Cinética de secagem da acerola (Malpighia emarginata D.C.).

Abstract

The present work was developed with the objective to dry acerola in a drier of fixed stream bed and to study the effect of the temperature and air speed of drying during the process. The fruits of acerola had been dry in the temperatures of 50, 60 and 70 °C, in the air speeds of drying the 1,0, 1,5 and 2,0 m s", being the data applied to the models of Page and Thompson. The fruits of acerola in natura had been triturated until the pulp form for the determination of the isotherms of sorption (adsorption and desorption) in the temperatures of 30, 40 and 50 °C, and the experimental data had been applied to the models of GAB, BET, Smith, Oswin, Halsey and Peleg. After the drying the fruits had been processed until the dust form, which was used for the determination of ascorbic acid. The kinetic of drying of acerola occurred inside of the period of decreasing tax, being little influenced for the air speed of drying and strong for the temperature. The fruits of acerola had been dehydrated in time approximately of 16 h and 20 min, 9 h and 7 h and 36 min when submitted to the temperatures of 50, 60 and 70 °C respectively. The models of Page and Thompson i f had adjusted to the experimental data of the dryings well, with coefficients of determination (R2) superior 98,80%. The mathematical models of GAB and Peleg had been the ones that better had represented the experimental data the curves of adsorption of the pulp of acerola, and of GAB and BET for the desorption curves. The increase of the temperature and the air speed of drying influenced in the degradation of the ascorbic acid during the drying.