Hygroscopic behavior of acerola powder obtained by spray-drying

Abstract

Acerola is a tropical fruit characterized by a high content of vitamin C. The food sorption isotherms reflect the way that the water binds to the food. This study aimed to fit mathematical models to the adsorption isotherms of the acerola pulp powder obtained by spray-drying, and. It was used acerola pulp containing 17.1% (m m-1) maltodextrin, and a spray-dryer with drying air temperature of 154°C. The mathematical models of GAB, BET, Henderson, and Oswin were applied to determine the isotherms, using temperatures of 25, 35 and 45°C. The hygroscopicity, degree of caking and solubility analysis were performed to characterize the powders. The powder showed hygroscopicity of 5.18, degree of caking of 3.67 and solubility of 94.88%. The evaluated mathematical models showed mean relative errors ranging from 10.18 to 29.13% and a coefficient of determination (R2) ranging from 0.939 to 0.977. At 25°C, the Oswin model was the best fitted, whereas at 35 and 45°C the best fitting was obtained by the Henderson model. Type III (J-shape) isotherms were obtained, typical of high-sugar foods. The powder showed a low hygroscopicity and degree of caking in addition to a high solubility.

Keywords

• dehydration
• tropical fruit
• isotherm.