Structural and physicochemical properties of freeze-dried açaí pulp (Euterpe oleracea mart.)

Abstract

The objective of this study was to characterize the structural and physicochemical properties, the bioactive compounds and the antioxidant activity of freeze-dried açaí pulp (FDAP). The morphology of freeze-dried açaí pulp showed a continuous matrix with a spongey aspect, and the X-ray diffractometry indicated that 96.17% of the molecular structure was in the amorphous state and 3.82% in the crystalline state. Freeze-dried açaí pulp presented an interesting chemical composition of macronutrients, which constituted mainly of lipids (49.14 g/100 g d.b.), proteins (9.19 g/100 g d.b.), total crude fiber (20.29 g/100 g d.b.) and total sugars (2.71 g/100 g d.b.). It also showed great amount of total phenolic compounds (1405.03 mg gallic acid/100 g d.b.) and anthocyanins (127 mg cyanidine-3-glucoside/100 g d.b.), allowing for functional properties allegations. There was significant increase in the water absorption and water solubility indices when the freeze-dried açaí pulp was submitted to a gradual increase in temperature, properties that are adequate for industrial use. Thus, the consumption of freeze-dried açaí pulp should be encouraged and also its use by the food industry in order to develop new food products.