Anais do Simpósio Latino Americano de Ciências de Alimentos
Anais do 14 SLACA - Simpósio Latino Americano de Ciência de Alimentos

Fresh dragon fruits have a short shelf life, so it is important to use adequate preservation methods to increase its post-harvest life. This work aimed to produce powders, from fruits of red-fleshed pitaya (Hylocereus costaricensis Web. Britton and Rose). Formulations with concentrations of 20, 25 and 30% maltodextrin were prepared, named PV 20%, PV 25% and PV 30%, respectively. These were submitted to chemical, physical and physicochemical analysis and later freeze-dried. The powders obtained were characterized as to chemical, physical and physicochemical parameters, scanning electron microscopy (SEM) and water adsorption isotherms at 25 ºC. By the characterization of these, based mainly on the parameters of moisture content, water activity, color, betalains (betacyanins and betaxanthin) of the formulations after drying, a formulation (PV 25%) was selected for the determination of water adsorption isotherms at three temperatures (20, 30 and 40 ºC) and conducting the study of accelerated storage under controlled conditions of temperature (30 and 40 ºC) and relative humidity (83%). The powder samples showed low moisture content, maximum 8.44% and low water activity, maximum 0.319; the concentration of betacyanins ranged from 84.70 to 135.87 mg/g and betaxanthin from 77.36 to 148.80 mg/g. The SEM revealed amorphous surfaces, with a tendency for less agglomeration of the particles as the maltodextrin concentration increased in the formulations. The GAB, Oswin, and Peleg models showed good fits in all samples, both at 25 ºC and at temperatures of 20, 30, and 40 ºC, in the selected powder. As for the storage study, under the mentioned conditions, it was found that the packaging did not completely prevent moisture absorption, promoting an increase in water activity and a decrease in betalains concentration, besides influencing other parameters evaluated.