Development of dry acerola (Malpighia emarginata D.C) and ciriguela (Spondias purpúrea L.) mixed pulp obtained by spouted bed drying and freeze-drying

Abstract

During processing by drying, the fruit pulps can undergo changes in their quality. This study aimed to select the best conditions for spouted bed drying and freeze-drying of acerola-ciriguela mixed pulp. For spouted bed drying, the influence of drying temperature, feed rate, and concentration of maltodextrin was investigated using a 2³- central experimental design. A similar design was used for freeze-drying, but temperature, vacuum chamber pressure, and maltodextrin concentration were selected as the independent variables. In both cases, the moisture content, water activity, hygroscopicity, and ascorbic acid retention were used as responses. Optimization of both processes was done according to the desirability function. The higher the temperature and the concentration of maltodextrin, the lower the moisture content of the final product obtained by spouted bed drying. Increases in temperature and maltodextrin concentration also caused significant reductions in water activity of both products. Retention of ascorbic acid was maximized in the spouted bed-dried product when combining low drying temperature and slow suspension flow, while in the freeze-dried one by high temperature and chamber pressure. These results highlighted the great potential of the mixed powder of acerola-ciriguela produced by freeze-drying as an ingredient to enrich foods in vitamin C.