Resumen de Variation of physical properties of banana along drying for cvs. "Musa nana" and "Musa cavendishii"

M. J. Barroca, Raquel P. F. Guiné

• português

  O presente trabalho teve como objectivo proceder à secagem de duas variedades de banana (Musa nana e Musa cavendishii) à temperatura de 50 ºC e 70 ºC e comparar as propriedades dos frutos secados com as do fruto em fresco. Com os resultados obtidos concluiu-se que a densidade aparente aumenta com a perda de água durante a secagem e que os produtos secados têm menos luminosidade e são mais acastanhados, independentemente da variedade da banana. Em relação à textura, verificou-se uma redução da dureza superior a 60 % com a secagem a 70 ºC para ambas as variedades, quando comparado com o fruto fresco. Por outro lado, não se observou uma alteração significativa na coesividade e elasticidade da banana com a secagem, independentemente da temperatura de secagem e da variedade.

• English

  Bananas from two different cultivars, Musa nana and Musa cavendishii, were dried by hot air at two different temperatures (50 ºC and 70 ºC) with the purpose of comparing their properties with the corresponding fresh products. Along the drying process, it was possible to conclude that bulk density of both types of banana increased as the water content was diminishing. The results also indicate that drying originated darker products when compared to the fresh ones, with lower L* (luminosity) and b* (yellowness) and with higher a* (intensification of reddish color). These results were obtained for both cultivars under study and the two hot air temperatures (50 ºC and 70 ºC). With respect to texture, it was observed a reduction of hardness, with drying at 70 ºC, higher than 60 % for the two banana varieties, when compared with the fresh fruits. In addition, the values of cohesiveness and springiness are similar among the fresh and dried state, independently of the banana variety and the temperature of drying.