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Keywords:

  • Electron microscopy;
  • hybridisation system;
  • Lactobacillus acidophilus;
  • microencapsulation;
  • prebiotic substrate;
  • probiotics

Summary

The objective of this study was to evaluate the effects of prebiotic substrates on the growth of Lactobacillus acidophilus ATCC 43121 and to investigate the utilisation of these prebiotic substrates as coating materials for microencapsulation. The cell growth of L. acidophilus ATCC 43121 was significantly increased in the presence of fructooligosaccharide, lactulose and raffinose. The microencapsulation of L. acidophilus ATCC 43121 cells was carried out by dry surface reforming process (hybridisation) using the selected prebiotic substrates and the enteric coating material, SuretericTMsans. Scanning and transmission electron microscopy revealed that the double-microencapsulated bacteria exhibited smooth, rounded external surfaces, with a thick external coating composed of the prebiotic substrates and the Sureteric. The acid (artificial gastric juice) or heat tolerance (55 °C) of the double-microencapsulated preparations (prebiotic and enteric coating) was significantly higher than that of the uncoated and single-coated (enteric coating) preparation at prolonged acid (5 h) or heat exposure (3 h). On the contrary, no significant differences were found in salt tolerance. During the storage up to 20 days at 25 and 37 °C, the stability of L. acidophilus ATCC 43121 was significantly improved by double-microencapsulation.