Microencapsulação de Lactobacillus acidophilus por spray drying empregando pectina e concentrado proteico de soro de leite como agentes encapsulantes

Abstract

The Increase in nutritional awareness has driven the demand for and consumption of functional foods. Among these, probiotics stand out, defined as live microorganisms that, when administered in adequate daily amounts, confer benefits to human health. However, these microorganisms are sensitive to adverse conditions and to exert their effects they need to remain metabolically viable until the intestine. Thus, strategies for maintaining the viability of probiotics have been developed, among them, microencapsulation, suggested as a promising method for protecting probiotics. Furthermore, the choice of encapsulating agents is essential, as the material used contributes to the efficiency of microencapsulation and the stability of microcapsules. As the physicochemical characteristics of encapsulating agents are different, a combination of materials is often chosen, seeking better results. The objective was to evaluate the microencapsulation technique by spray drying, using pectin and whey protein concentrate as encapsulating agents on the viability of Lactobacillus acidophilus. Microcapsules were produced with different concentrations of pectin (ATM or BTM) and whey protein concentrate (CPS): T1 = 1:7 ATM:CPS; T2 = 0.5:7.5 ATM:CPS; T3 = 1:7 BTM:CPS and T4= 0.5:7.5 BTM:CPS, and evaluated for the efficiency of microencapsulation, the viability of the encapsulated material in gastric and intestinal juice in vitro, and during storage (under refrigeration 4 ºC ± 1 and room temperature 25 ºC ± 1), at times 0, 15, 30, 45, 60 and 90 days. The microcapsules were characterized in terms of morphology and physical-chemical properties. The encapsulation efficiency varied between 80.91% (T4) and 91.72% (T2). The viability of the microcapsules, after the simulated digestive tract conditions, was 80.63% (T2) followed by 79.96% (T3) and 71.65% (T4), indicating good performance of the microcapsule treatments in protecting the probiotics. When stored at 4 ºC ± 1, T2 preserved probiotic viability longer (90 days), while at room temperature (25 ºC ± 1), T3 and T4 maintained bacterial viability for up to 60 days, compared to T2, whose viability was up to 45 days. The morphology of the microcapsules presented a spherical shape and some concavities. Water activity values varied between 0.35 ± 0.05 and 0.51 ± 0.01; humidity between 4.38 ± 0.05% and 5.83 ± 0.20%; solubility between 74.61% and 82.06%; and hygroscopicity between 9.47% and 12.28%. In Spectroscopy in the Infrared Region by Fourier Transform, the spectra demonstrated the characteristics of encapsulating agents after spray drying. Considering the best results obtained regarding the maintenance of probiotic viability in simulated gastrointestinal conditions and under storage conditions, microcapsules with T2 and T3, especially T3, stood out. In general, the microencapsulation of Lactobacillus acidophilus with the encapsulating agents used was found to be feasible, since the encapsulation efficiency was adequate and the viability of the simulated gastrointestinal conditions, storage at room and refrigerated temperatures, were favorable in terms of preservation. of probiotics, in most of the evaluated treatments.