Qualidade, compostos bioativos e conservação pós-colheita de goiaba ‘paluma’ sob recobrimentos a base de fécula de sementes de jaca

Abstract

Brazil is among the largest producers of guava, occupying the third place, with the Southeast and Northeast of the most prominent, being the Paluma cultivar the most planted. However, guava has a short postharvest once it for presents large ethylene production, elevated respiratory rate, rapid loss of firmness, and great susceptibility to decay. Thus, the development of postharvest technologies is necessary, especially using biodegradable materials, such as coatings with starch and other sustainable materials. The use of fruit coatings using these materials, however, require evaluate the behavior under intermittent temperature, for example, during cold storage and after transferring to the environment in which the fruit is going to be traded. In this context, the aim of this study was to evaluate the influence of coatings based on starch of seed jackfruit and its compositions with chitosan or sodium alginate in the quality and postharvest conservation of 'Paluma' guava fruit, during storage and after transferring to room conditions. The experiment was conducted at the Laboratório de Biologia e Tecnologia Pós -Colheita do Centro de Ciências Agrárias, Universidade Federal da Paraíba. The guavas were from a commercial orchard from Nova Floresta municipality, Paraíba state, Brazil. The experiment was conducted in a factorial scheme 4 x 2, being as factors 4 treatments and 2 temperature conditions, with 19 periods, and periods x treatments, nested within the environment. The coatings used were: jackfruit seed based starch 4% (F); combination of jackfruit seed starch 2% + 2% chitosan (CF); jackfruit seed starch 2% + 2% alginate (FA), and the control (uncoated) fruits. Guavas under different coatings were stored under refrigeration at 10 ± 2 ° C for 24 days and evaluated every 4 days. In parallel, followed by the cold storage, from the 12th, 16th and 20th day, parcels from each treatment were transferred to the room conditions at 25 ± 3 ° C and then evaluated every two days, making three more periods of evaluation after the transferring temperature. Fruit coated with CF presented greater firmness, kept the green color, and showed higher content of soluble solids. Fruit covered with CF + FA showed lower dehydration, lower rates of severe damage, and greater acceptance.Guavas coated with CF + FA showed lower decline in the ascorbic acid content, even after transferring to the room conditions, especially when this occurred after the 12th and 16th days of refrigeration. The PET content was kept in fruits coated with CF, which also had higher total antioxidant activity.