Utilização de absorvedores de etileno e da refrigeração na pós-colheita de goiaba (Psidium guajava)

• Autor(a) principal: Matos, Patrícia Nogueira
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFS
• Texto Completo: http://ri.ufs.br/jspui/handle/riufs/16158
• topic: Tecnologia de alimentos; Goiaba; Indústria; Embalagens; Frutas; Conservação; Armazenamento; Goiaba cv. Paluma; Embalagem ativa; Permanganato de potássio; Temperatura de armazenamento; Active packaging; Potassium permanganate; Atorage temperature; CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS

Guava (Psidium guajava) is a climacteric fruit, which has a low shelf life due to its high respiratory rates and ethylene synthesis. The control of guava maturation is essential to increase its useful life. Thus, the objective of the present work was to evaluate the effect of active packaging containing ethylene absorbers on the quality and post-harvest preservation of chilled and uncooked guavas. The fruits went through stages of selection, cleaning, sanitization, rinsing, drainage and wrapping. The guavas were packed in low density polyethylene bags (LDPE) containing 300g of fruit per package. These were submitted to ten treatments, containing combinations of five concentrations of potassium permanganate and two temperatures, where: C0 (without sachet), C1 (2.5 g KMnO4. kg-1 ), C2 (5 g KMnO4. kg- ) and C3 (10 g KMnO4. kg- ), T10 (chilled 10 ± 2 ° C, 63% RH); T24 (environment 24 ± 2 ° C, 77% RH), thus obtaining the following treatments C0 + T10; C1 + T10; C2 + T10; C3 + T10; C0 + T24, C1 + T24; C2 + T24; and C3 + T24. The fruits were stored at their respective temperatures for 20 days. Samples were collected for analysis of loss of mass, firmness, instrumental color, pH, total acidity, soluble solids, ratio, vitamin C, total chlorophyll, lycopene and activity of the enzyme PME. The experiment was carried out in a completely randomized experimental design with a factorial scheme of two factors: concentration of potassium permanganate and storage temperature (factor 1) and storage days (factor 2), using quadruplicates. Data were analyzed by ANOVA and means were compared using the Scott-Knott test (p≤0.05). The weight loss of the guavas was higher for the samples under ambient conditions, reaching a maximum of 2.07 ± 0.18% after 20 days. The parameter a * indicating the green color of the guavas presented negative values during the refrigerated storage, indicating the maintenance of the green color in the fruit peel. Guavas conditioned with the treatment C1 + T10 showed the highest maintenance of the color of the rind (a *) and of the pulp (C *). During storage there was a significant reduction (p <0.05) in the total chlorophyll content and increase in the lycopene contents of the guavas, and it was important to note that only the guavas of the C1 + T10 treatment did not show an increase in the lycopene contents during the 20 days of storage. It was verified that the treatments C0, C2 and C3, stored under refrigeration, showed no variation in the TSS, ATT and pH during the whole storage, which indicates the control of the ripening of these fruits. The guavas of the treatment C1 and C3 + T10, did not present significant difference in the values of firmness, however, the other treatments presented increase of the fruit softening. The activity of PME increased on the 5th day, probably this increase, is related to higher fruit metabolism, due to respiratory activity. In this way, the use of refrigeration is indispensable to maintain the quality of the 'Paluma' guava. The use of potassium permanganate sachets containing 2.5 g KMnO4. kgassociated with the use of refrigeration delayed the evolution of guava color and controlled the loss of firmness through the control of ethylene.