Desidratação da polpa de guabiroba (Campomanesia xanthocarpa Berg) por diferentes processos e avaliação da estabilidade dos compostos bioativos presentes

Abstract

The objective of this work was to obtain the pulp of guabiroba dehydrated by three different processes, in a heater with circulation and air renewal, heater without air circulation and in lyophilizer, using as a carrier maltodextrin. It was initially determined from a preliminary study which were the best concentrations of the carrier agent (0, 10, 20, 30 and 40% (m / m)) and what would be the best drying temperature for the heater (50, 60 and 70ºC), evaluating the quality of the physical and physical-chemical characteristics of the final product. The properties analyzed for the dehydrated product under the pre-established conditions were moisture, water activity, color, concentration of bioactive compounds (ascorbic acid, phenolic compounds and carotenoids), total titratable acidity, solubility and reconstitution time. The concentration of the carrier agent and the set drying temperature was 20% (m / m) and 60°C respectively, this choice was justified because this sample had better visual and handling conditions, as well as greater conservation of the bioactive compounds and coloration of samples. The results showed that the powder obtained by the lyophilization process had a coloring hue close to yellow and the dried samples in heater with and without air circulation was orange / brown chlorination, and all the drying processes studied obtained a significant difference of (ΔE) relative to the in natural sample. In general, for all three processes, the appearance of the powder can be considered loose with sticky texture. It was also observed that the powders presented good solubility (74, 73 and 81%) and a reconstitution time of 312, 375 and 255 seconds, for samples dehydrated in heater with and without circulation and air and Lyophilized, respectively. The moisture content of the guabiroba pulp powder with 20% maltodextrin ranged from 7.3% to 8.2% and the water activity from 0.31 to 0.35, these values were reached after a drying time of 16 (air circulation), 24 (no air circulation) and 48 hours (lyophilization). Regarding the bioactive compounds, when comparing the product before and after drying, the impact was clear, however, despite the observed losses, guabiroba powders presented a good concentration of retained compounds in the lyophilized samples, followed by samples dehydrated in an oven with and without air circulation, for ascorbic acid the retention index was 12.1; 2.5 and 3.5%, for the phenolic compounds, 59.2; 17.1 and 25.5% and for carotenoids 42.7; 6.2 and 5.3%, respectively. The study during the storage of guabiroba powder showed a significant decrease in the concentrations of bioactive compounds, especially in lyophilized samples, however, even though, evaluating the results together, the product shows high technological and bioactive potential and can be used as an ingredient in the food industry. In general, drying proved to be an excellent strategy to improve the use of guabiroba pulp, avoiding the high wastage of this food and contributing to the promotion and appreciation of this regional raw material, becoming a source of income for small farmers