Spouted-bed drying of acerola pulp (Malpighia emarginata DC): Effects of adding milk and milk protein on process performance and characterization of dried fruit powders

摘要

In this work, the production of acerola (Malpighia emarginata DC) based powder formulations by spouted bed drying was investigated. Dairy matrices (milk powder, reconstituted milk and concentrated whey-protein) were used as drying adjuvants in order to obtain an ingredient-like ready-to-use final product. High-density polyethylene particles were used in the spouted bed dryer and an intermittent feeding strategy was adopted. Physicochemical attributes of both sample formulations and final powders were assessed, and the water sorption isotherms of powdered matrices were determined at 25 degrees C and fitted to the GAB Model. The performance of the dryer was evaluated in regard to the fluid dynamics and the thermal efficiency of the process. Spouted bed dried matrices produced with acerola pulp and milk powder presented the highest powder production rates (0.0895 g powder/min), production yields (24.75%) and satisfactory thermal efficiency (40.4%). The use of milk powder as adjuvant resulted in a significant ascorbic acid retention (72.9%) after thermal processing. The sorption isotherms showed that the addition of dairy adjuvants was responsible for reducing the equilibrium monolayer moisture of powdered samples. Practical Application Brazil is one of the world's largest producers of acerola fruit. The production of fruit-flavored products is a trend to the food industry that aims to exploit the desirable marketing, flavoring and nutritional characteristics of fruits to increase products' acceptance and consumption. The motivation of this work was to evaluate the spouted bed drying as an appropriate processing strategy for producing food ingredients based on acerola and using alternative dairy-based drying adjuvants. The data shown here can be used for the development of new acerola-based food products and for clarifying the role that dairy adjuvants play on the physicochemical attributes of powdered matrices.