Biofilmes e refrigeração na conservação pós-colheita de abacates (Persea american Miller)

Abstract

The avocado (Persea americana Miller), is one of the fruit trees that has been gaining interest among rural producers and consumers. Variations in color, shape, skin, size, seed and pulp depend on groups and cultivars. There is a great variety of avocado, among which we can cite: Prince, Hass, Ouro verde, Fuerte, Choquette, Manteiga, Breda and Margarida. Avocado is a very energetic kind of food, being rich in vitamins A, B, C and E. It is provided with high antioxidant activity and phenolic compounds which help prevent diseases. Post harvest losses can be defined as those that occur after harvest. In developing countries, more than 40 % of losses of fruit and vegetables happen after harvest and during processing. However, in lower percentage, these losses occur during sale and consumption. In Brazil, a great amount of agricultural products is lots during post harvest and, in order to decrease there losses, some conservation techniques, such as refrigeration, irradiation and the use of biofilms based on manioc starch, wax, chitosan, kefir and others, are used. This work aimed at applying edible biofilms based on chitosan 2 % and manioc starch on cultivars 'Breda', 'Choquette', and 'Ouro verde' and store thena under refrigeration. The fruits were harvested at the experimental farm of State University of Maringá, campus Diamante do Norte, Paraná and analyzed as for mass loss, skin and pulp determination of lipids, phenolic compounds and antioxidant activity. Avocado with coverings had lower mass loss, as for color, in yellow during storage. Regarding total titrable acidity, there was a decrease after some ripening. Out of the cultivars we studied, Ouro verde had the highest lipid content (around 16 %), while Choquette and Breda had an average of 13 % and 9 % respectively. Out of the three cultivars, Breda had the highest potential for antioxidant activity and high amonts of phenolic compounds. From the results we obtained, it was possible to observe that the use of biofilms was efficient in all cultivars, being that biofilms based manioc starch 2% were the best for cultivars Ouro verde and chitosan 2% for cultivars Breda and Choquette, in storage at 13°C. Under these conditions, the fruits maintained their quality for 15 days, being in good conditions for comercialization.