Effect of different concentrations of thermoprotectant on microencapsulation of Lactobacillus rhamnosus GG by spray-drying, and its effect on physicochemical properties and viability

Lactobacillus rhamnosus GG (LGG) is an acceptable probiotic strain that can live and grow at a gastrointestinal acidic pH and on a bile-rich medium. The influence of spray-drying microencapsulation of LGG on the physicochemical parameters and survivability was investigated in the present work. LGG was spray-dried with three different maltodextrin concentrations (6, 12, and 18% w/v). The inlet and outlet air temperatures of the spray-dryer were kept at 170 ± 5°C and 75 ± 5°C, respectively. The physicochemical parameters (moisture content (wet basis), water activity, and colour), viability (colony forming unit/g), and simulated gastrointestinal digestion were all investigated. Only 18% MD was selected on the basis of moisture content and log CFU/g. The total soluble solids (TSS) of 16.28 ± 0.93 °Brix were obtained using 18% MD. The end product had a moisture content of 5.40 ± 0.20%, and a water activity of 0.32 ± 0.02 aw, which were acceptable. The L*, a*, and b* of the final product were 95.14 ± 0.19, -2.33 ± 0.02, and 7.17 ± 0.13, respectively. The spray-dried powder had final probiotic viability of around 108 CFU/g. Based on the study, maltodextrin at 18% (w/v) concentration can be considered as an ideal formulation with acceptable powder characteristics for shielding probiotic microorganisms from harmful conditions of spray-drying.