Deterioração pós-colheita da mandioca minimamente processada

• Ano de defesa: 2009
• Autor(a) principal: Medeiros, Eber Antonio Alves
• Orientador(a): Puschmann, Rolf
• Banca de defesa: Finger, Fernando Luiz , Sediyama, Maria Aparecida Nogueira , Silva, Washington Azevedo da
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Fisiologia Vegetal
• Departamento: Controle da maturação e senescência em órgãos perecíveis; Fisiologia molecular de plantas superiores
• País: BR
• Palavras-chave em Português: Mandioca; Processamento mínimo; Antioxidantes; Embalagem com atmosfera modificada; Pós-colheita
• Palavras-chave em Inglês: Cassava; Minimal processing; Antioxidants; Modified atmosphere packaging; Postharvest
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::BOTANICA::FISIOLOGIA VEGETAL
• Link de acesso: http://locus.ufv.br/handle/123456789/977

The roots of cassava present high postharvest perishability due to physiological deterioration that develops in wounded tissues usaully within two to three days after harvest at room temperature. The physiological deterioration is characterized by the appearance of blue-black streaks in the root vascular tissue and storage parenchyma, which progresses through the whole length of the root, being the initial cause for the poor acceptability for fresh consumption. This darkening is attributed to reactions involving the enzymes phenylalanine ammonia lyase, polyphenol oxidase and peroxidase. The objective of this work was to evaluate the effects biochemical, physiological and physical phases by the called minimal processing, the use of antioxidants and of packaging on the development of physiological deterioration in cassava roots during a period of preservation, in order to extend the shelf-life of the product, as well as to ensure food safety during the commercialization, distribution and consumption. Cassava roots cv Cacauzinha with sixteen months old were used for the minimal processing. To process the roots, the sanitizer sodium dichlorine s-triazinetrione dihydrate at concentration of 200 mg L-1 showed a better control of the macrobiotic contamination. The length of time for centrifugation necessary to remove the excess water adhered was 60 seconds at 800 g. The antioxidants ascorbic acid and citric acid provided better control to inhibit the development postharvest physiological deterioration used at 3 % solution, and the combination of both in a ratio of 2:1 showed positive effect in controlling Pseudomonas sp. contamination. The plastic films polypropylene and polyolefin multilayer controlled the development of postharvest physiological deterioration for six and twelve days of storage at 8 ± 2 °C and 90 ± 5 % RH, respectively. The modified atmosphere promoted by the polypropylene film, changed the level of O2 to 5 % and CO2 to close 8 %, controlling the incidence of physiological deterioration for six days and the development of Pseudomonas sp. up to nine days. Treatment with the antioxidants ascorbic acid and citric acid provided lower values of pH, total soluble and reducing sugars content, activity of the enzymes phenylalanine ammonia lyase, polyphenol oxidase and peroxidase, as well as browning index and incidence of postharvest physiological deterioration and Pseudomonas sp. compared to untreated roots. However, the contents of starch and the content of phenolic compounds showed higher values when treated with antioxidants. Treatment with ascorbic acid and citric acid controlled postharvest physiological deterioration up to six days at 8 °C.