Solubility as a fundamental variable in the characterization of wall material by spray drying of food components: Application to microencapsulation of Bifidobacterium animalis subsp lactis

The physical and chemical properties of wall materials used in the microencapsulation of active compounds obtained by spray drying determine their application and incorporation into food matrices. Mixtures of 20% wt/wt protein and gum arabic in the following proportions were spray-dried: 75:25 50:50 25:75. The proteinaceous materials used were whole milk powder, soy protein isolate, and skimmed milk powder. The solubility, hygroscopicity, water activity, moisture, bulk density, and the morphology of the powders were evaluated. The physicochemical characterization revealed that increasing the gum arabic concentration in the dispersion to be encapsulated leads to increases in the hygroscopicity and solubility of the powders. In turn, the solubility was increased at low protein concentrations in skimmed milk powder. In conclusion, the physicochemical characterization of spray-dried powders ensures that the selected wall material possesses the necessary requirements for application in various food matrices. The microorganism probiotics have been widely used in the food industry interested in improving the human health and can be conserved by spray drying using different wall materials. Practical applicationsThis study evaluated the physicochemical and morphological properties of mixtures with varying proportions of different wall materials and their application potential in the encapsulation of probiotic microorganisms as the Bifidobacterium animalis. Application of wall materials with a low solubility favored the stability of the probiotic strain encapsulated during storage; this property plays an important role for the subsequent application of the encapsulated food compound, either for release or for the retention of the compound encapsulated. In all cases, these evaluated materials could be used to partially replace gum arabic.