Atmosfera modificada e refrigeração na conservação pós-colheita de atemóia cv. Gefner

Abstract

Atemoya (A. squamosa L. x A. Cherimola Mill.) is well accepted and appreciated by consumers; however its commercialization is hampered due to rapid ripening. Nowadays are incipient techniques and technologies that aim at postharvest quality with a longer shelf life. The objective was to evaluate the effect of using two modified atmosphere packaging, which differ in density, keeping under refrigeration for 28 days fruits of atemoya tree cv. Gefner grown in northern Minas Gerais. The fruits were harvested at physiological maturity stage and the experiment conducted at Laboratory of Postharvest Physiology of Fruits, located in the Campus UNIMONTES Janaúba MG. The research was carried out in two experiments. The experiment 1, control, unpackaged fruits, conducted in a completely randomized design. The fruits were stored in cold chamber at 15 ± 1 °C and 85 ± 5% RH for 6 days, and evaluated every 02 days by visual estimation of chilling injury (CI), using the scale: 0 absence of spots and blemishes on the skin; 1 = small brown pints; 2 = small brown spots; 3 =darker and larger spots. Experiment 2, fruits stored in passive modified atmosphere by means of two packaging (EMB) having a thickness of 25 microns and differing in density, EMB 1 has 0.9987g/cm³ density and EMB 2 has 1.094 g/cm³. The experimental design was completely at random, and the fruit were kept under refrigeration in a cold chamber at 15 ± 1 °C and 85 ± 5% RH for 28 days, and evaluated every 04 days. The analyzed variables were: fresh weight loss of the fruit, firmness, soluble solids, pH, titratable acidity, color, starch, total sugars, reducing sugars and non-reducing sugars. In Experimento 1 from the 2nd day of storage, 100% of the fruit showed CI related to stage 2 of the scale, which reached stage 3 on the 6th day of storage. The result justifies the need the modified atmosphere to store atemoya under 15 °C for 28 days. It was found at the end of 28 days, in the experiment 2, that EMB 1 and EMB 2 packs presented fruit with quality for marketing, keeping characteristics such as average values of 22º Brix, decreasing of titratable acidity, light green color of skin and in good lightness. The EMB I showed better weight maintenance, with 1.54% loss of fresh weight while in the EMB 2 it was 2.36%. There was a higher solubilization of total sugars and non-reducing sugars in EMB 1. Thus, EMB 1 is more indicated for the atemoya fruit grown in northern Minas Gerais.