Evolution of ascorbic acid degradation during hot air drying of papaya maradol (Carica papaya).

Abstract

Papaya maradol (Carica papaya) is a fragile, perishable fruit, highly accepted worldwide. To keep the quality of papaya from harvest to the consumers, conservation techniques are often used; among them, one of the most important is the drying. Hot air drying is the most common method used for dehydration, but the temperature employed may cause the degradation of food qualities suchs as color, nutritional substances, for example, ascorbic acid. Degradation of ascorbic acid has been considered as one of the major causes of quality during processing and this molecule is usually selected as an index of the nutrient quality because of its labile nature compared to other nutrients in foods. Depending on the severity of the treatment, it can cause varying degrees of loss of ascorbic acid during drying and the degradation can be accentuated by the effect of variables involucrated: temperature, air velocity and thickness. Thus, the aim of this work was to study the ascorbic acid degradation during drying, with a model that describes it depending of the variables process. In order to carry out this objective, experimental drying in a convective dryer were realized, two sizes of sample of papaya maradol were employed (1.0 and 1.5 cm of thickness), three temperatures (50, 60 and 70°C) and two air velocities (1.0 and 1.5 m/s); ascorbic acid and moisture content were measured at different time during the process. This data were analyzed, according to statistics analysis, the result showed that the variable which one most affected the degradation of ascorbic acid during drying convective, was the temperature. The conclusion of this work shows that the degradation of ascorbic acid followed a kinetic of first order reaction and the validation with the model showed a good prediction of ascorbic acid during convective in the product.