Comportamento p?s-colheita de goiabas (Psidium guajava l.) embaladas em diferentes materiais.

A especifica??o de embalagens apropriadas para as frutas ? uma tarefa complexa. Diferentemente de outros produtos, as frutas continuam respirando ap?s a colheita, durante o transporte e comercializa??o. Neste trabalho foram conduzidos experimentos para se avaliar (i) a influ?ncia de luz; (ii) a influ?ncia de permanganato de pot?ssio; (iii) e a influ?ncia de diferentes materiais de embalagens no processo de matura??o de goiabas em sistemas fechados sob atmosfera e luminosidade controladas. Os experimentos realizados foram divididos em dois grupos (a) na presen?a e (b) aus?ncia de luz. Os frutos foram embalados selados em frascos de vidro, polietileno teraftalato e em sacos de polietileno a v?cuo, com a presen?a e aus?ncia de sach?s de KMnO4 como absorvedores de etileno. As frutas foram avaliadas em seu est?gio de matura??o de acordo com a apar?ncia, cor da casca, resultados de acidez total titul?vel, s?lidos sol?veis totais e teor de vitamina C. Na aus?ncia de luz solar as goiabas embaladas apresentaram um per?odo de conserva??o relativamente superior, quando comparadas nas mesmas condi??es com as expostas ? luz. Nos sistemas utilizados obteve-se tempos de 20 a 45 dias para o amadurecimento dos frutos. Os melhores resultados foram obtidos para embalagens em PE a v?cuo (35 a 45 dias). O uso de absorvedores de etileno como o KMnO4, n?o propiciaram aumento nos tempos de prateleiras para goiabas e a sua presen?a levou a danos na casca do fruto (manchas escuras). Os resultados indicam a import?ncia da luz e a transpar?ncia dos materiais como fator acelerador no processo de amadurecimento das goiabas. Diferentemente das embalagens convencionais para goiabas, de papel?o ondulado com orif?cios, os sistemas fechados com atmosfera controlada retardaram o tempo de amadurecimento dos frutos em at? 10 vezes em rela??o ?s amostras controle, expostas ao ar ambiente. S?o apontados tamb?m, os caminhos para a escolha materiais no desenvolvimento de embalagens para goiabas. Seladas e usando materiais polim?ricos capazes de evitar trocas gasosas com o ambiente e a passagem da radia??o vis?vel / ultravioleta.The specification of appropriate packaging for fruits is a complex task. Differently of other products, fruits continue breathing after harvesting, during the transport and commercialization. In this work the experiments were devised to evaluate (i) the light influence; (ii) the influence of potassium permanganate; (iii) and the influence of different materials of packaging in the maturation process of guavas, in closed systems, under controlled atmosphere and luminosity. The experiments had been divided in two main groups (a) under presence and (b) light absence. The fruits were packed tightly sealed in glass and polyethylene terephthalate bottles and in bags of polyethylene under vacuum, with the presence and absence of sachet of KMnO4, as absorbers of ethylene. The fruits were evaluated, during their period of maturation, in accordance with the appearance, color of the rind, results of total titrable acidity, total soluble solids and vitamin C content. In the absence of light, packed guavas presented a longer period of conservation, when compared with ones with light under the same packaging conditions. The used systems achieved 45 days for the matureness of the fruits. The best results were obtained for packaging in PE under vacuum (up to 35 to 45 days). The presence of ethylene absorbers, such as KMnO4, did not propitiated increase in the times of shelves for guavas and its presence were responsible for damages in the rind of the fruit (dark spots). The results indicate the importance of gas tightening, the light and the transparency of the materials as factors in the of guavas maturation process. Differently of the conventional packaging for guavas, made of cardboard wavy with orifices, the closed systems with controlled atmosphere delayed the time of matureness of the fruits up to 10 times in relation to experiment control samples, exposed to light and surrounding air. The results indicate also new ways to the development and the importance of materials in the packaging for guavas. The packaging should be tight sealed, using polymers capable to prevent gaseous exchanges with the environment and non transparent the to ultraviolet radiation