Resumo

Patulin is a toxic secondary metabolite of a number of fungal species belonging to the genera Penicillum and Aspergillus, especially Penicillium expansum contaminating apples and their derivatives. More recently, patulin was reported being produced by Penicillium sclerotigenum rot in yam with green. However, in a study of artificial infection, P. sclerotigenum was able to infect and cause rot in apple, banana and pear. The present study aimed to detect the mycotoxin patulin being produced by P. sclerotigenum in samples of bananas, pears and apples inoculated with this fungus. The surfaces of samples of banana, pear and apple were disinfected with 70% alcohol and then 1cm incisions were made on the surface of each fruit, with two incisions and three replicates for each fruit. Mycelium discs of PE03 and PE14 isolates of P. sclerotigenum grown in YES medium at 25 ° C for 7 days were placed on each incision. Then the fruits were incubated in a cloud chamber for seven days to develop rot. Fragments of the lesion with 2 g of weight were used for the extraction of patulin in chloroform overnight at 0oC. The extracted material was filtered off on filter paper and subjected to qualitative evaporation of the chloroform in the exhaust gas chamber. The samples were resuspended in 50μL of chloroform and 10 μL of aliquot of each sample was subjected to thin layer chromatography qualitative (TLC), using the mobile phase solution of toluene / dioxane / acetic acid (180/45/5 v/v). The chromatogram was visualized in UV light at 312/365 nm. The positive controls were standard patulin (Sigma) 1mg/mL, patulin extracted from isolated PE03 and PE14 of P. sclerotigenum and yam extract infected with fungus. Negative controls were extracts of yam, banana, apple and pear without fungi. All samples of fruit (banana, pear and apple) and yam infected with P. sclerotigenum were positive in TLC, with varied fluorescence intensity of about 365nm and the yellow, indicating that some samples showed more and sometimes less patulin. And for the banana samples all replicates were equally and high fluorescence intensity. All negative control samples behaved as expected. This work is unprecedented and will be complemented by quantification of patulin by HPLC in order to be the first report of mycotoxins in banana, even in artificial fungal infection.