Xantana Pruni de baixa viscosidade como agente encapsulante e sílica pirogênica como antiagregante na estabilidade de probiótico microencapsulado em spray dryer

Abstract

Probiotics are live microorganisms that, when consumed in adequate concentrations, exert several health benefits. However, the conditions of processing, storage, consumption and passage through the digestive tract can affect the viability of probiotics. Therefore, it is extremely important to identify and optimize processes that aim to maintain this viability for an extended period. The spray dryer microencapsulation is one of the most used methods for this purpose, and in this technique it is necessary that the encapsulating agent offers strength and stability. The high viscosity of commercial xanthan makes it unsuitable for use as an encapsulating agent in a spray dryer, reducing the quality and yield of the process. However the use of low viscosity Pruni xanthan can be a solution. The objective was to microencapsulate Lacticaseibacillus rhamnosus GG in a spray dryer, using low viscosity Pruni xanthan as an encapsulating agent and fumed silica (Aerosil®) as an anti-caking agent, as well as to evaluate the effect of the concentration of these variables in the process. For the preparation of microcapsules in a spray dryer, different concentrations of xanthan Pruni BV (0.75 to 1.75%) and fumed silica (0.45 to 1.15%) were used, established according to a complete factorial design 22 in two levels (-1, +1) and with three repetitions in the midpoint. The microcapsules obtained were stored at room temperature, refrigerated and frozen, and evaluated for up to 120 days. Morphological, physical, bacterial viability and resistance to simulated digestion conditions were performed. The effect of xanthan on the encapsulation efficiency of probiotics was greater when the Aerosil® concentration was fixed at the maximum value investigated, with results above 85.83% in all treatments. Microencapsulated probiotics remained viable during 120 days of storage at all temperatures evaluated, with the greatest reduction being observed at room temperature. Under freezing and refrigeration temperature, the concentration, at 120 days of storage, remained in the range of 8 log CFU g-1 . The microcapsules had a spherical shape, with the presence of concavities. Microencapsulated microorganisms resisted simulated digestion and had high viability in the enteric portion, with a concentration of 8.97 log CFU g-1 . The high encapsulation efficiency, as well as the maintenance of viability during 120 days and the resistance of the microcapsules under simulated digestion conditions indicate that the use of low viscosity Pruni xanthan as an encapsulating agent is suitable for the microencapsulation process in a spray dryer, increasing the protection of the microorganism.