Armazenamento na qualidade pós-colheita da goiaba (Psidium guajava L.)

Abstract

Guava (Pisidium guajava L.) has great relevance among fruit trees cultivated and exploited commercially in Brazil and around the world. Guava, being a climacteric fruit, has a reduced shelf life after harvest, due to its unrestrained ripening process, which leads to it perishing very quickly during storage. To improve its conservation, edible coatings have been studied; among them agar, which is a carbohydrate, which offers transparency, flexible mechanical properties, high gelling strength and homogeneity. These characteristics make agar suitable for use as edible coatings, having exploratory potential for this purpose. This study aimed to evaluate the post-harvest conservation of guavas subjected to edible agar-based coating and different storage temperatures. The study was carried out at the Federal Technological University of Paraná, Campus Santa Helena. 'Suprema' guavas acquired from the Cooperativa Agroindustrial de Carlópolis (COAC) were used, which were standardized in color and size. After that, they were sanitized, immersed in a chlorinated solution for 3 minutes, dried and selected. The experiment was carried out in a 5x2 factorial scheme, with four replications and two fruits per plot, with treatments: (distilled water, 6, 8, 12, and 15% agar) and two temperatures (5 and 25ºC). The guavas were immersed in the agar solutions, placed in trays and stored at 5 and 25°C for 25 days. At 5, 15 and 25 days, the guavas were evaluated for their physical-chemical characteristics such as pH, titratable acidity (TA), total soluble solids (TSS), TSS/AT ratio, color, firmness and weight loss. ‘Suprema’ guavas coated with agar and stored at 5°C showed an increase of 10 days in shelf life, compared to fruits stored at room temperature, with shelf life extended by 25 days. The coatings had the greatest influence, especially when associated with a temperature of 25°C. It is concluded that the use of agar as an edible coating is a promising solution to preserve the quality of fresh guavas, especially in storage conditions at room temperature. The temperature factor also contributed to maintaining the quality of guavas, especially when stored at a temperature of 5°C. The research reinforces the potential of agar as a viable alternative to minimize post-harvest losses, especially in the absence of cold rooms. However, more in-depth investigations are essential to improve the results and consolidate this approach