Co-encapsulação de Lactobacillus rhamnosus e compostos antociânicos extraídos do mirtilo (Vaccinium myrtillus)

Abstract

Regular consumption of probiotics and foods rich in antioxidants such as blueberries are known to be beneficial in maintaining health. This effect is attributed to the therapeutic properties of probiotic microorganisms and the presence of phenolic compounds in blueberry. However, the physicochemical stability and bioavailability of these active substances have represented a great challenge for the food industry. Encapsulation is the technique of wrapping solid, liquid or gaseous materials in small capsules that release their contents under controlled conditions. This technology has been used to enable the protection of these compounds in food, in addition to improving their use by promoting the successful delivery of these bioactive substances in the gastrointestinal tract. Thus, the aim of this study was to evaluate whether co-encapsulation of different concentrations of blueberry extract would have a positive effect on the survival of probiotic bacteria of Lactobacillus rhamnosus. The microcapsules were produced by spray drying, using inulin, gum arabic and maltodextrin as encapsulating agents. The concentrations used were 0% (control capsule; ME-0%), 10% (ME-10%), 50% (ME-50%) and 100% (ME-100%) of blueberry extract. Subsequently, the microcapsules were evaluated for morphology, particle size and distribution, encapsulation efficiency, anthocyanin content, color, resistance to heat treatment, gastrointestinal system simulation and storage viability. An efficiency greater than 80% of encapsulation was obtained. The average size of the microcapsules was between 1.74 μm and 6.29 μm and the shape presented was spherical and with the presence of concavities. Microcapsules with higher concentration of blueberry extract showed greater resistance of Lactobacillus rhamnosus to heat treatments, greater release of these in the intestine during passage through the simulated gastrointestinal system, as well as longer shelf life during storage. Finally, the results of this study showed that the co-encapsulation of blueberry extract improved the viability, and consequently, the survival of Lactobacillus rhamnosus, demonstrating the protective effect of blueberry extract for microencapsulated probiotic culture in spray drying. Furthermore, the encapsulation of probiotic bacteria together with fruit extracts has been little studied.