Ozônio como agente fungicida na pós-colheita do mamão (Carica papaya L.)

• Ano de defesa: 2012
• Autor(a) principal: Costa, André Rodrigues da
• Orientador(a): Faroni, Lêda Rita D'antonino
• Banca de defesa: Berbert, Pedro Amorim
• 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: Fitossanitário; Antracnose
• Palavras-chave em Inglês: phytosanitary; Anthracnose
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA
• Link de acesso: http://locus.ufv.br/handle/123456789/3622

Fungal diseases of postharvest, mainly anthracnose, are one of the causes of papaya depreciation with losses in trading. The process normally used for this disease control in postharvest includes hydrothermal treatment at 49 °C for 20 minutes, followed by cooling for the same period, besides the application of fungicides. Disadvantages linked to conventional treatments lead to search for new methods to control postharvest anthracnose in papaya. One alternative is ozone gas (O3) usage, for being a strong oxidizing and antimicrobial agent, which can be generated on site by an electrical discharge, dismissing the need for handling, storage, or disposal of packaging. This study aimed to evaluate the effectiveness of ozone dissolved in water to control anthracnose in papaya and check the influence of this treatment on these fruits physical and chemical characteristics. Papaya (Carica papaya L.) Golden cultivar was used, harvested at maturity stage 1, with up to 15% yellow color. To evaluate the ozone effect in controlling anthracnose, fruits were inoculated with spore suspension of Colletotrichum gloeosporioides and C. magna at a concentration of 2.3 x 106 CFU mL-1. Subsequently, fruits ozonation was performed in tank with water containing dissolved ozone at a concentration of 0.8 mg L-1 for periods of 40, 80, 120, and 160 minutes. Non-ozonated fruits were used as control. After this process, the fruits were stored in chambers at 11 °C and 80 to 85% RH for 15 days. Analyzes were performed in this period in the first and 15th days. Subsequently, the chamber temperature was changed to 25 °C and analyzes was made on the 17°, 19°, 21°, and 23° days of storage. Data were subjected to variance analysis using SAEG (SAEG, 2007) statistical software. The comparison of analysis mean values of the ozonated or non-ozonated fruit stored for zero and 15 days was performed by the F test at 5% probability. In the second step, fruits stored at 25 °C for eight days were analyzed from the 15th day. Split plot scheme was made and in the parcels there were five periods of exposure (0, 40, 80, 120, and 160 minutes) to Ozone dissolved in water; and in subplots there were five periods of fruits storage (0, 2, 4, 6, and 8 days, except for CO2 production, that in subplot there were four storage periods, from the second day) in a completely randomized design (CRD) with two replicates, except percentage of injured area, with three replicates. Analyzes were of percentage of injured area, CO2 production, fresh mass loss, titratable acidity, soluble solids, skin color, vitamin C content, pulp firmness, and pH. During storage at 11 °C, there was no significant increase in lesioned area by anthracnose. The papayas showed increased respiratory rate with a trend towards smaller increase for those exposed to ozone. The firmness decreased during this period. Values of Hue° decreased and values of Chroma and Color Difference increased. Fruit fresh mass suffered a decrease and parameters suffered titratable acidity, soluble solids, and vitamin C content; pH showed no change during this period. During storage at 25 °C, lowest percentage of lesioned area in fruits treated with ozone was recorded in comparison to untreated fruits. The fruits exposed to ozone dissolved in water also showed less loss of firmness and lower respiration rate during storage. The color parameters (Chroma, Hue°, and Color Difference), pH, soluble solids, and titratable acidity of ozonated papayas did not differ from those observed in fruits exposed to ozone dissolved in water. It can be concluded that the application of ozone dissolved in water at a concentration of 0.8 mg L-1 for up to 160 minutes is efficient in reducing the severity of anthracnose in postharvest of papaya Golden cultivar without, however, adversely affecting fruits quality.