Secagem por aspersão e liofilização da polpa de pitaya (Hylocereus undatus Haw. Britton e Rose).

Abstract

The red pitaya white pulp (Hylocereus undatus Haw. Britton and Rose) is a fruit whose consumption in recent years has grown in Brazil, due to its pleasant and sweet taste, in addition to being a food rich in bioactive compounds. However, it is a highly perishable product, therefore it is necessary to use processes which promote the reduction of post harvest losses. Therefore, this study aimed to perform spray drying and freeze drying slurries of red pitayas with white pulp (Hylocereus undatus Haw. Britton and Rose). Formulations were prepared with the pulp of dragon fruit and maltodextrin different concentrations (25, 30 and 35%) which were dehydrated in a spray drier with drying air temperature of 150 °C and lyophilized at -55 °C. The whole pulp and formulations were analyzed for chemical, physical and physicochemical parameters. The lyophilized powders and dried in spray dryer were characterized by the chemical, physical and physicochemical parameters and certain water adsorption isotherms at 25 °C. Based on the results of the water content parameters, water activity, color, vitamin C and yield was selected the lyophilized powder with 35% maltodextrin, which was subjected to accelerated storage for 20 days under conditions of controlled moisture of the air (83%) and temperature (30 to 40 °C). Lyophilized samples showed low water content (1,774%) and low water activity (0,103). The models of GAB, Oswin Peleg and showed good fits the adsorption isotherms of water from pitaya post, highlighting the model Peleg with the best fit. As for the storage study, there were significant changes in most parameters assessed: total titratable acidity, lightness (L*) and redness (+a*) significantly decreased throughout storage; and the water content, water activity and the intensity of yellow (+b*) showed a significant increase.