Microencapsulação probiótica da polpa da ameixa por liofilização.

Abstract

The present work had as objective to elaborate microcapsules of the pulp of the nondairy probiotic plum by lyophilization, through the addition of the probiotic bacterium Bifidobacterium animalis subsp. Lactis, using different concentrations of maltodextrin and inulin (3, 5, 7%), and subsequently subjected to different freezing temperatures (50, 100 and 150 °C) and freezing times (2, 4 and 6 hours) . The fresh and fermented plum pulp samples and the microcapsules were characterized in terms of physicochemical parameters, yield, bioactive compounds and technological analysis. The microcapsules were also submitted to viability tests of the probiotic bacteria (B. animalis subsp. Lactis) during storage at a temperature of 25°C. A 2³ factorial design with central points totaling 11 experiments, aimed at optimizing the drying process. The lyophilization of the microcapsules was carried out in a benchtop lyophilizer for 48 hours. The microencapsulation process of the probiotic plum showed great efficiency in relation to the removal of free water present in this food matrix, since the pulps of the liquid probiotic plum obtained water content values above 87% and after the microencapsulation process by freeze drying , the microcapsules presented values below 3.76% and consequently reduced values were obtained for water activity, which promotes better stability for the microcapsules during the storage process. Furthermore, the reduction in the water content of the liquid probiotic pulp promoted an increase in the concentration of organic acids in the microcapsules, since the microcapsules have higher contents in relation to total acidity. Regarding the contents of bioactive compounds, all the experiments carried out in this research have values with high concentration, but the total phenolic compounds and tannins stand out in this, since they were the organic components with the highest concentration as for the liquid pulp samples as for the microcapsules. Regarding the cell viability of the probiotic bacteria, the liquid pulp obtained maximum values ranging from 2.98x10¹¹ to 2.88x10¹¹(CFU/ml) for the formulations developed with the lowest concentrations of maltodextrin and inulin (carrier agents). For the probiotic microcapsules, the independent variables of the microencapsulation process, promoted a significant effect, considering that the experiments submitted to lower temperatures with longer freezing time and higher concentrations of carrier agents, had higher concentrations of viable cells. A similar behavior was observed for the efficiency of the process as it presents a significant effect, with a maximum value of 97%. The freezedrying microencapsulation process resulted in very low yield rates in all the experiments carried out in this research, with no significant effects. During the storage of the probiotic plum microcapsules, there was a natural reduction in relation to the viability of the probiotic bacteria, but at the end of the 28day storage period, the microcapsules showed no reduction in their logarithmic cycle, which can be considered food with probiotic properties.