Ozonização: uma estratégia para remoção de resíduos de agrotóxicos em alimentos

• Ano de defesa: 2013
• Autor(a) principal: Heleno, Fernanda Fernandes
• Orientador(a): Queiroz, Maria Eliana Lopes Ribeiro de
• Banca de defesa: Afonso, Robson José Cássia Franco , Queiroz, José Humberto de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Agroquímica
• Departamento: Agroquímica analítica; Agroquímica inorgânica e Físico-química; Agroquímica orgânica
• País: BR
• Palavras-chave em Português: Resíduos de agrotóxicos; Ozônio; Qualidade dos frutos
• Palavras-chave em Inglês: Pesticide residues; Ozone; Fruit quality
• Área do conhecimento CNPq: CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ANALITICA
• Link de acesso: http://locus.ufv.br/handle/123456789/225

The indiscriminate use of pesticides and non-observance of shortage periods causes some active ingredients to be detected at concentrations above the maximum residue limits (MRLs) in various foods. In this context, there is a need of studying the pesticide residues dissipation in food because of the commercial product application, as well as developing strategies for pesticide residues removal, or reduction that remain in food after the harvest. The treatments using ozone have been studied as an alternative for food decontamination in recent years, for presenting a number of advantages, as for example, the ozone high oxidation potential even at low concentrations. The present work consists of three parts. In the first part the solid-liquid extraction with low temperature partition (SLE/LTP) was optimized and validated for the determination of difenoconazole in strawberry samples by gas chromatography with an electron capture detector (GC/ECD). The method showed recovery values ! 98%, repeatability with variation coefficients " 15% and a detection limit of 9.0 &#956;g kg- 1. The method was applied to determine the difenoconazole residues dissipation in strawberry after repeated applications of the commercial product. The results have shown that there is rapid fungicide dissipation; however the residual concentration increases after multiple applications. In the second part of this work, the ozone application effect on the difenoconazole residues reduction in strawberry, and the quality of ozonated strawberries were evaluated. Strawberries infected with the commercial product containing difenoconazole were exposed to ozone gas at concentrations of 0.3, 0.6 and 0.8 mg L-1 for 1 h. The treatments with ozone reduced until 95% of difenoconazole residues in strawberries. Some characteristics of these fruits were monitored during storage at 4 °C for 10 days. Some parameters such as pH, mass loss and total color difference were not significantly (p > 0.05) changed. The ozone treatment affected significantly (p < 0.05) the soluble solids parameters, titratable acidity and ascorbic acid (vitamin C), preventing the sharp decline of these characteristics during storage. In the third section it was evaluated the chlorothalonil removal of grape samples by the fruits immersion in distilled water bubbled with ozone. This strategy allowed the removal of 60% of chlorothalonil from grapes peel and pulp, regardless the ozone bubbled concentration. However, the quality of the fruit stored at 1 °C for eight weeks was altered because of the treatment. The grapes treatment with ozone at a concentration of 3 mg L-1 changed most of the quality parameters evaluated. The grapes treatment with ozone at 2 mg L-1 maintained the fruit quality for a longer period than the control grapes (the ones with no ozone treatment).