Efeito de atmosfera modificada no controle de podridões pós-colheita e na qualidade de caqui cv. Fuyu

Abstract

Este trabalho teve por objetivo avaliar o efeito de atmosfera modificada (AM) no controle de podridões pós-colheita e na extensão do período de armazenamento de caqui cv. Fuyu. Realizou-se, primeiramente, a identificação dos agentes causais das principais doenças pós-colheita de caqui, coletados em diferentes regiões produtoras do Estado de São Paulo. Dentre os patógenos identificados, Lasiodiplodia theobromae, Pestalotiopsis sp. e Rhizopus stolonifer apresentaram maior incidência. Posteriormente, avaliou-se o efeito de composições gasosas sobre o crescimento micelial in vitro de L. theobromae, Pestalotiopsis sp., R. stolonifer e Alternaria alternata. Placas com os respectivos patógenos foram expostas a misturas gasosas (3% O2 e 5%, 8%, 10% ou 12% CO2; 5% O2 e 5%, 8%, 10% ou 12% CO2) sob fluxo contínuo de gases, à 25°C. Como testemunha utilizou-se 21% O2/0,03% CO2. Os resultados mostraram que para L. theobromae, houve tendência de estímulo do crescimento micelial para todas as atmosferas. Para Pestalotiopsis sp. e A. alternata, as atmosferas de 3% O2 e 10% ou 12% CO2 exerceram maior efeito de inibição, enquanto que, para R. stolonifer, as atmosferas de 3% O2 e 8%, 10% ou... .

This study was conducted to evaluate the effect of modified atmosphere (MA) on postharvest disease control and shelf life of ‘Fuyu’ persimmons. Firstly, it was carried out the identification of causal organisms related to the main postharvest diseases in persimmon fruits, from different producing areas of the State of São Paulo. Among the pathogens identified, Lasiodiplodia theobromae, Pestalotiopsis sp. and Rhizopus stolonifer had the highest incidence. Secondly, it was evaluated the in vitro effect of gas compositions on the mycelial growth of L. theobromae, Pestalotiopsis sp, R. Stolonifer and Alternaria alternata. These pathogens were exposed to gas mixtures (3% O2 + 5%, 8%, 10% or 12% CO2 and 5% O2 + 5%, 8%, 10% or 12% CO2) under continuous flow at 25°C. Plates with pathogens exposed to 21% O2/0,03% CO2 were used as the control. The results showed that L. theobromae mycelial growth was stimulated by all atmospheres. The atmosphere of 3% O2 + 10% or 12% CO2 had the greatest inhibition effect on Pestalotiopsis sp. and A. alternata. For R. stolonifer the atmospheres of 3% O2 + 8%, 10% or 12% CO2 and 5% O2 + 10% or 12% CO2 significantly inhibited the pathogen growth. In order to check the effect of MA on the fruit quality, persimmons were enclosed in packaging systems: 12-μm PVC (polyvinyl chloride); 80-μm LDPE (low density polyethylene); 80-μm LDPE (3% O2/8% CO2); 63-μm PO (multilayer polyolephynic); 63-μm PO (3% O2/8% CO2); 58-μm PO; 50-μm LDPE; 38- μm microperforated PO; 50-μm LDPE (3% O2/8% CO2); 50-μm LDPE (3% O2/10% CO2). Furthermore, to verify the effect of MA on disease control, persimmons were inoculated with spore suspension of R. stolonifer (5x105 cfu.mL-1) and enclosed in the packaging systems: 50- μm LDPE; 50-μm LDPE (3% O2/8% CO2); 50-μm LDPE (3% O2/10% CO2). Fruits in corrugated cardboard boxes were used as control... (Complete abstract, click electronic address below).