Octenyl succinic anhydride tigernut starch: Structure, physicochemical properties and stability of curcumin-loaded Pickering emulsion

In recent years, there has been increasing attention to starch particle-stabilized Pickering emulsions. In this study, the tigernut starch (TNS) was isolated from the tigernut meal, and further octenyl succinic anhydride tigernut starch (OSATNS) was prepared by a semi-dry method. The structure of OSATNS was analyzed and characterized by degrees of substitution (DS), contact angle, SEM, and FTIR. OSATNS was then used to stabilize the curcumin-loaded Pickering emulsion to improve the water solubility and stability of the curcumin. The results showed that OSATNS with 3 %-9 % OSA exhibited a DS range of 0.012 to 0.029, and its contact angle increased from 69.23° to 84.76°. SEM revealed that TNS consisted of small starch particles averaging 7.71 μm, and esterification did not significantly alter their morphology or size. FTIR analysis confirmed successful OSA incorporation by revealing two new peaks at 1732 cm-1 and 1558 cm-1. After 7 days of storage, Pickering emulsions stabilized with OSATNS-9 % exhibited superior stability and curcumin retention compared to Tween 80 emulsions, maintaining retention rates above 80 % even after different heat treatments. In conclusion, this study shows the potential application of OSATNS in stabilizing Pickering emulsions and demonstrates its good thermal stability and protection against curcumin during storage.

Improved light and ultraviolet stability of curcumin encapsulated in emulsion gels prepared with corn starch, OSA-starch and whey protein isolate

The objective of this study was to enhance the bioavailability and stability of curcumin (Cur) by encapsulating it in corn starch (CS)/octenylsuccinic acid modified (OSA)-starch-whey protein isolate (WPI) emulsion gels (EGs). As the volume fraction of the oil phase increased, the droplet size and ζ- potential of the EGs decreased. The encapsulation efficiency and bioavailability of Cur in CS/OSA-starch-WPI EGs with a 60% oil ratio were 96.0% and 67.3%, respectively. The release rate of free fatty acid and the bioavailability of Cur from the EGs after digestion were significantly higher compared to Cur dissolved in oil. EGs with an oil phase volume fraction of 75% and 80% demonstrated greater protection against light irradiation but were less effective against UV irradiation compared to EGs with a 60% oil phase volume fraction. Encapsulation in EGs proved to be an effective method for enhancing the bioavailability and stability of Cur.

Effect of dry heat and its combination with vacuum heat on physicochemical, rheological and release characteristics of Alocasia macrorrhizos retrograded starches

Retrograded starches have received increasing attention due to their potential excipient properties in pharmaceutical formulations. However, to evade its application-oriented challenges, modification of retrograded starch is required. The study emphasizes influence of dry heating and the dual heat treatment by dry heating amalgamation with the vacuum heat treatment on quality parameters of retrograded starch. The starch was isolated by using two different extraction media (0.05 % w/v NaOH and 0.03 % citric acid) from Alocasia macrorrhizos and then retrograded separately. Further, retrograded starches were first modified by dry heating and afterwards modified with combination of dry and vacuum heating. Modification decreased moisture, ash content and increased solubility. Modified Samples from NaOH media had higher water holding capacity and amylose content. X-ray diffraction revealed type A and B crystals with increasing crystallinity of retrograded heat-modified samples from NaOH media. Thermogravimetric analysis, differential scanning calorimetry confirmed thermal stability. Shear tests showed shear-thinning behavior whereas dominant storage modulus (G/) over loss modulus (G//), depicting gel-like behavior. Storage, loss, and complex viscosity initially increased, then decreased with temperature. In-vitro release reflects, modified retrograded starches offers versatile drug release profiles, from controlled to rapid. Tailoring starch properties enables precise drug delivery, enhancing pharmaceutical formulation flexibility and efficacy.

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.

A smart thermoresponsive macroporous 4D structure by 4D printing of Pickering-high internal phase emulsions stabilized by plasma-functionalized starch nanomaterials for a possible delivery system

Hierarchically porous structures combine microporosity, mesoporosity, and microporosity to enhance pore accessibility and transport, which are crucial to develop high performance materials for biofabrication, food, and pharmaceutical applications. This work aimed to develop a 4D-printed smart hierarchical macroporous structure through 3D printing of Pickering-type high internal phase emulsions (Pickering-HIPEs). The key was the utilization of surface-active (hydroxybutylated) starch nanomaterials, including starch nanocrystals (SNCs) (from waxy maize starch through acid hydrolysis) or starch nanoparticles (SNPs) (obtained through an ultrasound treatment). An innovative procedure to fabricate the functionalized starch nanomaterials was accomplished by grafting 1,2-butene oxide using a cold plasma technique to enhance their surface hydrophobicity, improving their aggregation, and thus attaining a colloidally stabilized Pickering-HIPEs with a low concentration of each surface-active starch nanomaterial. A flocculation of droplets in Pickering-HIPEs was developed after the addition of modified SNCs or SNPs, leading to the formation of a gel-like structure. The 3D printing of these Pickering-HIPEs developed a highly interconnected large pore structure, possessing a self-assembly property with thermoresponsive behavior. As a potential drug delivery system, this thermoresponsive macroporous 3D structure offered a lower critical solution temperature (LCST)-type phase transition at body temperature, which can be used in the field of smart releasing of bioactive compounds.

Differences in the structural properties of three OSA starches and their effects on the performance of high internal phase Pickering emulsions

The emulsifying properties of emulsions are significantly influenced by the structural properties of octenyl succinic anhydride (OSA) starch. The purpose of this work was to elucidate the effect of the structure of OSA starch on its performance as an emulsifier to stabilize Pickering high-internal-phase emulsions (HIPEs). The degrees of substitution (DS) of the three OSA starches were 0.0137, 0.0177 and 0.0236, and their degrees of branching (DB) were 13.96 %, 14.20 % and 14.32 % measured by 1H NMR, which were sequentially labeled as OSA1, OSA2, and OSA3. The OSA3 starch with higher DS and DB had a lower critical micelle concentration (CMC) (0.11 mg/mL). Its emulsification activity (EAI) and emulsion stability (ES) were 61.8 m2/g and 72.5 min, respectively, which were higher than OSA1 and OSA2 starches. The contact angle of the three OSA starches increased from 45.35° to 80.03° with increasing DS and DB. Therefore, it is hypothesized that OSA3 starches have better emulsification properties. The results of physical stability of HIPEs confirmed the above results. These results indicated that DS and DB have a synergistic effect on emulsion properties, and OSA starch with higher DS and DB values were more conducive to the construction of stable HIPEs systems.

Composite formation of whey protein isolate and OSA starch for fabricating high internal phase emulsion: A comparative study at different pH and their application in biscuits

The composites formed by whey protein isolate (WPI) and octenyl succinate anhydride (OSA)-modified starch were characterized with a focus on the effect of pH, and their potential in fabricating high internal phase emulsions (HIPEs) as fat substitutes was evaluated. The particles obtained at pH 3.0, 6.0, 7.0, and 8.0 presented a nanosized distribution (122.04 ± 0.84 nm-163.24 ± 4.12 nm) while those prepared at pH 4.0 and 5.0 were remarkably larger. Results from the shielding agent reaction and Fourier transform infrared spectroscopy (FT-IR) showed that the interaction between WPI and OSA starch was mainly hydrophobic at pH 3.0-5.0, while there was a strong electrostatic repulsion at pH 6.0-8.0. A quartz crystal microbalance with dissipation (QCM-D) study showed that remarkably higher ΔD and lower Δf/n were observed at pH 3.0-5.0 after successive deposition of WPI and OSA starch, whereas slight changes were noted for those made at higher pH values. The WPI-OSA starch (W-O) composite-based HIPEs made at pH 3.0 and 6.0-8.0 were physically stable after long-term storage, thermal treatment, or centrifugation. Incorporation of HIPE into the biscuit formula yielded products with a desirable sensory quality.

Developing biopolymer-stabilized emulsions for improved stability and bioaccessibility of lutein

Lutein is essential for infant visual and cognitive development but has low stability and solubility. This study aimed to enhance the stability and bioaccessibility of lutein using oil-in-water emulsions stabilized with biopolymers. Commercially available octenylsuccinylated (OS) starches, including capsule TA® (CTA), HI-CAP®100 (HC), and Purity Gum® 2000 (PG), along with gum Arabic (GA) variants Ticaloid acacia Max® (TAM), TICAmulsion® 3020 (TM), and pre-hydrate gum Arabic (PHGA), were chosen as emulsifiers. By screening the effect of biopolymer concentration and oil volume fraction (Φ), emulsions stabilized with CTA, HC, or TM at 20% and 30% (w/v) concentration and 70% Φ exhibited a gel-like structure and were selected for further assessments. After a week at 25 °C, emulsions stabilized by CTA and HC showed no significant change in droplet size, while TM emulsion exhibited a 1.58-fold increase. At 45 °C, all emulsions exhibited increase in droplet size. Lutein retention is higher in CTA emulsions at both storage temperatures than free lutein. In vitro bioaccessibility of all lutein emulsions was higher than that of free lutein. These findings highlight the superior stability and bioaccessibility of the lutein emulsion stabilized by OS starch, positioning it as a promising carrier to broaden lutein applications in infant foods.

Preparation of crosslinked starches with enhanced and tunable gel properties by the cooperative crosslinking-extrusion combined modification

Due to its safety and palatability, the citric acid crosslinking modification is an excellent way to modify the properties of starch gels. However, the application of this method is restricted by the low degree of crosslinking of gels produced by this method in the hydrogel system. To produce citric acid-crosslinked starch with improved strength and tunable gel characteristics, a novel ion-esterification cooperative crosslinking-extrusion combined (CCEC) modification approach is presented in this study. The linear and nonlinear rheological characteristics of the samples were measured to evaluate the effectiveness of CCEC modification. Findings disclosed that at 0.1 % strain, the elastic modulus of the CCEC-modified starch (SC-0.5Zn2+, G' = 1522.29 ± 36.31) exhibited a significant rise of 387.27 % as compared to the elastic modulus of citric acid-crosslinked starch (SC, G' = 318.29 ± 11.62). Furthermore, changing the cation concentration allowed for efficient control of the gel's rheological characteristics. The samples were characterized by SEM, FTIR, XRD, and XPS. The CCEC-modified gels had a smaller pore size distribution and a denser honeycomb porous structure. The CCEC modification reaction involves ester bonds and electrostatic attraction. This research is essential to elucidate how coupled physicochemical modification techniques affect the manipulation of starch gel characteristics.

Proteosomes based on milk phospholipids and proteins to enhance the stability and bioaccessibility of β-carotene

Proteosomes (P) based on milk fat globule membrane's phospholipids (MPs), whey protein isolate (WPI) and sodium caseinate (CasNa) were developed by ultrasonication to encapsulate β-carotene. Entirely milk-ingredients based proteosomes (WPI-MPs-P and CasNa-MPs-P) revealed homogenous distribution with size diameters < 250 nm. WPI-MPs-P depicted positive ζ-potential values (+15.7 ± 0.5 mV), while CasNa-MPs-P demonstrated negative (-32.5 ± 3.4 mV) values of surface charge, respectively and hydrophilic nature of proteosomes was observed by measuring contact-angle (θ). AFM and SEM exhibited spherical to oval and slightly irregular morphology of nanocarriers. For various concentrations of β-carotene, the highest encapsulation efficiency of β-carotene was 90 ± 0.2% and 92 ± 0.8% in WPI-MPs-P and CasNa-MPs-P respectively. FTIR analyses confirmed the hydrophobic and electrostatic interactions-based encapsulation of β-carotene. Beneficial antioxidant-potential of β-carotene was retained after its encapsulation in the proteosomes. Proteosomes increased the digestive-stability (>50%) and bioaccessibility (>85%) of β-carotene. Thus, milk-ingredients based proteosomes offer a novel-strategy to develop functional dairy products to overcome widespread vitamin-A-deficiency.

Development of Emulsion Gels Stabilized by Chitosan and Octenyl Succinic Anhydride-Modified β-Cyclodextrin Complexes for β-Carotene Digestion and 3D Printing

β-cyclodextrin (β-CD)-based emulsion gels encapsulated with nutrition for three-dimensional (3D) printing are promising, while obstacles such as low bioaccessibility of bioactive compounds and the molding process in food manufacturing hinder their application. This study intended to develop stable composite emulsion gels using the complexes of chitosan (CS) and octenyl succinic anhydride (OSA)-modified β-CD (OCD) to conquer these challenges. The esterification of OSA generated more negatively charged OCD and ester groups, which aided in the combination of OCD and CS through enhanced electrostatic and hydrogen bonding interactions. The addition of CS improved the emulsification properties of the complexes and acted as a bridge link in the aqueous phase, thereby increasing the gel strength of the composite emulsion gels. Moreover, the encapsulation of β-carotene destabilized the strength of the emulsion gels by lowering the interfacial tension. The emulsion gel stabilized by OCD3/CS-0.75% at an initial pH not only successfully encapsulated β-carotene and presented the highest bioaccessibility of 41.88 ± 0.87% in the in vitro digestion but also showed excellent 3D printability. These results provided a promising strategy to enhance the viscoelasticity of β-CD-based emulsion gels and accelerate their application in bioactive compound delivery systems and 3D food printing.

High internal phase emulsion stabilized by sodium caseinate:quercetin complex as antioxidant emulsifier

High internal phase emulsion (HIPE) was produced and stabilized using a novel antioxidant emulsifier formed by the complexation between sodium caseinate (SC) and quercetin (Q). Colloidal complexes, produced via an alkaline process, showed great ability to reduce the interfacial tension between oil-water phases, promoting stabilization of the HIPEs even at low concentrations (1.5% w/v in the aqueous fraction). HIPEs at 0.80 volume fraction of dispersed phase presented remarkable viscosity due to the high-packing network of oil droplets surrounded by a thin liquid layer. Moreover, the emulsions showed a gel-like behavior and kinetic stability for 45-days at 25 °C. The approach of SC:Q complexes on HIPEs development is promising to reduce lipid oxidation, translated by the formation of hydroperoxides and malondialdehyde during storage, especially for the complex formed with the highest amount of the phenolic compound. In this study, the development of HIPEs with outstanding kinetic and oxidative stability is reported as a potential alternative for the development of healthier products with reduced saturated and trans-fat content.

The colloid and interface strategies to inhibit lipid digestion for designing low-calorie food

Although fat is one of the indispensable components of food flavor, excessive fat consumption could cause obesity, metabolism syndromes and an imbalance in the intestinal flora. In the pursuit of a healthy diet, designing fat reducing foods by inhibiting lipid digestion and calorie intake is a promising strategy. Altering the gastric emptying rates of lipids as well as acting on the lipase by suppressing the enzymatic activity or limiting lipase diffusion via interfacial modulation can effectively decrease lipolysis rates. In this review, we provide a comprehensive overview of colloid-based strategies that can be employed to retard lipid hydrolysis, including pancreatic lipase inhibitors, emulsion-based interfacial modulation and fat substitutes. Plants-/microorganisms-derived lipase inhibitors bind to catalytic active sites and change the enzymatic conformation to inhibit lipase activity. Introducing oil-in-water Pickering emulsions into the food can effectively delay lipolysis via steric hindrance of interfacial particulates. Regulating stability and physical states of emulsions can also affect the rate of hydrolysis by altering the active hydrolysis surface. 3D network structure assembled by fat substitutes with high viscosity can not only slow down the peristole and obstruct the diffusion of lipase to the oil droplets but also impede the transportation of lipolysis products to epithelial cells for adsorption. Their applications in low-calorie bakery, dairy and meat products were also discussed, emphasizing fat intake reduction, structure and flavor retention and potential health benefits. However, further application of these strategies in large-scale food production still requires more optimization on cost and lipid reducing effects. This review provides a comprehensive review on colloidal approaches, design, principles and applications of fat reducing strategies to meet the growing demand for healthier diet and offer practical insights for the low-calorie food industry.

Oxidation stability of oil-in-water emulsion prepared from perilla seed oil and soy sauce with high salt concentration using OSA-starch

The O/W emulsions were prepared using perilla seed oil (PSO) dispersed in soy sauce (PSE) and in distilled water (PWE), respectively. Octenyl succinic anhydride-modified starch (OSA starch, 3 wt%) showed the most efficient emulsifying ability and its stabilities of emulsion and oxidation in PSE and PWE were studied at different storage periods (0, 4, and 8 weeks) and temperatures (4, 25, and 40 °C). Negligible change in droplet diameter of PSE was observed without coalescence or flocculation during storing for 8 weeks at 4 °C. The stabilizing ability of OSA-starch despite the high ionic strength of soy sauce is attributed to the starch backbone, which promotes steric repulsions between droplets. A lower oxidation degree was observed for PSE prepared than PWE and PSO under all storage conditions. Thus, the O/W emulsion prepared from PSO and soy sauce can be applied to the production of ω-3 fatty acid-enriched Asian-style emulsified products.

Thermal Stability Improvement of Core Material via High Internal Phase Emulsion Gels

Biocompatible particle-stabilized emulsions have gained significant attention in the biomedical industry. In this study, we employed dynamic high-pressure microfluidization (HPM) to prepare a biocompatible particle emulsion, which effectively enhances the thermal stability of core materials without the addition of any chemical additives. The results demonstrate that the HPM-treated particle-stabilized emulsion forms an interface membrane with high expansion and viscoelastic properties, thus preventing core material agglomeration at elevated temperatures. Furthermore, the particle concentration used for constructing the emulsion gel network significantly impacts the overall strength and stability of the material while possessing the ability to inhibit oxidation of the thermosensitive core material. This investigation explores the influence of particle concentration on the stability of particle-stabilized emulsion gels, thereby providing valuable insights for the design, improvement, and practical applications of innovative clean label emulsions, particularly in the embedding and delivery of thermosensitive core materials.

Mechanism underlying joint loading and controlled release of β-carotene and curcumin by octenylsuccinated Gastrodia elata starch aggregates

This study aimed to fabricate a novel codelivery system to simultaneously load β-carotene and curcumin in a controlled and synergistic manner. We hypothesized that the aggregates of octenylsuccinated Gastrodia elata starch (OSGES) could efficiently load and control the release of β-carotene and curcumin in combination. Mechanisms underlying the self-assembly of OSGES, coloading, and corelease of β-carotene and curcumin by relevant aggregates were studied. The OSGES could form aggregates with a size of 120.2 nm containing hydrophobic domains surrounded by hydrophilic domains. For coloading, the increased solubilities were attributed to favorable interactions between β-carotene and curcumin as well as interactions with octenyl and starch moieties via hydrophobic and hydrogen-bond interactions, respectively. The β-carotene and curcumin molecules occupied the interior and periphery of hydrophobic domains of OSGES aggregates, respectively, and they did not exist in isolation but interacted with each other. The β-carotene and curcumin combination-loaded OSGES aggregates with a size of 310.5 nm presented a more compact structure than β-carotene-only and curcumin-only loaded OSGES aggregates with sizes of 463.5 and 202.9 nm respectively, suggesting that a transition from a loose cluster to a compact cluster was accompanied by coloading. During in vitro digestion, the joint effect of β-carotene and curcumin prolonged their release and increased their bioaccessibility due to competition between favorable hydrophobic and hydrogen-bond interactions and the unfavorable structure erosion and relaxation of the loaded aggregates. Therefore, OSGES aggregates were designed for the codelivery of β-carotene and curcumin, indicating their potential to be applied in functional foods and dietary supplements.

Influence of interfacial properties/structure on oxygen diffusion in oil-in-water emulsions

Oxygen diffusion played an important role in the lipid oxidation of food emulsions. In this study, a simple method was developed to quantitatively observe the oxygen diffusion in the oil-water biphasic system, and it was further applied to investigate the relationship between the oxygen diffusion and lipid oxidation in O/W emulsions. Various factors that related to the emulsion oxidation were considered, from their influence on the oxygen diffusion and lipid oxidation in the emulsions. Results showed that there was obvious correlation between the oxygen diffusion and lipid oxidation in O/W emulsions, which reveals the inhibition of oxygen diffusion could apparently slow down the lipid oxidation. Moreover, the changes of oil phase, water phase and interfacial layer of the emulsions, which were related to the oxygen diffusion, could improve the oxidative stability of the emulsions effectively. Our findings are helpful for deep understanding the mechanisms of the lipid oxidation in food emulsions.

Hydrophobic modified agar: Structural characterization and application in encapsulation and release of curcumin

In this study, three kinds of anhydrides with different structures were introduced into agar molecules to study the effects of varying degrees of substitution (DS) and anhydride structures on the physicochemical properties and curcumin (CUR) loading capacity. Increasing the carbon chain length and saturation of the anhydride affects the hydrophobic interaction and hydrogen bonding of the esterified agar, thereby changing the stable structure of the agar. Although the gel performance declined, the hydrophilic carboxyl group and the loose porous structure provide more binding sites for the adsorption of water molecules, hence providing excellent water retention (1700 %). Next, CUR was used as a hydrophobic active ingredient to study agar microspheres' drug encapsulation and in vitro release ability. Results showed that the excellent swelling and hydrophobic structure of esterified agar could promote the encapsulation of CUR (70.3 %). The release process is controlled by pH, and the release of CUR under weak alkaline conditions is significant, which can be explained by the pore structure, swelling characteristics, and carboxyl binding of agar. Therefore, this study shows the application potential of hydrogel microspheres in loading hydrophobic active ingredients and sustained release and provides the possibility for the application of agar in drug delivery systems.

Effect of sodium alginate on the yogurt stability was dependent on the thickening effect and interaction between casein micelles and sodium alginate

The effect of sodium alginate (SA) on the yogurt stability and the related mechanisms were investigated. It was found that low-concentration SA (≤0.2 %) increased the yogurt stability, while high-concentration SA (≥0.3 %) decreased the yogurt stability. Sodium alginate increased the viscosity and viscoelasticity of yogurt and this effect was positively correlated with its concentration, suggesting that SA worked as the thickening agent in yogurt. However, addition of ≥0.3 % SA damaged the yogurt gel. These results suggested that interaction between milk protein and SA might play an important role in the yogurt stability besides the thickening effect. Addition of ≤0.2 % SA did not change the particle size of casein micelles. However, addition of ≥0.3 % SA induced aggregation of casein micelles and increased the size. And the aggregated casein micelles precipitated after 3 h storage. Isothermal titration calorimetry analysis showed that casein micelles and SA were thermodynamically incompatible. These results suggested that the interaction between casein micelles and SA induced aggregation and precipitation of casein micelles, which was critical in the destabilization of yogurt. In conclusion, the effect of SA on the yogurt stability was dependent on the thickening effect and the interaction between casein micelles and SA.

Capsaicin encapsulated in W/O/W double emulsions fabricated via ethanol-induced pectin gelling: Improvement of bioaccessibility and reduction of irritation

Capsaicin is a water-insoluble bioactive component with several beneficial physiological functions. However, the widespread application of this hydrophobic phytochemical is limited by its low water-solubility, intense irritation, and poor bioaccessibility. These challenges can be overcome by entrapping capsaicin within the internal water phase of water-in-oil-in-water (W/O/W) double emulsions via using ethanol to induce pectin gelling. In this study, ethanol was used both to dissolve capsaicin and to promote pectin gelation, thereby forming capsaicin-loaded pectin hydrogels that were used as the internal water phase of the double emulsions. Pectin addition improved the physical stability of the emulsions and led to a high encapsulation efficiency of capsaicin (>70 % after 7d storage). After simulated oral and gastric digestion, capsaicin-loaded double emulsions maintained their compartmentalized structure, avoiding capsaicin leakage in the month and stomach. The double emulsions were digested in the small intestine, thereby releasing the capsaicin. Capsaicin bioaccessibility was significantly enhanced after encapsulation, which was attributed to mixed micelle formation by the digested lipid phase. Furthermore, encapsulation of capsaicin within the double emulsions reduced the irritation in the gastrointestinal tissues of mice. This kind of double emulsion may have great potential for the development of more palatable capsaicin-loaded functional food products.

Protein-Based High Internal Phase Pickering Emulsions: A Review of Their Fabrication, Composition and Future Perspectives in the Food Industry

Protein-based high internal phase Pickering emulsions (HIPEs) are emulsions using protein particles as a stabilizer in which the volume fraction of the dispersed phase exceeds 74%. Stabilizers are irreversibly adsorbed at the interface of the oil phase and water phase to maintain the droplet structure. Protein-based HIPEs have shown great potential for a variety of fields, including foods, due to the wide range of materials, simple preparation, and good biocompatibility. This review introduces the preparation routes of protein-based HIPEs and summarizes and classifies the preparation methods of protein stabilizers according to their formation mechanism. Further outlined are the types and properties of protein stabilizers used in the present studies, the composition of the oil phase, the encapsulating substances, and the properties of the constituted protein-based HIPEs. Finally, future development of protein-based HIPEs was explored, such as the development of protein-based stabilizers, the improvement of emulsification technology, and the quality control of stabilizers and protein-based HIPEs.

The Fabrication and Characterization of Pickering Emulsion Gels Stabilized by Sorghum Flour

Pickering emulsion gels have potential application as solid fat substitutes and nutraceutical carriers in foods, but a safe and easily available food-derived particle emulsifier is the bottleneck that limits their practical application. In this study, the function of sorghum flour as a particle emulsifier to stabilize the oil-in-water (O/W) Pickering emulsion gels with medium chain triglycerides (MCT) in the oil phase was introduced. Sorghum flour had suitable size distribution (median diameter, 21.47 μm) and wettability (contact angle, 38°) and could reduce the interfacial tension between MCT and water. The oil phase volume fraction (φ) and the addition amount of sorghum flour (c) had significant effects on the formation of Pickering emulsion gels. When c ≥ 5%, Pickering emulsion gels with φ = 70% could be obtained. Microstructure analysis indicated that sorghum flour not only played an emulsifying role at the O/W interface but also prevented oil droplets from coalescing through its viscous effect in the aqueous phase. With increases in c, the droplet size of the emulsion gel decreased, its mechanical properties gradually strengthened, and its protective effect on β-carotene against UV irradiation also improved.

Pickering emulsion stabilized by hydrolyzed starch: Effect of the molecular weight

HYPOTHESIS

The emulsifying ability of starch is influenced by its molecular weight. Reducing the molecular weight of starch is expected to influence interfacial adsorption and membrane elasticities, thereby affecting its emulsifying ability through Pickering effects. Hence, it should be possible to tailor the emulsifying ability of starch by adjusting its molecular weight.

EXPERIMENTS

Waxy corn starch (CS) and rice starch (RS) were hydrolyzed with pullulanase to obtain high (HM) and low molecular weight (LM) fractions. After the molecular weight was determined by size exclusion chromatography, the fractions were used to prepare model oil-in-water emulsions. The stability, microscopy, and particle size of the emulsions were characterized, and the underlying emulsification mechanism was subsequently studied through dynamic laser scattering, surface tension analysis, interfacial rheology, and Pearson's correlation calculations.

FINDINGS

In the molecular weight range obtained in this study, the smaller the molecular weight of starch, the stronger its emulsifying ability. The decrease in molecular weight resulted in considerable different adsorption and interfacial elasticities with smaller fractions occupying less area on the interface and forming interfaces with higher elasticities, resulting in higher stabilities through Pickering effects. Results thus suggest that the emulsifying ability of starch may be tailored by adjusting its molecular weight.

Impact of polysaccharide mixtures on the formation, stability and EGCG loading of water-in-oil high internal phase emulsions

Water-in-oil (W/O) high internal phase emulsions (HIPEs) were prepared using polyglycerol polyricinoleate (PGPR) and polysaccharide blends consisting of konjac glucomannan (KGM) and octenyl succinic anhydride starch (OSA-starch). The formation, stability, and functionality of these emulsions were varied by adjusting the ratio of KGM and OSA-starch. Interfacial tension measurements indicated that the OSA-starch co-adsorbed to the water-oil interface with PGPR, which would have led to the formation of a polysaccharide-layer that helped prevent separation of the HIPEs. The centrifugal stability, rheological and microstructural results indicated that the W/O HIPEs exhibited well pH, ionic and thermal stability. The encapsulation efficiency, stability, and bioaccessibility of the EGCG in the W/O HIPEs were evaluated by using EGCG as a model hydrophilic nutraceutical. This study provides useful insights into the utilization of emulsion technology to reduce the fat content and improve the nutritional profile of foods with oily continuous phases, such as spreads.

Effects of M/G Ratios of Sodium Alginate on Physicochemical Stability and Calcium Release Behavior of Pickering Emulsion Stabilized by Calcium Carbonate

The gel properties of sodium alginate (SA) have been revealed to be strongly correlated with its ratio of D-mannuronate to L-guluronate (M/G ratio). Herein, we focused on SA with different M/G ratios to conduct an in-depth study on the effect of the M/G ratio difference on physicochemical stability and calcium release behavior of the Pickering emulsion stabilized by calcium carbonate (CaCO₃). The oil phase was added to the aqueous phase, prepared by SA with different M/G ratios (2.23, 0.89, and 0.56) and CaCO₃, for one-step shearing to obtain the E1, E2, and E3 emulsions, respectively. The results of the particle size, microstructure, long-term stability, rheological, and microrheological properties of the emulsions showed that the E3 emulsion, prepared by SA with a smaller M/G ratio, had a smaller particle size and has remained in a flow condition during the long-term storage, while the E1 and E2 emulsions had a gelation behavior and a stronger viscoelasticity. Moreover, the emulsion, as a liquid calcium supplement, is not only convenient for oral intake while meeting the calcium needs of the body, but also controls the release of Ca²⁺. The calcium release of the emulsions in a simulated gastric environment demonstrated that the calcium release ratio increased with the decrease of SA concentration, with the increase of M/G ratio, and with the decrease of oil phase volume.

The fabrication, characterization, and application of chitosan-NaOH modified casein nanoparticles and their stabilized long-term stable high internal phase Pickering emulsions

The demand for facile delivery systems from natural biopolymers with long-term storage stability to deliver liposoluble nutraceuticals such as β-carotene (BC) is increasing. In this work, a facile and reliable emulsifier of chitosan (CS)-NaOH-modified casein (CA) nanoparticles (NPs) was fabricated for the stabilization of high internal phase Pickering emulsions (HIPPEs) with versatile stability. Dynamic light scattering, TEM, FTIR, and interface tension results indicated that CS-CA NPs exhibited nanoscale (109-373 nm), positive charge (22-38 mV), pH-response, spherical in shape, assembled spontaneously by non-covalent interactions, and high surface activity. Optical microscopy, confocal laser scanning microscopy (CLSM), and rheometer results demonstrated that HIPPEs were emulsified by a dense and compact 3D network between the continuous phase and the interfacial region. Hence, the CS-CA NP-stabilized HIPPEs showed long-term storage stability (over 18 months at ambient temperature) and thermostabilization (1 month at 80 °C). The robust and compact CS-CA NPs dramatically declined the contents of primary and secondary oxidation production in HIPPEs than that by corn oil. Moreover, CS-CA NPs stabilized HIPPEs appreciably enhanced the bioaccessibility (2.56 times) and chemical stability (thermal, UV-light, and storage) of BC. This research evidenced that CS-protein or polysaccharide-CA-based systems could be an encouraging formulation to commercially construct tunable HIPPEs with adorable stability for liposoluble nutraceuticals with enhanced attributes.

High internal phase Pickering emulsions stabilized by a cod protein-chitosan nanocomplex for astaxanthin delivery

High internal phase Pickering emulsions (HIPPEs) stabilized by a food protein have attracted widespread attention. In this study, a novel cod protein-chitosan nanocomplex was prepared through electrostatic interactions and used as a particle emulsifier to stabilize the oil-water interface. The application of the cod protein-chitosan nanocomplex was demonstrated in the formation of stable HIPPEs with an internal phase as high as 84%. The influence of the system composition on the stability, microstructure and rheology of the HIPPEs was determined. The HIPPEs stabilized by the cod protein-chitosan nanocomplex formed a compact three-dimensional network structure, which gave the emulsion a higher storage modulus, viscoelasticity and good thixotropy. Interestingly, the chemical stability of astaxanthin was significantly improved by the developed HIPPEs. The bioavailability of astaxanthin in the HIPPEs stabilized by the nanocomplexes of 2.0% (w/w) cod protein and 0.1% (w/w) chitosan reached 49%. In summary, these results demonstrated that the food-grade cod protein-chitosan nanocomplex had potential in the development of HIPPEs, which could be used as carriers for hydrophobic bioactive compound delivery.

Sodium starch octenyl succinate facilitated the production of water-soluble yellow pigments in Monascus ruber fermentation

Natural water-soluble Monascus pigments (WSMPs) have been in increasing demand but have not been able to achieve industrial production due to the low production rate. This study aimed to improve the biosynthesis and secretion of extracellular yellow pigments (EYPs) through submerged fermentation with Monascus ruber CGMCC 10,910 supplemented with sodium starch octenyl succinate (OSA-SNa). The results demonstrated that the yield was 69.68% and 48.89% higher than that without OSA-SNa in conventional fermentation (CF) and extractive fermentation (EF), respectively. The mainly increased EYP components were Y3 and Y4 in CF, but they were mainly Y1 and Y2 as well as secreted intracellular pigments, including Y5, Y6, O1, and O2, in EF. Scanning electron microscopy analysis revealed that the mycelium presented an uneven surface profile with obvious wrinkles and small fragments with OSA-SNa. It was found that a higher unsaturated/saturated fatty acids ratio in the cell membrane resulted in increased permeability and facilitated the export of intracellular yellow pigments into the broth with OSA-SNa treatment. In addition, a higher NAD⁺/NADH ratio and glucose-6-phosphate dehydrogenase activity provided a reducing condition for yellow pigment biosynthesis. Gene expression analysis showed that the expression levels of the key genes for yellow pigment biosynthesis were significantly upregulated by OSA-SNa. This study provides an effective strategy to promote the production of WSMPs by microparticle-enhanced cultivation using OSA-SNa. KEY POINTS: • OSA-SNa addition facilitated the production of Monascus yellow pigments. • Mycelial morphology and membrane permeability were affected by OSA-SNa. • The key gene expression of yellow pigments was upregulated.

Simple method for fabrication of high internal phase emulsions solely using novel pea protein isolate nanoparticles: Stability of ionic strength and temperature

The oil-in-water high internal phase emulsions (HIPEs) could be stabilized by pea protein isolate nanoparticles (PPINs) induced by potassium metabisulfite (K₂S₂O₅). Confocal laser scanning microscope proved that PPINs were attached on the oil-water interface, indicating characteristic of Pickering HIPEs. The HIPEs stabilized by PPINs of higher concentration had smaller droplet size, better storage and centrifugal stability than that of PPINs of low concentration because there were enough particles to constitute the thick interface film. The storage modulus was higher than loss modulus indicating that HIPEs exhibited gel-like structure. At different temperatures and ionic strengths, HIPEs exhibited flocculation but still maintained a stable gel-like structure. The strain curve of HIPEs showed Type III nonlinear behavior due to the flocculation of emulsion droplets. HIPEs stabilized by PPINs might be a potential alternative to partially hydrogenated oils to reduce intake of trans fatty acids.

A Comparison of Microfluidic-Jet Spray Drying, Two-Fluid Nozzle Spray Drying, and Freeze-Drying for Co-Encapsulating β-Carotene, Lutein, Zeaxanthin, and Fish Oil

Various microencapsulation techniques can result in significant differences in the properties of dried microcapsules. Microencapsulation is an effective approach to improve fish oil properties, including oxidisability and unpleasant flavour. In this study, β-carotene, lutein, zeaxanthin, and fish oil were co-encapsulated by microfluidic-jet spray drying (MFJSD), two-fluid nozzle spray drying (SD), and freeze-drying (FD), respectively. The aim of the current study is to understand the effect of different drying techniques on microcapsule properties. Whey protein isolate (WPI) and octenylsuccinic anhydride (OSA) modified starch were used as wall matrices in this study for encapsulating carotenoids and fish oil due to their strong emulsifying properties. Results showed the MFJSD microcapsules presented uniform particle size and regular morphological characteristics, while the SD and FD microcapsules presented a large distribution of particle size and irregular morphological characteristics. Compared to the SD and FD microcapsules, the MFJSD microcapsules possessed higher microencapsulation efficiency (94.0–95.1%), higher tapped density (0.373–0.652 g/cm³), and higher flowability (the Carr index of 16.0–30.0%). After a 4-week storage, the SD microcapsules showed the lower retention of carotenoids, as well as ω-3 LC-PUFAs than the FD and MFJSD microcapsules. After in vitro digestion trial, the differences in the digestion behaviours of the microcapsules mainly resulted from the different wall materials, but independent of drying methods. This study has provided an alternative way of delivering visual-beneficial compounds via a novel drying method, which is fundamentally essential in both areas of microencapsulation application and functional food development.