Effect of high oxygen concentration atmosphere in the postharvest of fresh fruits and vegetables

Abstract

The postharvest life of fruits and vegetables can be expanded with the adoption of appropriate conservation techniques that maintain quality for more time and reduce losses. The use of atmospheres with high concentration of O2 has been suggested as an alternative to solve the problems of accumulation of acetaldehyde and ethanol in storage plants when atmospheres with low O2 and high CO2 are used. The treatment under hyperbaric pressure allows exposure of in natura products in atmospheres enriched with oxygen with more than 21 kPa, with reduced energy demand. Recent studies demonstrate the using of hyperbaric pressures to delaying the physiological ripening and senescence in plants, increase antioxidant compounds and inducing natural resistance, and extending the life of vegetables after harvest. Mango and guava are economically important due to their wide acceptance for fresh consumption, given its good taste, flavor and nutritional value, however have a short shelf life. In this context, the objective of this study is to determine the influence of high concentrations of O2 on the physiology and metabolism pro- and anti-oxidative of mangoes and guavas under hyperbaric atmosphere treatment, searching for the increase of shelf life. The experiments will be carried out in the Laboratório de Tecnologia de Produtos Agrícolas da FCAV-UNESP, Campus de Jaboticabal. Mangoes 'Tommy Atkins' and guavas 'Pedro Sato' harvested at maturity stage mature-green, obtained from commercial orchards in the region will be used. The experiment will be divided into two parts: the first, the hyperbaric treatments will be applied on mangoes and guavas, at pressures of 1 (control), 3, 5, 7, and 9 atmabs, and at the ambient temperature (22 ºC), and the second part the hyperbaric atmospheres will be applied in the same levels of pressure on mangoes and guavas under refrigeration (12 °C). The analyzes will include determination of weight loss, firmness, peel and pulp colors, carbon dioxide, ethylene, acetaldehyde and ethanol productions, soluble solids, titratable acidity, soluble and reducing sugars, ascorbic acid, total antioxidant activity, total extractable polyphenols, lycopene, beta carotene, polyamines, enzymatic activity, lycopene, incidence of decay and sensory analysis.