ABSTRACT
The antimicrobial action of chitosan against several phytopathogens in agriculture has been tested, including Penicillium digitatum, which is the major pathogen that causes postharvest decay of oranges. However, the biopolymer action has not been tested against other fungi that are capable of developing molds in orange fruit. This study have demonstrated that chitosan is able to inhibit the growth in vitro and in vivo of two Penicillium species, which were isolated from decay oranges fruit and identified as Penicillium citrinum and Penicillium mallochii, using molecular methods. This is the first report of P. mallochii acting as an orange phytopathogen. The commercial chitosan with higher molecular weight demonstrated a reduction in the disease incidence of 50-70 % for the inoculum P. citrinum and of 40 % for the inoculum P. mallochii for the in vivo experiments. The data obtained opens interesting alternative options to synthetic fungicide to prevent orange decay caused by the potential phytopathogenic species of Penicillium here identified.
Subject(s)
Chitosan/pharmacology , Citrus sinensis/drug effects , Fruit/drug effects , Fungicides, Industrial/pharmacology , Penicillium/drug effects , Citrus sinensis/microbiology , Fruit/microbiology , Microbial Sensitivity TestsABSTRACT
Tendo em vista que a escassez e a perda/desperdício de alimentos é uma realidade crescente devido as falhas em toda a logística de produção e pós colheita, a nanotecnologia em embalagens apresenta-se, nos últimos anos, como uma alternativa para solucionar alguns desses problemas. Portanto, este trabalho visa analisar as propriedades dos filmes de Goma Tara com Nanopartículas de Prata (AgNP) para futura aplicação em frutos. Os filmes produzidos neste trabalho, em especial aqueles com maior concentração de AgNP, apresentaram uma espessura ideal (entre 0,0457 e 0,0570mm), maiores valores de gramatura (52,53 g.m-2), alta solubilidade (cerca de 98%), menores teores de umidade (36,35%) e maior retenção de transferência de vapor dágua, cerca de 800 g.μm.m-2.dia-1.mmHg-1, comprovando sua eficiência como embalagem para conservação de alimentos.
Subject(s)
Food Preservation/methods , Food Packaging , Plant Gums , Nanoparticles , Silver , FruitABSTRACT
In this work, changes in the hyphal morphology due to chitosan treatment in some fungal species were studied. Scanning electron microscope (SEM) observations revealed that chitosans with molar fraction of acetyl groups (F A 0.16 and 0.18) and degree of polymerization (DP 1,089 and 1,242) had a direct effect on the morphology of the chitosan-treated fungi, reflecting its potential for causing a delay in the growth of Alternaria alternata (500 µg × mL-1), Botrytis cinerea (1,000 µg × mL-1), Penicillium expansum (1,000 µg × mL-1) and Rhizopus stolonifer (500 µg × mL-1). Mycelial aggregation and structural changes such as excessive branching, swelling of the cell wall and hyphae size reduction were observed in the micrographs.
