Avaliação do tratamento hidrotérmico na qualidade e conservação pós-colheita da banana 'Prata-Anã'

Abstract

Banana is a climacteric fruit, tropical and susceptible to injury by chilling. During transport and commercialization, fruits are exposed to low temperatures in order to delay ripening and senescence, but they can be damaged if temperature is too low. We carried out two experiments, each one being a chapter of this thesis. The objective in the first chapter was to evaluate the effect of temperatures (46, 48, 50, 52, 54 and 56 °C) in immersion times (2, 4, 6 and 8 minutes) on the physical and chemical quality of ‘Prata-Anã’ banana stored at 14 °C. In the the second chapter was to analyze the characteristics of 'Prata-Anã' banana submitted to 50, 52, 54 and 56 °C for 2 minutes and stored in refrigerated chambers at 10, 12 and 13.5 °C. The bananas of the 1st experiment were harvested in the region of Jaíba-MG, while those of the 2nd experiment were harvested in the region of Janaúba-MG. The fruits were harvested at maturity stage 1, plucked in bouquets and submitted to the mentioned treatments. Besides these treatments, there was the control, fruits that were not submitted to hydrothermal treatment. Each bouquet was packed in a polyolefinic package with a thickness of 25μm and a density of 1,094g / cm³ for the 1st experiment and 0.9987g/cm³ for the 2nd experiment. The fruits were placed in standard carton boxes for export and stored at 14 °C for 25 days in the 1st experiment and at 10, 12 and 13.5 °C, in the 2nd experiment. Afterwards the fruits were removed from the refrigerated chamber and the variables analyzed were: Hue, chroma and peel lightness, fruit firmness with peel and pulp firmness, titratable acidity and soluble solids in the 1st experiment. In the 2nd experiment, the evaluated variables were: fresh weight loss, pH, maturation index, solute leakage, vitamin C, chilling, color index, total phenolic compounds and carotenoids. In the first experiment, the 'Prata-anã' banana submitted to hydrothermal treatment preserved its green color for 25 days of cold storage at 14 °C. The treatments of 54 °C and 56 ° C at all times of immersion caused scalings on the 'Prata-anã' banana peel. In the second experiment, Prata-Anã banana was yellow on the day of the removal of the refrigerated chamber, regardless of the treatment, banana ripening probably occurred due to influence of preharvest management and the edaphoclimatic conditions on the field during fruit growth, besides the use of different packaging from the one used in the 1st experiment, getting different results. Although bananas were yellow, it was observed that temperatures of 54 and 56 °C were effective in increasing antioxidants amount. In general, 'Prata-Anã' bananas subjected to hydrothermal treatment and stored for 25 days at 10, 12 and 13.5 °C completed the ripening process and maintained its original taste when exposed to 25 °C.