Starch- and carboxymethylcellulose-coated bacterial nanocellulose-pectin bionanocomposite as novel protective prebiotic matrices

The present research evaluated the effects of starch and carboxymethylcellulose (CMC) incorporation with bacterial nanocellulose-pectin bionanocomposite (BNC-pec) on the protection of Bacillus coagulans under drying and simulated gastrointestinal (SGI) conditions. The BNC-pec used for the bacteria entrapment was coated with starch and CMC. This was followed by the investigation of the surface morphology, molecular bondings and crystallinity of such hydrocolloids. SEM images revealed that starch created smooth and compact surface compared to CMC did disrupted and patchy for BNC-pec. FTIR analysis revealed the hydrogen bonds as the most important intermolecular interactions in the matrices, and there existed no evidence of the formation of chemical bonds via coating, thus entrapping the cells without chemical reactions. In addition, the coating transformed the semi-crystallinity structure of the BNC-pec into amorphous. Prebiotic score of BNC-pec increased more in the case of the CMC-coated compared to starch-coated. Although the BNC-pec increased the survivability to approximately 95%, CMC and starch coating could not improve it during microwave drying. CMC and starch caused an upgrade in the survival rate resulting from the BNC-pec from 75 to 92.68 and 9737%, respectively under SGI conditions. In order to improve the cell viability under both drying and SGI conditions, the prebiotic matrix was prepared using 60% BNC, 15% pectin and 25% CMC or starch as coating. The matrices yielded high survivability of B. coagulans at 66.67 (CMC-coated) and 61.67% (starch-coated) compared to free cell (47.93%). The present findings proposed novel prebiotic bionanocomposites as good promises for probiotics protection. (C) 2016 Elsevier Ltd. All rights reserved.