Search

This research is aimed at preparing the β-galactosidase (βg) and vitamin C (VC) cocapsules stabilized by milk proteins. The effect of different independent parameters including core-coating ratio (10-100%), whey protein isolate (0 : 1), sodium caseinate (0 : 1), and ultrasound power (50-150 W) on physicochemical properties of microcapsules was investigated. The response surface methodology (RSM) defined the optimal conditions. Increasing the WPI values had different effects on the particle size and polydispersity index (PDI). The zeta potential values decreased by decreasing SC values. The βg had better encapsulation efficiency in comparison to VC. Increasing the core-coating ratio showed a negative effect on the enzyme activity. Among the test parameters, the core-coating ratio was effective on the viscosity of microcapsules. Two optimum conditions for co-encapsulation were determined as WPI, SC, core-coating ratio, and ultrasound power of 0, 1, 100%, and 79.4 W and 0.2, 0.8, 100%, and 75 W for microcapsules I and II, respectively. In the next step, the structural and morphological properties of the optimum samples were analyzed. The heterogeneous morphology of microcapsules was observed by SEM analysis. The formation of new interactions between wall materials, βg, and VC was confirmed by FT-IR analysis. XRD analysis revealed that the WPI-coated sample had a higher crystallinity index. Generally, the successful co-encapsulation of βg and VC exhibited the potential of the resultant microcapsules for the industrial production of VC fortified and lactose-free milk. [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]

This study aimed to investigate the effect of voltage (6, 9, and 12 kV) and whey protein isolate (WPI) to lactose (Lac) ratio (3:1, 4:1, and 5:1) on the fabrication of Lactobacillus acidophilus LA5-loaded bionanocomposite powder by the electrospraying method. The highest powder production yield obtained at the lowest value of voltage and WPI/Lac ratio. The entrapment efficiency increased with increasing voltage and decreasing WPI/Lac ratio. After 28 days of storage, respectively a significant and non-significant reduction in the viability of free and encapsulated L. acidophilus was observed. The highest viability of encapsulated and free probiotics was observed at 4 °C. In contrast, the lowest viability of encapsulated and free probiotics was observed at 20 °C. The morphology of the optimized electrosprayed capsules was spherical, round, and smooth. The average size distribution of the electrosprayed capsules was 435 nm. The results of FTIR showed that probiotic bacteria were loaded within the optimized bionanocomposite powder. Investigating the thermograms of the optimized electrosprayed particles and pure powder of WPI and Lac showed that the glass transition temperature of the electrosprayed particles with L. acidophilus was near to that of its polymeric materials. [Display omitted] • L. acidophilus LA5 was loaded successfully in WPI/lactose bionanocomposite powder by electrospraying. • The viability of the loaded L. acidophilus LA5 was studied at −18, 4 and 20 °C during 28 days. • The SEM images of the electrosprayed capsules optimized were spherical, round, similar, and smooth. • The FTIR showed it was possible to establish physical and chemical bonds between probiotic bacteria and used polymers. [ABSTRACT FROM AUTHOR]

Gelatin was extracted from beluga sturgeon (Huso huso, SG) and the effects of sturgeon gelatin hydrolysates (SGH) on physicochemical, textural, and rheological properties of yogurt during 28 days of refrigerated storage were explored in this study. SGH at 2 g/dL in yogurt showed the best survival of Lactobacillus bulgaricus , Streptococcus thermophilus , and Bifidobacterium lactis. Based on the results, SGH at 1 g/dL significantly decreased the flow behavior index (n) while increasing the values of k (consistency coefficient), complex viscosity (η*), and yield stress (τ 0). Dynamic shear rheological properties indicated higher storage modulus (G′), loss modulus (G″), and η * values at all frequency values compared to control (Yc) whereas Ysgh1 g/dL (yogurt with added SG and SGH) had a better solid-like behavior and elastic gel structure. Ysgh had a higher acidification rate during fermentation and water-holding capacity compared to Yc. However, syneresis and hardness increased and decreased at 2 g/dL SGH, respectively. Overall, SGH might be useful as the potential natural ingredients of fat-free set-type yogurt. • Sturgeon gelatin hydrolysates increased the fermentation rate and were associated with lower syneresis. • Sturgeon gelatin hydrolysates caused more solid-like behavior and elastic gel structure, especially at 1 g/dL. • Yogurt containing 1 g/dL sturgeon gelatin hydrolysates showed the highest hardness, adhesiveness and springiness. [ABSTRACT FROM AUTHOR]

Microencapsulation, as one of the most modern methods, has a significant effect on the survival of probiotic bacteria. The present study aimed to determine an optimal formulation for Lactobacillus rhamnosus ATCC 7469 microencapsulation by freeze-drying and using Whey protein isolate, (WPI) crystalline nanocellulose (CNC) and inulin (INU) as wall materials, which can improve the survival of probiotic bacteria against the gastrointestinal condition. For this purpose, WPI, CNC, and INU were used as wall components for the encapsulation of L. rhamnosus ATCC 7469 by mixture design. Then the optimal formulation (WPI: 57.22%, CNC: 25.00%, INU: 17.78%) was determined for minimization of Z-average and zeta potential, as well as maximization of encapsulation efficiency and viability after 60 min at simulated gastrointestinal condition using numerical optimization. FTIR and SEM tests were performed to investigate the interaction between the wall compounds and the surface morphology of the capsules. The selected optimum capsule significantly improved the survivability of probiotic bacteria in simulated gastrointestinal conditions (p < 0.05). • L. rhamnosus ATCC 7469 successfully was microencapsulated in WPI/CNC/INU biocomposite. • The ratio of WPI/CNC/INU in microcapsules wall were optimized by mixture design. • The viability of the microencapsulated L. rhamnosus ATCC 7469 was studied at gastrointestinal condition. • SEM and FTIR tests were used to characterize the properties of the microcapsules. [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]