Oil Body Emulsions Research Articles

Enhancing the physicochemical stability and bioaccessibility of curcumin-loaded soybean oil bodies emulsions in the in vitro elderly model

Curcumin, a hydrophobic polyphenol, provides numerous health benefits, but its limited water solubility, stability and bioavailability hinder its applications in the food and pharmaceutical products, while its biological fate in elderly is unclear. In this study, a natural soybean oil bodies-curcumin (SOB-C) emulsion was fabricated using a pH-driven method without the use of organic solvents to minimize environmental impact. The digestive properties, curcumin bioaccessibility, free fatty acids (FFA), and microstructural changes of SOB-C were investigated using an in vitro elderly digestion model. The findings indicated that curcumin was successfully encapsulated within SOB with an efficiency of up to 90%. Compared to free curcumin, the curcumin encapsulated within SOB demonstrated a significant enhancement in the light, storage stability, and an extension of the curcumin's half-life up to 74 days. The in vitro elderly digestion findings demonstrated that SOB-C significantly improved the bioaccessibility of curcumin, increasing it from 14.30% to 38.98%, surpassing the efficacy of the two commercial curcumin. The reduced FFA release rate from SOB-C supports its potential utility in low-fat food formulations. The results indicated the SOB play a significant role in encapsulating and stabilizing hydrophobic bioactives, which are promising curcumin delivery system to be used in food products for the elderly.

Unlocking the potential of rice bran oil body as fat replacement in cookies: single and double crosslinked binary emulsion-filled gels based on lutein-loaded rice bran oil body emulsion.

Rice bran oil body is rich in nutritional value, which is a byproduct of rice processing. The aim of this study is to develop a novel emulsion-filled gel with lutein-loaded rice bran oil body and investigate its functionality as a fat replacer in cookies. The effects of incorporating structured oil body in the form of emulsion-filled gel instead of butter in cookies with a ratio of 0, 10, 20 and 50 wt% formulation were determined by measuring appearance, texture, thermodynamic properties, moisture distribution and microstructure. The results demonstrated the relationship between geometry, moisture and structure. The 20 wt% emulsion-filled gel substitution ratio yielded mobility and distribution abilities of melted fat and sugar in the cookies that were closest to those of butter. The addition of emulsion-filled gel increased the L* value and decreased the a* value, while the b* value of the cookie increased due to the advanced delivery of lutein by oil body. By controlling the addition ratio, the texture of the cookies can be adjusted. Starch granules were separated due to colloidal particles, reducing saturated fat content and decreasing cookie gelatinization enthalpy. The fat coating on starch particles enhanced the binding capacity of free water, improving air entrapment and forming a constrained gluten network structure. These findings provide a theoretical basis for rice bran oil body as a novel substitute for butter in the development of healthy, high-quality cookies. © 2024 Society of Chemical Industry.

Characteristic and stability changes of peanut oil body emulsion during the process of demulsification using heptanoic acid

In this paper, the changes in oil body emulsion (OBE) during heptanoic acid demulsification (HD) were investigated from the macro and microscopic points of view. Specifically, the OBE particle size increased from 3.04 to 8.41 µm, while the zeta potential absolute decreased to 2.89 mV. The interfacial tension and apparent viscosity of OBE were reduced significantly. Heptanoic acid could contribute to oil droplets aggregation. The findings indicated that high-molecular proteins, including lipoxygenase (97.58 kDa) and arachin (70.28 kDa), detached from the OBs’ interface. HD caused alterations in the secondary structure of protein and the environment around proteins changed. The HD mechanism was speculated that the addition of heptanoic acid resulted in the reduction in pH and changes of environment surrounding OBE, which triggered polymerization and the phase transformation of the oil droplets. Overall, this study is vital for solving the problem of demulsification during aqueous enzymatic extraction (AEE).

Physicochemical properties, photostability, and digestive characteristics of natural emulsion system fabricated by recombinant rice bran oil bodies for lutein ester delivery

Rice bran oil bodies (RBOBs), as natural oil-in-water emulsions, can be used as a good carrier for delivering hydrophobic functional ingredients. In this work, the lutein ester-loaded rice bran oil body (LRBOB) emulsions were successfully prepared by restructuring the RBOBs natural structure through heat treatment and high-pressure homogenization. The physicochemical properties, photostability, and in vitro digestion of LRBOB emulsions with different oil body concentrations were investigated. The LRBOB emulsion with 50% RBOBs had maximum lutein ester encapsulation efficiency (94%) with larger mean particle size (566.44 ± 18.05 nm) and zeta potential (−43.87 ± 0.8 mV), exhibiting good physical stability and an amorphous structure of lutein ester. Meanwhile, the emulsion droplets formed a network structure through mutual adsorption, as observed by CLSM. Moreover, the apparent viscosity of LRBOB emulsion was increased with the increase of RBOBs concentration, showing a shear thinning behavior. Within the linear viscoelastic range, the emulsions mainly displayed elastic rheological characteristics. Furthermore, the photooxidation studies showed that the LRBOB emulsion retained a maximum of 37% lutein ester after 96 h of UV irradiation, and the half-life was extended to 58.89 h. Meanwhile, a higher amount of RBOBs effectively reduced lipid and protein oxidation and minimized color difference, indicating that RBOBs could effectively improve the stability of lutein ester. Based on the results of in vitro simulated digestion, LRBOB emulsion showed higher free fatty acid release (32%) and lutein ester bioaccessibility (40.17%) in the adult model, but is not recommended for infant diets. This work will provide a new delivery vehicle for the utilization of raw lutein materials, expanding the potential applications of natural plant oil bodies.

The physicochemical stability and in vivo gastrointestinal fates of flaxseed oil bodies with the introduction of soluble flaxseed gum polysaccharides

The natural oil bodies (OBs) were considered minimally processed entities for delivering bioactive lipids and minor lipid concomitants, such as α-linolenic acid (ALA), tocopherols, etc. when incorporated into food systems. The current study investigated the physicochemical stability and in vivo gastrointestinal digestion of flaxseed OBs with the introduction of soluble flaxseed gum polysaccharides (SFG), which always consistently coexisted in flaxseed milk. The results showed that the particle sizes of flaxseed OB emulsions consistently decreased by 37.46% (p < 0.05), while the zeta potential values gradually increased by 60.91% (p < 0.05) as the SFG concentrations raised from 0.1% to 0.5% (wt %). SFG improved the physical stability of flaxseed OB emulsions by preventing bridging flocculation among adjacent OBs, and achieving the movement restriction of single OBs via the direct interface anchoring and network structure formation in bulk aqueous phase. SFG apparently suppressed the gastrointestinal lipolysis rate of flaxseed OBs due to the complex coacervation with intrinsic interfacial proteins, subsequent deep encapsulation and gastric emptying delaying of OB remnants. Then, the slower micellar absorption and chylomicron transport within rat enterocytes were occurred, contributing to the suppressed ALA accumulation and subsequent conversion into n-3 long chain fatty acids in rat upper jejunum. Collectively, the introduction of SFG in flaxseed OBs at high concentration allows lower intestinal ALA bioaccessibility.

Effects of three polyphenols with different numbers of phenolic hydroxyls on the structural and interfacial properties and lipid-protein co-oxidation of oil body emulsions

Oil bodies (OBs) are organelles for storing lipids, and they are composed of lipid cores and monolayer phospholipid protein membranes. During storage, membrane proteins anchored in the lipid core are often damaged by lipid oxidation products, leading to oxidative damage and a decreased quality of emulsified foods. Here, three natural antioxidants (gallic acid (GA), epigallocatechin gallate (EGCG), and tannic acid (TA)) were added to OB emulsions to study the effects of polyphenols on protein interfacial properties during oxidation and the lipid-protein co-oxidation behavior. Compared to GA, EGCG and TA with higher molecular weights and hydroxyl substitution showed better antioxidant activity, metal chelating activity, iron reduction ability, and affinity for OB. The polyphenols significantly reduced the contents of free amino and sulfhydryl groups in OB. Infrared spectroscopy analysis indicate that hydrogen bonding and hydrophobic interactions may exist between the polyphenols and OB. During storage, polyphenols inhibited >23% of the primary and secondary lipid oxidation products in the emulsions, whereas the formation of carbonyl groups and disappearance of sulfhydryl groups were only inhibited by 10.7% and 7.4%, respectively, indicating that polyphenols preferentially inhibited lipid oxidation over protein oxidation. Electrophoresis results showed that moderate oxidation (3 days of storage) disrupted the disulfide bonds of proteins. Note that moderate oxidation enhanced the interfacial properties of OB proteins, whereas excessive oxidation led to protein aggregation. This study offers new perspectives on using polyphenols to regulate the lipid-protein co-oxidation in OB, as well as the different properties of OB proteins after oxidation.

Curcumin-loaded oil body emulsions prepared by an ultrasonic and pH-driven method: Fundamental properties, stability, and digestion characteristics

In this study, oil bodies (OBs) loaded with curcumin (Cur) were successfully prepared via an ultrasonic and pH-driven method. Ultrasonic treatment significantly improved the encapsulation efficiency (EE) and loading capacity (LC) of Cur, producing OB particles with small size, uniform distribution, and high ζ-potential absolute values. When the ultrasonic power was 200 W, the EE, LC, and ζ-potential absolute value were the greatest (88.27 %, 0.044 %, and −25.71 mV, respectively), and the OBs possessed the highest yellowness, representing the best treatment result. The confocal laser scanning microscopy (CLSM) and cryo-scanning electron microscopy (cryo-SEM) results was also intuitionally shown that. Moreover, circular dichroism (CD) proved that ultrasonic treatment could unfold the surface protein structure, further enhancing the stability. Therefore, the cream index (CI), peroxide value (POV), and thiobarbituric acid reactive substances (TBARS) were the lowest when the ultrasonic power was 200 W. In this case, the Cur loaded in OBs was well protected against hostile conditions, evidenced by the highest Cur retention rate and the lowest degradation rate constant. Finally, the in vitro gastrointestinal digestion simulation results showed that the ultrasonic treatment effectively increased the release of FFA, bioaccessibility, and stability of Cur, especially when the ultrasonic power was 200 W. This research offers a new OB-based delivery system to stabilize, deliver, and protect Cur for food processing.

Effects of Roasting Temperatures on Peanut Oil and Protein Yield Extracted via Aqueous Enzymatic Extraction and Stability of the Oil Body Emulsion.

Oil body emulsions (OBEs) affect the final oil yield as an intermediate in the concurrent peanut oil and protein extraction process using an aqueous enzyme extraction (AEE) method. Roasting temperature promotes peanut cell structure breakdown, affecting OBE composition and stability and improving peanut oil and protein extraction rates. Therefore, this study aimed to investigate the effects of pretreatment at different roasting temperatures on peanut oil and protein yield extracted through AEE. The results showed that peanut oil and protein extraction rates peaked at 90 °C, 92.21%, and 77.02%, respectively. The roasting temperature did not change OBE composition but affected its stability. The OBE average particle size increased significantly with increasing temperature, while at 90 °C, the zeta potential peaked, and the interfacial protein concentration hit its lowest, indicating OBE stability was the lowest. Optical microscopy and confocal laser scanning microscopy confirmed the average particle size findings. The oil quality obtained after roasting treatment at 90 °C did not differ significantly from that at 50 °C. The protein composition remained unaffected by the roasting temperature. Conclusively, the 90 °C roasting treatment effectively improved the yield of peanut oil extracted using AEE, providing a theoretical basis for choosing a suitable pretreatment roasting temperature.

Construction of soybean oil bodies–xanthan gum composite oleogels by emulsion-templated method: Preparation, characterization, and stability analysis

Oil bodies (OBs), a special tissue that stores oil in plant cells, are rich in polyunsaturated fatty acid, vitamin E, phytosterols, and other functional components. In this study, different concentrations of xanthan gum (XG)-stabilized OBs were prepared using the electrostatic deposition technique, and oleogels were prepared via freeze-drying and shearing effects. The relationships between the properties of OB emulsions (OBEs), intermediate products (freeze-dried samples), and end products (oleogels) were explored. The XG addition significantly enhanced the stability of OBs. Particularly, when it achieved 1.5%, the average particle size of OBEs was the least at 892.03 nm, the ζ-potential absolute value was greater than 30 mV, and the porosity was a minimum of approximately 3.68%. Freeze-dried samples with XG had less oil on their surfaces, and their hardness and springiness were significantly and positively correlated with XG addition. The excellent stability of the OBEs and freeze-dried samples resulted in the formation of a dense and stable three-dimensional network structure to hold the oil. The oil holding capacity, rheological properties (including higher yield stress, stronger elastic, and thixotropy behavior), and thermal stability of the oleogels improved with increasing XG addition. Moreover, the compact networks and excellent oil holding capacity of the OB-based oleogels with XG effectively hindered high-temperature destruction and oil oxidation. The correlation analysis and the scheme model indicated that the oleogel properties could be traced back to the interaction effects among the OB components. These results provide guidance for the design and quality control of OB-based oleogels.

Demulsification of Emulsion Using Heptanoic Acid during Aqueous Enzymatic Extraction and the Characterization of Peanut Oil and Proteins Extracted.

Peanut oil body emulsion occurs during the process of aqueous enzymatic extraction (AEE). The free oil is difficult to release and extract because its structure is stable and not easily destroyed. Demulsification can release free oil in an oil body emulsion, so various fatty acids were selected for the demulsification. Changes in the amount of heptanoic acid added, solid-liquid ratio, reaction temperature, and reaction time were adopted to investigate demulsification, and the technological conditions of demulsification were optimized. While the optimal conditions were the addition of 1.26% of heptanoic acid, solid-liquid ratio of 1:3.25, reaction temperature of 72.7 °C, and reaction time of 55 min, the maximum free oil yield was (95.84 ± 0.19)%. The analysis of the fatty acid composition and physicochemical characterization of peanut oils extracted using four methods were studied during the AEE process. Compared with the amount of oil extracted via other methods, the unsaturated fatty acids of oils extracted from demulsification with heptanoic acid contained 78.81%, which was significantly higher than the other three methods. The results of physicochemical characterization indicated that the oil obtained by demulsification with heptanoic acid had a higher quality. According to the analysis of the amino acid composition, the protein obtained using AEE was similar to that of commercial peanut protein powder (CPPP). However, the essential amino acid content of proteins extracted via AEE was significantly higher than that of CPPP. The capacity of water (oil) holding, emulsifying activity, and foaming properties of protein obtained via AEE were better than those for CPPP. Overall, heptanoic acid demulsification is a potential demulsification method, thus, this work provides a new idea for the industrial application of simultaneous separation of oil and proteins via AEE.

Effects of Quillaja Saponin on Physicochemical Properties of Oil Bodies Recovered from Peony (Paeonia ostii) Seed Aqueous Extract at Different pH.

Peony seeds, an important oil resource, have been attracting much attention because of α-linolenic acid. Oil bodies (OBs), naturally pre-emulsified oils, have great potential applications in the food industry. This study investigated the effects of extraction pH and Quillaja saponin (QS) on the physicochemical properties of peony oil body (POB) emulsions. POBs were extracted from raw peony milk at pH 4.0, 5.0, 6.0, and 7.0 (named pH 4.0-, 5.0-, 6.0-, and 7.0-POBs). All POBs contained extrinsic proteins and oleosins. The extrinsic proteins of pH 4.0- and pH 5.0-POB were 23 kDa and 38 kDa glycoproteins, the unknown proteins were 48 kDa and 60 kDa, while the 48 kDa and 38 kDa proteins were completely removed under the extraction condition of pH 6.0 and 7.0. The percentage of extrinsic proteins gradually decreased from 78.4% at pH 4.0-POB to 33.88% at pH 7.0-POB, while oleosin contents increased. The particle size and zeta potential of the POB emulsions decreased, whereas the oxidative stability, storage stability, and pI increased with the increasing extraction pH. QS (0.05~0.3%) increased the negative charges of all the POB emulsions, and 0.1% QS significantly improved the dispersion, storage, and the oxidative stability of the POB emulsions. This study provides guidance for selecting the proper conditions for the aqueous extraction of POBs and improving the stability of OB emulsions.

Effect of Heat Treatment on the Digestive Characteristics of Different Soybean Oil Body Emulsions.

Soybean oil body (SOB) emulsions were prepared using OBs extracted at pH 11.0 and pH 7.0. The pH 11.0-SOB comprised oleosins, whereas pH 7.0-SOB comprised extrinsic proteins and oleosins. All SOB emulsions were heated at 60-100 °C for 15 min. Heating may lead to the release of extrinsic proteins from the surface of pH 7.0-SOB due to heat-induced denaturation. The total proportion of α-helix and β-sheets gradually decreased from 77 (unheated) to 36.2% (100 °C). During stomach digestion, the extrinsic protein hydrolysis of heated pH 7.0-SOB emulsions was fast between 60 and 80 °C, and it then slowed between 90 and 100 °C; heating inhibited the oleosin hydrolysis of pH 7.0- and 11.0-SOBs. Heat treatment promoted aggregation and coalescence, and it resulted in increased particle sizes for all emulsions. Larger aggregates were found in heated pH 7.0-SOB emulsions, and larger oil droplets were found in heated pH 11.0-SOB emulsions. After intestinal digestion, the droplets of all SOB emulsions gradually dispersed, and particle sizes decreased. Different heating temperatures had lesser effects on particle sizes and microstructures. Lipolysis was affected by the extraction pH and heating. For pH 11.0-SOB emulsions, the FFA release tendency was greatly affected by the heating temperature, and heating to 80 °C resulted in the highest FFA release (74%). However, all pH 7.0-SOB emulsions had similar total FFA releases. In addition, the droplet charges of heated pH 7.0-SOB emulsions were lower than those of unheated pH 7.0-SOB emulsions in both the intestine and stomach phases; however, the charge changes in different pH 11.0-SOB emulsions showed the opposite tendency. This study will offer guidance regarding the application of SOB emulsions in food.

Construction of different properties single and double cross-linked binary emulsion filled gels based on rice bran oil body emulsion

Rice bran oil bodies (RBOBs) are rich in nutritional value. RBOBs are a by-product of rice processing. In this study RBOBs with different fractions (0–10%) were filled in binary networks formed by soy protein isolate (SPI) and flaxseed gum (FG). Two types of emulsion-filled gel (EFG) were constructed via Ca2+ crosslinking or double-crosslinking with transglutaminase (TG) and Ca2+. Microstructure and fluorescence spectra revealed that RBOBs were integrated into the structural matrix, resulting in altered gel network structure. Ca2+ crosslinking induced droplet aggregation and led to the formation of a segregated network structure, increasing surface roughness. TG and Ca2+ double cross-linking yielded a homogeneous gel network. Meanwhile, double-crosslinking and filling of RBOB emulsion resulted in a denser structure with higher water-holding capacity. Rheology and tribological tests demonstrated that RBOBs acted as active fillers in EFGs constructed via two crosslinking methods, improving the colloidal strength by forming different structures. Thixotropy of double- crosslinked EFG is obvious better than Ca2+-crosslinked EFG, which has higher creep recovery rate. During friction sliding, Ca2+ crosslinking and double-crosslinking resulted in different friction behavior. Filling with 10% RBOBs fraction leads to better friction behavior. This study provides a new idea for the potential application of oil bodies as fat substitutes.

Oil body extraction from high-fat and high-protein soybeans by laccase cross-linked beet pectin: physicochemical and oxidation properties.

Soybean oil bodies (SOB) are droplets of natural emulsified oil. Soybean oil emulsifies well but it is easily oxidized during storage. Beet pectin is a complex anionic polysaccharide, which can be adsorbed on the surface of liposomes to improve their resistance to flocculation. Laccase can covalently cross-link ferulic acid in beet pectin, and its structure is irreversible, which can improve the stability of polysaccharides. At pH2.5, laccase cross-linked beet pectin high-oil soybean oil body (HOSOB) and high-protein soybean oil body (HPSOB) emulsions showed obvious aggregation and severe stratification, and the oxidation of the emulsions was also high. The flocculation of emulsions decreased with an increase in the pH. The effect of pH on the flocculation of emulsion was confirmed by confocal laser electron microscopy. The ζ potential, emulsification, and rheological shear force increased with increasing pH whereas the particle size and surface hydrophobicity decreased with increasing pH. This experiment indicates that the physicochemical stability of the two composite emulsions was strongly affected under acidic conditions but stable under neutral and weakly alkaline conditions. Under the same acid-base conditions, the degree of oxidation of HPSOB composite emulsion changes substantially. The results of this study can provide a basis for the design of very stable emulsions to meet the demand for natural products. © 2023 Society of Chemical Industry.

Effects of FeII, tannic acid, and pH on the physicochemical stability of oil body emulsions

This study examined the effects of solution pH (3.0, 5.0, and 7.0), FeII, and tannic acid (TA) on oil body (OB) emulsions and monitored changes in emulsion particle size, zeta potential, appearance, microstructure, and oxidation stability over 14 days of storage at 37 °C. The chelation efficiency, zeta potential, and fourier-transform infrared spectroscopy results showed that the ability of TA to chelate FeII and the absolute charge of TA-Fe complexes increased with the pH. In addition, the distribution of these complexes in the emulsions was influenced by their electrostatic and hydrogen bonding interactions with the OB. At pH 3.0 and 5.0, the TA-Fe and OB emulsion particles attracted each other, resulting in droplet flocculation. At pH 7.0, the TA-Fe and OB emulsion particles carried the same (negative) charge, and had little effect on physical stability of OB emulsions. TA generally inhibited the oxidation of OB emulsions but promoted the concentration of the primary and secondary oxidation products (61.48 mmol/kg and 50.5 μmol/kg, respectively) of FeII-containing emulsions at pH 3.0. The obtained results provide new insights into the efficacy of TA as a natural antioxidant for emulsified foods and thus pave the way to increasing their quality and shelf life.

The effect of sodium alginate on the nanomechanical properties and interaction between oil body droplets studied using atomic force microscopy

This study investigates the nanomechanical properties of different oil bodies (OBs), including soybean, peanut, sesame, and rapeseed, coated with sodium alginate (ALG), and the interaction between ALG-coated OBs using atomic force microscopy (AFM). Hooke's law, Reissner theory, and the Membrane model were respectively applied to analyze the nanomechanical properties of the linear and non-linear mechanics of the ALG-coated OBs. It was found that stiffness Kb and modulus ER from the linear deformation of ALG-coated OBs increased with the increase of the ALG layer thickness, while modulus Em from the non-linear deformation was larger than ER and correlated with the compression degree of the ALG layer. The interaction between pure OBs depended on the OB type. Electrostatic interaction which is related to the surface ζ-potential of the OBs occurs at a relatively long interaction distance, while at a relatively short distance, interfacial deformation of OBs occurs and the interaction force is affected by the structure and mechanics of OB interfacial membrane. After coating by ALGs, the electrostatic repulsion occurred from a longer distance than that between pure OBs, and both electrostatic repulsion and steric hindrance exist for a long interaction distance as the ALG-coated OBs continued to approach each other. ALG coating can also weaken the electrostatic screening effect of salt ions, avoiding aggregation of OBs and thus improving their stability. The present work demonstrates the feasibility of using AFM to study the mechanical properties and interaction of OB droplets at the molecular level, and reveals the mechanism of the influence of polysaccharide macromolecules on the stability of OB emulsions from the microscopic scale.

Study on oil body emulsion gels stabilized by composited polysaccharides through microgel particles compaction and natural gelation

Oil bodies (OBs), oil storage organelles of oilseeds, are natural, green, and sustainable products that have received much attention in recent years. Different ratios (4:0, 3:1, 2:2, 1:3, 0:4, w/w) of gelatinous polysaccharide κ-carrageenan (κ-Car) mixed with non-gelatinous polysaccharide xanthan (Xan) were used to stabilize OB emulsion gels by microgel particles (MPs) compaction or natural gelation with a total polysaccharide concentration of 0.5 wt%, respectively. Effects of two different treatments of polysaccharides on OB emulsion gels were compared by Fourier transform infrared spectroscopy (FTIR), rheology, and varied microscopy techniques, respectively. For natural gelation, the texture of OB emulsion gels was too rough to be employed in the food system. After compounding κ-Car with Xan, κ-Car and Xan were cross-linked to form a tighter network structure which improved the stability of OB emulsion gels by restricting the movement of OBs and water. Besides, the texture of OB emulsion gels became homogeneous. In addition, MPs compacted closely as micro-units to form a different type of network could benefit to homogeneous texture. The surface area of gels was expanded after microgel treatment, and the hydrogen bond strength enhanced. Unfortunately, the water seepage was more severe after microgel treatment. However, with the increase of Xan proportion before microgel treatment, the instability of OB emulsion gels stabilized by MPs could be improved significantly. This study allowed us to gain a better understanding of tailoring the texture of OB emulsion gels and broadening the application of OBs to low-fat food systems. • The stability of oil body emulsion gels can be advanced by mixing polysaccharides. • Microgel particles facilitated uniform texture of oil body emulsion gels. • Dense network structure was beneficial to the stability of oil body emulsion gels.

Interfacial characteristics of artificial oil body emulsions (O / W) prepared using extrinsic and intrinsic proteins: Inspired by natural oil body

In order to explore the stabilization mechanisms of intrinsic protein (IP) and extrinsic protein (EP) in natural oil-bodies, the effects of adding EP and IP in different relative proportions on the stability, interfacial characteristics, and digestibility of artificial oil body (AOB) emulsions were studied. The stability test results showed that the AOB emulsion prepared using 40% EP/60% IP exhibited the highest ζ-potential (−36.3 mV) and storage stability. According to the results of interface properties, competitive adsorption occurred at the interface in the emulsions prepared using IPs and EPs. Furthermore, by measuring the bioavailability of free fatty acids and curcumin during the digestion process, it was elucidated that 40% EP/60% IP developed a stable interfacial membrane, which facilitated the targeted release of curcumin in the intestine and yielded higher bioavailability. These results lay the foundation for clarifying the stabilization mechanism of natural oil body emulsions from an interfacial perspective.

Oil body-based one-step multiple phases and hybrid emulsion gels stabilized by sunflower wax and CMC: Application and optimization in 3D printing

In this paper, novel oil body (OB) based emulsion gels were prepared by mixing different ratios of two phases: Carboxymethyl-cellulose-coated OBs (CMC-OB) phase and Sunflower wax-based soybean oil (SW–SO) oleogel phase. The stabilization mechanism of OB emulsion gels was investigated by multiple microscopy techniques, and the decorating ability and 3D printability have been evaluated and optimized combined with the rheology analysis. Multiple phases and hybrid emulsion gels could be prepared by a one-step method due to the natural oil-in-water (O/W) structure of OB. In the first case, an (O1/W1)/O2 type emulsion gel was obtained when the OB-CMC phase content was 50 wt% and below, which with a higher elastic modulus was better for formability in 3D printing. Another case was that the OB-CMC phase was the continuous phase when the OB-CMC phase was 60, 70 wt%, and the emulsion gel system was O2/(O1/W1) structure with a 15 μm emulsion size and an unsatisfactory 3D printing capability. Then, two different approaches to improving the 3D printability of O2/(O1/W1) emulsion gels were compared, namely by increasing the strength of the inner phase and external phase by adding SW and OB content, respectively. With the addition of OBs, more suitable printing ink for 3D printing was obtained for the tight compaction of OBs in the external phase. The OB-based multiple phases and hybrid emulsion gels without low-molecular weight emulsifiers facilitated the broadening of OB applications in healthy, green, sustainable food products and 3D printing.

Effects of tannic acid on the physical stability, interfacial properties, and protein/lipid co-oxidation characteristics of oil body emulsions

Herein, we investigated the effects of tannic acid (TA) concentration (0.02–0.70 mg/mL) on the physical stability, interfacial properties, and lipid/protein co-oxidation behavior of oil body (OB) emulsions. The results suggest that the lowest average particle size (0.416 μm), highest absolute ζ-potential (34.03 mV), and best anti-aggregation properties were obtained at a TA concentration of 0.10 mg/mL. Fourier transform infrared spectroscopic analysis showed that TA engaged in hydrogen bonding and hydrophobic interactions with OB proteins, while interfacial property analysis revealed that the influence of TA on OB interfacial proteins was complex and indicated the occurrence of synergistic and competitive interfacial adsorption. At low concentrations (0.02–0.30 mg/mL), TA competed with OB interfacial proteins for adsorption sites, whereas at high concentrations (0.50 and 0.70 mg/mL), it engaged in noncovalent interactions with these proteins to increase the thickness of the OB interfacial layer and thus strengthen the physical barrier responsible for oxidative resistance. Notably, TA increased the oxidative stability of OBs during storage regardless of its concentration, which was related to the capture of TA by the OB interface. Thus, this study explains the action mechanism of TA and OB proteins, provides insights into the co-oxidation of OB lipids and proteins, and deepens our understanding of the oxidation of natural food emulsions.