Optimization of a spray-drying process for the production of maximally viable microencapsulated Lactobacillus pentosus using a mixture of starch-pulque as wall material

The objective of this study was to optimize the spray-drying process for the production of microencapsulated Lactobacillus pentosus with maximum viability using a starch-pulque mixture. A central model with a rotating design composed of two factors was used: inlet air temperature (92-148 degrees C) and total solids in the mixture (24-31%). The most optimal conditions of the drying process were an air inlet temperature of 100 degrees C with 30% total solids with a 98% encapsulation efficiency. The properties of the powders obtained were good with low values for moisture content (3%), water activity (0.26) and hygroscopicity (7.0 g/100 g). For the microencapsulated cells, the resistance to bile salts obtained was > 98.9%, and the resistance to a low pH was 100%. The survival of L pentosus was high during storage at 4 degrees C. The mixture of a commercial modified starch (N-Lok) with pulque showed good characteristics as an encapsulating material.