Caracterização e conservação pós-colheita de duas cultivares de inhame: da costa (Dioscorea cayannensis) e São tomé (Dioscorea alata).

Abstract

The yam is a monocotyledonous plant, belonging to the Dioscoreaceae family, genus Dioscorea, with the species D. cayennensis Lam. and D. alata L., the most commercially cultivated in the Northeast region, with predominance of the first species. It is a tuber of high nutritional value, that can be used in agroindustry, being extremely energetic, source of carbohydrates, in which the starch is among the main constituents, rich in minerals and vitamins of the complex B. The importance of the loss of water, flavor and even the visual aspect is a critical factor for the conservation of vegetables, and may represent the greater percentage of their loss. To try to maintain the characteristics of each product in natura it is fundamental that an environment with the cold chain and relative humidity be maintained until the commercialization. The objective of this work was to characterize and evaluate the postharvest quality of Da Costa (Dioscorea cayennensis) and São Tomé (Dioscorea alata) yams cultivated under modified atmosphere and use of the cold during storage. The yams of the two cultivars were harvested at the stage of commercial maturation, processed and submitted to the following treatments: Control with polyethylene packaging and refrigeration; Addition of ascorbic acid in the polyethylene packaging and refrigeration; Vacuum and refrigeration polyethylene packaging; Packing of polyethylene under vacuum and freezing. Analyzes of centesimal composition (moisture, proteins, lipids and carbohydrates), chemical and physicochemical analyzes (pH, soluble solids, titratable acidity, SS/AT, reducing sugars and total soluble sugars) and analyzes during storage (loss of mass, appearance, cooking time, total extractable polyphenols and peroxidase activity). The cultivar São Tomé presented moisture contents and lipids higher than the cultivar Da Costa. In the different methods of conservation evaluated, it can be concluded that although there was no significant mass loss during storage of 16 days, there was a change in the appearance with occurrence of darkening, characteristic of the action of oxidases enzymes. The cooking time decreased mainly for the Da Costa cultivar at the end of the storage with the use of the vacuum method plus freezing. Removal of oxygen, with addition of cold in the vacuum method used, ensured a good appearance of the samples. It is concluded that the best treatment for preservation of the yam was the use of polyethylene packaging under vacuum under freezing.