Optimization of a water-in-oil emulsion containing Limosilactobacillus reuteri: Applicability of pequi oil as a continuous phase

Abstract

• Encapsulation by w/o emulsion enables probiotic addition to non-aqueous matrices. • Most stable emulsions presented a high emulsification index even after the storage. • Encapsulation efficiency was more than 96 % in the two best emulsion treatments. • Satisfactory cell maintenance and survival were obtained by emulsion encapsulation. The use of emulsions in probiotic encapsulations has gained attention because emulsions enable the addition of probiotic cells to non-aqueous matrices. Phase proportions and surfactant concentrations are the main factors responsible for emulsion stability. Interest in alternative oils with functional properties, such as pequi oil, is also increasing. The aim of this study was to optimize water-in-oil emulsions containing Limosilactobacillus reuteri DSM 20016, with various surfactant concentrations (5, 10 and 20 g/kg) and w/o ratios (30:70, 40:60 and 50:50). The emulsion stability (emulsification index, backscattering, and turbiscan stability), probiotic encapsulation efficiency, and cell viability during storage and under in vitro gastrointestinal simulation were analyzed. The two most stable emulsions had 40:60 w/o and 10 or 20 g/kg of surfactant. Both samples promoted high encapsulation efficiency and protection during storage and in vitro gastrointestinal testing. A new formulation constructed under optimal conditions, with soybean oil replaced by pequi oil as the continuous phase, showed a slight improvement in emulsion stability and the same cell viability parameters. Therefore, this carrier is appropriate for use in probiotic emulsion systems.