Secagem por aspersão da polpa de pitaya (Hylocereus polyrhizus).

Abstract

This work was carried out with the objective of obtaining a powder product from the pitaya whole pulp by means of spray drying and evaluating its stability during 60 days of storage under controlled conditions of relative humidity (83%) and temperatures (30 and 40 °C). Three formulations were made with the pitaya whole pulp with the addition of maltodextrin, in three concentrations (25, 30 and 35%), and dehydrated at the drying air temperatures of 150, 170 and 190 oC. The best powder was selected by the results of the analysis of the parameters of betacyanins and redness (+a*). The best results were obtained at the temperature of 150 °C and 25% maltodextrin. The moisture adsorption isotherms of the selected powder at different temperatures (20, 30 and 40 oC) were determined and the GAB, Oswin and Peleg models fitted to the experimental data. From the verified results the pitaya whole pulp was considered acid and with considerable betacyanin content. The powder had a moisture content of 2.02 to 2.60% and it was verified that during the storage of the selected powder the moisture content, the water activity and solubility of the samples increased. The moisture adsorption isotherms of the selected powder were classified as Type III and the Oswin and GAB models were the best fit to the experimental data. With the increase in temperature there was a greater increase in the degradation of the betacyanins and the redness of the selected pitaya powder with inverse behavior for the luminosity.