The aim of this study was to evaluate the impact of duration (10, 20 and 30min) and power (100 and 300W) of high-intensity ultrasound (20kHz) on physicochemical properties of beef myofibrillar ...proteins in order to investigate novel process for modification of its functional characteristics. Results showed that augmentation of duration and power of ultrasound led to enhance pH. Also, the water holding capacity and gel strength were improved by increasing pH. The highest value in pH, reactive sulfhydryl content, water holding capacity and gel strength was obtained in sample subjected to 30min of ultrasound at 300W. The particle size distribution of the proteins was decreased after ultrasound treatment because of the cavitation force of ultrasound waves. In this circumstance, an improvement of emulsifying properties can be obtained. Ultrasonic waves had significant effects on the rheological properties of myofibrillar proteins. Treated samples were more elastic and stiffer than control, although the inverse trend was observed after 30min treatment at each power. Finally, a reducing trend in viscosity was observed by increasing time and power of sonication. Ultrasonic treatment could successfully improve functional properties with effect on physicochemical properties of myofibrillar proteins.
•Impact of ultrasound treatment on characteristics of myofibrillar protein were studied.•Different ultrasound duration and intensity caused to reduce viscosity and particle size.•It had a significant effect on rheological properties.•Results indicated that it led to improve functional properties.
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Particle-stabilized Pickering emulsions pose several challenges to scientists researching food delivery systems. This study investigated Pickering emulsions co-stabilized by ...zein-propylene glycol alginate composite nanoparticles (size: 416.4 ± 8.5 nm) and rhamnolipid, quillaja saponin and tea saponin (0.01–1.00%, w/v). The results showed that different types and concentrations of natural small molecular surfactants (NSMS) had an important influence on the stability, microstructure and rheological properties of the Pickering emulsions. The surfactants were able to not only diffuse into the interfacial gaps but also adsorb onto the surface of particles to modulate the interfacial wettability, which was dependent on their types and concentrations. The negatively charged surfactants endowed the droplets with electrostatic repulsion and steric hinderance to prevent their flocculation and coalescence. In vitro digestion fate demonstrated that the presence of natural surfactants delayed the lipid digestion of the Pickering emulsions in the small intestine, particularly by decreasing the release rate of free fatty acids from 57.37% to 10.76% and 7.84% with the addition of quillaja saponin and tea saponin, respectively. The combination of nanoparticles and individual surfactants at the intermediate concentration (0.50%, w/v) exerted a synergistic effect on stabilizing the Pickering emulsions and inhibited lipolysis in the gastrointestinal tract, exhibiting potential applications as a fat replacer.
The effects of extrusion processing temperature on the rheological, dynamic mechanical analysis and tensile properties of kenaf fiber/high-density polyethylene (HDPE) composites were investigated for ...low and high processing temperatures. The rheological data showed that the complex viscosity, storage and loss modulus were higher with high processing temperature. Complex viscosities of pure HDPE and 3.4wt% composite with zero shear viscosity of ⩽2340Pas were shown to exhibit Newtonian behavior while composites of 8.5 and 17.5wt% with zero shear viscosity ⩾30,970Pas displayed non-Newtonian behavior. The Han plots revealed the sensitivity of rheological properties with changes in processing temperature. An increase in storage and loss modulus and a decrease in mechanical loss factor were observed for 17.5wt% composites at high processing temperature and not observed at low processing temperature. Processing at high temperature was found to improve the tensile modulus of composites but displayed diminished properties when processed at low processing temperature especially at high fiber content. At both low and high processing temperatures, the tensile strength and strain of the composite decreased with increased content of the fiber.
Chitosan-based scaffolds offer significant potential in tissue engineering and regenerative medicine. Whilst exhibiting great bio-regenerative and biocompatible properties, their mechanical ...properties remain quite poor. The presented research is focused on the modification of macroporous chitosan scaffolds with various amounts of bioactive ceramics (hydroxyapatite) and its influence on the physical and rheological properties of the composite scaffold. Chitosan/hydroxyapatite composite scaffolds with a highly porous microstructure have been prepared by suspending hydroxyapatite (HAp) particles into the chitosan matrix. According to SEM imaging, homogeneous dispersion of the inorganic phase in a chemically-crosslinked chitosan matrix had been achieved. The obtained composite scaffolds exhibited lower swelling capacity with respect to pure chitosan after 24 h of incubation in Hanks’ balanced salt solution. Rheological measurements show an increase in storage and loss modulus indicating an improvement in mechanical properties under shear stress. Furthermore, no significant change in loss factor (tanδ) was observed indicating no change in composite viscoelastic properties with an increase in HAp content.
•Higher concentration of κ-carrageenan accelerated the gelation of oyster protein.•The κ-carrageenan increased the gel strength of oyster protein (OP).•OP/κ-carrageenan gel had more compact network ...structure compared with OP.
Proteins and polysaccharides commonly coexist in the food system, forming complexes and coacervates to make tailor-made food. In this study, the effects of κ-carrageenan on the rheological behavior, network structure, textures, and molecular force of oyster protein (OP treated with high-pressure homogenization were investigated. Rheological results showed that κ-carrageenan improved the storage modulus of OP, and the higher concentration of κ-carrageenan accelerated the gelation of OP. The second derivative of infrared spectroscopy revealed that κ-carrageenan contributed to the formation of β-sheet in OP. Molecular force and texture analysis showed that κ-carrageenan might promote the increase of hydrophobic bonds and disulfide bonds, which was helpful to enhance gel strength. The microstructure showed that the OP gel with 1.5% κ-carrageenan had a compact network structure with abundant minor mesh and sheet edge. This study reveals the gelation mechanism of OP/κ-carrageenan and provides the theoretical basis for developing innovative oyster products.
With an aim to prepare a novel formula for healthy oleogel, diacylglycerol (DAG)-rich oil as a continuous oil phase, ethyl cellulose (EC) as a gelator and γ-oryzanol (GO) as an antioxidant were used. ...Effects of EC viscosity and EC/GO mass ratio on the physicochemical properties were studied. Besides, interactions between the components were analyzed by Fourier transform infrared spectroscopy and molecular dynamics (MD) simulation. The EC with a viscosity of 18–22 mPa s resulted in slightly higher oil binding capacity (99.84% vs 98.55% at 10% EC, and 99.92% vs 99.49% at 12% EC) and significantly stronger hardness and gel strength of DAG oil oleogels than EC with a viscosity of 45–55 mPa s. Moreover, the hardness and rheological properties of oleogels were negatively correlated to GO addition. MD simulation was used to understand this effect of GO addition, showing that EC-GO complex had lower binding energy (−107.14 kJ/mol) than the complexes of GO-DAG (−105.64 kJ/mol) and EC-DAG (−101.96 kJ/mol), leading to the disruption of the capacity of EC to structure DAG-rich oil. Interactions between the components were mainly governed by van der Waals interactions. The peroxide value of the oleogels decreased by 1.89 mmol/kg as EC18/GO mass ratio changed from 12:0 to 12:4, indicating good antioxidant activity of GO. Overall, the characteristics of DAG oil oleogels could be modulated by the addition of GO. The study may provide considerable potential to develop healthy and stable oleogels with high DAG, low saturated and trans-fatty acids for food industry.
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•Diacylglycerol-rich oil was gelled with ethyl cellulose to form a healthy oleogel.•4% addition of γ-oryzanol (GO) markedly reduced the hardness of oleogel.•Negative effect of GO on oleogel properties was revealed by theoretical calculation.•Enhanced oxidative stability of oleogel was obtained in the presence of GO.
The state of dispersion of two types of graphite nanoplates, namely graphene nanoplates (GnPs) and expanded graphite (EG), in polycarbonate (PC)/poly(styrene-acrylonitrile) (SAN) = 60/40 wt.% blends ...prepared with a two-stage melt-mixing approach is investigated and its influence on the melt rheological and electrical properties is evaluated. By using two different parameter sets in the first mixing step, different states of the filler dispersion are achieved in the PC. After mixing with SAN, the more stringent premixing conditions (higher mixing speed and longer mixing time) resulted in a lower proportion of visible graphitic structures. The EG achieved a better dispersion than the GnPs. The electrical conductivity is lower for each filler type when the samples show a better dispersion. On the other hand, a better dispersion led to a higher reinforcing effect (as observed in melt rheological studies). By determining the shear dilution exponent and applying the Eilers equation to the rheological results, the strengthening effect and the differences in the state of the filler dispersion between the two premixing conditions were evaluated.
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•Dispersion of two types of graphite nanoplates in PC/SAN blends investigated.•Due to the premixing in the PC, the nanoplates are in the PC after mixing with SAN.•Two different premixing conditions influence the dispersion of fillers differently.•Lower electrical conductivity for blends with better filler dispersion.•Eilers equation applied to rheological results able to detect dispersion differences.
This study examined the potential effect of ball milling on maize starch (MS), pink potato starch (PPS), and their blends in various ratios (90:10, 80:20, and 70:30) on the pasting and rheological ...properties. Ball-milling led to changes in the particle size, ranging from 652.9 to 6488 nm, and a decrease in relative crystallinity (RC), as confirmed by XRD. Ball-milling increased amylose concentration in blend with the ratio of 90:10 up to 32.53 %, indicating structural alterations and molecular interactions. FESEM analysis confirms significant changes in the surface and particle sizes and starch gels with honeycomb structures. FTIR and Raman spectroscopy revealed a decrease in the intensity of the 1044 cm−1 and 480 cm−1 bands, respectively, signifying structural changes. Pasting parameters like peak viscosity and gelatinization behavior varied with PPS incorporation. The 80:20 blend had the highest viscosity, demonstrating PPS's capacity for high-viscosity starch paste. Rheological measurements of starch blends exhibited shear-thinning behavior, whereas the viscoelastic properties of the blends are influenced by particle size and the ratio of pink potato starch. Ball-milling treatment affects the granules and causes molecular-level interactions between the particles. This results in unique rheological properties of the starch blends, making them suitable for various applications.
Apple pomace (AP) was processed into a freeze-dried powder to add into stirred-type yogurt to create 1, 2, and 3% (w/w) AP-fortified yogurt. Both texture analysis and rheological testing were used to ...evaluate the effect of AP on the structure and texture of yogurt during cold storage. The results indicated that apple pomace altered the structure of stirred yogurt, making it firmer and more cohesive, increased its viscosity and significantly reduced whey release during cold storage. Stronger influence on the parameters was observed at higher AP concentrations. Apple pomace added to a diluted yogurt system has the potential to stabilise the acid drink and reduce the sedimentation of protein aggregates. Addition of AP to already fermented milk gel allowed a higher concentration of AP (up to 6% w/w) to be incorporated, which made the stirred yogurt and yogurt drinks a vehicle for delivering a higher level of dietary fibre and phytochemicals (as compared to AP added to milk prior to fermentation). This study demonstrated that apple pomace has a potential as a natural stabiliser as well as a dietary fibre source in stirred type yogurts and yogurt drinks.
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•Apple pomace (3%) reduced the syneresis of stirred yogurt by half that of the control.•AP addition (2–3%) resulted in a firmer, more viscous and cohesive stirred yogurt.•AP contributed total phenolics and dietary fibre to stirred yogurt.•AP (4–6%) could stabilise yogurt drinks with low MSNF (<5%).
