Glycation of whey protein isolate and emulsions prepared by conjugates

Pea protein isolate-wheat bran arabinoxylan glycated complex improves the physical stability and bioaccessibility of O/W emulsion

The developing of green plant based protein as excellent emulsifier to prepare stable O/W emulsion has become crucial in food processing. This study investigated the emulsification property enhancing of pea protein isolate (PPI) through glycation with wheat bran arabinoxylan (WBAX) to form a covalent complex (PPI-WBAX), the stability and the application in encapsulating β-carotene of the prepared PPI-WBAX emulsion. Results showed that glycation improved the emulsification property of PPI as evidenced by the increased emulsifying activity index (6.7 %) and emulsion stability index (232.7 %), and this was due to the excellent spatial structure that was beneficial for adsorption at the oil-water interface of PPI-WBAX complex formed by covalently linking the amino group of PPI to the carbonyl group at the end of WBAX, indicated by spectral results. The PPI-WBAX emulsion exhibited good physical stability upon exposure to different environmental stressors with the particle size and zeta-potential exhibiting non-significant changes and the oil droplets exhibiting uniform and small size. During the application, the PPI-WBAX emulsion exhibited high encapsulation (98.64 % ± 0.04 %) and retention rates (77.64 % ± 1.27 %) after storage for 28 days. In vitro digestion increased the lipid digestibility (94.06 % ± 0.45 %) and β-carotene bioaccessibility (32.51 % ± 1.39 %) of the PPI-WBAX emulsion.

Maillard reaction conjugates of millet bran globulin and Arabic gum for curcumin encapsulation: Physicochemical characterization, storage stability, and in vitro digestion

In this study, millet bran globulin (MBG) and Arabic gum (AG) conjugates were prepared through the Maillard reaction (MR) and applied to curcumin-loaded Pickering emulsions. The effect of MR on MBG-AG conjugates (MBG-AG con) was evaluated by the degree of grafting (DG), the absorbance of intermediate reactants, and the browning index. The emulsifying properties of MBG-AG con with different DGs were assessed using the emulsifying activity index (EAI) and emulsifying stability index (ESI). Curcumin-loaded Pickering emulsions were prepared using optimized conjugates. Results indicated that MR enhanced the conjugates emulsifying properties, leading to improved emulsion performance. Compared to MBG, the optimized conjugates exhibited approximately 252.3 % and 167.1 % increases in EAI and ESI, respectively. The formation of MBG-AG con was confirmed through polyacrylamide gel electrophoresis, Fourier transform infrared, and fluorescence spectroscopy. Morphological changes before and after MR were observed through scanning electron microscopy. In comparison to MBG-stabilized emulsions, conjugate-stabilized emulsions exhibited smaller droplets, higher curcumin encapsulation efficiency (over 80 %), and better apparent viscosity. During simulated digestion, the bioavailability of curcumin reached 88.67 % in Pickering emulsions stabilized by 5 % conjugates. This study demonstrated the potential application of MBG-AG con prepared via MR in stabilizing Pickering emulsions, providing new theoretical insights into curcumin encapsulation.

Collaborative stabilizing effect of trehalose and myofibrillar protein on high internal phase emulsions: Improved freeze-thaw stability and 3D printability

This study investigated the improvement of adding trehalose (Tre) on freeze-thaw (F-T) stability and 3D printability of myofibrillar protein (MP)-based high internal phase emulsions (HIPEs), also the underlying mechanism. Appropriate Tre addition formed thicker shell-like structure around MP by hydrogen bonds, and induced protein unfolding to ameliorate amphiphilicity. Additionally, Tre promoted the MP diffusion to interface to reduce interfacial tension. After interface saturation, Tre inducing MP rearrangement contributed more to form compact interface layer. Larger interface coverage increased hydrophobic interactions between droplets, constructing stronger MP-Tre-HIPEs gel network, inhibiting more free water to form ice crystals, confirmed by reduced destabilization index and freezing point. Such gel network enhanced their own viscoelasticity and thixotropic recovery, exhibiting superior printing accuracy. Conversely, excessive Tre aggregates (15 %-20 %) competed with MP for interfacial adsorption and filled between interfacial layer of adjacent droplets, weakening gel network. These findings expanded MP-HIPEs high-value application in frozen-foods and 3D printing.

Effects of whey protein-inulin conjugates with varying degrees of glycosylation on hepatic antioxidant capacity, immunomodulation and gut microbiota in mice

In this study, whey protein isolate-inulin (WPI-In) conjugates with varying degrees of glycosylation (DG) were prepared, characterized, and examined for their potential immunomodulatory effects and regulation of gut microbiota in mice. The data indicated that an increase in DG significantly affects the microstructure and functionalities of WPI-In conjugates. The WPI-In conjugates with high DG promoted the growth and development of the thymus while altering gut microbiota composition by increasing the relative abundance of Bacteroidetes and reducing that of Firmicutes. Additionally, the WPI-In conjugates enhanced liver antioxidant capacity and the secretion of immunoglobulin G, and elevated levels of anti-inflammatory cytokines (IL-4 and IL-2), while decreasing pro-inflammatory cytokine (TNF-α) content in serum. Spearman correlation analysis suggested that the enhancement of liver antioxidant capacity and regulation of immune-related indicators may be associated with the gut microbiota altered by WPI-In conjugates. Therefore, WPI-In conjugates demonstrate beneficial properties, indicating potential applications in food systems.

Structural modification of whey protein isolate via electrostatic complexation with Tremella polysaccharides and its effect on emulsion stability at pH 4.5

Emulsions play an important role in food systems by encapsulating and delivering active compounds, but maintaining their stability under various conditions can be challenging. This study explored how the concentrations of Tremella polysaccharides (TPs) (0-0.75 %) affects the structural of whey protein isolate (WPI) and the stability of their emulsions at pH 4.5. At this pH, electrostatic interactions between WPI and TPs exposed hydrophobic groups within the protein, increased β-sheet contents, and improved the hydrophilic-hydrophobic balance, which enhanced emulsifying performance. WPI-TPs complexes (WTS) showed a high emulsifying activity index (57.85 m2/g) and emulsion stability index (82.03 %). Compared to WPI-only emulsions, WTS emulsions had smaller particle sizes, lower Turbiscan Stability Index (TSI) values, and higher viscoelasticity, thermal stability, freeze-thaw stability, and re-emulsification capacity. Importantly, when the TPs concentration in WTS emulsions exceeded 0.375 %, the TSI value dropped below 1, showing no particle migration or peak thickness, indicating full emulsion stability. These findings suggest that TPs help stabilize WPI emulsions near their isoelectric point (pH 4.5) and offer a promising approach to improving WPI functionality in acidic environments. The WTS system provides a reliable way to stabilize emulsions under acidic conditions, supporting the development of natural, stable emulsifiers for food applications.

Revealing the mechanism underlying the viscosity improvement of rice protein yogurt by the presence of in-situ-produced dextrans

The in-situ-produced dextrans (DXs) could effectively enhance the viscosity of rice protein (RP) yogurt, but the reason for this improvement has not been elucidated. This study aims to reveal the mechanism underlying the viscosity improvement of RP yogurt by the presence of in-situ DXs. DXs synthesized in RP yogurts under different optimum conditions were purified and fully characterized. RP yogurts were simulated by mixing RP, DXs, lactic acid, and acetic acid according to their real concentrations. The impacts of DXs on the physicochemical properties of RP and the molecular dynamics of the polymers were examined. The minor difference in branching degree (from 5.79 % to 7.08 %) and conformation of DXs could not result in a significant difference in their macromolecular and thermal properties. DXs interacted with RP through hydrogen bonds, leading to a refolding of RP and the formation of a "core-shell" structure. The immobilized water molecules in the networks of DXs and RP-DX mixtures, the friction force among the DX molecules, and the hydrogen bonds formed between DXs and RP were responsible for the viscosity improvement of RP yogurts containing in-situ DXs. This study may guide the application of DXs in plant-protein food and prompt the exploitation of plant-protein resources.

Characterization of whey protein concentrate-maltodextrin-pomegranate peel phenolic compounds ternary conjugate as a novel food-grade stabilizer for nano-pickering emulsion

Developing effective food-grade stabilizers for nano-Pickering emulsions (NPEs) presents a considerable challenge, as conventional binary systems often exhibit limited functionality. The potential of ternary conjugates incorporating bioactive phenolic compounds remains underexplored. This study aimed to synthesize a novel stabilizer through covalent bonding of whey protein concentrate (WPC), maltodextrin (MD), and pomegranate peel extract (PPex) under alkaline conditions. Ultrasonication-assisted extraction (UAE), microwave-assisted extraction (MAE), and their combination (UM) were employed to extract phenolic compounds from pomegranate peel. By optimizing MAE power (300-600 W), UAE power (200 W), and extraction times (5, 10, 20 min), the highest levels of phenolic compounds (421 ± 0.13 mg Gallic acid/100 g dry peel) and antioxidant activity (90.54 ± 0.481 %) were achieved using UAE at 200 W for 30 min combined with MAE at 300 W for 5 min. Ternary conjugates were formulated with varying concentrations of PPex (0.04 %, 0.08 %, and 0.12 %). Fourier-transform infrared spectroscopy (FTIR) confirmed the interactions between WPC, MD, and PPex. NPEs prepared with ternary conjugates containing 0.12 % PPex exhibited superior stability, enhanced antioxidant activity, and reduced release of free fatty acids during in vitro digestion. Furthermore, the emulsion demonstrated a progressively organized network microstructure, contributing to improved dispersion stability. This study underscores the potential of a ternary conjugate with 0.12 % PPex to enhance NPE stability, presenting a novel approach to developing stable food-grade NPE for functional foods. Additionally, it adds value to pomegranate peel by forming natural protein-polysaccharide- phenolic compounds complex particles.

Enhancing the Stability of Litsea Cubeba Essential Oil Emulsions Through Glycosylation of Fish Skin Gelatin via Dry Maillard Reaction

Emulsions are widely utilized in food systems but often face stability challenges due to environmental stresses, such as pH, ionic strength, and temperature fluctuations. Fish skin gelatin (FSG), a promising natural emulsifier, suffers from limited functional properties, restricting its broader application. This study explored the enhancement of emulsion stability in Litsea cubeba essential oil systems through the glycosylation of fish skin gelatin (FSG) with dextran via the dry Maillard reaction. Among dextrans of varying molecular weights (10 kDa, 100 kDa, 200 kDa, and 500 kDa), the 200 kDa dextran exhibited the best emulsification performance, achieving a remarkable 160.49% increase in stability index. The degree of grafting (DG) increased with molecular weight, peaking at 34.77% for the 500 kDa dextran, followed by 23.70% for the 200 kDa variant. The particle size of the FSG-Dex 200 kDa conjugate emulsion was reduced to 639.1 nm, compared to 1009-1146 nm for the unmodified FSG, while hydrophobicity improved by 100.56%. The zeta potential values approached 30 mV, indicating enhanced stability. Furthermore, glycosylation significantly improved antioxidant activity, as evidenced by increased radical scavenging capacity in both DPPH and ABTS assays. These findings underscore the potential of glycosylated FSG as a natural emulsifier in food applications.

Characteristics of pomegranate (Punica granatum L.) peel polyphenols encapsulated with whey protein isolate and β-cyclodextrin by spray-drying

Pomegranate peel polyphenols (PPPs) are recognized as promising food additives due to their diverse bioactivities; however, their application is limited by poor stability. To address this critical issue, three types of PPPs microcapsules were prepared using β-cyclodextrin (CD), whey protein isolate (WPI), and a composite material of CD-WPI through ultrasound treatment (US). Results revealed that ultrasound treatment can enhance the PPPs-wall material interaction, as evidenced by MD simulations. The encapsulation efficiency of CD-WPI-PPPs was 93.73 %, which was significantly higher than that of CD-PPPs and WPI-PPPs (p < 0.05). The degradation rate constant of CD-WPI-PPPs was reduced by 95.83 %, and its t1/2 was extended by 23-fold compared to that of unencapsulated PPPs. Furthermore, CD-WPI-PPPs exhibited greater DPPH scavenging activity and inhibited polyphenol release during oral and gastric digestion while promoting release during intestinal digestion. These outcomes were attributed to enhanced integrity and interactions between PPPs and composite materials in the microcapsules formed through ultrasound treatment, as supported by SEM images and FT-IR spectra. Consequently, the application of US in the preparation of PPPs microcapsules presents a promising strategy for developing natural nutrient additives for food applications, thereby enhancing the functional properties of food products.

The Effects of Substrates and Sonication Methods on the Antioxidant Activity of Kefir Postbiotics

Sonoporation stimulates cell growth as it improves the permeability of the membrane and increases the uptake of impermeable molecules in the extracellular matrix. We evaluated the effects of substrates (whey, whole, and skim milk) and ultrasonic treatments (ultrasonication and thermosonication) on the antioxidant activity (AA) of water-soluble kefir postbiotics (WSKPs). The samples were evaluated in terms of antioxidant activity (ABTS, DPPH, FRAP, and ORAC), water-soluble protein content, proteolysis (SDS-PAGE profiles), and cell membrane permeability. The levels of AA in all WSKPs depended on the substrate and method of obtaining them. However, the WSKPs from whey had higher antioxidant activity with DPPH (11.11 mg TE/100 mL), ABTS (12.77 mg TE/100 mL), and FRAP (5.18 mg TE/100 mL). Also, the WSKPs from whey had the highest values for water-soluble protein (1.45–1.32 mg/mL) and proteolysis degree and the lowest percentage of dead cells (11.4–28%). These results suggest that the production of WSKPs from whey might add value to whey production. Furthermore, WSKPs have potential as a functional ingredient in the production of beverages or foods with antioxidant activity.

Oral food-derived whey protein isolate-Tremella fuciformis polysaccharides pickering emulsions with adhesive ability to delivery magnolol for targeted treatment of ulcerative colitis

Magnolol (Mag) is a promising natural compound with therapeutic potential for ulcerative colitis (UC). Here we designed and fabricated an oral food-grade whey protein isolate-Tremella fuciformis polysaccharides (WPI-TFPS) stabilized pickering emulsions to encapsulate Mag (Mag-WPI-TFPS) for targeted treatment of UC. With the assistance of the WPI-TFPS, pickering emulsions were well encapsulated and formed stable microparticles with a particle size of approximately 9.49 ± 0.047 μm, a 93.63 ± 0.21 % encapsulation efficiency and a loading efficiency of 21.53 ± 0.01 %. In vitro, the formulation exhibited sustained-release properties in simulated colon fluid with a cumulative release rate of 60.78 % at 48 h. In vivo, the Mag-WPI-TFPS specifically accumulated in the colon tissue for 24 h with stronger fluorescence intensity, which demonstrated that TFPS and WPI had a good adherence ability to inflamed mucosa by electrostatic attraction and ligand-receptor interactions. As expected, compared with Free-Mag, the oral administration of Mag-WPI-TFPS remarkably alleviated the symptoms of UC and protected the colon tissue in DSS-induced UC mice. More importantly, WPI-TFPS enhanced gut microbiota balance by increasing the diversity and relative abundances of Lactobacillaceae and Firmicutes. Overall, this study presents a convenient, eco-friendly, food-derived oral formulation with potential as a dietary supplement for targeted UC treatment.

Effects of thermal treatment on the formation and properties of whey protein isolate/whey protein hydrolysate-sodium hyaluronate complexes

In dairy products, the added sodium hyaluronate may form complexes with proteins, thereby affecting product properties. In the present study, the interaction between whey protein isolate (WPI)/ whey protein hydrolysate (WPH) and sodium hyaluronate (SH) was characterized under thermal treatment at different temperatures (25 ℃, 65 ℃, 90 ℃ and 121 ℃) after studying effects of protein/SH ratio and pH on complex formation. The addition of SH reduced the particle size of WPI/WPH and increased potential value in the system, with greater variation with increasing treatment temperature. The structural properties of complexes were studied. The binding with SH decreased the contents of free amino group and free thiol group, as well as the fluorescence intensity and surface hydrophobicity. FTIR results and browning intensity measurement demonstrated the formation of Maillard reaction products. Moreover, the attachment of SH improved the thermal stability of WPI/WPH and decreased their antigenicity.

Stabilizing effect of silver carp myofibrillar protein modified by high intensity ultrasound on high internal phase emulsions: Protein denaturation, interfacial adsorption and reconfiguration

This study evaluated the impact of high intensity ultrasound (HIU) on myofibrillar proteins (MP) from silver carp, and investigated the stabilizing effect of HIU-treated MP (UMP) on high internal phase emulsions (HIPEs). Ultrasonic cavitation induced protein denaturation by decreasing size and unfolding conformation, to expose more hydrophobic groups, particularly UMP at 390 W, showing the smallest particle size (181.71 nm) and most uniform distribution. These structural changes caused that UMP under 390 W exhibited the highest surface hydrophobicity, solubility (92.72 %) and emulsibility (115.98 m2/g and 70.4 min), all of which contributed to fabricating stable HIPEs with oil volume fraction up to 0.8. UMP-based HIPEs possessed tightly packed gel network and self-supporting appearance due to the adsorption of numerous proteins at the oil-water interface and the reduction of interfacial tension by protein reconfiguration. The larger interface coverage reinforced cross-linking between interfacial proteins, thus increasing the viscoelasticity and recoverability of HIPEs, also the resistance to centrifugal force, high temperature (90 °C, 30 min) and freeze-thaw cycles. These findings furnished insightful perspectives for MP deep processing through HIU, expanding the high-value application of UMP-based HIPEs in fat replacer, nutritional delivery system with high encapsulation content and novel 3D printing ink.

Dandelion polysaccharides improve the emulsifying properties and antioxidant capacities of emulsions stabilized by whey protein isolate

In this study, the effects of dandelion polysaccharide (DP) and its carboxymethylated derivative (CMDP) on the emulsifying characteristics and antioxidant capacities of emulsions stabilized by whey protein isolate (WPI) were determined. The addition of both DP and CMDP reduced the particle size and zeta potential of the emulsions. Using 1.0 % WPI and 1.0 % CMDP as emulsifier, the emulsifying activity index (EAI) and emulsifying stability index (ESI) were 32.61 ± 0.11 m2/g and 42.58 ± 0.13 min, respectively, which were higher than the corresponding values of 27.19 ± 0.18 m2/g and 36.17 ± 0.15 min with 1.0 % WPI and 1.0 % DP. Fourier-transform infrared spectroscopy (FT-IR), far-ultraviolet circular dichroism (Far-UV CD), and fluorescence (FS) spectra analyses confirmed that the α-helix and β-sheet structures in WPI-polysaccharide complexes were reduced compared with those in pure WPI, whereas the random-coil content was enhanced by the addition of polysaccharides. Moreover, DP and CMDP effectively improved the antioxidant capacity and inhibited oxidation of the emulsions during storage. Therefore, DP and its carboxymethylated derivative exhibit great potential to be applied in the emulsion-based delivery system.

Effect of various oligosaccharides on casein solubility and other functional properties: Via Maillard reaction

This study explored the improvement of casein (CN)'s properties by conjugating it with oligosaccharides, namely, fructooligosaccharide (FOS), galactooligosaccharide (GOS), isomaltooligosaccharide (IMO), and xylo-oligosaccharide (XOS) via Maillard reaction to identify the most optimal oligosaccharides and modification conditions. The degree of grafting was 30.5 ± 0.41 % for CN-FOS, 33.7 ± 0.62 % for CN-GOS, 38.9 ± 0.51 % for CN-IMO, and 43.7 ± 0.54 % for CN-XOS. With the degree of grafting rising, more oligosaccharides were conjugated, causing greater changes in CN properties. The CN-XOS underwent significant alterations, as the introduction of oligosaccharides led to a decrease in particle size by around 51 nm. Furthermore, the hydroxyl groups caused a reduction in surface hydrophobicity, which in turn decreased the proportion of hydrophobic groups. The solubility of CN-XOS increased significantly at pH 3, by approximately 30.99 %. Additionally, the conjugation of oligosaccharides substantially boosted the rates of DPPH, ABTS, and -OH radical scavenging by 4.61 times, 2.20 times, and 2.58 times, respectively, and also improved the thermal stability of the modified CN. Moreover, the process lowered the protein digestibility, possibly enhancing its applicability as an active substance transporter. This research offers additional theoretical backing for altering CN with oligosaccharides and implementing it in the food and pharmaceutical sectors.

Structure and functionality of whey protein, pea protein, and mixed whey and pea proteins treated by pH shift or high-intensity ultrasound

Three modifications (pH shift, ultrasound, combined pH shift and ultrasound) induced alterations in pure whey protein isolate (WPI), pea protein isolate (PPI), and mixed whey and pea protein (WPI-PPI) were investigated. The processing effect was related to the protein type and technique used. Solubility of WPI remained unchanged by various treatments. Particle size was enlarged by pH shift while reduced by ultrasound and combined approach. All methods exposed more surface hydrophobic groups on WPI, while pH shift and joint processing was detrimental to its emulsifying activity. The PPI and mixture exhibited similar responses toward the modifications. Solubility of PPI and the blend enhanced in the sequence of pH shift and ultrasound > ultrasound > pH shift. Individual approach expanded while co-handling diminished the particle diameter. Treatments also caused more disclosure of hydrophobic regions in PPI and WPI-PPI and emulsifying activity was ameliorated in the order of pH shift and ultrasound > ultrasound > pH shift.

Tunability of Pickering particle features of whey protein isolate via remodeling partial unfolding during ultrasonication-assisted complexation with chitosan/chitooligosaccharide

The potential of ultrasonication-driven molecular self-assembly of whey protein isolate (WPI) with chitosan (CS)/chitooligosaccharide (COS) to stabilize Pickering emulsions was examined, based on CS/COS ligands-induced partial unfolding in remodeling the Pickering particles features. Multi-spectral analysis suggested obvious changes in conformational structures of WPI due to interaction with CS/COS, with significantly higher unfolding degrees of WPI induced by COS. Non-covalent interactions were identified as the major forces for WPI-CS/COS conjugates. Ultrasonication enhanced electrostatic interaction between CS's -NH3 groups and WPI's -COO- groups which improved emulsification activity and storability of WPI-COS stabilized Pickering emulsion. This was attributed to increased surface hydrophobicity and decreased particle size compared to WPI-CS associated with differential unfolding degrees induced by different saccharide ligands. CLSM and SEM consistently observed smaller emulsion droplets in WPI-COS complexes than WPI-CS/COS particles tightly adsorbed at the oil-water interface. The electrostatic self-assembly of WPI with CS/COS greatly enhanced the encapsulation efficiency of quercetin than those stabilized by WPI alone and ultrasound further improved encapsulation efficiency. This corresponded well with the quantitative affinity parameters between quercetin and WPI-CS/COS complexes. This investigation revealed the great potential of glycan ligands-induced conformational transitions of extrinsic physical disruption in tuning Pickering particle features.

Emulsification and encapsulation properties of conjugates formed between whey protein isolate and carboxymethyl cellulose under acidic conditions

In this study, carboxymethyl cellulose (CMC) was used to interact with whey protein isolate (WPI) to prepare conjugates as emulsifiers and embedding agents, which can be used under acidic conditions. Firstly, the effects of ratios and pH values on the formation of WPI-CMC conjugates were investigated. The turbidity and particle size of WPI were reduced in the presence of CMC at pH 4.6 (near the isoelectric point). Then the characterization of physicochemical properties indicated that electrostatic interactions played a major role in the formation of WPI-CMC conjugates, thereby changing the structure and function of conjugates. CMC and WPI reached the optimal aggregation state at pH 4.6 and a ratio of 4:1. The conjugates exhibited excellent emulsifying activity and stability for the oil-in-water emulsions. WPI-CMC conjugates also could provide protection to allicin by preventing degradation under environmental stresses, while maintaining its antioxidant activity.

Antioxidant stability and in vitro digestion of β-carotene-loaded oil-in-water emulsions stabilized by whey protein isolate-Mesona chinensis polysaccharide conjugates

The aim of this study was to investigate the delivery of functional factor β-carotene by emulsion stabilized with whey protein isolate-Mesona chinensis polysaccharide (WPI-MCP) conjugate. Results showed that the WPI-MCP complex had better antioxidant properties than WPI. Correspondingly, the emulsions stabilized by this complex also had better oxidative stability compared with protein emulsions alone. The particle size of WPI-MCP emulsion was smaller and had a better stability when MCP was added at 0.2 % (w/v). The sizes of WPI-MCP and WPI emulsions were 3594.33 and 7765.67 nm at pH 4, indicating improved emulsion stability around isoelectric point of WPI. At different NaCl concentrations, the absolute values of zeta-potential of WPI-MCP emulsions were larger than that of WPI emulsions except 0.1 % (mol/L) NaCl. The sizes of WPI and WPI-MCP emulsions were 2384.32 and 790.12 nm, respectively. During in vitro digestion, WPI-MCP stabilized emulsions slowed down the release of free fatty acids and achieved about 80 % bioaccessibility of β-carotene, indicating that WPI-MCP-stabilized emulsions encapsulating β-carotene can effectively control the release of bioactive substances. These studies have potential significance and value for the construction of food-grade emulsion delivery system.

Investigation of structural and physicochemical properties of microcapsules obtained from protein-polysaccharide conjugate via the Maillard reaction containing Satureja khuzestanica essential oil

In this study, some common proteins including, whey protein isolate (WPI), soy protein isolate (SPI), and gelatin (G) conjugated with maltodextrin (MD) via Maillard reaction and were then used to encapsulate Satureja khuzestanica essential oil (SKEO). The higher glycation degree was obtained at a pH of 9 and 3 h of heating at 60 °C for SPI and WPI, and 90 °C for G. The results of FTIR and intrinsic fluorescence test showed the possibility of covalent binding formation between proteins and maltodextrin. The encapsulation efficiencies were obtained about 83.84 %, 88.95 %, and 89.27 % for MD-SPI, MD-G, and MD-WPI, respectively. Moreover, the Maillard reaction-based microcapsules had higher antioxidant activity than the physical mixture of protein-polysaccharide. The addition of SKEO to microcapsules improved antimicrobial activity. The results of this study demonstrated that MD-WPI and MD-G, as encapsulating materials, can be used to enhance the physiochemical properties of microcapsules loaded with SKEO.

Behavior of protein-polysaccharide conjugate-stabilized food emulsions under various destabilization conditions

The sensitivity of protein-stabilized emulsions to flocculation, coalescence, and phase separation under destabilization conditions (i.e., heating, aging, pH, ionic strength, and freeze-thawing) may limit the widespread use of proteins as effective emulsifiers. Therefore, there is a great interest in modulating and improving the technological functionality of food proteins by conjugating them with polysaccharides, through the Maillard reaction. The present review article highlights the current approaches of protein-polysaccharide conjugate formation, their interfacial properties, and the behavior of protein-polysaccharide conjugate stabilized emulsions under various destabilization conditions, including long-term storage, heating and freeze-thawing treatments, acidic conditions, high ionic strength, and oxidation. Protein-polysaccharide conjugates are capable of forming a thick and cohesive macromolecular layer around oil droplets in food emulsions and stabilizing them against flocculation and coalescence under unfavorable conditions, through steric and electrostatic repulsion. The protein-polysaccharide conjugates could be therefore industrially used to design emulsion-based functional foods with high physicochemical stability.

Advances in preparation and application of food-grade emulsion gels

Emulsion gel is a semi-solid or solid material with a three-dimensional net structure produced from emulsion through physical, enzymatic, chemical methods or their combination. Emulsion gels are widely used in food, pharmaceutical and cosmetic industries as carriers of bioactive substances and fat substitutes due to their unique properties. The modification of raw materials, and the application of different processing methods and associated process parameters profoundly affect the ease or difficult of gel formation, microstructure, hardness of the resulting emulsion gels. This paper reviews the important research undertaken in the last decade focusing on classification of emulsion gels, their preparation methods, the influence of processing method and associated process parameters on structure-function of emulsion gels. It also highlights current status of emulsion gels in food, pharmaceutical and medical industries and provides future outlook on research directions requiring to provide theoretical support for innovative applications of emulsion gels, particularly in food industry.

Food protein glycation: A review focusing on stability and in vitro digestive characteristics of oil/water emulsions

Recently, increasing studies have shown that the functional properties of proteins, including emulsifying properties, antioxidant properties, solubility, and thermal stability, can be improved through glycation reaction under controlled reaction conditions. The use of glycated proteins to stabilize hydrophobic active substances and to explore the gastrointestinal fate of the stabilized hydrophobic substances has also become the hot spot. Therefore, in this review, the effects of glycation on the structure and function of food proteins and the physical stability and oxidative stability of protein-stabilized oil/water emulsions were comprehensively summarized and discussed. Also, this review sheds lights on the in vitro digestion characteristics and edible safety of emulsion stabilized by glycated protein. It can further serve as a research basis for understanding the role of structural features in the emulsification and stabilization of glycated proteins, as well as their utilization as emulsifiers in the food industry.