 1,3 glucanase (GLU), superóxido dismutase (SOD) e catalase (CAT). As pressões hiperbáricas não apresentaram efeito fungistático sobre os patógenos, entretanto, houve redução no crescimento micelial e na taxa de germinação de B. cinerea após 3 dias na pressão de 800 kPa. As pressões elevadas de 600 e 800 kPa durante 3 dias reduziram a incidência (25%) e a severidade do mofo cinzento (68%), após 4 dias de armazenamento (3+4 dias). Enquanto a incidência e severidade da mancha de Alternaria (Alternaria sp.) não tiveram redução expressiva em ambos os períodos. Na pressão de 800 kPa, os frutos inoculados com B. cinerea e Alternaria sp. apresentaram um retardo no amadurecimento, evidenciado pelo menor conteúdo de licopeno e menor atividade da enzima POD, a qual está relacionada à senescência dos frutos. As pressões elevadas (600 e 800 kPa) promoveram a atividade das enzimas PAL, GLU e CAT dos tomates inoculados de ambos os patógenos por 3 dias, mantendo tendência similar após as condições de ambiente. Os frutos tratados com as pressões elevadas apresentaram incremento no conteúdo de polifenóis totais em relação ao controle, durante os períodos de armazenamento. As pressões não influenciaram a atividade da enzima SOD dos tomates, após os períodos de tratamentos. As pressões hiperbáricas de 600 e 800 kPa foram eficientes na redução de doenças na pós-colheita de tomates e também podem ter induzido a atividade de enzimas envolvidas na resistência às doenças.
Fungal rots are one of the major causes of postharvest losses in tomatoes, and they are controlled by cultural management and fungicidal applied in preharvest. The postharvest hyperbaric treatment is a physical method that it have potential to be used in commercial for reducing fungal decay. In this work, the efficiency of hyperbaric pressures to control rot development of Botrytis cinerea and Alternaria sp. in vitro and ‘Debora’ tomatoes were evaluated, also the activity of antioxidant and defense-related enzymes.The experiments were carried out in a hyperbaric pressure system at FCAV-UNESP Postharvest Technology Laboratory, Campus de Jaboticabal, using the pressures of 100 (control), 200, 400, 600 and 800 kPa at a temperature of 23 ± 1 ° C for 3 and 6 days. In vitro assay the Petri dishes with the fungi were kept at pressures after they were incubated until the control colony reached the edge. In vivo assay, tomatoes inoculated with the fungus were kept at 3 and 6 days under the treatment pressures, after they were stored for more 2 and 4 days at ambient conditions (23 °C, 50% RH, 100 kPa) to simulate the commercialization. It was evaluated the mycelial growth, germination rate of fungal conidia, incidence and severity of fruit rot, antioxidant metabolism (lycopene content and total polyphenols) and activity of defence-related enzymes (eroxidase (POD), phenylalanine ammonia-lyase (PAL), β 1,3 glucanase (GLU), superoxide dismutase (SOD) and catalase (CAT)). The hyperbaric pressures had no fungistatic effect on the pathogens, however, there was a reduction in mycelial growth and in the germination rate of B. cinerea after 3 days at 800 kPa. High pressures of 600 and 800 kPa for 3 days reduced the incidence (25%) and gray mold severity (68%) after 4 days of the storage (3 + 4 days). While the incidence and severity of black rot (Alternaria sp.) didn´t decrease significantly in both periods. At the pressure of 800 kPa, the fruits inoculated with B. cinerea and Alternaria sp. demonstrated a delay in ripening, as evidenced by the lower lycopene content and lower activity of the POD enzyme, which is related to fruit senescence. The high pressures (600 and 800 kPa) promoted the activity of the PAL, GLU and CAT enzymes of the tomatoes inoculated from both pathogens for 3 days, maintaining a similar trend after the ambient conditions. The fruits treated with high pressures demonstrated an increase in the total polyphenols content in relation to the control during storage periods. The pressures didn´t influence the activity of the SOD enzyme of the tomatoes, after the periods of treatments. Hyperbaric pressures of 600 and 800 kPa were efficient in reducing diseases in postharvest tomatoes and they must have induced the activity of enzymes involved in resistance to diseases.
Fungal rots are one of the major causes of postharvest losses in tomatoes, and they are controlled by cultural management and fungicidal applied in preharvest. The postharvest hyperbaric treatment is a physical method that it have potential to be used in commercial for reducing fungal decay. In this work, the efficiency of hyperbaric pressures to control rot development of Botrytis cinerea and Alternaria sp. in vitro and ‘Debora’ tomatoes were evaluated, also the activity of antioxidant and defense-related enzymes.The experiments were carried out in a hyperbaric pressure system at FCAV-UNESP Postharvest Technology Laboratory, Campus de Jaboticabal, using the pressures of 100 (control), 200, 400, 600 and 800 kPa at a temperature of 23 ± 1 ° C for 3 and 6 days. In vitro assay the Petri dishes with the fungi were kept at pressures after they were incubated until the control colony reached the edge. In vivo assay, tomatoes inoculated with the fungus were kept at 3 and 6 days under the treatment pressures, after they were stored for more 2 and 4 days at ambient conditions (23 °C, 50% RH, 100 kPa) to simulate the commercialization. It was evaluated the mycelial growth, germination rate of fungal conidia, incidence and severity of fruit rot, antioxidant metabolism (lycopene content and total polyphenols) and activity of defence-related enzymes (eroxidase (POD), phenylalanine ammonia-lyase (PAL), β 1,3 glucanase (GLU), superoxide dismutase (SOD) and catalase (CAT)). The hyperbaric pressures had no fungistatic effect on the pathogens, however, there was a reduction in mycelial growth and in the germination rate of B. cinerea after 3 days at 800 kPa. High pressures of 600 and 800 kPa for 3 days reduced the incidence (25%) and gray mold severity (68%) after 4 days of the storage (3 + 4 days). While the incidence and severity of black rot (Alternaria sp.) didn´t decrease significantly in both periods. At the pressure of 800 kPa, the fruits inoculated with B. cinerea and Alternaria sp. demonstrated a delay in ripening, as evidenced by the lower lycopene content and lower activity of the POD enzyme, which is related to fruit senescence. The high pressures (600 and 800 kPa) promoted the activity of the PAL, GLU and CAT enzymes of the tomatoes inoculated from both pathogens for 3 days, maintaining a similar trend after the ambient conditions. The fruits treated with high pressures demonstrated an increase in the total polyphenols content in relation to the control during storage periods. The pressures didn´t influence the activity of the SOD enzyme of the tomatoes, after the periods of treatments. Hyperbaric pressures of 600 and 800 kPa were efficient in reducing diseases in postharvest tomatoes and they must have induced the activity of enzymes involved in resistance to diseases.
Descrição
Palavras-chave
atmosfera hiperbárica, Botrytis cinerea, enzimas antioxidantes, proteínas PR, Solanum lycopersicum L.