Physicochemical and enzimatic transformations of "eva" apples stored under modified atmosphere

The need for a permanent market supply of fresh fruit has generated great interest in postharvest techniques that can promote useful life and quality of the fruit. The aim of this study was to evaluate the efficiency of atmospheric modification using different polymeric films in maintaining postharvest quality and prolonging the shelf life of Eva (Mallus sp) apples. For this, fruits from the city of Barbacena - MG, selected and sanitized were packed in plastic trays and wrapped in the corresponding films. The films used were: polypropylene - 20 µm, low-density polyethylene - 14 µm and high-density polyethylene - 7 µm. Another group of fruits (control) was not submitted to a modified atmosphere. Subsequently, all the the packages were stored under refrigeration (0 ° C ± 0.5) for 210 days and the evaluations of the following variables were performed every 30 days of storage: hydrogen potential (pH), titratable acidity, soluble solids, weight loss, firmness, total pectin, soluble pectin, pectin methyl esterase and polygalacturonase. The work was conducted in a completely randomized design (4x8), with 4 treatments and 8 experimental times. Each treatment consisted of three replicates and each experimental unit consisted of six fruits. The results were submitted to variance analysis and means were compared by the Tukey test at 5% probability and regression analysis. The low density polyethylene (14 µm) packaging provided the best conservation of the Eva cultivar apple textural characteristics. A necessidade de um abastecimento permanente do mercado com frutas frescas tem gerado um grande interesse em técnicas de conservação pós-colheita que possam promover a extensão da vida útil e da qualidade desses frutos. Objetivou-se, neste estudo, avaliar a eficiência da modificação atmosférica, utilizando diferentes filmes poliméricos na manutenção da qualidade pós-colheita e no prolongamento da vida útil de maçãs "Eva" (Mallus sp). Para tanto, frutos colhidos em Barbacena - MG, selecionados e sanitizados foram acondicionados em bandejas plásticas com seis frutos cada e estas, envoltas nos filmes correspondentes a cada tratamento. Foram utilizados filmes de polipropileno - 20 µm, polietileno de baixa densidade - 14 µm e polietileno de alta densidade - 7 µm. Um outro grupo de frutos (controle) não foi submetido à atmosfera modificada. Feito isso, as embalagens foram armazenadas em câmara fria (0°C±0,5) por 210 dias e as avaliações foram realizadas a cada 30 dias de armaze