The hydrolysis of surfactants in acidic environments has been overlooked when evaluating their functionality. This gap is addressed here by investigating the breakdown of sucrose monopalmitate (SMP) on both ester and glycosidic bonds. As the main pathway, glycosidic hydrolysis generated reducing sugars and monosaccharide monopalmitate; ester hydrolysis was minor. The first-order kinetics were accelerated at low pH and elevated temperatures. At pH 3 and 20 °C, 10 w/w% SMP was hydrolyzed after 4 weeks. After hydrolysis, surfactants showed higher hydrophobicity, inhibited interfacial adsorption, enlarged micelle sizes, promoted aggregation, and a lower critical micelle concentration. These changes reduce the elasticity of the interface, thereby undermining foaming and emulsifying activities but inhibiting lipid oxidation. Emulsions initially stabilized with SMP (pH 3) exhibited droplet growth during storage, which was attributed to disruptions in the oil-water interface as the disaccharide-based polar head is cleaved. These findings reveal the critical role of changing the molecular characteristics of emulsifiers to tune their interfacial behavior.

Lactoferrin (LF), a bioactive protein with excellent emulsifying properties, suffers from conformational instability and aggregation in ethanolic environments, limiting its application in functional beverages. This study demonstrates that epigallocatechin gallate (EGCG) effectively stabilizes LF in a 15 % (v/v) ethanol-water system. The stabilization is achieved through competitive hydration, molecular complexation, and conformational rearrangement, leading to improved emulsifying capacity. At the optimal mass ratio of LF to EGCG (3:1), the nanoparticles exhibited the smallest diameter (32.85 +/- 0.28 nm) and the highest zeta potential (+36.67 +/- 0.67 mV), indicating enhanced stability. Fluorescence and circular dichroism spectroscopy revealed involvement of tryptophan (Trp) and tyrosine (Tyr) residues in LF-EGCG interactions, with increased alpha-helix content upon EGCG binding. Molecular docking revealed that hydrogen bonding and hydrophobic interactions drive the binding, with a maximum binding energy of -10.1 kcal/mol. Molecular dynamics simulations showed ligand migration from an initial binding site (Delta Gbind = -37.62 kJ/mol) to a more stable secondary site (Delta Gbind =-44.46 kJ/mol) in 15 % ethanol-water. Emulsification behavior was composition-dependent, with optimal emulsifying activity index (EAI; 40.14 m2/g) at a 1:1 LF: EGCG ratio. However, at a 3:1 ratio, moderate EAI (36.67 m2/g) was maintained while enhancing emulsion and protein stability (TSI = 39.6). This work elucidates the molecular mechanism by which EGCG stabilizes LF in ethanolic environments, facilitating the rational design of robust protein-polyphenol complexes for functional beverage applications.

The aim of this study was to understand the effect of pH and oil subphase when stabilising emulsions by plant protein-based microgels versus non-microgelled counterparts. Potato protein microgels (PoPM) were used to stabilise Pickering oil-in-water (O-W) emulsions at pH 3 and 7 and subphase of varying polarity-tetradecane and octanol and compared against conventional emulsions stabilised by non-microgelled potato protein (PoP). Confocal microscopy and static light scattering were used to monitor changes in droplet size and microstructure during storage, whilst interfacial shear rheology was used to assess the viscoelasticity of the adsorbed interfacial protein layers using various subphases. Despite the larger oil droplet sizes and lower interfacial viscoelasticity observed for octanol emulsions, systems stabilised by PoPM appeared more resilient to environmental variations irrespective of pH or subphase. This is most likely due to the ca. 4 x larger size of the adsorbed entities of PoPM, promoting steric hindrance and the higher mechanical strength of the adsorbed PoPM films. Strikingly PoP unfolding (confirmed via dynamic light scattering and small angle X-ray scattering (SAXS)) facilitated similar aggregation of PoP to thermally cross-linked PoPM, with resultant emulsion stability behaviour of PoP-stabilised emulsions resembling PoPM-stabilised ones at pH 3. Overall, this study highlights the importance of understanding how using plant protein microgels may offer benefits to interfacial stabilisation when the polarity of subphase varies, such as stabilising essential oils versus vegetable oils, which has been relatively underexplored in the literature.

This study aimed to enhance the basic criteria for protein extraction from hazelnuts via the response surface technique and to explore the antioxidant characteristics of the isolated hazelnut protein. The purified hazelnut protein with high quality was obtained using the ÄKTA pure system through a HiTrap DEAE FF column. The refined parameters for extraction included: an extraction duration of 2 h, a temperature set at 33 °C, a liquid-to-solid ratio 8:1, and a 2.32 g protein extraction yield/50 g hazelnut press cake. The crude hazelnut protein was identified by LC-MS, which primarily included 41 proteins (only 10 shown). Antioxidant-activity investigations revealed that purified hazelnut protein had high scavenging activity of DPPH radicals. Furthermore, H2O2-induced cell oxidative damage was reduced by increasing cell viability and reducing ROS levels. The basis for purified hazelnut protein extraction was also explored. Our findings showed that hazelnut protein may be a promising natural antioxidant.

p-toluic acid (p-TA) is an essential raw material to meet the rapidly growing demands of chemical industrial development. Several studies have addressed process intensifications or catalysts development of the traditional p-xylene (PX) oxidation process in public literature, even on an industrial scale. However, limited in-depth research has been reported on developing kinetic models for PX oxidation to p-TA, particularly under conditions without acetic acid and bromide salts. In this work, a novel synthesis pathway has been developed for the mild condition preparation of p-TA, specifically without bromine, and in the absence of acetic acid as a solvent. The kinetics model incorporating oxygen concentration and mass transfer was established to predict the PX oxidation behaviors. Semicontinuous and continuous experiments have demonstrated that the proposed kinetics model accurately predicts PX oxidation behaviors under oxygen-rich,-poor, and various mass transfer conditions. This work provides valuable insights into the oxidation of aromatic compounds and the kinetic modeling process under conditions of solvent-free and complex mass transfer.

Sucrose monopalmitate (SMP) is an effective surfactant for emulsification, but exhibits poor stability in low pH environments, due to neutralized surface charges. To improve SMP-based emulsions, we used food-grade amino acids as co-surfactants. Lysine, histidine, phenylalanine, and tryptophan lowered the water-oil interfacial tension. Tryptophan was the most effective, providing sufficient electrostatic repulsion to stabilize emulsion droplets by adsorbing onto the oil surface and becoming protonated at pH 3. However, tryptophan was counterproductive to stabilize SMP-based emulsions between pH 4 and 5. A minimum concentration (0.4 w/v%) of tryptophan prevented droplet coalescence and creaming. Incorporating tryptophan with SMP before emulsification resulted in larger droplets compared to post-emulsification addition. Tryptophan-costabilized emulsions induced flocculation with κ-carrageenan via electrostatic adsorption but showed higher compatibility with polysaccharides with weaker charges. Tryptophan enhanced oxidative stability of unsaturated lipids creating a cationic shield to repel transition metals in the aqueous phase and stabilizing cleavage of lipid hydroperoxides.

Water-in-Oil high internal phase emulsions (W/O HIPEs) have great potential in developing novel healthy food products. However, the high content of the aqueous phase poses great risks in physical stability and lipid oxidation. This study aimed to understand the relationship between physical stability and lipid oxidation of W/O HIPEs, focusing on the roles of emulsifiers, aqueous phase volume, and NaCl concentration. The findings revealed that increasing the polyglycerol polyricinoleate (PGPR) concentration (10 wt%) significantly enhanced physical stability and slowed lipid oxidation at various temperatures. W/O emulsions with varying aqueous phase volumes (30-80%) maintained good physical stability; however, a higher aqueous phase volume significantly accelerated lipid oxidation. Furthermore, the inclusion of NaCl (10-300 mM) improved the physical stability of W/O HIPEs but also accelerated lipid oxidation. Notably, W/O HIPEs with 50 mM NaCl showed both optimal physical and oxidative stability. Additionally, based on the fitting equation of the primary oxidation products, it was predicted that the oxidation reaction of the W/O emulsion followed a zero-order oxidation kinetics model. By altering the structure of the emulsion system, the physical stability and lipid oxidation stability of the emulsion could be regulated, thereby extending the storage time of food products. Overall, these findings emphasized the critical role of interfacial properties in lipid oxidation, providing new insights for optimizing food formulations to enhance long-term stability.

This study aims to understand the bulk and interfacial performance of potato protein microgels. Potato protein (PoP) was used to produce microgels of submicrometer diameter via a top-down approach of thermal cross-linking followed by high-shear homogenization of the bulk gel. Bulk "parent" gels were formed at protein concentrations [PoP] = 5-18 wt %, which subsequently varied in their bulk shear elastic modulus (G') by several orders of magnitude (1-100 kPa), G' increasing with increasing [PoP]. The PoP microgels (PoPM) formed from these parent gels had diameters varying between 100 and 300 nm (size increasing with increasing G' and [PoP]), as observed via dynamic light scattering and atomic force microscopy (AFM) of PoPM adsorbed onto silicon. Interfacial rheology (interfacial shear storage and loss moduli, Gi' and Gi″) and interfacial tension (γ) of adsorbed films of PoP (i.e., nonheated PoP) and PoPM (both at tetradecane-water interfaces) were also studied, as well as the bulk rheology of the PoPM dispersions. The results showed that PoPM dispersions (at 50 vol %) had significantly higher bulk viscosity and shear thinning properties compared to the nonmicrogelled PoP at the same overall [PoP], but the bulk rheological behavior was in sharp contrast to the interfacial rheological performance, where Gi' and Gi″ of PoP were higher than for any of the PoPM. This suggests that the deformability and size of the microgels were key in determining the interfacial rheology of the PoPM. These findings may be attributed to the limited capacity for "unfolding" and lateral interactions of the larger PoPM at the interface, which are presumed to be stiffer due to their production from the strongest PoP gels. Our study further confirmed that heating and cooling the adsorbed films of PoPM after their adsorption showed little change, highlighting that hydrogen bonding was limited between the microgel particles.

In this study, we prepared high internal phase emulsions based on pumpkin seed oil body (HIPEs-PSOB) with 83% oil phase at pH 6.5, pH 9.0 and pH 11.0. The pH 11.0-HIPE-PSOB contained almost oleosin of 14.5 kDa, while other HIPEs-PSOB had oleosin and extrinsic proteins. With the increase of extraction pHs, the content of bound water, immobilized water, particle size, viscosity, viscoelastisity and shear stress decreased, and the free water and isoelectric point of HIPEs-PSOB increased. During stomach digestion, the hydrolysis rate of extrinsic proteins of all HIPEs-PSOB was higher than that of oleosin, and the proteins were hydrolyzed to produce resistant peptides. CLSM showed that all HIPEs-PSOB coalesced during gastric and the droplets were significantly reduced and dispersed in the intestine. The total FFA release decreased with the increase in extraction pH. This study provided a theoretical basis for the investigation and application of OBs and HIPEs.

Poor oxidation stability restricts the further application of docosahexaenoic acid (DHA) in the food industry. To resolve this challenge, sugar beet pectin (SBP)-whey protein isolate (WPI) conjugates were prepared to encapsulate algal oils as DHA-loaded emulsions. Then, the properties of the conjugates were characterized, and the physicochemical stability of the emulsions was investigated. The results revealed that when the ratio of SBP to WPI was 2:1 and the reaction time was 11 h, the grafting degree (GD) reached 44.75% at its maximum and the surface hydrophobicity (H-0) was 4.75 x 10(5) at its minimum. Additionally, the conjugates generated a thick interfacial layer and steric hindrance coated DHA to protect oil droplets against environmental stresses. Besides, the formed reduction substances enhanced the oxidation stability of the conjugate-stabilized emulsion when compared to the complex. In conclusion, the SBP-WPI conjugates encapsulate algae oil more effectively and exhibit promising application prospects in the food industry.

Soy protein isolate (SPI) and sodium carboxymethyl cellulose (CMC-Na) were combined in varying proportions and subjected to the Maillard reaction through spray drying and dry-heat methods. The effects of different mixing ratios and reaction times on the physicochemical properties of the reaction products were investigated, with a focus on their application as wall material for bifidobacterium lactis BB-12. The solubility of the system was significantly enhanced by the Maillard reaction, reaching its maximum at an SPI:CMC-Na ratio of 1:2. At this proportion, after a 6-hour dry-heat Maillard reaction, there was a significant increase in ultraviolet absorption and browning degree of the product, while the free amino acid content decreased significantly. Fluorescence spectroscopy revealed that the conformation around tryptophan residues remained in its natural form, whereas circular dichroism spectroscopy showed a decrease in α-helix and Random coil structure content upon addition of CMC-Na, accompanied by an increase in β-sheet and β-turn content. This stretching effect on protein molecules facilitated functional property expression. Compared to unencapsulated probiotics BB-12 microcapsules prepared using secondary spray drying with a wall-core volume ratio of 6:1 exhibited higher encapsulation efficiency along with good storage stability, tolerance to gastrointestinal conditions, and heat stability. These findings have practical implications for preserving bioactive substances in the food industry.

Clear emulsions are used as flavor carriers by the beverage industry because of their favorable optical properties. A transparent microemulsion with small droplets requires a high concentration of surfactants, and is often non-dilutable, posing a significant challenge to their application in the food industry. The formation of dilutable microemulsions by modulating the compatibility of oil composition and co-solvents was studied. While single-fold lemon oil exhibited poor loading capacity overall, no precipitation occurred due to the stronger interaction between monoterpenes and sucrose monopalmitate (SMP). Conversely, emulsification of five-fold lemon oil with 20 % ethanol demonstrated a higher loading capacity and a stronger dilution stability than other lemon oils. This is likely due to the balanced composition of surface-active monoterpenes and other components in five-fold lemon oil which facilitated the effective use of micellar space and aided in the retention of both surfactants and co-solvents post-dilution. The emulsification of higher-folded lemon oil, however, was favored by the use of propylene glycol as a surfactant exhibiting stronger dilution stability than ethanol, though it required twice as much co-solvent. The high concentration of surface-active monoterpene in the lower-folded lemon oils competes with propylene glycol for interfacial incorporation. This study demonstrated that co-solvents and oil composition play interactive roles in producing dilutable optically clear emulsions, and it provides a blueprint for the food industry to design colloidal systems using a minimum of surfactants.

This study delved into the role of undenatured type II collagen (C-Ⅱ) in κ-carrageenan (KC), konjac glucomannan (KGM) and C-Ⅱ ternary interpenetrating polymer network (IPN) hydrogel by structural modulation and properties characterization. The C-Ⅱ nanofibrils exhibited robust cross-linking with the KC/KGM primarily via intermolecular interactions and physical entanglement while retaining the native triple-helical conformation. Incorporating moderate levels of C-Ⅱ nanofibrils resulted in densification of the hydrogel network, significantly reducing pore sizes from 2.11 ± 0.64 to 0.52 ± 0.29 μm. The rigid KC/KGM first network and the flexible C-Ⅱ nanofibrils second network were interspersed, forming an effective "energy dissipation" mode, which enhanced the mechanical properties of hydrogels. In addition, the intermolecular interactions promoted a more uniform and stable distribution of hydrogen protons, and enhanced the water-holding capacity, swelling properties, freeze-thaw stability and thermal stability of hydrogel. However, excessive concentrations of C-Ⅱ nanofibrils led to aggregate formation, resulting in phase separation and negating the beneficial effects on hydrogel properties. These findings underscored the potential of C-Ⅱ nanofibrils in hydrogel design, offering a blueprint for developing functional hydrogels with tailored properties for food applications.

Rhamnolipid-stabilized nanoemulsion (NE)/nanostructured lipid carrier (NLC)/solid lipid nanoparticle (SLN) was incorporated into kappa-carrageenan/konjac glucomannan (KC-KGM) composite hydrogel to explore the effect of lipid composition on properties and lutein delivery performances of filled hydrogels (FH). The viscosity and crystallinity of emulsified lipids increased with the elevation of solid lipid content. Rheology and texture profile analysis suggested that solidified lipid particles led to greater modulus, hardness, and chewiness in FH. The creep-recovery test confirmed NLC-FH had the shortest retardation time and the highest recovery rate. NLC-FH also exhibited better stress attenuation capacity and lower stress relaxation, verifying that the filling of NLC improved the viscoelasticity of FH more effectively. When exposed to UV light, the inclusion of EGCG in NE/ NLC/SLN-FH prolonged the half-life of lutein from 2.05 to 13.91, 19.28, and 33.02 h respectively. Lutein remained the most stable when embedded in NLC-FH with the addition of EGCG as its half-life extended by 11 times during storage. During in vitro digestion, FH retarded the release of lutein in the early digestion phase (mouth & stomach), whereas EGCG enhanced the release of lutein during intestinal digestion and the bioaccessibility of lutein was shown to be the highest in NE-FH (29.67%), followed by NLC-FH (28.22%) and SLNFH (23.37%). These findings expanded the application of rhamnolipid-stabilized lipids in hybrid gel systems for property improvement and the delivery of lipophilic compounds.

The oral bioavailability of curcumin is inherently low, which significantly limits its application in food systems. The objective of this study was to evaluate the impact of high-pressure processing on the stability and bioaccessibility of curcumin within an emulsion gel during simulated gastrointestinal transit and to assess its cellular uptake. Our findings suggest that increasing pressure levels and high κ-carrageenan concentrations can enhance the stability of the curcumin delivery system. Elevated κ-CG concentrations were found to retard the action of proteases on dissociating protein molecules from the gel network. The emulsion gel effectively slowed the release of free fatty acids and reduced the curcumin release rate during the gastric phase. Scanning electron microscopy images revealed that higher pressures induced the formation of a more uniform and dense network structure in the gel. While the gel network structures were well-preserved after gastric digestion, they were disrupted into smaller particles following intestinal digestion, with particle size increasing with higher applied pressures. Cytotoxicity assays indicated that the digesta from the intestinal phase was highly toxic to Caco-2 cells. Among the tested samples, the emulsion gel prepared with 1.0% κ-CG at 600 MPa demonstrated the highest curcumin bioavailability, reaching 63.82 ± 7.10%. These findings underscore the potential of HPP-induced emulsion gels as a viable delivery system for enhancing curcumin bioaccessibility and cellular uptake.

In this study, the response surface method (RSM) was used to optimize the deproteinization process of polysaccharides from Vitis vinifera L. SuoSuo (VTP). The antioxidant capacities of polysaccharides before and after deproteinization were evaluated. The structure of deproteinized VTP (DVTP), which has relatively strong antioxidant activity, was characterized, and the protective effect of DVTP on H2O2-induced HT22 cell damage was evaluated. The results of the RSM experiment revealed that the ideal parameters for deproteinization included a chloroform/n-butanol ratio (v/v) of 4.6:1, a polysaccharide/Sevage reagent (v/v) ratio of 2:1, a shaking time of 25 min, and five rounds of deproteinization. Preliminary characterization revealed that the DVTP was an acidic heteropolysaccharide composed of seven monosaccharides, among which the molar ratio of galacturonic acid was 40.65. FT-IR and the determination of uronic acid content revealed that DVTP contained abundant uronic acid and that the content was greater than that of VTP. In vitro, the antioxidant activity assay revealed that the hydroxyl radical scavenging capacity and total antioxidant capacity of DVTP were greater than those of VTP. In the range of 0.6~0.8 mg/mL, the DPPH scavenging capacities of VTP and DVTP were greater than that of vitamin C. In addition, cell viability was measured via a CCK-8 assay, which revealed that DVTP had a strong defense effect on H2O2-induced damage to HT22 cells. These findings suggest that DVTP has high antioxidant activity and could be used as a natural antioxidant in functional foods and medicines.

The particle aggregation of 0-carotene has been a challenge for the development of powdery microcapsules with a high loading. Herein, solvent-free 0-carotene high loaded microcapsules based on the wet-milling technique were fabricated by using a complex stabilizer composed of octenyl succinic anhydride modified starch (OSA -starch) and tea saponin (TS). The influence of biopolymer-surfactant interactions on the particle aggregation inhibition of 0-carotene in the microcapsules was investigated. The particle size distribution, micromorphology, redispersibility and in vitro digestion of the microcapsules were altered by regulating the addition sequence and the mass ratio of both stabilizers. The optimized 0-carotene microcapsule presented a small particle size after rehydration (275.1 nm) with the high encapsulation efficiency and loading capacity (99.04% and 18.87%, respectively). As analyzed by FTIR and XRD, the hydrogen bonding and hydrophobic interactions between 0-carotene and wall materials were involved in the amorphization of 0-carotene. SEM and CLSM images jointly verified that the biopolymer-surfactant complex retarded the expansion of the microcapsules, and the dents on the surface of microcapsules facilitated the moisture infiltration during rehydration. Moreover, the wall material composition of microcapsules further affected the bioaccessibility of 0-carotene during the simulated digestion, and the bioaccessibility of 0-carotene was increased from 2.73% to 15.97% due to the enhanced micellization and transport capacity of 0-carotene.