Isolation And Selection Of Heat Resistant Molds In The Production Process Of Apple Nectar [isolamento E Seleção De Fungos Filamentosos Termorresistentes Em Etapas Do Processo Produtivo De Néctar De Maçã]

摘要

Heat resistant molds are able to survive the pasteurization process applied to apple products. This study aimed at detecting and identifying heat resistant molds during the processing of apple nectar (pH 3.4; 11.6 °Brix) in order to select the most heat resistant mold. The isolation was carried out after heat shock at 70°C, during 2 hours, and incubation at 30°C, in PDA (3% agar), where rose bengal was added. The identification of macro and microscopic structures was carried out after incubation in three different media (G25N, CYA, MEA) and temperatures. Different heat shocks, from 80°C/20 minutes to 97°C/15 minutes, were applied to select the most heat resistant mold. Eleven strains were selected, of which five were heat-resistant: three strains were isolated from apple and concentrated apple juice and were identified as Neosartorya fischeri; one strain, isolated from apple, was identified as Byssochlamys fulva and one strain, isolated from the product after the first pasteurization, was identified as Eupenicillium sp. The most heat-resistant strains belong to N. fischeri and B. fulva, which were able to survive at 95°C/20 minutes. Among the six remaining, one was identified as Aspergillus sp., however, none of them was heat resistant.