Utilização do ozônio como fitossanitário na conservação pós-colheita da batata baroa

• Ano de defesa: 2013
• Autor(a) principal: Ribeiro, Patrícia Helena
• Orientador(a): Faroni, Lêda Rita D'antonino
• Banca de defesa: Mendonça, Eduardo Gomes de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Engenharia Agrícola
• Departamento: Construções rurais e ambiência; Energia na agricultura; Mecanização agrícola; Processamento de produ
• País: BR
• Palavras-chave em Português: Armazenamento; Arracacia xanthorrhiza; Erwinia - Controle; Ozônio
• Palavras-chave em Inglês: Storage; Arracacia xanthorrhiza; Erwinia - Control; Ozone
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA
• Link de acesso: http://locus.ufv.br/handle/123456789/3682

The soft rot caused by Erwinia bacteria is responsible for big production losses during transporting, storing and commercialization of arracacha, being considerated one of the most developed diseases in roots. The most used postharvest treatment before the commercialization of the roots is the washing for 30 minutes in networks immersed in a tank with water. Although the washing process accelerates the soft rot attack, it s practically impossible to commercialize the roots with no washing due to consumer s refusal. The washing process of the roots improves their appearance, but contributes to largest loss of water during the commercialization time because it damages the external film of protection and makes the contamination by bacteria and fungi easier to happen. In Brazil there are no products registered in MAPA (Ministry of Agriculture, Livestock and Development) for control of Erwinia in acarracha. The disadvantages associated with conventional treatments necessitate the search for new methods of controlling soft rot in postharvest of acarracha. An alternative to traditional methods of postharvest treatment of vegetables is the application of ozone gas, which can be generated on site by means of an electric discharge and is a strong oxidizing agent and antimicrobial characterized mainly by presenting a high reactivity and half-life between 15 and 50 min, being degraded in O2, showing no toxic residue. This paper aimed to evaluate the effectiveness of ozone dissolved on water in the control of bacteria of the genus Erwinia roots of acarracha, by visual analysis and by the activity of pectinolytic enzymes: pectinmethylesterase and polygalacturonase in their statements during the storage period; and analyze the effect of treatment with ozone on the physicochemical characteristics of acarracha. For evaluating the effect of ozone in controlling Erwinia, the roots were harvested and washed manually treated with ozone dissolved in water at a concentration of 1.52 mg L-1. The gas continuous flow was applied, at a flow rate of 2 L min-1 in distilled water at 20 ° C and the roots dipped after water saturation, with durations 10, 20, 30 and 90 minutes. For the control arracachas were treated with atmospheric air dissolved in distilled water at 20 ° C, and a flow rate equal periods of exposure to ozone treatment was used. After this process, the roots were placed in a climatic chamber at 23 ± 2 ° C and 85 ± 5% RH for 10 days and analyzed daily. Were analyzed: the look of roots, the specific activity of enzymes pectinolícas: pectinesterase (PME) and polygalacturonase (PG), weight loss (WL), total color difference (ΔE), the starch content, total soluble sugars (TSS) , Reducing Sugars (RS) and non-reducing sugars (NRS). Visual analysis of the roots of acarracha ozonated showed no difference to the control independently of the treatment employed. There was also no visual difference between different ozone treatments. At the end of storage, PME in 30 min treatments showed lower average in arracachas exposed to ozone compared to control. In 90 min treatments, the control showed lower mean roots exposed to ozone. The PG in roots treated with ozone for 90 min showed lower activity compared to control. The mass loss decreased with increasing exposure time and increased with increasing storage period, but there was no statistical difference between roots exposed or not exposed to ozone. ΔE, the starch content, TSS, RS and NRS showed no statistical difference between roots exposed or not exposed to ozone. It was found in the roots ozonized that RS had significant exposure time and storage period quadratic effect, reaching a maximum of 5.29 days and minimum at 42.16 min. A significant and positive correlation between WL x ΔE, WL x TSS and PM x NRS and TSS x NRS and significant and negative correlation between PG x PME. The remaining coefficients showed no significant correlation. It can be concluded that the application of ozone dissolved in water at saturation concentration of 1.52 mg L-1 was not effective in controlling bacteria of the genus Erwinia on roots of acarracha by visual and enzymatic analyzes, and not affected physicochemical characteristics of arracacha.