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Probiotics must survive in foods and passage through the human mouth, stomach, and small intestine to reach the colon in a viable state and exhibit their beneficial health effects. Probiotic viability can be improved by encapsulating them inside hydrogel-based delivery systems. These systems typically comprise a 3D network of cross-linked polymers that retain large amounts of water within their pores. This study discussed the stability of probiotics and morphology of hydrogel beads after encapsulation, encapsulation efficiency, utilization of natural polymers, and encapsulation mechanisms. Examples of the application of these hydrogel-based delivery systems are then given. These studies show that encapsulation of probiotics in hydrogels can improve their viability, provide favorable conditions in the food matrix, and control their release for efficient colonization in the large intestine. Finally, we highlight areas where future research is required, such as the large-scale production of encapsulated probiotics and the in vivo testing of their efficacy using animal and human studies. • Encapsulation can protect probiotics from noxious environmental conditions • Natural polymer hydrogels are promising systems for delivery of probiotics. • Proteins and polysaccharides are incredibly marvelous polymers to produce of hydrogels. [ABSTRACT FROM AUTHOR]

In this study, active biodegradable films from chitosan (CS) containing 5% w/w Origanum vulgare ssp. gracile essential oil (EO) and 4% w/w cellulose nanofibers (CNF) or lignocellulose nanofibers (LCNF) as nanoreinforcement were developed. GC–MS analysis showed that the most components of EO were carvacrol (49.43%) and then γ-terpinene (17.71%). The CS-EO film had high antioxidant activity and was more effective against E. coli and B. cereus bacteria than bionanocomposite films, which shows the release controlling effect of CNF and LCNF on the bioactive compounds from CS films. EO had not significant effect on the mechanical properties of the films (p > 0.05), while nanofibers had significant effects (p < 0.05) on strain to break (STB) and ultimate tensile strength (UTS). Incorporation of EO and CNF/LCNF in the CS-film also considerably improved solubility and water vapor barrier properties of the films. Color properties were significantly affected by adding of EO and CNF/LCNF. Formation of new hydrogen bonds between the chitosan chains, the EO and nanofibers were confirmed using FT-IR spectroscopy. Morphology of films was viewed using AFM and SEM, suggesting good dispersion of the CNF/LCNF. In general, the properly dispersion state and improving effect of LCNF on properties of CH-EO films was more than CNF. [ABSTRACT FROM AUTHOR]

The performance of whey protein isolate (WPI) and pectin as wall materials in encapsulation of Ziziphora clinopodiodes essential oil by ultrasonication method was compared. In this regard, using the response surface methodology, the influence of ultrasonication (US) power (50–150 W) and core-coating ratio (10–100%) on the properties of microcapsules was evaluated. Increasing US power and core-coating ratio, caused to increase and decrease the particle size, respectively. The polydispersity index (PDI) of WPI coated microcapsules was increased by increasing of US power. The Zeta potential values were increased by increasing of core-coating ratio. Also, the effect of core-coating ratio on encapsulation efficiency was more than US power. Morphological studies by SEM on optimized microcapsules showed regular spherical shapes. X-ray diffraction analysis revealed that the type of the wall material had no effect on the structural properties of the microparticles. FT-IR analysis confirmed the pronounced effect of electrostatic interactions in the formation of microcapsules. [ABSTRACT FROM AUTHOR]

The aim of this research was to prepare of bionanocomposite films based on chitosan (CH) incorporated with Carum copticum essential oil and reinforced with cellulose nanofibers (CNF) or lignocellulose nanofibers (LCNF). The FTIR analysis showed new interactions in bionanocomposites. AFM and SEM analyses showed an increased roughness for bionanocomposites but suggested good dispersion of CNF and LCNF in CH matrix. X-ray diffraction confirmed that the degree of crystallinity was increased by addition of CNF/LCNF. The results suggested that the CH-EO film had high antioxidant activity and was more effective against E. coli and B. cereus bacteria than CH-EO CNF and CH-EO-LCNF films, which shows the release controlling effect of nanofibers. Mechanical properties were improved with addition of EO and CNF/LCNF. Incorporation of EO and CNF/LCNF improved water vapor barrier properties of films. In general, uniform dispersion and improving effect of LCNF on properties of CH-EO films was more than CNF. [ABSTRACT FROM AUTHOR]

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%. [ABSTRACT FROM AUTHOR]