In situ produced exopolysaccharides by Bacillus coagulansIBRC-M 10807 and its effects on properties of whole wheat sourdough.

This study aimed to investigate in situ exopolysaccharides (EPSs) production by Bacillus coagulans IBRC-M 10807 under different fermentation conditions to improve the technical-functional properties of whole wheat flour sourdough and obtain high-quality products. For this purpose, the effectiveness of four efficient factors including B. coagulans (8 Log CFU/g), FOS (0%, 2.5%, and 5% based on flour weight), fermentation temperature (30, 35, and 40°C), and fermentation time (12, 18, and 24 h) was investigated on the production of functional sourdough. Our work focused on optimizing probiotic sourdough by investigating probiotic viability, pH, total titratable acidity, antioxidant properties, and EPS measurement. The first optimal formulation for maximized production of the in situ EPSs by the numerical optimization included FOS 0%, B. coagulans IBRC-M 10807 8 Log CFU/g, fermentation temperature of 30°C, and fermentation time of 12 h. In this case, EPSs was 59.28 mg/g and probiotic was 10.99 Log CFU/g. The second optimal formula by considering the highest viability of probiotic together with EPS production was determined as FOS 4.71%, B. coagulans IBRC-M 10807, 8 Log CFU/g, fermentation temperature of 30°C, and fermentation time of 20 h. The predicted amount of the EPSs and probiotic viability via the second formulation were 54.4 mg/g and 11.18 Log CFU/g, respectively. Analyses of optimal sourdough using FTIR, SEM, and DSC revealed that FOS and probiotics significantly reduced the enthalpy of amylopectin retrogradation and delayed it compared to other samples. Therefore, improving the final product's technological capabilities and shelf life can be credited with potential benefits.

Development of bacterial cellulose based slow-release active films by incorporation of Scrophularia striata Boiss. extract.

Novel bacterial cellulose (BC) based monolayer and multilayer films, incorporating 5wt.% Scrophularia striata Boiss. extract (SE) were obtained. The effect of lamination and ß-cyclodextrin (ß-CD) inclusion complexation of SE on morphological, physical, antioxidant and release properties of films were investigated. FT-IR results reflected that some new interactions have occurred between BC and ß-CD. The XRD analyses showed a decrease in diffraction intensities of BC by addition of free SE. SEM results indicated that the intrinsic compactness of the BC film was preserved by addition of SE/ß-CD complex. Lamination and SE/ß-CD addition enhanced the mechanical properties. SE loaded films exhibited a good antioxidant activity. Release studies indicated that the release rate and diffusion coefficient (D) of SE in 95% ethanol simulant were significantly decreased by lamination and complexation of SE with ß-CD. Results suggest that SE loaded BC films may be used as controlled release antioxidant food active packaging.

Effect of chitin nanofiber on the morphological and physical properties of chitosan/silver nanoparticle bionanocomposite films.

The effects of silver nanoparticles (AgNPs) at 1% wt. and different concentrations of chitin nanofiber (CHNF) (1.5-6% wt.) on tensile properties, water vapor permeability (WVP), solubility, swelling, color properties and morphological characteristics of chitosan nanocomposite films were studied. FTIR results confirmed that the affinity of CHNF for interaction with chitosan chains is more than AgNPs. SEM images showed that CHNF was uniformly distributed in the polymer matrix. X-ray diffraction confirmed that the degree of crystallinity was increased by addition of 6% CHNF. Response surface methodology (RSM) was used to determine the optimum amount of CHNF as nano filler. The optimization was based on maximizing tensile strength, Young's modulus, elongation at break, L* and decreasing WVP, solubility and swelling. The results showed that the AgNPs had a negative effect on mechanical and color properties of chitosan films. But incorporation of CHNF improved their mechanical and barrier properties significantly. Lowest WVP, solubility and swelling of nanocomposite films were respectively for 6, 2 and 2% wt. of CHNF content. Considering all physical and mechanical parameters, the optimal value calculated for CHNF, was 4.55%.