Encapsulation of Lactobacillus plantarum in porous maize starch

This study investigated the survival of probiotic Lactobacillus plantarum 299v microencapsulated in native maize starch or partially hydrolyzed maize starches after acid, bile and heat treatments. Scanning electron microscopy and confocal scanning laser microscopy confirmed that naturally present cavities and channels in native maize starch were enlarged by enzymatic hydrolysis allowing them to be filled with probiotics. The formulations using the modified starches had significantly higher initial viable cells compared to native starch after freeze-drying. Compared to free cells, the microencapsulated probiotic bacteria showed a significant improvement in acid tolerance. When comparing unmodified and modified starches, the enzymatic treatments did not significantly improve relative survival, but did result in significantly higher total probiotic numbers after exposure to acid (pH = 2.0, 1 h), bile salt (3% w/v, 4 h) and heat (60 °C, 15min). These results demonstrate that porous maize starch granules allow for a high probiotic loading efficiency and provide enhanced protection to various stressful conditions compared to free cells.