Spray dried lactobacilli maintain viability and feruloyl esterase activity during prolonged storage and under gastrointestinal tract conditions

The use of lactobacilli with feruloyl esterase (FE) activity in the development of functional foods has gained considerable interest in recent years. Microencapsulation of FE-producing bacteria to facilitate their incorporation into food is a challenge. The aim of this study was to evaluate survival and maintenance of FE activity during storage at 4 degrees C and under simulated gastrointestinal tract (GIT) conditions of microcapsules of FE-producing Lactobacillus (Lb.) strains obtained by spray drying. Lb. fermentum CRL1446 and Lb. johnsonii CRL1231 powders maintained viability at concentrations >= 10(6) CFU/g (minimum probiotic dose) when stored at 4 degrees C for 12 months. Lb. acidophilus CRL1014 powders were only able to maintain >= 10(6) CFU/g during 4 months of storage. FE activity was conserved in three microencapsulated strains evaluated, an increase of specific activity being observed until month 12 of storage. Powders of the three strains incubated under GIT conditions maintained their viability (>= 10(6) CFU/g), but specific FE activity was only detected in Lb. fermentum and Lb. johnsonii powders (0.80-0.83 and 0.21-0.56 U/mg, respectively). CRL1446 and CRL1231 microcapsules were able to resist prolonged storage and GIT conditions, retaining FE activity and preserving their probiotic potential and could be incorporated into functional foods.