Influence of electrostatic interactions on the formation and stability of multilayer fish oil-in-water emulsions stabilized by whey protein-xanthan-locust bean complexes

Structural characterization and mast cell stabilizing activity of Red-edge tea polysaccharide

The potential anti-allergic properties of tea have been demonstrated in studies supporting theanine and catechin. However, research on tea polysaccharides' anti-allergic properties has been limited. In this study, we extracted red-edge tea crude polysaccharide (RETPS) and evaluated its anti-allergic activity using the mast cell, passive cutaneous anaphylaxis, and passive systemic anaphylaxis models. We purified RETPS using the DEAE-52 cellulose column, analyzed its composition and structural characteristics, and compared the anti-allergic properties of different polysaccharide fractions. The purified components RETPS-3 and RETPS-4 displayed higher galacturonic acid content and lower molecular weight (106.61 kDa and 53.95 kDa, respectively) compared to RETPS (310.54 kDa). In addition, RETPS-3 and RETPS-4 demonstrated superior anti-allergic activity than RETPS in mice's passive cutaneous and systemic allergic reactions. Our findings provide evidence of the anti-allergic potential of tea polysaccharides and offer a theoretical foundation for developing tea polysaccharides as a functional anti-allergic food product.

Formation mechanism of off-flavor and the inhibition regulatory strategies in the algal oil-loaded emulsions-a review

Algal oil rich in docosahexaenoic acid is easily oxidized and degraded to produce volatile short-chain compounds, leading to the deterioration of product flavor. Currently, the emulsion delivery of algal oil provides a promising approach to minimize oxidative deterioration and conceal its off-flavor. However, algal oil emulsions would also experience unanticipated oxidation as a result of the large specific surface area between the aqueous phase and the oil phase. The current paper offers a mechanism overview behind off-flavor formation in algal oil emulsions and explores corresponding strategies for the inhibition regulation. Additionally, the paper delves into the factors influencing lipid oxidation and the perception of off-flavors in such emulsions. To mitigate the development of off-flavors in algal oil emulsions resulting from oxidation, it is crucial to decline the likelihood of lipid oxidation and proactively prevent the creation of off-flavors whenever possible. Minimizing the release of volatile off-flavor compounds that are inevitably generated is also considered effective for weakening off-flavor. Moreover, co-encapsulation with particular desirable aroma substances could improve the overall flavor characteristics of emulsions.

Effect of xanthan gum (XG) and carrageenan (CG) ratio on casein (CA)-XG-CG ternary complex: Used to improve the stability of liquid diabetes formula food for special medical purposes

Poor storage stability limits the application of liquid diabetes formula food for special medical purposes (L-D-FSMP) in maintaining blood sugar stability in diabetic patients. This work aims to improve the stability of L-D-FSMP by adjusting the ratio of xanthan gum (XG) and carrageenan (CG) in casein (CA)-XG-CG ternary complex. The centrifugal sedimentation rate results showed that the compound ratio of XG and CG had a greater impact on L-D-FSMP storage stability. Transmission electron microscopy (TEM) results showed that the combination of CA, XG and CG occurred. Fourier transform infrared spectroscopy (FTIR) results showed that CA, XG and CG were mainly combined through hydrogen bonds and ionic bonds to form a CA-XG-CG ternary complex. When the ratio of XG and CG was 1:1, the number of disulfide bonds was the largest. The results of three-phase contact angle and emulsifying ability confirmed that when the ratio of XG and CG was 1:1, CA-XG-CG had the strongest emulsifying ability. The particle size distribution and zeta-potential results showed that when the ratio of XG and CG was 1:1, L-D-FSMP had the narrowest particle size distribution range and the strongest stability. These results may provide valuable information for the production of stable L-D-FSMP.

Interfacial multilayer self-assembly of protein and polysaccharides: Ultrasonic regulation, stability and application in delivery lutein

In this study, the layer-by-layer adsorption behavior of sodium caseinate, pectin, and chitosan on the oil-water interface was illustrated using multi-frequency ultrasound. We investigated the impact of ultrasound on various factors, such as particle size, zeta potential, and interfacial protein/polysaccharide concentration. It was observed that ultrasound has significantly decreased droplet size and increased the surface area at the interface, hence promoting the adsorption of protein/polysaccharide. In the sonicated multilayer emulsion, the concentrations of interface proteins, pectin, and chitosan increased to 84.82 %, 90.49 %, and 83.31 %, respectively. The findings of the study indicated that the application of ultrasonic treatment had a significant impact on the emulsion's surface charge and the prevention of droplet aggregation. As a result, the stability of the emulsion system, including its resistance to salt, temperature, and storage conditions, has been significantly improved. Moreover, the emulsion showed an increase in the retention rate of lutein by 21.88 % after a high-temperature water bath and by 19.35 % after UV irradiation. Certainly, the multilayer emulsion treated with ultrasound demonstrated a superior and prolonged releasing behavior. These findings demonstrated the suitability of the ultrasound treatment for the preparation of emulsions to deliver bioactive compounds.

Encapsulation of grape seed oil in oil-in-water emulsion using multilayer technology: Investigation of physical stability, physicochemical and oxidative properties of emulsions under the influence of the number of layers

Many studies have shown that grape seed oil (GSO) is one of the vegetable fats that are plentiful in essential fatty acids and can be used as a fat substitute or to modify fat in food products to reduce saturated fatty acids. However, due to its low solubility and high sensitivity to oxidation, it is necessary to develop delivery systems that can distribute GSO in food more effectively. Recently, the preparation of emulsions using the layer-by-layer (LBL) method has many advantages in delivering lipid-soluble functional compounds. This research was used to check the formation of GSO oil-loaded primary, secondary and tertiary multilayer emulsions stabilized by mixture of anionic gelatin, cationic chitosan, and anionic basil seed gum (BSG) as the aqueous phase at pH 5, prepared using a layer-by-layer electrostatic deposition technique. Multilayer emulsions prepared by GSO and a mixture of gelatin, chitosan, and BSG as the aqueous phase at pH 5. Finally, the effect of the number of layers on the physicochemical properties (particle size, viscosity, turbidity, refractive index, and physical stability) and oxidative stability (peroxide value, thiobarbituric acid value, and fatty acid profile) during the storage time (30 days) at two temperatures 25 °C & 4 °C was investigated. Also, the zeta potential and Fourier transform infrared spectroscopy (FTIR) of mono-layer and multi-layer emulsions were investigated. The results revealed that by increasing the number of layers of multi-layer emulsion of GSO, the stability has improved. Thus, the tertiary emulsion has been more effective than the other two emulsions in maintaining the physicochemical characteristics and stability over time (P < 0.001). Morphological characterization and FTIR spectroscopy results confirmed that gelatin, chitosan, and BSG were successfully loaded into the LBL emulsions. This study can improve the original percept of multilayer emulsions and promulgate their potential applications for the entire encapsulation of essential fatty acids to enrich and prevent peroxide attack.

Combined effects of high-intensity ultrasound treatment and hydrogen peroxide addition on the thermal stabilities of myofibrillar protein emulsions at low ionic strengths

In this study, the effects of high-intensity ultrasound (HIU) treatment combined with hydrogen peroxide (H2O2) addition on the thermal stability of myofibrillar protein (MP)-stabilized emulsions in low-salt conditions were investigated. Results showed that compared to using either HIU or H2O2 treatment alone, HIU treatment combined with H2O2 was most effective in enhancing the physical stability of emulsions. Moreover, the emulsion stabilized by MPs co-treated with HIU and H2O2 exhibited the most uniform distribution, highest absolute zeta potential, and optimal rheological properties upon heating. This combination effect during heating was caused by the inhibition of disulfide bond cross-linking of myosin heads by H2O2 and the dissociation of filamentous myosin structures using the HIU treatment. In addition, the results of oxidative stability analysis indicated that the addition of H2O2 increased the content of oxidation products; however, the overall influence on the oxidative stability of emulsions was not significant. In conclusion, the combination of HIU and H2O2 treatment is a promising approach to suppress heat-induced MP aggregation and improve the thermal stability of corresponding emulsions.

The droplet breakup model and characteristics of pH-shifted peanut protein isolate-high methoxyl pectin stabilised emulsions under ultrasound

The effect of pH on the occurrence states of peanut protein isolate (PPI) and high methoxyl pectin (HMP), and droplet breakup model of the emulsions under ultrasound were studied. Particle size distribution and scanning electron microscopy results showed that PPI-HMP existed a soluble complex at pH 5.0, had no interaction at pH 7.0, and was co-soluble at pH 9.0. Droplet breakup model results revealed that the characteristics of emulsion stabilised by PPI-HMP treated at pH 5.0 was different from that at pH 7.0 and 9.0. The average diameter of the droplet well satisfied the model. According to rheological properties, interface tension, and microstructure, the formation mechanism and characteristics of emulsion stabilised by PPI-HMP treated at pH 5.0 was different from that at pH 7.0 and pH 9.0. The research provided a reference for constructing emulsions using pH-shifted PPI-HMP under ultrasound.

Pickering Emulsions Stabilized by Tea Water-Insoluble Protein Nanoparticles From Tea Residues: Responsiveness to Ionic Strength

Tea water-insoluble protein nanoparticles (TWIPNs) can be applied to stabilize Pickering emulsions. However, the effect of ionic strength (0–400 mmol/L) on the characteristics of Pickering emulsions stabilized by TWIPNs (TWIPNPEs) including volume-averaged particle size (d_4,3), zeta potential, microstructure and rheological properties is still unclear. Therefore, this work researched the effect of ionic strength on the characteristics of TWIPNPEs. The d_4,3 of TWIPNPEs in the aquatic phase increased with the increase in ionic strength (0–400 mmol/L), which was higher than that in the SDS phase. Furthermore, the flocculation index of TWIPNPEs significantly (P < 0.05) increased from 24.48 to 152.92% with the increase in ionic strength. This could be verified from the microstructure observation. These results indicated that ionic strength could promote the flocculation of TWIPNPEs. Besides, the absolute values of zeta potential under different ionic strengths were above 40 mV in favor of the stabilization of TWIPNPEs. The viscosity of TWIPNPEs as a pseudoplastic fluid became thin when shear rate increased from 0.1 to 100 s⁻¹. The viscoelasticity of TWIPNPEs increased with increasing ionic strength to make TWIPNPEs form a gel-like Pickering emulsion. the possible mechanism of flocculation stability of TWIPNPEs under different ionic strengths was propose. TWIPNs adsorbed to the oil-water interface would prompt flocculation between different emulsion droplets under the high ionic strength to form gel-like behavior verified by CLSM. These results on the characteristics of TWIPNPEs in a wide ionic strength range would provide the theoretical basis for applying Pickering emulsions stabilized by plant proteins in the food industry.

Effect of NaCl on the Rheological, Structural, and Gelling Properties of Walnut Protein Isolate-κ-Carrageenan Composite Gels

In this study, we discovered that a certain concentration of Na⁺ (15 mM) significantly improved the bond strength (12.94 ± 0.93 MPa), thermal stability (72.68 °C), rheological properties, and textural attributes of walnut protein isolate (WNPI)-κ-carrageenan (KC) composite gel. Electrostatic force, hydrophobic interaction, hydrogen bond, and disulfide bond were also significantly strengthened; the α-helix decreased, and the β-sheet increased in the secondary structure, indicating that the protein molecules in the gel system aggregated in an orderly manner, which led to a much denser and more uniform gel network as well as improved water-holding capacity. In this experimental research, we developed a new type of walnut protein gel that could provide technical support for the high-value utilization and quality control of walnut protein.

Protein-polysaccharide interactions for the fabrication of bioactive-loaded nanocarriers: Chemical conjugates and physical complexes

As unique biopolymeric architectures, covalently and electrostatically protein-polysaccharide (PRO-POL) systems can be utilized for bioactive delivery by virtue of their featured structures and unique physicochemical attributes. PRO-POL systems (i. e, microscopic /nano-dimensional multipolymer particles, molecularly conjugated vehicles, hydrogels/nanogels/oleogels/emulgels, biofunctional films, multilayer emulsion-based delivery systems, particles for Pickering emulsions, and multilayer coated liposomal nanocarriers) possess a number of outstanding attributes, like biocompatibility, biodegradability, and bioavailability with low toxicity that qualify them as powerful agents for the delivery of different bioactive ingredients. To take benefits from these systems, an in-depth understanding of the chemical conjugates and physical complexes of the PRO-POL systems is crucial. In this review, we offer a comprehensive study concerning the unique properties of covalently/electrostatically PRO-POL systems and introduce emerging platforms to fabricate relevant nanocarriers for encapsulation of bioactive components along with a subsequent sustained/controlled release.

Effects of the Incorporation of Calcium Chloride on the Physical and Oxidative Stability of Filled Hydrogel Particles

In this study, the effects of calcium chloride (CaCl2) addition on the physical and oxidative stabilities of filled hydrogel were investigated. The results revealed that CaCl2 significantly enhanced the particle size, interfacial layer thickness, apparent viscosity, and viscoelastic behavior of filled hydrogels and decreased their light and whiteness values (p < 0.05). This phenomenon was mainly attributed to the strong binding ability between Ca2+ and protein/pectin mixtures, which were present in the interfacial area or aqueous phase, as verified by cryo-scanning electron microscopy results. Moreover, lower levels of CaCl2 (2 or 4 mM) significantly enhanced the oxidative stability of filled hydrogels (p < 0.05), particularly at a concentration of 4 mM. However, a higher level of CaCl2 (6 or 8 mM) resulted in an electrostatic shielding effect, which resulted in the aggregation of multiple droplets and the flocculation of the filled hydrogels, which negatively affected the oxidative stability of filled hydrogels. The findings of this study indicated that appropriate Ca2+ levels (4 mM) improved the physical and oxidative stability of filled hydrogel, and this finding may provide useful insights for the development of effective delivery systems for specific applications.

Study on the emulsification and oxidative stability of ovalbumin-pectin-pumpkin seed oil emulsions using ovalbumin solution prepared by ultrasound

Pumpkin seed oil (PSO), which is a valuable compound with high nutritional value used for the prevention of various chronic diseases, is prone to oxidation. In this work, small and uniform (su) ovalbumin (OVA) and pectin (PEC) were used to stabilize PSO in the form of an emulsion. The results showed that suOVA-PEC-PSO emulsion with a droplet size of 9.82 ± 0.05 μm was successfully self-assembled from PSO, PEC, and suOVA solution (with a droplet size of 230.13 ± 14.10 nm) treated with 300 W ultrasound, owing to the formation of a more stable interfacial film on the surface of droplets. The interfacial, rheological, emulsifying, and antioxidant properties of the suOVA-PES-PSO emulsions were excellent, owing to the synergistic effects between PEC and suOVA solution. Moreover, the physical stability of the suOVA-PEC-PSO emulsions to salt stress, a freeze-thaw cycle, and heat treatment was also increased and the oxidation of linolenic acid was notably delayed. These results have extended the food-related applications of OVA and PSO, and provide a promising foundation for further exploration of the self-assembly of composite emulsions by small and uniform proteins.

Influence of Whey Protein Micro-Gel Particles and Whey Protein Micro-Gel Particles-Xanthan Gum Complexes on the Stability of O/W Emulsions

Appropriate pretreatment of proteins and addition of xanthan gum (XG) has the potential to improve the stability of oil-in-water (O/W) emulsions. However, the factors that regulate the enhancement and the mechanism are still not clear, which restricts the realization of improving the emulsion stability by directional design of its structure. Therefore, the effects of whey protein micro-gel particles (WPMPs) and WPMPs-XG complexes on the stability of O/W emulsion were investigated in this article to provide theoretical support. WPMPs with different structures were prepared by pretreatment (controlled high-speed shear treatment of heat-set WPC gels) at pH 3.5–8.5. The impact of initial WPC structure and XG addition on Turbiscan Indexes, mean droplet size and the peroxide values of O/W emulsions was investigated. The results indicate that WPMPs and XG can respectively inhibit droplet coalescence and gravitational separation to improve the physical stability of WPC-stabilized O/W emulsions. The pretreatment significantly enhanced the oxidative stability of WPC-stabilized O/W emulsions. The addition of XG did not necessarily enhance the oxidative stability of O/W emulsions. Whether the oxidative stability of the O/W emulsion with XG is increased or decreased depends on the interface structure of the protein-XG complex. This study has significant implications for the development of novel structures containing lipid phases that are susceptible to oxidation.

Application of Advanced Emulsion Technology in the Food Industry: A Review and Critical Evaluation

The food industry is one of the major users of emulsion technology, as many food products exist in an emulsified form, including many dressings, sauces, spreads, dips, creams, and beverages. Recently, there has been an interest in improving the healthiness, sustainability, and safety of foods in an attempt to address some of the negative effects associated with the modern food supply, such as rising chronic diseases, environmental damage, and food safety concerns. Advanced emulsion technologies can be used to address many of these concerns. In this review article, recent studies on the development and utilization of these advanced technologies are critically assessed, including nanoemulsions, high internal phase emulsions (HIPEs), Pickering emulsions, multilayer emulsions, solid lipid nanoparticles (SLNs), multiple emulsions, and emulgels. A brief description of each type of emulsion is given, then their formation and properties are described, and finally their potential applications in the food industry are presented. Special emphasis is given to the utilization of these advanced technologies for the delivery of bioactive compounds.