Effectiveness of partially hydrolyzed rice glutelin as a food emulsifier: Comparison to whey protein

Enhanced stability and oxidation resistance of Acer truncatum Bunge seed oil Pickering emulsion using rice bran protein modified by phytic acid

The potential applications of Acer truncatum Bunge seed oil in the food and medical industries are constrained by its susceptible fatty acid composition, which is prone to oxidation. In this study, rice bran protein (RBP) was employed as an emulsifier for the fabrication of Acer truncatum Bunge seed oil Pickering emulsion. The impact of antioxidant-phytic acid (PA) on the stability of Pickering emulsion and the underlying mechanisms were further investigated. The findings indicate that PA is capable of interacting with RBP, resulting in a change in its spatial conformation. When the PA concentration was increased from 0 to 0.01 % (w/v), the number of α-helices of RBP-PA particles decreased by 5 %, the number of β-sheets and interfacial adsorbed proteins increased by 2.89 % and 39.83 %. Additionally, and the surface hydrophobicity was increased from 50 ± 3.63 (a.u.) to 429 ± 20.03 (a.u.), and the range of the particle size distribution was reduced from 1 to 10 μm to 295-459 nm, and the zeta potential decreased from -23.43 ± 0.46 mV to -53.4 ± 1.35 mV. The Acer truncatum Bunge seed oil Pickering emulsion, containing 0.01 % PA, exhibits favourable static stability and lipid oxidative stability, allowing for storage at room temperature for a period exceeding 50 days.

Health effects of synthetic additives and the substitution potential of plant-based additives

The growth of the world population and the rapid industrialization of food have led to food producers' increased reliance on food additives. While food additives offer numerous conveniences and advantages in food applications, the potential risks associated with synthetic additives remain a significant concern. This report examines the current status of safety assessment and toxicity studies of common synthetic additives, including flavorings (sweeteners and flavor enhancers), colorants, preservatives (antimicrobials and antioxidants), and emulsifiers. The report also examines recent advances in promising plant-based alternative additives in terms of active ingredients, sensory properties, potential health benefits, food application challenges, and their related technologies (edible coatings/films and nanoencapsulation technologies), providing valuable references and insights for the sustainable development of food additives.

Characterization, stability, and curcumin bioaccessibility of buckwheat flower polysaccharide conjugate emulsion

In this study, buckwheat flower polysaccharide conjugates (BFPCs) were synthesized and evaluated for their emulsification properties. The stability of BFPC-stabilized emulsions was assessed through particle size analysis, zeta potential measurements, microscopic observations, and rheological tests. Gum Arabic served as a control to compare BFPC's emulsifying efficacy across varying storage conditions, including exposure to metal ions, pH variations, and different heat treatment temperatures. Results showed that BFPC significantly lowered interfacial tension (16.2 mN/m) and effectively stabilized emulsions containing 60 wt% medium-chain triglycerides at a concentration of 1.0 wt%. Over a 20-day storage period, BFPC emulsions demonstrated robust resistance to heat (60-90°C), acidic conditions (pH 2.0-9.0), and ion concentrations (Na+, Ca2+). Moreover, in a high oil phase emulsion, BFPC enhanced the bioavailability of curcumin to 27.05%, markedly higher than the 7.10% observed without emulsification, underscoring its potential in nutrient delivery applications. PRACTICAL APPLICATION: Due to its excellent resistance, long-time emulsifying stability under different conditions, and its good effect in curcumin embedding, BFPC has a broad prospect and can be widely used under various conditions in food industry.

Synergistic effect of protein foams and polysaccharide on the invisible hemostasis of acellular dermal matrix sponges

Efficient management of hemorrhage is vital for preventing hemorrhagic shock and safeguarding wounds against infection. Inspired by the traditional Chinese steamed bread-making process, which involves kneading, foaming, and steaming, we devised a hemostatic sponge by amalgamating an acellular dermal matrix gel, hydroxyethyl starch, and rice hydrolyzed protein. The integration of hydroxyethyl starch bolstered the sponge's mechanical and hemostatic attributes, while the inclusion of rice hydrolyzed protein, acting as a natural foaming agent, enhanced its porosity This augmentation facilitated rapid blood absorption, accelerated clot formation, and stimulated the clotting cascade. Experimental findings underscore the exceptional biocompatibility and physicochemical characteristics of the hemostatic sponge, positioning it on par with commercially available collagen hemostatic sponges for hemorrhage control. Mechanistically, the sponge fosters aggregation and activation of red blood cells and platelets, expediting coagulation kinetics both in vivo and in vitro. Notably, this hemostatic sponge activates the clotting cascade sans crosslinking agents, offering a premium yet cost-effective biomaterial with promising clinical applicability.

Rice proteins - Gum arabic coacervates: Effect of pH and polysaccharide concentration in oil-in-water emulsion stability

In the context of replacing animal proteins in food matrices, rice proteins (RP) become promised because they come from an abundant plant source, are hypoallergenic, and have high digestibility and nutritional value. However, commercial protein isolates obtained by spray drying have low solubility and poor functionality, especially in their isoelectric point. One way to modify these properties is through interaction with polysaccharides, such as gum arabic (GA). Therefore, this work aims to evaluate the effects of pH and GA concentration on the interaction and emulsifying activity of RP:GA coacervates. First, the effects of pH (2.5 to 7.0) and GA concentrations (0.2 to 1.0 wt%, giving rise to RP:GA mass ratios of 1:0.2 to 1:1.0) in RP:GA blends were evaluated. The results demonstrated that biopolymers present opposite net charges at pH between 2.5 and 4.0. At pH 3.0, insoluble coacervates with complete charge neutralization were formed by electrostatic interactions, while at pH 5.0 it was observed that the presence of GA prevented the RP massive aggregation. Second, selected blends with 0.4 or 1.0 wt% of GA (RP:GA mass ratios of 1:0.4 or 1:1.0) at pH 3.0 or 5.0 were tested for their ability to stabilize oil-in-water emulsions. The emulsions were characterized for 21 days. It was observed that the GA increased the stability of RP emulsions, regardless of the pH and polysaccharide concentration. Taken together, our results show that it is possible to combine RP and GA to improve the emulsifying properties of these plant proteins at pH conditions close to their isoelectric point, expanding the possibility of implementation in food systems.

Applications of Plant Bioactive Compounds as Replacers of Synthetic Additives in the Food Industry

According to the Codex Alimentarius, a food additive is any substance that is incorporated into a food solely for technological or organoleptic purposes during the production of that food. Food additives can be of synthetic or natural origin. Several scientific evidence (in vitro studies and epidemiological studies like the controversial Southampton study published in 2007) have pointed out that several synthetic additives may lead to health issues for consumers. In that sense, the actual consumer searches for "Clean Label" foods with ingredient lists clean of coded additives, which are rejected by the actual consumer, highlighting the need to distinguish synthetic and natural codded additives from the ingredient lists. However, this natural approach must focus on an integrated vision of the replacement of chemical substances from the food ingredients, food contact materials (packaging), and their application on the final product. Hence, natural plant alternatives are hereby presented, analyzing their potential success in replacing common synthetic emulsifiers, colorants, flavorings, inhibitors of quality-degrading enzymes, antimicrobials, and antioxidants. In addition, the need for a complete absence of chemical additive migration to the food is approached through the use of plant-origin bioactive compounds (e.g., plant essential oils) incorporated in active packaging.

Effects of casein phosphopeptides on thermal stability and sensory quality of whey protein emulsions containing calcium beta-hydroxy-beta-methylbutyrate

This study aimed to elucidate the effect of casein phosphopeptides (CPP) on the thermal stability and sensory quality of whey protein emulsions containing calcium beta-hydroxy-beta-methylbutyrate (WPEs-HMB-Ca). The interaction mechanism among CPP, HMBCa, and WP in the emulsions before and after autoclaving (121 °C, 15 min) was systematically investigated from macroscopic external and microscopic molecular perspectives. It was found that WPEs-HMB-Ca treated by autoclaving resulted in an increase in droplet size (d4,3 = 24.09 μm) due to aggregation/flocculation of proteins, along with a stronger odor with higher viscosity, compared to those without autoclaving. When CPP:HMB-Ca = 1:25 (w/w) in the emulsion, the droplets exhibited a more uniform and consistent state in the emulsion. In addition, CPP was able to inhibit the formation of complex spatial network structures of proteins during autoclaving by binding with Ca2+, thus improving the thermal stability and storage stability of WPEs-HMB-Ca. This work might provide theoretical guidance for developing functional milk drinks with good thermal stability and flavor.

Solubility and conformational characterization of rice glutelin after high temperature treatment

Enhancing the solubility of rice glutelin in neutral aqueous solution is the prerequisite for the development of rice protein drinks and ingredients. Herein, glutelin was first dissolved in an aqueous solution of pH 12, and then heated at 121 °C for 20 min. The results showed that the solubility of glutelin increased from 2.55 mg/mL to 20.7 mg/mL at pH 7. The size of glutelin aggregates at pH 7 decreased from 900 nm to 400 nm after high temperature treatment (HTT), which was confirmed by atomic force microscopy. The results of small angle X-ray scattering showed that HTT induced the conformational unfolding of glutelin, and the protein in the aggregate was rod like shape as well as the mean square rotation radius decreased from 64.9 to 54.8 Å. Furthermore, Raman spectrum results also agree with the unfolding of glutelin conformation, which was mainly reflected in the changes of tyrosine and tryptophan residues, as well as the decreasing of α-helix content and increasing of β-sheet content. After being freeze-dried, HTT glutelin has a re-solubilization capacity of 15.48 mg/mL in pH 7 aqueous solution, which was superior to that of spray dried glutelin powder (pH 7, 9.19 mg/mL).

Effect of Enzymatic Hydrolysis on Solubility and Emulsifying Properties of Lupin Proteins (Lupinus luteus)

Solubility and emulsifying properties are important functional properties associated with proteins. However, many plant proteins have lower techno-functional properties, which limit their functional performance in many formulations. Therefore, the objective of this study was to investigate the effect of protein hydrolysis by commercial enzymes to improve their solubility and emulsifying properties. Lupin protein isolate (LPI) was hydrolyzed by 7 commercial proteases using different E/S ratios and hydrolysis times while the solubility and emulsifying properties were evaluated. The results showed that neutral and alkaline proteases are most efficient in hydrolyzing lupin proteins than acidic proteases. Among the proteases, Protamex® (alkaline protease) showed the highest DH values after 5 h of protein hydrolysis. Meanwhile, protein solubility of LPI hydrolysates was significantly higher (p < 0.05) than untreated LPI at all pH analyzed values. Moreover, the emulsifying capacity (EC) of undigested LPI was lower than most of the hydrolysates, except for acidic proteases, while emulsifying stability (ES) was significantly higher (p < 0.05) than most LPI hydrolysates by acidic proteases, except for LPI hydrolyzed with Acid Stable Protease with an E/S ratio of 0.04. In conclusion, the solubility, and emulsifying properties of lupin (Lupinus luteus) proteins can be improved by enzymatic hydrolysis using commercial enzymes.

Fabrication and characterization of a cannabidiol-loaded emulsion stabilized by a whey protein-maltodextrin conjugate and rosmarinic acid complex

A cannabidiol (CBD)-loaded oil-in-water emulsion stabilized by a whey protein (WP)-maltodextrin (MD) conjugate and rosmarinic acid (RA) complex was fabricated, and its stability characteristics were investigated under various environmental conditions. The WP-MD conjugates were formed via dry-heating. The interaction between WP and MD was assessed by browning intensity, reduced amount of free amino groups, the formation of high molecular weight components in sodium dodecyl sulfate-PAGE, and changes in secondary structure of whey proteins. The WP-MD-RA noncovalent complex was prepared and confirmed by fluorescence quenching and Fourier-transform infrared spectroscopy spectra. Emulsions stabilized by WP, WP-MD, and WP-RA were used as references to evaluate the effect of WP-MD-RA as a novel emulsifier. Results showed that WP-MD-RA was an effective emulsifier to produce fine droplets for a CBD-loaded emulsion and remarkably improved the pH and salt stabilities of emulsions in comparison with WP. An emulsion prepared with WP-MD-RA showed the highest protection of CBD against UV and heat-induced degradation among all emulsions. The ternary complex kept emulsions in small particle size during storage at 4°C. Data from the current study may offer useful information for designing emulsion-based delivery systems which can protect active substance against environmental stresses.

Enhancing the Formation and Stability of Oil-In-Water Emulsions Prepared by Microchannels Using Mixed Protein Emulsifiers

Although natural emulsifiers often have many drawbacks when used alone, their emulsifying ability and stability can usually be improved unexpectedly when used in combination. In this study, monodisperse emulsions stabilized by combining two natural protein emulsifiers, i.e., whey protein isolate (WPI) and sodium caseinate (SC), in different proportions were prepared using microchannel (MC) emulsification. The influences of temperature, pH, ionic strength, and storage time on the microstructure and stability of the emulsions were examined. Analysis of the microstructure and droplet size distribution revealed that the WPI-, SC-, and mixed protein-stabilized emulsions exhibited uniform droplet distribution. The droplet size and ξ-potential of the MC emulsions stabilized by mixed protein emulsifiers were higher than those of the emulsions stabilized by WPI or SC separately. The emulsions stabilized by the two types of proteins and mixed emulsifiers had better stability under high salt concentrations than the synthetic emulsifier Tween 20. WPI-SC-stabilized emulsions were more resistant to high temperatures (70–90°C) and exhibited excellent stabilization than those stabilized by WPI and SC, which was attributed to the more sufficient coverage provided by the two types of protein emulsifier layers and better protein adsorption at the oil-water interface. These results indicate that WPI-SC is a potential stabilizer for MC emulsion requirements. This study provides a basis for the formulation of monodisperse and stable natural emulsion systems.

Recent application of protein hydrolysates in food texture modification

The demand for clean labels has increased the importance of natural texture modifying ingredients. Proteins are unique compounds that can impart unique textural and structural changes in food. However, lack of solubility and extensive aggregability of proteins have increased the demand for enzymatically hydrolyzed proteins, to impart functional and structural modifications to food products. The review elaborates the recent application of various proteins, protein hydrolysates, and their role in texture modification. The impact of protein hydrolysates interaction with other food macromolecules, the effect of pretreatments, and dependence of various protein functionalities on textural and structural modification of food products with controlled enzymatic hydrolysis are explained in detail. Many researchers have acknowledged the positive effect of enzymatically hydrolyzed proteins on texture modification over natural protein. With enzymatic hydrolysis, various textural properties including foaming, gelling, emulsifying, water holding capacity have been effectively improved. It is evident that each protein is unique and imparts exceptional structural changes to different food products. Thus, selection of protein requires a fundamental understanding of its structure-substrate property relation. For wider applicability in the industrial sector, more studies on interactions at the molecular level, dosage, functionality changes, and sensorial attributes of protein hydrolysates in food systems are required.

Interfacial characteristics and in vitro digestion of emulsion coated by single or mixed natural emulsifiers: lecithin and/or rice glutelin hydrolysates

BACKGROUND

The interfacial characteristics and in vitro digestion of emulsion were related to emulsifier type. The mean droplet diameter, ζ-potential, microstructure, interfacial tension, Quartz crystal microbalance with dissipation (QCM-D) and in vitro gastrointestinal fate of emulsions stabilized by soybean lecithin, hydrolyzed rice glutelin (HRG) and their mixture were researched.

RESULTS

The value of interfacial tension was much more dramatically declined for the sample containing 20 g kg^-1 of HRG. For QCM-D, a rigid layer was formed for all the samples after rinsing. The layer thickness was 0.87 ± 0.20, 2.11 ± 0.31 and 2.63 ± 0.22 nm, and adsorbed mass was 87.17 ± 10.31, 210.56 ± 20.12 and 263.09 ± 23.23 ng cm^-2 , for HRG, lecithin and HRG/lecithin, respectively, indicating both HRG and lecithin were adsorbed at the oil-water interface. Structural rearrangements at the interface occurred for HRG/lecithin. The kinetics and final amount of lipid digestion depended on emulsifier type: lecithin > HRG/lecithin > HRG. These differences in digestion rate were primarily due to differences in the aggregation state of the emulsifiers.

CONCLUSION

The incorporation of lecithin into HRG emulsions had better interfacial properties comparing with HRG emulsion and facilitated lipid digestibility. These results provide important information for the rational design of plant-based functional food. © 2021 Society of Chemical Industry.

Proposed Methods for Testing and Comparing the Emulsifying Properties of Proteins from Animal, Plant, and Alternative Sources

The food industry is trying to reformulate many of its products to replace functional ingredients that are chemically synthesized or isolated from animal sources (such as meat, fish, eggs, or milk) with ingredients derived from plant or microbial sources. This effort is largely a result of the demand for foods that are better for the environment, human health, and animal welfare. Many new kinds of plant- or microbial-derived proteins are being isolated for potential utilization as functional ingredients by the food industry. A major challenge in this area is the lack of standardized methods to measure and compare the functional performance of proteins under conditions they might be used in food applications. This information is required to select the most appropriate protein for each application. In this article, we discuss the physicochemical principles of emulsifier functionality and then present a series of analytical tests that can be used to quantify the ability of proteins to form and stabilize emulsions. These tests include methods for characterizing the effectiveness of the proteins to promote the formation and stability of the small droplets generated during homogenization, as well as their ability to stabilize the droplets against aggregation under different conditions (e.g., pH, ionic composition, temperature, and shearing). This information should be useful to the food industry when it is trying to identify alternative proteins to replace existing emulsifiers in specific food applications.

Structure and in vitro bioactive properties of O/W emulsions generated with fava bean protein hydrolysates

The use of plant-derived proteins in the generation of food products is gaining popularity as an alternative to proteins of animal origin. This study described the emulsifying and bioactive properties of fava bean protein hydrolysates (FBH) generated at low and high degree of hydrolysis (DH), i.e., FBH₈ (low DH: 8.4 ± 0.3) and FBH₂₁₀ (high DH: 15.6 ± 0.7) when adjusted to three different pHs (3.0, 5.0 and 8.0). Overall, FBH₈, had more favourable emulsifying properties compared to the FBH_210. The emulsion generated with FBH₈ at pH 8.0 also had the highest antioxidant activity when measured by the oxygen radical absorbance capacity (ORAC) and ferric reducing antioxidant power (FRAP) assays with values of 1108.6 ± 3.8 and 1159.9 ± 20.5 μmol Trolox Eq·g^-1 emulsion, respectively. The antioxidant activity of the emulsions, in most cases, remained unchanged following in vitro simulated gastrointestinal digestion. Both the FBH₈ and FBH₂₁₀ emulsions following in vitro simulated gastrointestinal digestion were able to inhibit the activities of dipeptidyl peptidase-IV (DPP-IV) and angiotensin converting enzyme (ACE) with ∼45% and 65% inhibition, respectively. These results indicated that hydrolysates from fava bean may find use for the generation of bioactive emulsions.

Effects of ultrasound extraction on the physicochemical and emulsifying properties of rice bran protein

In this study, rice bran protein was prepared by ultrasound-assisted extraction, and its physicochemical and emulsifying properties were also evaluated. Results demonstrated that a significant increase in protein yield was observed when ultrasound-assisted method was employed for extracting protein. Noticeably, obtained rice bran protein possessed excellent physicochemical properties, such as oil absorption capacity, protein solubility and foaming property. More hydrophobic groups were exposed in the process of ultrasound-assisted extraction, which led to the increase of surface hydrophobicity. More importantly, the ultrasound-assisted extraction could improve emulsifying properties of rice bran protein, and the emulsions prepared using protein samples exhibited the great stability. Besides, it was also found that emulsifying properties of protein samples presented a decrease trend with increasing ultrasound power and time. All in all, ultrasound-assisted extraction is a suitable alternative process for preparing rice bran protein.

Impact of arabinoxylan on characteristics, stability and lipid oxidation of oil-in-water emulsions: Arabinoxylan from wheat bran, corn bran, rice bran, and rye bran

To investigate the impact of arabinoxylan (AX) on the physical and oxidative stability of oil-in-water emulsions, AX from wheat bran, corn bran, rice bran, or rye bran was incorporated into the production of whey protein isolate-stabilised emulsions. Decreased interfacial charge and increased mean particle diameters were recorded in all fresh emulsions with 0.1%-0.5% AX, as recorded by the ζ-potential and particle size measurement, indicating the adsorption of AX onto the oil droplets. No phase separation was observed in all emulsions with ≤0.3% AX after 14-day storage in dark. Spectrophotometric analysis demonstrated that all AX lowered the peroxide value and thiobarbituric acid reactive substance concentration in emulsions, with AX from rice bran being slightly more effective. Consequently, AX has the potential to be used as a natural interfacial antioxidant in emulsions, and the antioxidant capacity of AX varies with its source.

Influence of Hydrolysis on the Bioactive Properties and Stability of Chickpea-Protein-Based O/W Emulsions

This study evaluated the effect of enzymatic hydrolysis on the emulsion microstructure and bioactive properties of oil-in-water emulsions generated using chickpea protein concentrate (CP) and its 10 and 210 min Alcalase CP hydrolysates (CPH₁₀ and CPH₂₁₀, respectively) at three pH values (2.5, 5.0, and 7.5). Chromatographic profiles demonstrated CP protein breakdown following hydrolysis. Increasing the degree of hydrolysis resulted in increased emulsion droplet size and decreased viscoelastic moduli. The antioxidant capacities of the emulsions generated with CPH₁₀ and CPH₂₁₀ increased significantly compared to those generated with CP and were pH-dependent. Both angiotensin-converting enzyme and dipeptidyl peptidase-IV inhibitory activities were significantly increased in emulsions stabilized with CPH₂₁₀; however, these results were also pH-dependent. In vitro gastrointestinal digestion of the emulsions resulted in a significant increase in all bioactivities. These results demonstrate the potential for enzymatic hydrolysis to beneficially modulate the emulsifying and bioactive properties of CP proteins.

Whey protein and maltodextrin-stabilized oil-in-water emulsions: Effects of dextrose equivalent

The aim of this work is to evaluate the effect of dextrose equivalent (DE) of maltodextrins (MD) on the stability of whey protein and maltodextrin stabilized oil-in-water (o/w) emulsions. Emulsions with DE 15 maltodextrin (MD 15) exhibited better stability under light acidic (pH 6), neutral and alkaline (pH 8-9) conditions, as well as during temperature ramps (20-60 °C). After 15-days of storage, MD 15 emulsion showed increase in polydispersity and decrease in the average droplet size. The apparent viscosity of the emulsions decreased with increasing DE. The shear stresses of all emulsions fitted well with the power law model (R² > 0.9), while MD 15 showed the most stable k and n indexes. The brightness and whiteness of emulsion decreased with increases in DE. In conclusion, emulsions with MD 15 exhibited better stability, which suggests their good potential for use in the preparation of energy drinks.

Effect of enzymatic degraded polysaccharides from Enteromorpha prolifera on the physical and oxidative stability of fish oil-in-water emulsions

To explore the potential application of enzymatic degraded polysaccharides from Enteromorpha prolifra (EEP) as antioxidant in fish oils, a stable fish oil emulsion system incorporating EEP was established. Effects of emulsifier (Tween 80, gum arabic and lecithin) and EEP concentration on the physical characteristics of fish oil emulsions were investigated. The results indicated that Tween 80 was the best choice, and 1% (w/w) of EEP was the optimum concentration for the preparation of fish oil emulsions. Influence of EEP on the oxidative stability and physical stability of fish oil emulsions was compared with that of antioxidants V_E and TBHQ by determining the physical properties, lipid hydroperoxide formation, secondary reaction products formation, pH and long chain polyunsaturated fatty acid content, during storage at 45 °C. The results indicated that the fish oil emulsion system (5% oil, 1% EEP and 1% Tween 80, w/w) possessed good physical and oxidative stabilities.

Comparative assessment of physicochemical and antioxidative properties of mung bean protein hydrolysates

Two commercial plant proteases namely ficin and bromelain, were acquired to hydrolyze mung bean protein over 300 min hydrolysis, and the physicochemical and antioxidative properties of the obtained hydrolysates were investigated. Bromelain-treated mung bean protein hydrolysates presented a higher degree of hydrolysis in comparison with ficin-treated hydrolysates, further modifying their physicochemical and emulsifying properties. All mung bean protein hydrolysates exhibited 50% scavenging of DPPH radical (IC50) in the concentration range from 8.67 to 16.22 μg mL-1. Our results also showed that strong metal ion-chelating activity was found in the ficin- (higher activity) and bromelain-treated protein hydrolysates. In addition, oxidative stability of linoleic acid was significantly enhanced by two selected protein hydrolysates, particularly the bromelain-treated hydrolysate with the highest inhibition effect of linoleic acid oxidation (94.55 ± 0.10%). Interestingly, both of these two hydrolysates could effectively retard lipid oxidation of sunflower oil and sunflower oil-in-water emulsion, while the ficin-treated hydrolysate showed slightly better performance. Therefore, mung bean protein hydrolysates showed potential to inhibit lipid oxidation, which could be advantageous in the food industry for producing fortified food.

Effect of enzyme types on the stability of oil-in-water emulsions formed with rice protein hydrolysates

BACKGROUND

Common oil-in-water plant-based emulsions are allergenic and unstable to environmental stress, leading to increased consumer concerns about the food industry. To solve the problem of safety and instability, we investigated the influence of environmental stress on the stability of emulsions containing various rice protein hydrolysates, and compared the performance to whey protein, a common food emulsifier.

RESULTS

Rice protein hydrolysates were obtained by enzymatic hydrolysis with different proteases (neutrase, trypsin and alcalase). We evaluated the stability of emulsions produced with different hydrolysates according to storage, pH, ionic strength and thermal processing. Trypsin hydrolysates formed emulsion as stable as emulsion containing whey protein against a range of environmental stress containing pH (pH 6 to 7), salt (< 150 mmol L^-1 NaCl) and temperature (30-90 °C). Moreover, a higher partition coefficient of protein in emulsion showed that the trypsin hydrolysates were easy to adsorb at the oil-water droplet interface, indicating its higher stability.

CONCLUSION

The results obtained in the present study suggest that trypsin hydrolysates could be utilized as natural emulsifiers to stabilize emulsion instead of traditional animal-based emulsifiers, opening many opportunities with respect to hypoallergenic emulsion systems in the food industry. © 2019 Society of Chemical Industry.

Emulsifying Properties of Polysaccharide Conjugates Prepared from Chin-Brick Tea

Chin-brick tea polysaccharide conjugates (TPC-C) were prepared to study their emulsion capabilities. Interfacial tension and the effects of some factors, such as storage time, metal ion concentrations (Na⁺, Ca²⁺), pH (2.0-8.0), and heat treatment (70-100 °C) on the emulsions stabilized by TPC-C were studied. The interfacial tension of TPC-C (10.88 mN/m) was lower than that of gum arabic (15.18 mN/m) at a concentration of 0.08%. As the TPC-C concentration increased from 0.1 to 3.0 wt %, the mean particle diameter (MPD) (d₃₂) of emulsions stabilized by TPC-C decreased from 1.88 to 0.16 μm. Furthermore, at a concentration of 0.5 wt % or higher, the MPD (d₃₂) of emulsions stabilized by TPC-C at 25 and 60 °C for 10 days was between 0.20 and 0.50 μm. In the tested pH conditions from 2.0 to 8.0, the MPD (d₃₂) of emulsions stabilized by 2.0 wt % TPC-C was less than 0.20 μm. At Na⁺ concentration conditions between 0.10 and 0.50 mol/L, the MPD (d₃₂) of emulsions was between 0.19 and 0.20 μm, and the zeta potential values varied from -34.10 to -32.60 mV. However, with an increasing Ca²⁺ concentration from 0.01 to 0.05 mol/L, the MPD (d₃₂) of emulsions was between 0.20 and 21.65 μm, and the zeta potential raised sharply from -34.10 to -28.46 mV. The emulsions stabilized by TPC-C have a decent storage stability after a high-temperature heat treatment. Overall, tea polysaccharide conjugates strongly stabilized the emulsions, which support their new application as natural emulsifiers.

Lipo-Dipeptide as an Emulsifier: Performance and Possible Mechanism

A lipo-dipeptide (C₁₃-lysine-arginine, C₁₃-KR) was designed as a potential emulsifier with good emulsifying properties under acidic condition. Compared with two traditional emulsifiers (whey protein isolate and Tween 80), C₁₃-KR emulsion had the minimum mean size but the highest zeta potential (around +100 mV). Moreover, C₁₃-KR emulsion showed better stability against environmental stresses, such as high salt concentrations and high temperature. The C₁₃-KR particles had the fastest move rate around 400 Hz when it attained an equilibrium state. Furthermore, C₁₃-KR emulsifier could sharply reduce the interfacial tension and had the lowest tension value at the oil/water interface. The interfacial tension of C₁₃-KR emulsifier was only 3.6 mN/m (0.5% w/v). In conclusion, the lipo-dipeptide C₁₃-KR could be considered as an emulsifier to produce emulsion under acidic condition.

Development of Topical Delivery Systems for Flightless Neutralizing Antibody

Flightless I (Flii) is an actin remodeling protein important for cytoskeletal regulation and cellular processes including migration, proliferation, and adhesion. Previous studies have clearly identified Flii as a novel therapeutical target for improved wound repair and have demonstrated Flii regulation using Flii neutralizing antibodies (FnAb) in different models of wound healing in vivo. Here we describe the development of an optimized topical delivery system that can neutralize Flii activity in the epidermis. Topical delivery of FnAb is an attractive approach as it provides a convenient application, sustained release, localized effect, and reduced dosage. Three successful formulations were developed, and their physical and chemical stability examined. The in vitro release revealed prolonged and sustained release of FnAb in all the tested formulations. Additionally, penetration studies using intact porcine skin showed that FnAb penetrated the epidermis and upper papillary dermis. The penetrated FnAb significantly reduced Flii expression compared to dosed matched IgG controls. This study has successfully developed a topical delivery system for FnAb that could serve as a potential platform for future localized wound treatments.