Evolução das propriedades físicas, reológicas e químicas durante o amadurecimento da banana Prata-Anã / Evolution of the chemical, reological and physical properties during the ripening of the banana `Prata-Anã.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The ripening kinetics of the banana Prata-Anã harvested at different development stages (18, 19 and 20 weeks) and stored under different temperatures was studied. From each randomly collected bunch, just the second and third hands were used, as being divided into bouquets with four fruits. The experiment was carried out at two stages. In the first stage, the modifications of the fruits kept at temperatures 10, 15, 20 and 25C for 10 days in BOD-type chambers with relative humidity varying from 90 to 95% were evaluated. In the second stage, the fruits stored at the temperatures 10C and 15C for 10 days were transferred to 25C temperature and evaluated until the 6 day under storage at this temperature. For both stages, the loss of the fruit fresh matter was analyzed and they were subjected to analyses in order to study the ripening kinetics based on chemical changes, peel color change and the pulp softening, by applying mechanical tests. In addition, the transpiration coefficient of the fruit was calculated. Based on the results, some conclusions may be drawn as follows. The 18-week development stage showed the best delay in the fruit ripening process, as those fruits stayed green for 10 day even when stored at temperatures 20C and 25C. Besides, the maintenance of the fruits at temperatures 10C and 15C for 10 days caused no visible damages by cold injuries, since at the 4th day after transferring to 25C the fruits presented evolution in the color peel, total soluble sugar contents, and both pulp and peel firmnesses, which characterizes the ripening process. However, only those fruits previously store at 15C showed to be totally yellowish at the 6th day under storage,tored at 15C after transfer to 25C. The fruits under development for 19 weeks showed ripening evolution signs from the 7th and 6th days, when stored at temperatures 20C and 25C, respectively, as presenting complete ripening characteristics at the end of 10 days. The fruits with 20 weeks under development only maintained totally green during those 10 days when stored at 10C. However, soon after those fruits with 19 and 20 weeks under temperatures 10C and 15C were transferred to 25C temperature, the change in the physical and chemical indexes of the fruits occurred, as reaching levels that characterized their complete ripening. In the attempt to using a single index to represent the evolution of the peel color in the banana Prata-anã, the CCI index was efficient in describing the evolution of the peel color during ripening. Besides, it presented high correlation with either the maximum forces of pulp and peel penetration and with the contents of sugar and starch. The Gaussian and Sigmoid models with three parameters and Gompertz and Sigmoid models with four parameters satisfactorily describe the changes in texture as well as in color and contents of sugar and starch, so they can be used in automated quality control systems. Concerning to the transpiration coefficients, a variation occurred as a function of the development stage and storage temperature; the values varied from 515.02 to 210.53 10-12 kg. kg-1s-1Pa-1 that are higher than the potato` but lower than the carrot`, therefore pointing out the banana Prata-anã to show higher and lower water loss, relative to those two products, respectively.

ASSUNTO(S)

postharvest preservation banana engenharia de processamento de produtos agricolas cor color propriedades mecânicas mechanical properties banana conservação pós-colheita

ACESSO AO ARTIGO

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