Structural and rheological properties of mung bean protein emulsion as a liquid egg substitute: The effect of pH shifting and calcium

Effect of alkaline treatment duration on rapeseed protein during pH-shift process: Unveiling physicochemical properties and enhanced emulsifying performance

This study aims to investigate the influence of alkaline treatment duration (0-5 h) on the physicochemical properties and emulsifying performance of rapeseed protein during pH-shift process. Results showed that a 4-h alkaline treatment significantly reduced the particle size of rapeseed protein and led to a notable decrease in disulfide bond content, as well as alterations in subunit composition. Moreover, solubility of rapeseed protein increased from 18.10 ± 0.13% to 40.44 ± 1.74% post-treatment, accompanied by a ∼ 40% enhancement in emulsifying properties. Morphological analysis revealed superior plasticity and sharper contours in 4-h alkali-treated rapeseed protein emulsions compared to untreated counterparts. Rheological analysis indicated higher viscosity and elasticity in the alkali-treated group. Overall, 4-h alkaline treatment markedly enhanced the multifaceted functional attributes of rapeseed protein during pH-shift process, rendering it a promising emulsifier in the food industry.

Fabrication of food polysaccharide, protein, and polysaccharide-protein composite gels via calcium ion inducement: Gelation mechanisms, conditional factors, and applications

Food gel is a kind of macromolecular biopolymer with viscoelasticity, which has good water retention and gelling ability, especially gels formed by protein and/or polysaccharide. The addition of calcium ions triggers gelation by interacting with the gel matrix, enhancing gels' textural and rheological properties like hardness, viscosity and elasticity. Thus calcium ions enrich the range of applications of food gels. This review focuses on forming a calcium-induced gel and improving the texture properties. It summarizes the mechanisms of gelation induced by calcium ions in polysaccharide, protein, and polysaccharide-protein systems and their gel properties. The effects of influencing factors in calcium ion concentration, types and mixing ratios of matrices, acid, and alkaline environments, as well as treatment methods on calcium-induced gel characteristics, are presented. Additionally, the current applications of calcium-induced gels in food industries and challenges are presented.

Extraction and characterization of mung bean proteins using different alkaline solutions

This study investigated the effects of alkaline solutions on the production and characteristics of mung bean proteins (MBPs). MBPs were prepared using alkaline solutions of NaOH, NaHCO3, and Na2CO3 and designated MPN, MPH, and MPC, respectively. The yield, protein recovery, and crude protein content of MBP were not significantly different at different alkali concentrations (0.01-0.1%). Although there was no significant difference in MBP yield between alkali types, protein recovery and crude protein content increased in the following order: MPN > MPC > MPH. The essential and branched-chain amino acid contents, molecular weight distribution, and ζ-potential did not differ between MBPs. Regarding MBP pH-dependent solubility, MPN solubility was lower at pH 6-8 than that of MPH and MPC. This pattern was commonly observed for other physical properties. Overall, MBP was prepared using NaHCO3, and Na2CO3 and its functional properties were better when Na2CO3 was used than when NaOH was used.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-024-01624-x.

Improvement of processable properties of plant-based high internal phase emulsions by mung bean protein isolate based on pH shift treatment

BACKGROUND

High internal phase emulsions (HIPEs) are unique emulsion systems that transform liquid oil into solid-like fats, thus avoiding the use of saturated fat and leading to a healthier and more sustainable food system for consumers. HIPEs with oil volume fraction (ϕ) of 75-85% were fabricated with mung bean protein isolate (MPI) under different pH shift treatments at 1.0% concentration through the one-step method. In the present study, we investigated the physical properties, microstructures, processing properties, storage stability and rheological properties of HIPEs.

RESULTS

The results suggested that the properties of MPI under different pH shift treatments were improved to different degrees, stabilizing HIPEs (ϕ = 75-85%) with various processability to meet food processing needs. Under alkali shift treatment conditions, the particle size of MPI was significantly reduced with better solubility. Moreover, the exposure of hydrophobic groups increased the surface hydrophobicity of MPI, awarding MPI better emulsifying properties, which could stabilize the HIPEs with higher oil phase fraction. In addition, the MPI under pH 12 shift treatment (MPI-12) had the best oil-carrying ability to form the stable HIPEs with oil volume fraction (ϕ) up to 85%, which was the highest oil phase in preparing the HIPEs using plant protein solely at a low concentration under neutral conditions.

CONCLUSION

A series of stable HIPEs with different processing properties was simply and feasibly fabricated and these are of great potential in applying edible HIPEs. © 2024 Society of Chemical Industry.

Yeast Proteins: Proteomics, Extraction, Modification, Functional Characterization, and Structure: A Review

Proteins are essential for human tissues and organs, and they require adequate intake for normal physiological functions. With a growing global population, protein demand rises annually. Traditional animal and plant protein sources rely heavily on land and water, making it difficult to meet the increasing demand. The high protein content of yeast and the complete range of amino acids in yeast proteins make it a high-quality source of supplemental protein. Screening of high-protein yeast strains using proteomics is essential to increase the value of yeast protein resources and to promote the yeast protein industry. However, current yeast extraction methods are mainly alkaline solubilization and acid precipitation; therefore, it is necessary to develop more efficient and environmentally friendly techniques. In addition, the functional properties of yeast proteins limit their application in the food industry. To improve these properties, methods must be selected to modify the secondary and tertiary structures of yeast proteins. This paper explores how proteomic analysis can be used to identify nutrient-rich yeast strains, compares the process of preparing yeast proteins, and investigates how modification methods affect the function and structure of yeast proteins. It provides a theoretical basis for solving the problem of inadequate protein intake in China and explores future prospects.

Smart proteins as a new paradigm for meeting dietary protein sufficiency of India: a critical review on the safety and sustainability of different protein sources

India, a global leader in agriculture, faces sustainability challenges in feeding its population. Although primarily a vegetarian population, the consumption of animal derived proteins has tremendously increased in recent years. Excessive dependency on animal proteins is not environmentally sustainable, necessitating the identification of alternative smart proteins. Smart proteins are environmentally benign and mimic the properties of animal proteins (dairy, egg and meat) and are derived from plant proteins, microbial fermentation, insects and cell culture meat (CCM) processes. This review critically evaluates the technological, safety, and sustainability challenges involved in production of smart proteins and their consumer acceptance from Indian context. Under current circumstances, plant-based proteins are most favorable; however, limited land availability and impending climate change makes them unsustainable in the long run. CCM is unaffordable with high input costs limiting its commercialization in near future. Microbial-derived proteins could be the most sustainable option for future owing to higher productivity and ability to grow on low-cost substrates. A circular economy approach integrating agri-horti waste valorization and C1 substrate synthesis with microbial biomass production offer economic viability. Considering the use of novel additives and processing techniques, evaluation of safety, allergenicity, and bioavailability of smart protein products is necessary before large-scale adoption.

Recent advances in mung bean protein: From structure, function to application

With the surge in protein demand, the application of plant proteins has ushered in a new wave of research. Mung bean is a potential source of protein due to its high protein content (20-30 %). The nutrition, structure, function, and application of mung bean protein have always been a focus of attention. In this paper, these highlighted points have been reviewed to explore the potential application value of mung bean protein. Mung bean protein contains a higher content of essential amino acids than soybean protein, which can meet the amino acid values recommended by FAO/WHO for adults. Mung bean protein also can promote human health due to its bioactivity, such as the antioxidant, and anti-cancer activity. Meanwhile, mung bean protein also has well solubility, foaming, emulsification and gelation properties. Therefore, mung bean protein can be used as an antioxidant edible film additive, emulsion-based food, active substance carrier, and meat analogue in the food industry. It is understood there are still relatively few commercial applications of mung bean protein. This paper highlights the potential application of mung bean proteins, and aims to provide a reference for future commercial applications of mung bean proteins.

Mung bean protein isolate: Extraction, structure, physicochemical properties, modifications, and food applications

The intake of plant-based proteins is rapidly growing around the world due to their nutritional and functional properties, as well as growing demand for vegetarian and vegan diets. Mung bean seeds have been traditionally consumed in Asian countries due to their unique botanical and health-promoting characteristics. In recent years, mung bean protein isolate (MBPI) has attracted much attention due to its ideal techno-functional features, such as water and oil absorption capacity, solubility, emulsifying, foaming, and thermal properties. Therefore, it can be utilized in a native or modified form in different food sectors, such as biodegradable/edible films, colloidal systems, and plant-based alternative products. This study provides a comprehensive review on the extraction methods, amino acid profile, structure, physicochemical properties, modifications, and food applications of MBPI.

Changes in physicochemical, structural and functional properties, and lysinoalanine formation during the unfolding and refolding of pH-shifted black soldier fly larvae albumin

The changes of physicochemical, structural and functional properties and the lysinoalanine (LAL) formation during the unfolding and refolding of black soldier fly larvae albumin (BSFLA) induced by acid/alkaline pH shift were explored. The results showed that acid/alkaline conditions induced unfolding of BSFLA structure, but also accompanied by the formation of some large aggregates due to the hydrophobic interactions, hydrogen bonds, and disulfide bonds. Compared with control or pH1.5 shift, pH12 shift treatment significantly increased the electrostatic repulsion, surface hydrophobicity, free sulfhydryl group, and deamidation reactions, but reduced the fluorescence intensity of BSFLA, and these change in protein conformation contributed to increase in solubility, emulsion activity, and emulsion stability. But the content of LAL in BSFLA was increased by 93.39 % by pH 12 shift treatment. In addition, pH1.5 shift modified BSFLA tended to form β-sheet structure through unfolding and refolding, resulting in the formation of aggregates with larger particle sizes, and reducing the solubility and the LAL content by 7.93 % and 65.53 %, respectively. SDS-PAGE profile showed that pH12/1.5 shifting did not cause irreversible denaturation of protein molecules. Therefore, pH12-shift is good way to improve the functional properties of BSFLA, but the content of LAL should be reduced to make it better used in food.

Improving the solubility and interfacial absorption of hempseed protein via a novel high pressure homogenization-assisted pH-shift strategy

A pH shift treatment aided by high pressure homogenization (HPH) with various pressures (0-120 MPa) was employed to structurally modify hempseed protein isolate (HPI). Compared with individual pH shift or HPH treatment, HPH-assisted pH shift improved the structural flexibility of HPI, as revealed by the increased random coil in protein secondary structure. With the incorporation of HPH into pH shift, the intrinsic fluorescence intensity was remarkably attenuated and redshifted, whereas the surface hydrophobicity was pronouncedly boosted, indicating the extensive unfolding of protein structure. Moreover, the cotreated HPI exhibited a smaller and more homogenous particle size, notably at a higher pressure. Consequently, the solubility was drastically raised by the cooperated treatments, to the maximum value (62.8 %) at 120 MPa. These physicochemical changes in the cotreated HPI facilitated a consolidated interfacial activity. Moreover, the cooperated treatment, especially highly pressured (120 MPa), facilitated the penetration and rearrangement of proteins at the oil-water interface.

Mung bean protein as an emerging source of plant protein: a review on production methods, functional properties, modifications and its potential applications

Plant protein is rapidly becoming more of a prime interest to consumers for its nutritional and functional properties, as well as the potential to replace animal protein. In the frame of alternative protein new sources, mung bean is becoming another legume crop that could provide high quality plant protein after soybean and pea. In particular, the 8S globulins in mung bean protein have high structural similarity and homology with soybean β-conglycinin (7S globulin), with 68% sequence identity. Currently, mung bean protein has gained popularity in food industry because of its high nutritional value and peculiar functional properties. In that regard, various modification technologies have been applied to further broaden its application. Here, we provide a review of the composition, nutritional value, production methods, functional properties and modification technologies of mung bean protein. Furthermore, its potential applications in the new plant-based products, meat products, noodles, edible packaging films and bioactive compound carriers are highlighted to facilitate its utilization as an alternative plant protein, thus meeting consumer demands for high quality plant protein resources. © 2023 Society of Chemical Industry.

Incorporation of fucoxanthin into 3D printed Pickering emulsion gels stabilized by salmon by-product protein/pectin complexes

The remarkable performance of fucoxanthin (FX) in antioxidant and weight loss applications has generated considerable interest. However, the application of fucoxanthin in the food and pharmaceutical industries is limited due to its highly unsaturated structure. This research aimed to investigate the synergistic mechanism of a unique Pickering emulsion gel stabilized by salmon byproduct protein (SP)-pectin (PE) aggregates and evaluate its ability to enhance the stability and bioavailability of FX. Various analytical techniques, including fluorescence spectroscopy, contact angle testing, turbidity analysis, and cryo-field scanning electron microscopy, were used to demonstrate that electrostatic and hydrophobic interactions between SP and PE contribute to the exceptional stability and wettability of the Pickering emulsion gels. Rheological analysis revealed that increasing the concentration of SP-PEs resulted in shear-thinning behavior, excellent thixotropic recovery performance, higher viscoelasticity, and good thermal stability of the Pickering emulsion gels stabilized by SP-PEs(SEGs). Furthermore, encapsulation of FX in the gels showed protected release under simulated oral and gastric conditions, with the subsequent controlled release in the intestine. Compared to free FX and the control group without PE (SEG-0), SEG-4 exhibited a 1.92-fold and 1.37-fold increase in the total bioavailable fraction of FX, respectively. Notably, during the study, it was observed that SEGs have the potential to serve as cake decoration for 3D printing to replace traditional cream under lower oil phase conditions (50%). These findings suggest that SP-PEs-stabilized Pickering emulsion gels hold promise as carriers for delivering bioactive compounds, offering the potential for various innovative food applications.

Effect of pectin concentration on emulsifying properties of black soldier fly (Hermetia illucens) larvae albumin modified by pH-shifting and ultrasonication

The effect of pectin concentration on the structural and emulsifying properties of black soldier fly larvae albumin (BSFLA) modified by pH-shifting (pH12) and ultrasound (US) was studied. The results (intrinsic fluorescence, surface hydrophobicity, Fourier transform infrared spectrum, and disulfide bonds) showed that modified BSFLA samples, especially pH12-US, were more likely to bind to pectin through hydrogen bonding, electrostatic interactions, and hydrophobic interactions due to the unfolding of BSFLA, the collapse of disulfide bonds and exposure of hydrophobic groups. Thus, a BSFLA-pectin complex with smaller particle size, more negative charges, and a relatively loose structure was formed. The emulsifying activity (EAI) and stability index (ESI) of pH12-US modified BSFLA were significantly enhanced by the addition of pectin, reaching the highest values (associated with 174.41 % and 643.22 % increase, respectively) at pectin concentration of 1.0 %. Furthermore, the interface modulus of the emulsion prepared by the modified BSFLA was mainly viscous, and had higher apparent viscosity, smaller particle size and droplet size, contributing to higher EAI and ESI. The study findings suggest the addition of pectin to pH12-US treated BSFLA could be used in industry to prepare BSFLA-pectin emulsion with exceptional/desirable properties.

Effect of pH-shifting on the water holding capacity and gelation properties of mung bean protein isolate

In this study, alkaline pH-shifting modified the globular structure of mung bean protein isolate (MBPI) to form flexible and stretched structures. In contrast, acidic pH-shifting increased the rigidity of MBPI. The increased flexibility (at the level of the secondary structure) and newly exposed intermolecular amino acid groups induced by alkaline pH-shifting improved the water holding capacity and gelation properties of proteins. Specifically, MBPI treated at pH 12 (MP12) showed the most flexible structure and highest water holding capacity and gel formation properties (least gelation concentration). The water-holding capacity of native MBPI increased from 1.56 g/g to 4.81 g/g, and its least gelation concentration decreased from 22 % to 15 % by pH-shifting at pH 12. Furthermore, MP12 formed stronger and more elastic heat-induced gels than native MBPI. We identified significant differences in the structural properties and water holding capacity, and gelation properties of acidic and alkaline pH-shifted MBPI and investigated the gelation properties of MP12 including rheological and morphological analyses. Our findings can facilitate the use of mung beans as a protein source in a wide range of food applications, including plant-based and processed meats.

Effects of limited enzymatic hydrolysis and polysaccharide addition on the physicochemical properties of emulsions stabilized with duck myofibrillar protein under low-salt conditions

This study aimed to investigate the role of hydrolysis and guar gum (GG) participation on the emulsification of the duck myofibrillar protein (MP) and the related stability of oil-in-water emulsion in low-salt condition. Emulsions were prepared using one of each or both treatments, and that prepared with trypsin hydrolysis and GG (T-GG) exhibited the highest stability. FTIR analysis confirmed the hydrogen bond interactions between the system components. T-GG treatment improved emulsion properties and decreased oil droplet size. Moreover, CLSM indicated that aggregation of T-GG oil droplets was prevented. Physical stability was assessed such as Turbiscan stability index, creaming index, and rheological properties. The adsorbed percentage for T-GG was the lowest. However, interfacial tension, droplet size, stability, and peroxide value analyses indicated that a denser interfacial membrane structure is formed with T-GG. Thus, T-GG treatment could be applied in the food industry, such as in nutrient delivery systems and fat mimetics.

Pulse Protein Isolates as Competitive Food Ingredients: Origin, Composition, Functionalities, and the State-of-the-Art Manufacturing

The ever-increasing world population and environmental stress are leading to surging demand for nutrient-rich food products with cleaner labeling and improved sustainability. Plant proteins, accordingly, are gaining enormous popularity compared with counterpart animal proteins in the food industry. While conventional plant protein sources, such as wheat and soy, cause concerns about their allergenicity, peas, beans, chickpeas, lentils, and other pulses are becoming important staples owing to their agronomic and nutritional benefits. However, the utilization of pulse proteins is still limited due to unclear pulse protein characteristics and the challenges of characterizing them from extensively diverse varieties within pulse crops. To address these challenges, the origins and compositions of pulse crops were first introduced, while an overarching description of pulse protein physiochemical properties, e.g., interfacial properties, aggregation behavior, solubility, etc., are presented. For further enhanced functionalities, appropriate modifications (including chemical, physical, and enzymatic treatment) are necessary. Among them, non-covalent complexation and enzymatic strategies are especially preferable during the value-added processing of clean-label pulse proteins for specific focus. This comprehensive review aims to provide an in-depth understanding of the interrelationships between the composition, structure, functional characteristics, and advanced modification strategies of pulse proteins, which is a pillar of high-performance pulse protein in future food manufacturing.

Effects of ultrasonic and steam-cooking treatments on the physicochemical properties of bamboo shoots protein and the stability of O/W emulsion

In this study, the effects of ultrasonic and steam-cooking treatments on the physicochemical and emulsifying properties of bamboo shoots protein (BSP) were investigated. The particle size and the polydispersity index (PDI) of U-BSP (ultrasonic-BSP) both decreased. Fourier transform infrared spectroscopy (FTIR) showed that the secondary structure of U-BSP was more loose. Furthermore, X-ray diffraction (XRD) and thermogravimetric (TGA) analysis suggested that crystallinity amd thermal stability of U-BSP both deceased. The water and oil holding capacity (WHC/OHC) of U-BSP increased, while steam-cooking treatment had the reverse effect. We also investigated the effects of ultrasonic and steam-cooking treatments on BSP-stabilized emulsions. The viscosity of emulsion stabilized by U-BSP increased and the distribution of emulsion droplets was more uniform and smaller. The results showed that ultrasonic treatment significantly improved the stability of BSP-stabilized emulsions, while steam-cooking treatment had a significant negative impact on the stability of BSP-stabilized emulsions. The work indicated ultrasonication is an effective treatment to improve the emulsifying properties of BSP.

A comprehensive review of mung bean proteins: Extraction, characterization, biological potential, techno-functional properties, modifications, and applications

The popularity of plant-based proteins has increased, and mung bean protein (MBP) has gained immense attention due to its high yield, nutritional value, and health benefits. MBP is rich in lysine and has a highly digestible indispensable amino acid score. Dry and wet extractions are used to extract MBP flours and concentrates/isolates, respectively. To enhance the quality of commercial MBP flours, further research is needed to refine the purity of MBPs using dry extraction methods. Furthermore, MBP possesses various biological potential and techno-functional properties, but its use in food systems is limited by some poor functionalities, such as solubility. Physical, biological, and chemical technologies have been used to improve the techno-functional properties of MBP, which has expanded its applications in traditional foods and novel fields, such as microencapsulation, three-dimensional printing, meat analogs, and protein-based films. However, study on each modification technique remains inadequate. Future research should prioritize exploring the impact of these modifications on the biological potential of MBP and its internal mechanisms of action. This review aims to provide ideas and references for future research and the development of MBP processing technology.

Effect of Microbial Transglutaminase Treatment on the Techno-Functional Properties of Mung Bean Protein Isolate

The purpose of this study was to investigate the improvement in techno-functional properties of mung bean protein isolate (MBPI) treated with microbial transglutaminase (MTG), including water- and oil-holding capacity, gelling properties, and emulsifying capacity. MBPI dispersions were incubated with MTG (5 U/g of protein substrate) at 45 °C with constant stirring for 4 h (MTM4) or 8 h (MTM8). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that MTG treatment for different durations increased the amount of high-molecular-weight proteins in MBPI, and most of the cross-linking by MTG was terminated at 8 h. Improved water-holding capacity, gelling properties, emulsifying capacity, and stability were observed after MTG treatment, and decreased protein solubility and surface hydrophobicity were observed. Furthermore, the texture of the heat-induced gels made from MTG-treated MBPI was evaluated using a texture analyzer. MTG treatment increased the hardness, gumminess, chewiness, and adhesiveness of the heat-induced gels. Field-emission scanning electron microscopy demonstrated the enhanced hardness of the gels. This research reveals that MTG-catalyzed cross-linking may adjust the techno-functional properties of MBPI, allowing it to be used as a soy protein alternative in food products, such as plant-based and processed meats.

Updates on Plant-Based Protein Products as an Alternative to Animal Protein: Technology, Properties, and Their Health Benefits

Plant-based protein products, represented by "plant meat", are gaining more and more popularity as an alternative to animal proteins. In the present review, we aimed to update the current status of research and industrial growth of plant-based protein products, including plant-based meat, plant-based eggs, plant-based dairy products, and plant-based protein emulsion foods. Moreover, the common processing technology of plant-based protein products and its principles, as well as the emerging strategies, are given equal importance. The knowledge gap between the use of plant proteins and animal proteins is also described, such as poor functional properties, insufficient texture, low protein biomass, allergens, and off-flavors, etc. Furthermore, the nutritional and health benefits of plant-based protein products are highlighted. Lately, researchers are committed to exploring novel plant protein resources and high-quality proteins with enhanced properties through the latest scientific and technological interventions, including physical, chemical, enzyme, fermentation, germination, and protein interaction technology.

pH-Shifting combined with ultrasound treatment of emulsion-filled β-conglycinin gels as β-carotene carriers: Effect of emulsion concentration on gel properties

In this work, emulsion-filled gels were prepared from natural and pH-shifting combined with ultrasound β-conglycinin (7S) as emulsifiers. The emulsifier modification and emulsion concentrations (5, 10, 15, 20 wt%) were evaluated on the structural and β-carotene release properties of the gels. Compared to the 7S hydrogel, the emulsion-filled gels exhibited better water-holding and textural properties. The 7S modification and the increase in emulsion concentration resulted in altered water distribution and improved microstructure and rheological properties of the emulsion-filled gels. The dense and homogeneous gel network was formed at an emulsion content of 15 wt%. The gels were regulated by different release kinetics in a simulated gastrointestinal environment. M-15 showed the highest bioaccessibility and chemical stability (72.25% and 89.87%) with good slow-release properties of β-carotene. These results will guide the development of encapsulated delivery systems for gel food products.

Preparation of plant-based meat analogs using emulsion gels: Lipid-filled RuBisCo protein hydrogels

RuBisCo from duckweed is a sustainable source of plant proteins with a high water-solubility and good gelling properties. In this study, we examined the impact of RuBisCo concentration (9-33 wt %) and oil droplet concentration (0 to 14 wt %) on the properties of emulsion gels designed to simulate the properties of chicken breast. The color (L*a*b*), water holding capacity (WHC), textural profile analysis, shear modulus, and microstructure of the emulsion gels were measured. The gel hardness and WHC increased significantly with increasing protein concentration, reaching values equivalent to chicken breast. The lightness of the emulsion gels was less than that of chicken breast, due to the presence of pigments (such as polyphenols) in the protein. Shear modulus versus temperature measurements showed that gelation began when the protein solutions were heated to around 40 °C and then the gels hardened appreciably when the temperature was further raised to 90 °C. The shear modulus of the gels then increased during cooling, which was attributed to the strengthening of hydrogen bonds at lower temperatures. The hardness of the gels increased slightly but then decreased when the oil droplet concentration was raised from 0 to 14 %. The lightness of the protein gels increased after adding the oil droplets, which was attributed to increased light scattering. Microstructure analysis showed that the RuBisCo proteins formed a particulate gel after heating, with the oil droplets being in the interstices between the particulates. In summary, RuBisCo proteins can be dissolved at high concentrations and can form strong emulsion gels. Consequently, they may be able to mimic the composition and textural attributes of real chicken.

Correlation between Protein Features and the Properties of pH-Driven-Assembled Nanoparticles: Control of Particle Size

This study sought to understand how the features of proteins impact the properties of nanoparticles assembled using the pH-shifting approach and the mechanism behind. Four legume protein isolates from faba bean, mung bean, soy, and pea were fractionated into natural aqueous-soluble (Sup) and aqueous-insoluble (Sed) fractions, which were proved to serve as shell and core, respectively, for the pH-driven-assembled nanoparticles. Using zein instead of Sed fractions as the core improved size uniformity, and particle size can be precisely controlled by adjusting core/shell ratios. Using the proteomic technique and silico characterization, the features of identified proteins indicated that hydrophobicity rather than molecular weight, surface charge, etc., mainly determined particle size. With molecular docking, structural analysis, and dissociation tests, the assembly of zein/Sup-based nanoparticles was dominantly driven by hydrophobic interactions. This study provides constructive information on the correlation between protein features and the properties of pH-driven-assembled nanoparticles, achieving a precise control of particle size.

Composition, morphology, interfacial rheology and emulsifying ability of soy hull polysaccharides extracted with ammonium oxalate and sodium citrate as extractants

BACKGROUND

Soy hull, a by-product of crop processing, is rich in pectin-like polysaccharides that have potential for thickening, gelling and emulsifying applications. The effect of ammonium oxalate (SHPA) and sodium citrate (SHPS) on the conformation, physicochemical properties and emulsifying ability of soy hull polysaccharide (SHP) were investigated.

RESULTS

The composition analysis showed that SHPS had more polysaccharide, protein, and higher molecular weight than SHPA. Images of atomic force microscopy (AFM) and scanning electron microscopy (SEM) showed that SHPS molecules appeared spherical bodies with smooth and firm surfaces, while SHPA molecules appeared chain-like bodies with rough and wrinkled surface. At the oil-water interface, SHPS adsorbed faster and formed a more elastic interfacial layer than SHPA. The characterization of the prepared emulsions showed that the SHPS emulsion was a smaller particle size and more stable system within 30 days than SHPA emulsion, especially at the SHPS concentration of 9 mg mL^-1 . Images of cryo-scanning electron microscopy (cryo-SEM) also demonstrated SHPS formed clearer network structure on the surface of the oil droplets, compared to SHPA.

CONCLUSION

Overall, ammonium oxalate and sodium citrate significantly influenced the composition and properties of the SHP. SHPS exhibited a better emulsifying ability than SHPA, which was mainly due to the higher protein content of SHPS and the sodium ion (Na⁺ ) residue of sodium citrate. This study is useful for the extraction and application of SHP and other plant-based polysaccharides. © 2023 Society of Chemical Industry.

Fabrication of grape seed proanthocyanidin-loaded W/O/W emulsion gels stabilized by polyglycerol polyricinoleate and whey protein isolate with konjac glucomannan: Structure, stability, and in vitro digestion

In this work, the effects of konjac glucomannan (KGM) concentrations on microstructure, gel properties, stability and digestibility of water-in-oil-in-water emulsion gels stabilized by polyglycerol polyricinoleate and whey protein isolate were investigated. Visual appearance indicated that a non-layered double emulsion gel was formed when KGM increased to 0.75%. Emulsion gels with 1.5% KGM showed the highest encapsulation, freeze-thaw and photochemical stability due to the formation of the smallest droplets, which were supported by microscopic observations. Moreover, the addition of KGM improved water holding capacity, rheological and texture properties of emulsion gels. Particularly, at 1.5% or 1.75% KGM, color and potential of hydrogen showed the most stable level after 14 days of storage. During in vitro digestion, KGM delayed the hydrolysis of protein and oil droplets, and then improved the bioavailability of grape seed proanthocyanidin. These results promoted the application of KGM in emulsion gels and the encapsulation of nutraceuticals.

Self-assembled emulsion gel based on modified chitosan and gelatin: Anti-inflammatory and improving cellular uptake of lipid-soluble actives

To obtain a green carrier for intestinal targeted delivery, an emulsion gel was designed by the self-assembly between gelatin and Pickering emulsion based on gallic acid modified-chitosan nanoparticles (GCS NPs). The emulsion gels loaded with garlic essential oil (Geo) and curcumin (Cur) were abbreviated as GOEG and GCEG, respectively. Meanwhile, the sodium alginate bead loaded with Geo (GOEGS₃) and the bead loaded with Cur (GCEGS) were prepared as controls. Results demonstrated that the emulsion gels significantly improved the bioaccessibility of Geo and Cur, showing great intestinal targeting delivery properties comparable to that of sodium alginate beads. Moreover, Caco-2 cell experiments indicated that GOEG and GCEG displayed good biocompatibility and enhanced cellular uptake of Geo and Cur. The emulsion gels also exhibited excellent anti-inflammatory properties in the lipopolysaccharide-induced cell model, exhibiting great potential for clinical application. This work provides some references for the preparation of multifunctional emulsion gels with excellent delivery performance by a green method.

pH-shifting alters textural, thermal, and microstructural properties of mung bean starch-flaxseed protein composite gels

The objective of this study was to investigate the effect of pH-shifting on the textural and microstructural properties of mung bean starch (MBS)-flaxseed protein (FP) composite gels. Results showed that different pH-shifting treatments caused changes in hydrogen bond interactions and secondary structures in composite gels, leading to the formation of loose or compact gel networks. The pH 2-shifting modified protein and starch molecules with shorter chains tended to form smaller intermolecular aggregates, resulting in the formation of a looser gel network. For pH 12-shifting treatment, conformational change of FP caused the unfolding of protein and the exposure of more hydrophobic groups, which enhanced the hydrogen bond and hydrophobic interactions between polymers, contributing to the formation of a compact gel network. Furthermore, pH 12-shifting improved the water-holding capacity (WHC), storage modulus, and strength of gels, while pH 2-treated gels exhibited lower WHC, hardness, and gumminess due to the degradation of MBS and denaturation of FP caused by extreme acid condition. These findings suggest that pH-shifting can alter the gel properties of bi-polymeric starch-protein composite systems by affecting the secondary structures of proteins and the hydrogen bonding between the polymers, and provide a promising way for a wide application of FP in soft gel-type food production.

Molecular structural modification of β-conglycinin using pH-shifting with ultrasound to improve emulsifying properties and stability

This present work underlines the effect of pH-shifting at pH 2 and pH 12 individually or combined with ultrasound treatment to modify the molecular structure of β-conglycinin (7S) on its emulsifying properties and stability. Fourier transform infrared (FTIR) spectroscopy and intrinsic fluorescence spectroscopy showed that pH-shifting improves the molecular structure of 7S, while ultrasound further promotes structural changes. In particular, the pH-shifting at pH 12 combined with ultrasound treatment (U-7S-12) resulted in more significant changes than the pH-shifting at pH 2 combined with ultrasound (U-7S-2). U-7S-12 showed a significant reduction in protein particle size from 152 to 34.77 nm and a relatively smooth protein surface compared to 7S. The protein had the highest surface hydrophobicity and flexibility at 81,560.0 and 0.45, respectively, and the free sulfhydryl content from 1.57 to 2.02 μmol/g. In addition, we characterized the emulsions prepared after 7S treatment. The single or combined treatment increased the interfacial protein adsorption of the samples, which showed lower viscosity and shear stress compared to 7S. The U-7S-12 emulsion exhibited the highest emulsifying properties and was more stable than other emulsions under creaming, heating, and freeze-thaw conditions. In summary, the concerted action of pH-shifting and ultrasound can modify the structure, and combined alkaline pH-shifting and ultrasound treatment can further improve the emulsifying properties and stability of 7S.

Progress in the Application of Food-Grade Emulsions

The detailed investigation of food-grade emulsions, which possess considerable structural and functional advantages, remains ongoing to enhance our understanding of these dispersion systems and to expand their application scope. This work reviews the applications of food-grade emulsions on the dispersed phase, interface structure, and macroscopic scales; further, it discusses the corresponding factors of influence, the selection and design of food dispersion systems, and the expansion of their application scope. Specifically, applications on the dispersed-phase scale mainly include delivery by soft matter carriers and auxiliary extraction/separation, while applications on the scale of the interface structure involve biphasic systems for enzymatic catalysis and systems that can influence substance digestion/absorption, washing, and disinfection. Future research on these scales should therefore focus on surface-active substances, real interface structure compositions, and the design of interface layers with antioxidant properties. By contrast, applications on the macroscopic scale mainly include the design of soft materials for structured food, in addition to various material applications and other emerging uses. In this case, future research should focus on the interactions between emulsion systems and food ingredients, the effects of food process engineering, safety, nutrition, and metabolism. Considering the ongoing research in this field, we believe that this review will be useful for researchers aiming to explore the applications of food-grade emulsions.