Desenvolvimento e controle do amadurecimento da Manga 'Úba'

• Autor(a) principal: Silva, Danielle Fabíola Pereira da
• Data de Publicação: 2009
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1137
• topic: Etileno; Graus-dia; Acetileno; Pós-colheita; Pré-colheita; Ethylene; Degree-days; Acetylene; Postharvest; Pre-harvest; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA

The aim of this study was to evaluate the physical, chemical and physiological changes that occurr during the development of the mango 'Uba', to establish the stages of fruit development; determine the total amount of heat or number of degree-days needed to complete the development of the fruit and verify the effects of exogenous ethylene on the pre and post-harvest, the ripening progress and on the commercial quality of the fruit. Field experiments and fruit for the other experiments were obtained in an orchard about 30 years old in Visconde do Rio Branco, MG (latitude 21 º 00'37 "S, longitude 42 ° 50'26"W and altitude of 352m). Three experiments were conducted. In experiment 1, weekly, from anthesis to ripening, 25 fruits were collected from 15 mango trees. Sampling occurred from August 2007 to January 2008. The characteristics evaluated were: units of heat (degree-days), length, smallest and largest diameter; CO2 production; color parameters L*, a* and b* of the skin and pulp; fresh and dry weight (fruit, peel, pulp and seed) Electrolyte leakage; pulp consistency; soluble solids (SS); titratable acidity (TA); ratio (ratio SS/TA), vitamin C; carotenoids; starch and soluble sugars. The development of the mango ' Ubá' lasted for 23 weeks. The pattern of development adjusted to a simple sigmoidal model. The respiratory climacteric of the fruit attached to the plant was reached between the 20th and 21st week after anthesis (SAA).The physiological maturity of the fruit was achieved in the 17th SAA following the accumulation of 1459.1 units of heat (UC). For experiment 2, in the 17th week after anthesis, 25 mango trees, five per treatment, were sprayed with ethephon at doses 0, 250, 500, 750 and 1000 mg L-1 plus 0.5% mineral oil .We collected 10 fruits from each plant every day until completely ripened, except for the 0 mg L-1, dose where, from 6 days after application of ethephon (DAAE), the harvest was weekly up to 41 DAAE. Treated fruit showed more intense staining of the pulp, less firmness and higher soluble solids content compared to non-treated pulp. The application of 500 or 750 mg L-1 of ethephon, followed by a harvest in the 3rd DAAE, allowed the production of commercial-quality fruit, besides dispensing acclimatization after the harvest. The use of ethephon in the pre-harvest anticipated fruit ripening of the fruit on the plant and harvest of mango 'Uba', and did not affect the final quality of fruit. For experiment 3, physiologically mature mangos 'Uba', but with green peels, were harvested on December 11, 2008 (18th SAA). Fruits with an average weight of 133.85 ± 1.89g were subjected to different doses of calcium carbide (0, 20, 40, 80 and 160 g/m3 chamber) and ethylene (0, 50, 100, 200 and 400 mL/m3 chamber) for 24h of exposure in refrigerated chambers (18.1 ± 0.71 ° C and 90 ± 3% UR), where they remained after the treatment until completely mature. The greatest losses of fresh mass were recorded on the 15th day of storage at rates of 20 and 160 g of CaC2 and 50 mL of ethylene. In fruits treated with calcium carbide, the respiratory peak occurred at 3, 6, 9, 9 and 12 days of storage for doses 160, 80, 40, 20 and 0 g, respectively. Those treated with the ethylene, climacteric respiratory was recorded at 3, 3, 6, 6 and 12 days of storage for doses 400, 200, 100, 50 and 0 mL, respectively. The change in skin color, as measured by hue angle was more accelerated in fruit treated with calcium carbide, compared to fruits treated with ethylene. In fruit treated with ethylene, the decrease in firmness was more abrupt compared to fruit treated with CaC2. However, the leakage was higher for fruit treated with CaC2. The soluble solids content increased throughout the period of evaluation, with higher doses of carbide or ethylene meaning a faster conversion of starch to sugar. There was anticipation and uniform ripening of mango 'Uba' regardless of the dose of calcium carbide and ethylene.