Microencapsulation of Lactobacillus acidophilus with konjac glucomannan hydrogel

In this study, a novel microcapsule was generated by the encapsulation of Lactobacillus acidophilus using konjac glucomannan (KGM) hydrogel. Micropowder of L. acidophilus was mixed with gel particles, which was encapsulated in a microcapsule wall material produced by the combination of konjac oligosaccharides (KO) and sodium alginate (SA). The encapsulation and stability (both storage and digested) along with the microstructure of the capsules were analysed by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The results revealed that the microencapsulation rate was 62.5%, Dialdehyde glucomannan (DAK)/gelatin crosslinked gel formed numerous interconnected pores, and the pore wall was thick and smooth, which could well protect the microorganisms inside. Study of the storage stability showed that microencapsulated L. acidophilus could be stored for longer at both 4 degrees C and 25 degrees C. Gastric fluid simulation results confirmed that microencapsulation improved the acid resistance of L. acidophilus. An enteric test revealed that the number of viable bacteria increased with an extension of the digestion time, and no solid particles were observed in the solution after 45 min. In addition, KO was applied as both prebiotic of L. acidophilus and anti-freeze agent. It is illustrated that the survival rates of L. acidophilus (with and without encapsulated) were significantly increased during freeze drying situation. This work contributes a pathway on the construction of advanced L. acidophilus microcapsules by using KGM as a main precursor. (C) 2017 Elsevier Ltd. All rights reserved.