Structure and functional properties of soy protein isolate-lentinan conjugates obtained in Maillard reaction by slit divergent ultrasonic assisted wet heating and the stability of oil-in-water emulsions

Nanoemulsions base on the Rice bran albumin-sweet potato leaf polyphenol-dextran complexes: Interaction mechanisms, stability and Astaxanthin release behaviour

In this study, rice bran albumin (RBA), sweet potato leaf polyphenols (SPLPs) and dextran were conjugated through covalent or non-covalent interactions to improve the stability and bioaccessibility of astaxanthin (AST) in emulsion systems. It was shown that the RBA-SPLPs-Dex ternary covalent complex demonstrated higher polysaccharide grafting, looser secondary structure, and exposed hydrophobic groups indicating that they were favourable for emulsion stabilisation. In long-term storage tests, RBA-SPLPs emulsifier modified by 50 mg/mL dextran (Dextran50) showed smaller particle size and cream index, respectively. Besides, the retention of loaded astaxanthin was improved by 59.43 % compared to the unmodified model, along with a strengthened inhibition of lipid oxidation in the storage experiment. Besides, Dextran50 also improved the environmental stress stability of the emulsion and demonstrated more efficient AST release behaviour during intestinal digestion. In conclusion, these emulsion systems stabilised with ternary complexes have great potential for the delivery of lipid-soluble bioactive ingredients.

Formation and functional improvement of α-casein, β-lactoglobulin, and hyaluronic acid conjugates via the Maillard reaction: Comparison with different mass ratios

Milk protein and hyaluronic acid (HA) at different mass ratios were systemically characterized using the Maillard reaction. Combining FTIR and molecular docking results, both conjugates, α-casein-HA (α-CN-HA) and β-lactoglobulin-HA (β-Lg-HA), were prepared via hydrogen-bond interactions. Binding of HA promotes the structural folding of milk proteins and alters their secondary structures. The α-CN-HA and β-Lg-HA conjugates exhibited significantly improved solubility thermal and antioxidant activity. The functional properties of the conjugates were modulated by varying the ratio of milk proteins to HA. The α-CN:HA 1:2 ratio had the highest denaturation temperature (110.1 °C). For β-Lg-HA, the highest denaturation temperature (112.1 °C) was observed at a 1:4 ratio. Antioxidant capacity increased with decreasing HA content; the highest value was observed at a mass ratio of 3:1 for both conjugates. Our findings suggest that Maillard reaction improves the physiological and functional properties of milk proteins and HA conjugates.

Physicochemical and functional properties of two kinds of Schisandra proteins and their antioxidant activity in H2O2-treated HepG2 cells

Schisandra chinensis protein (SCP) and Schisandra sphenantherae protein (SSP) were extracted by alkali extraction and isoelectric precipitation, and the amino acid compositions, structures, and physicochemical properties of the two proteins were analyzed to evaluate their functional properties. The effects of SCP and SSP on proliferation, protection, and anti-apoptosis of H2O2-treated HepG2 cells after oxidative stress were investigated. The results showed that SCP had a higher content of essential amino acids (16.27 ± 0.76) than SSP. Scanning electron microscopy and Fourier-transform infrared spectroscopy analyses, as well as substituent distribution in electrophoresis, revealed the structural differences between the two proteins; in particular, the disulfide bond content is higher in SCP, which was also found to be more stable in terms of heat tolerance (114.7 °C), solubility (47.18 %), emulsification (158.57 m2/g), emulsion stability (89.53 %), foaming (226 %), and foaming stability (90.32 %). In an in vitro experiment, SSP was more effective in protecting HepG2 cells from H2O2-treated oxidative damage, effectively inhibiting the levels of reactive oxygen species and malondialdehyde, maintaining the stability of cell membranes, promoting antioxidant mechanisms, and decreasing apoptosis by regulating the expression of genes and proteins related to the mitochondrial apoptotic pathway. These results suggest that both SCP and SSP are suitable as novel food additives, and that the excellent functional properties and thermal stability of SCP make it a potential nutritional resource in the food industry. In addition, SSP has potential as a protein resource with antioxidant activity.

Effect of ultrasound combined with TGase-type glycation on the structure, physicochemical, and functional properties of casein hydrolysate

This study investigated the effects of transglutaminase (TGase)-type glycation combined with ultrasound treatment on the structure, physicochemical properties, and functional properties of casein hydrolysate (CH). The results showed that TGase-type glycation and ultrasound treatment changed the secondary structure and reduced the fluorescence intensity of CH. Structural analysis revealed the intermolecular covalent interactions between oligochitosan and CH, confirming the occurrence of TGase-type glycation. The microstructure indicated that after 200 W sonication treatment, the structure of glycated CH was expanded and the molecular flexibility was enhanced. In addition, glycated CH treated with ultrasound treatment exhibited superior solubility, foaming capacity, antioxidant activity, and thermal stability. This study provides new insights into the combination of TGase-type glycation and ultrasound treatment, which may improve the function of casein and further increase its application in the food industry.

Soybean protein-soybean polysaccharide-EGCG ternary complex stabilized nanoemulsion and its application in loading pterostilbene: Emulsion stabilization mechanism, physical and digestion characteristics

Soybean protein isolate (SPI), soluble soybean polysaccharide (SSPS), and epigallocatechin gallate (EGCG) were utilized to prepare SPI-SSPS binary complex and SPI-SSPS-EGCG ternary complex, acting as natural emulsifiers to prepare oil-in-water (O/W) nanoemulsion using high-pressure homogenization (90 MPa, 5 times) and the emulsion stabilization mechanism was analyzed. The SPI-SSPS-EGCG complex stabilized emulsion with smaller particle sizes that dispersed evenly, exhibiting excellent stability at 25-100 °C and pH 9.0-11.0 in different storage time ranges (1, 3, 5, 7, 14 d). The pterostilbene (PTE) embedding rate of emulsion stabilized by SPI-SSPS complex and SPI-SSPS-EGCG complex increased significantly compared with SPI stabilized emulsion. Moreover, the ternary complex stabilized emulsion had improved bioaccessibility of PTE after simulating in vitro digestion, and it stabilized by covalent complex (28.23 ± 0.21 %) was better than that of the non-covalent (25.07 ± 0.48 %).

Recent advances in photoelectric methods application for cooking oil quality and safety evaluation: a review

Cooking oil is used daily in consumed food and culinary applications; therefore, its safety and quality are very important. Notably, susceptibility to contamination at each processing stage poses threats to living organisms. This review discusses the parameters of oil quality, as well as the role of the various non-destructive photoelectric techniques with respect to its quality and safety, including near-infrared spectroscopy (NIR), mid-infrared spectroscopy, Fourier transform near-infrared spectroscopy, Raman spectroscopy and fluorescence spectroscopy. Data on cooking oil quality, such as values of the following parameters, notably peroxides, thiobarbituric acid, anisidine, iodine, trans-fat and fatty acid profile, carbonyl compounds, adulteration and total polar components, are also demonstrated. Photoelectric methods are rapid and efficient tools for the preliminary screening of cooking oil when aiming to determine its quality before its entry into the food chain. Primarily, NIR has been used to predict most of the cooking oil safety and quality parameters, and thus is considered as the most convenient non-destructive method to be recommended. Accordingly, deep insight into state-of-the-art photoelectric/spectral technologies and the varieties of techniques available provides an opportunity to detect and predict the safety parameters of products prior to their processing and distribution. In this review, we highlight these perspectives with particular emphasis on the cooking oil. © 2025 Society of Chemical Industry.

The utilization of an ultrasonic mung bean protein-starch conjugate as a fat substitute in whipping cream

BACKGROUND

Amidst the rising trend of healthy eating, there is a surge in demand for low-fat food options. Within the realm of fat substitutes, modified proteins have shown the most effective ability to replace fat due to their nutritional attributes and functional properties. This study focused on the development of a fat substitute for low-fat whipping cream using the conjugate of ultrasonic mung bean protein and mung bean starch.

RESULTS

Our findings revealed that the emulsifying properties and solubility of the conjugates were significantly superior to those of mung bean protein alone (P < 0.05). This enhancement was attributed to a smaller particle size, depolymerization of protein molecules and increased total sulfhydryl content, especially the conjugate formed by 60 min ultrasonic mung bean protein and mung bean starch (UMBP60+MS). Incorporating UMBP60+MS as a fat substitute at a 10% ratio in the formulation of low-fat whipping cream resulted in a product with enhanced apparent viscosity, superior environmental stability, and commendable sensory characteristics. Moreover, the fat digestion rate was significantly reduced by 13.5% with the 10% substitution. This 10% substitution also endowed the whipping cream with the most desirable β'-type crystal morphology and the most stable three-dimensional network structure. An intimate encapsulation of fat globules by the conjugate was observed using cryogenic scanning electron microscopy.

CONCLUSION

The UMBP60+MS conjugate emerged as an effective fat substitute in whipping cream, providing significant contributions to addressing health concerns in the food industry. © 2024 Society of Chemical Industry.

Preparation, characterization, and stability of pectin-whey protein isolate-based nanoparticles with mitochondrial targeting ability

Quercetin (Que) is a polyhydroxy flavonoid with strong inhibitory activity against cancer cells. However, the poor water solubility and low bioavailability of Que. limit its application in the functional food industry. In the present study, the nanoparticle loaded with Que. was prepared with whey isolate protein (WPI) stabilized by triphenylphosphonium bromide (TPP) and pectin (P) as wall materials. The formation mechanism, release of Que., and antitumor activity of nanoparticles were investigated. The results showed that the optimal ratio of WPI: TPP: Que.: P in the preparation of nanoparticles (WPI-TPP-Que-P) was 50:8:1:20 (w/w/w/w). The encapsulation rate of Que. in the WPI-TPP-Que-P was 82.64 % with a particle size of 261.7 nm and a zeta potential of -42.1 mV. Compared with WPI-TPP-Que, the retention rate of WPI-TPP-Que-P increased by 4.03 % after in vitro digestion. The release kinetic result indicated that WPI-TPP-Que-P release was dominated by non-Fickian diffusion. In addition, WPI-TPP-Que-P was taken in and achieved intracellular targeting to mitochondria and promoted apoptosis (apoptosis rate: 83.6 %) by decreasing mitochondrial membrane potential and IL-10 content and improving the content of TNF-α in HepG-2 cells. This study highlights the promising application of P-modified mitochondria-targeted nanocarriers for enhanced Que. delivery.

Maillard reaction conjugates of millet bran globulin and Arabic gum for curcumin encapsulation: Physicochemical characterization, storage stability, and in vitro digestion

In this study, millet bran globulin (MBG) and Arabic gum (AG) conjugates were prepared through the Maillard reaction (MR) and applied to curcumin-loaded Pickering emulsions. The effect of MR on MBG-AG conjugates (MBG-AG con) was evaluated by the degree of grafting (DG), the absorbance of intermediate reactants, and the browning index. The emulsifying properties of MBG-AG con with different DGs were assessed using the emulsifying activity index (EAI) and emulsifying stability index (ESI). Curcumin-loaded Pickering emulsions were prepared using optimized conjugates. Results indicated that MR enhanced the conjugates emulsifying properties, leading to improved emulsion performance. Compared to MBG, the optimized conjugates exhibited approximately 252.3 % and 167.1 % increases in EAI and ESI, respectively. The formation of MBG-AG con was confirmed through polyacrylamide gel electrophoresis, Fourier transform infrared, and fluorescence spectroscopy. Morphological changes before and after MR were observed through scanning electron microscopy. In comparison to MBG-stabilized emulsions, conjugate-stabilized emulsions exhibited smaller droplets, higher curcumin encapsulation efficiency (over 80 %), and better apparent viscosity. During simulated digestion, the bioavailability of curcumin reached 88.67 % in Pickering emulsions stabilized by 5 % conjugates. This study demonstrated the potential application of MBG-AG con prepared via MR in stabilizing Pickering emulsions, providing new theoretical insights into curcumin encapsulation.

Goat's Skim Milk Enriched with Agrocybe aegerita (V. Brig.) Vizzini Mushroom Extract: Optimization, Physico-Chemical Characterization, and Evaluation of Techno-Functional, Biological and Antimicrobial Properties

The aim of this study was to develop a novel functional ingredient-goat's skim milk enriched with Agrocybe aegerita (V. Brig.) Vizzini mushroom extract (ME/M)-using Central Composite Design (CCD). The optimized ME/M ingredient was evaluated for its physico-chemical, techno-functional, biological, and antimicrobial properties. Physico-chemical properties were analyzed using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy, Scanning Electron Microscopy (SEM), and Dynamic Light Scattering (DLS). The ingredient exhibited a polymodal particle size distribution and contained glucans, along with a newly formed polypeptide resulting from the selective cleavage of goat milk proteins. A 0.1% ME/M solution demonstrated good emulsifying and foaming properties. Additionally, ME/M showed strong antiproliferative effects on human cancer cell lines, particularly Caco-2 (colorectal) and MCF7 (breast) cancer cells. The ingredient also promoted HaCaT cell growth without cytotoxic effects, suggesting its safety and potential wound-healing properties. Furthermore, the addition of ME/M to HaCaT cells inoculated with Staphylococcus aureus resulted in reduced IL-6 levels compared to the control (without ME/M), indicating a dose-dependent anti-inflammatory effect. The optimized ME/M ingredient also exhibited antibacterial, antifungal, anticandidal, and antibiofilm activity in one-fourth of MIC. These findings suggest that the formulated ME/M ingredient has strong potential for use in the development of functional foods offering both desirable techno-functional properties and bioactive benefits.

Stability and functionality of bovine lactoferrin powder after 9 years of storage

Bovine lactoferrin (bLF) is a multifunctional protein widely used in food industries. Most bLF products are delivered in a powder form; however, their stability remains unclear. Herein, freeze-dried bLF powders were stored at 4 °C and 40 % relative humidity (RH) for 9 years since 2016. After the long-term storage, their functional properties, including antibacterial ability, antioxidant ability and iron-binding ability, were determined and compared with those of eight commercial LF powders. The bLF powder stored for 9 years demonstrated comparable physicochemical and functional properties with those of commercial LF powders (e.g. >93 % water solubility, >100 mg/100 g iron-binding ability, and >1.7 logCFU/mL bacterial growth reduction against Salmonella enteritidis). The haemolysis test indicated that the bLF stored for 9 years exhibited good biocompatibility at a concentration of <5 mg/mL. Therefore, bLF powders can be stored for extremely long periods (>9 years) with minimal side effects. These findings can expand the utilisation of lactoferrin to many specific cases such as voyage and aerospace foods.

Green Synthesis of Sodium Alginate/Casein Gel Beads and Applications

Green-synthesized gel materials can efficiently absorb and remove organic dyes from wastewater. This investigation designed and synthesized a novel modification method of sodium alginate gel beads based on the protein glycosylation reaction (Maillard reaction) using green chemistry principles. The prepared gel beads were subsequently applied to examine their efficacy in adsorbing the organic dye methylene blue. The adsorption process and mechanism were characterized and analyzed. At an adsorption equilibrium of 300 K, the adsorption value can reach 908 mg/g. The dry casein glycosylated gel beads synthesized in this study demonstrate the potential for further development as a novel adsorbent for organic dyes in wastewater.

Structural and functional changes induced by different ultrasound-frequency-assisted xylose-glycation inhibits lysinoalanine formation in Tenebrio molitor protein

We explored the effects of sonication-assisted xylose (Xyl) grafting on the structure and functionality of Tenebrio molitor protein (MP). Different ultrasound frequencies (20, 25, 28, 20/25, 20/28, 25/28, 20/25/28 kHz) were used, and the inhibition mechanism of ultrasound-assisted Xyl grafting on the formation of lysinoalanine (LAL) was explored. The results suggested that the turbidity and browning products of MP significantly increase, with MP-Xyl-20 kHz exhibiting the highest grafting degree (43.78 %). Compared with MP, the total sulfhydryl content of MP-Xyl and MP-Xyl-20 kHz was significantly improved by 21.90 % and 98.80 % (P < 0.05). Circular Dichroism, Fourier Transform Infrared Spectroscopy, SEM, and AFM analysis showed changes in MP conformation following various frequencies ultrasound-assisted glycosylation. Notably, emulsifying capacity, stability, and foaming ability of MP-Xyl-20 kHz were significantly enhanced by 97.08 %, 48.03 %, and 55.01 %, respectively, compared with MP. The glycol-conjugated MP treated with ultrasound-assisted glycosylation (MP-Xyl-25/28 kHz) had the lowest LAL content (7.19 μg/mg), representing a 56.56 % and 46.70 % decrease compared to the control MP and MP-Xyl, respectively. The content of LAL exhibited a positive correlation with surface hydrophobicity, whereas it demonstrated a negative correlation with sulfhydryl and carbonyl groups. These findings indicated that sonication-assisted xylose improved the functional characteristics of MP, and the inhibition effect on LAL formation. The outcome of the study could be very beneficial in the modification of MP for food industrial applications.

Effects of whey protein-inulin conjugates with varying degrees of glycosylation on hepatic antioxidant capacity, immunomodulation and gut microbiota in mice

In this study, whey protein isolate-inulin (WPI-In) conjugates with varying degrees of glycosylation (DG) were prepared, characterized, and examined for their potential immunomodulatory effects and regulation of gut microbiota in mice. The data indicated that an increase in DG significantly affects the microstructure and functionalities of WPI-In conjugates. The WPI-In conjugates with high DG promoted the growth and development of the thymus while altering gut microbiota composition by increasing the relative abundance of Bacteroidetes and reducing that of Firmicutes. Additionally, the WPI-In conjugates enhanced liver antioxidant capacity and the secretion of immunoglobulin G, and elevated levels of anti-inflammatory cytokines (IL-4 and IL-2), while decreasing pro-inflammatory cytokine (TNF-α) content in serum. Spearman correlation analysis suggested that the enhancement of liver antioxidant capacity and regulation of immune-related indicators may be associated with the gut microbiota altered by WPI-In conjugates. Therefore, WPI-In conjugates demonstrate beneficial properties, indicating potential applications in food systems.

Novel technologies, effects and applications of modified plant proteins by Maillard reaction and strategies for regulation: A review

With an increase in awareness of health, environmental conservation and animal welfare, the market for plant proteins is expanding. However, the low solubility and poor functional properties of plant proteins near the isoelectric point limit their application in food processing. Glycosylation refers to the structural modification of proteins by introduction of polysaccharides to form protein-polysaccharide conjugates in the early stages of Maillard reaction. Glycosylation is a green and efficient method that has been proved to produce modified proteins with superior solubility, emulsifying and forming properties. Glycosylation and the application of protein-carbohydrate conjugates have become research hotspots in recent years. This paper presented a comprehensive review of the effects of glycosylation on the functional properties of plant proteins and the mechanisms of non-thermal physical treatments assisted glycosylation. It was demonstrated that glycosylation modified the structure of plant proteins and improved their functional properties. Non-thermal physical treatments assisted glycosylation increased the reactive sites of plant proteins and further improved their functional properties. Protein-carbohydrate conjugates could be applied in delivery systems, films, emulsifiers and other applications, which have significant research prospects in food applications.

Radio frequency heating assisted Maillard reaction of whey protein - gum Arabic: Improving structural and unlocking functional properties

Whey protein (WP) is a highly nutritious animal protein, but its functional properties are sensitive to environmental factors, such as temperature, pH, and ionic strength, which prevent its applications in various food systems. The conjugation of proteins with polysaccharides via the Maillard reaction is an efficient method to improve their functionalities. The purpose of this study was to use radio frequency (RF) heating technology to assist the covalent coupling of WP and gum Arabic (GA) for improving their grafting efficiency and functional properties. Results showed that under the optimal condition of RF heating, the degree of glycosylation (DG) of the conjugate could reach 19.19%, while the maximum DG value of the conjugate obtained by water bath (WB) heating was only 10.60%. There was a good correlation between the DG and dielectric properties of WP-GA conjugates. Structural analysis revealed that compared with their mixtures, the network structure of WP-GA conjugates was clear, the content of β-turn and random coil increased, and the fluorescence intensity and surface hydrophobicity decreased. In addition, glycosylation enhanced the emulsifying, foaming, and antioxidant properties of WP-GA conjugates. This study indicates that the RF heating technology has potential application values in the glycosylation modification of proteins.

The Effect of Protein-Starch Interaction on the Structure and Properties of Starch, and Its Application in Flour Products

Grains are an energy source for human beings, and the two main components-starch and protein-determine the application of grains in food. The structure and properties of starch play a decisive role in determining processing characteristics, nutritional properties, and application in grain-based foods. The interaction of proteins with starch greatly affects the structure, physicochemical, and digestive properties of the starch matrix. Scientists have tried to apply this effect to create foods tailored to specific needs. Therefore, studying the effect of protein on the structure and properties of starch in the starch-protein complexes will help in designing personalized and improved starch-based food. This paper reviews the latest research about the effects of endogenous and exogenous proteins on the structure and properties of starch, as well as factors influencing the interaction between protein and starch. This includes investigations of the chain and aggregation structure of proteins with starch, as well as assessments of impacts on thermal properties, rheology, gel texture properties, hydration properties, aging, and digestion. In addition, particular examples illustrating the effects of protein-starch interaction on starch properties in various foods are discussed, providing a reference for designing starch-protein foods that are rich in terms of nutrition and easier to process.

Maillard-derived mung bean protein-peach gum conjugates: A novel emulsifier to improve stability, antioxidants, and physicochemical properties of chia seed oil nanoemulsion

This research is designed to enhance the physio-chemical properties, constancy, and antioxidant activities of water-in-oil (W/O) emulsions containing chia seed oil (CSO) by utilizing mung bean protein isolate (MBPI)-peach gum (PG) conjugates, which were created through the Maillard reaction (MR), as the emulsifying agents. The emulsions were prepared using MBPI-PG produced through the Maillard reaction (EMRP) at concentrations of 0.5 %, 1 %, and 1.5 %. Another set of emulsions, serving as control samples, was prepared using MBPI-PG without the MR (EC) at the same concentrations. The EMRP samples demonstrated optimum characteristics during storage over 30 days at 25 °C, particularly at 1 % concentration, including the droplet size (176.37 nm), PDI (0.3), zeta potential (-47.52 Mv), quantity of absorbed protein (63.48 %), creaming index (22.99 %), and viscosity compared to EC. The emulsions prepared with MRP exhibited significantly lower POV (1.45 mM/kg oil) and TBARS (59.17 mM/kg oil) formation rates than EC. The EMRP1% formulation displayed the lowest release of antioxidant compounds among all formulations, suggesting low release control during storage. Molecular docking results confirmed that adding EMRP1% to the CSO emulsion significantly improved its quality and stability. This emulsifier could hold significant promise for future advancements in the food industry.

Effect of Extraction Methods and Preheat Treatments on the Functional Properties of Pumpkin Seed Protein Concentrate

This study explores the effect of different extraction methods and preheat treatments in obtaining protein concentrate from pumpkin seed flour. The effects on the yield and functional properties of pumpkin seed protein concentrate (PSPC) were compared alongside microwave and conventional preheating methods using alkali, salt, and enzyme-assisted alkali extraction techniques. Analytical assessments included proximate analysis, soluble protein content, water solubility index (WSI), emulsification activity (EA) and stability (ES), foaming capacity (FC) and stability (FS), and antioxidant activity (AA). Hydration and structural analyses were performed via time-domain nuclear magnetic resonance (TD-NMR) Relaxometry and Fourier-Transform Infrared (FTIR) Spectroscopy. In addition, color measurements were performed to evaluate the visual quality of the samples. The alkali extraction method paired with microwave heating (MH-AE) significantly outperformed other techniques, with an extraction yield and protein content of approximately 55% and 77%, respectively. This study demonstrated the superior yield and functional properties of PSPC using MH-AE, opening opportunities for future research in optimizing plant-based protein extraction techniques.

Effects of Maillard Reaction Durations on the Physicochemical and Emulsifying Properties of Chickpea Protein Isolate

This study investigated the physicochemical and emulsifying properties of chickpea protein isolate (CPI)-citrus pectin (CP) conjugates formed via the Maillard reaction across varying reaction durations. CPI and CP were conjugated under controlled dry-heating conditions, and the resulting conjugates were characterized by measuring their particle size, zeta potential, solubility, thermal stability, surface hydrophobicity, and emulsifying properties. The results showed that as reaction duration increased, the particle size and zeta potential of the CPI-CP conjugates increased significantly, reaching a maximum particle size of 1311.33 nm and a zeta potential of -35.67 mV at 12 h. Moreover, the Maillard reaction improved the solubility, thermal stability, and hydrophobicity of the CPI. Glycosylation increased the emulsifying activity index (EAI) and emulsifying stability index (ESI) of the CPI to 145.33 m2/g and 174.51 min, respectively. Optimal emulsions were achieved at a protein concentration of 1.5 wt% and a 10% volume fraction of the oil phase. The Maillard reaction promoted the interfacial protein content and the thickness of the interfacial layer while decreasing the droplet size and zeta potential of the emulsion. Additionally, the emulsion prepared with CPI-CP-12 h showed outstanding long-term stability. These results demonstrate that a moderate Maillard reaction with CP effectively enhances the physicochemical and emulsifying characteristics of CPI.

Modification approaches of walnut proteins to improve their structural and functional properties: A review

Walnut protein has a high gluten content and compact structure, which limits its water solubility and affects its applications. Therefore, improving the sustainability of walnut proteins is an urgent issue that must be addressed. Physical modification can directly alter the structure of walnut proteins, leading to enhanced functional properties. Chemical modifications typically involve the introduction of exogenous substances that react with walnut proteins to obtain novel products with improved processing attributes. As a highly specific modification technique, biomodification uses enzymes or microorganisms to break down walnut proteins into small peptide molecules or cross-link them to form soluble polymers, thereby enhancing their functional properties and bioactivity. This review presents various methods for modifying walnut proteins and their effects on the structure and functional properties of walnut proteins. The challenges associated with the application and development of these unique technologies are also discussed.

Flammulina velutipes protein-Flammulina velutipes soluble polysaccharide-tea polyphenols particles stabilized Pickering emulsions for the delivery of β-carotene

The delivery vehicles based on protein-polysaccharide-polyphenol are promising methods to encapsulate bioactive components with the aim of improving their solubility and bioavailability. In this study, we used Flammulina velutipes protein (FVP) and Flammulina velutipes soluble polysaccharides (FVSP) as raw materials and prepared FVP-FVSP and FVP-FVSP-TP composite particles loaded with tea polyphenols (TP), the high internal phase Pickering emulsions stabilized by FVP-FVSP and FVP-FVSP-TP for the delivery of β-carotene (BC) were created. FVP-FVSP-TP has more promise as Pickering emulsion stabilizer than FVP-FVSP because of the smaller particle size, proper contact angle, and lower surface tension. The optimal preparation conditions of the emulsion were 4 % particle concentration and 80 % oil phase volume fraction. The emulsions stabilized by FVP-FVSP and FVP-FVSP-TP were o/w emulsions. Compared to the emulsion stabilized by FVP-FVSP, the FVP-FVSP-TP stabilized emulsion had higher G', G″ values and viscosity and showed better thermal, centrifugal, storage and oil oxidation stability. Moreover, FVP-FVSP-TP stabilized emulsions could further enhance the retention rate and bioaccessibility of TP and β-carotene. This study provides a theoretical basis for the application of FVP and FVSP in Pickering emulsions, and a reference for the fabrication of delivery vehicles to improve the stability and bioaccessibility of bioactive substances.

Effect of ohmic heating-assisted glycation reaction on the properties of soybean protein isolate-chitosan complexes

The purpose of this study was to investigate the progress of glycation reaction reactions by conventional heating and ohmic heating (OH) treatment, and the effect of different electric field intensities on the structure, physical and chemical and functional properties of glycosylated proteins. The findings demonstrated that OH treatment was more efficacious than conventional heating in reducing the free amino group and increasing the absorbance at 420 nm. Concurrently, the α-helix and β-sheet content of soy protein isolate (SPI)-chitosan (CS) complexes exhibited a reduction to 18.01 % and 28.67 %, respectively, while the UV absorption peak demonstrated an increase in conjunction with the escalation of electric field intensity. When the electric field intensity was 6 V/cm, the emulsification activity index and emulsion stability index of SPI-CS complexes were found to be 95.52 m2/g and 55.60 min, respectively. The foaming capacity and foaming stability were found to be 148.33 % and 115.59 % respectively, while the solubility was also up to 91.37 %. Additionally, the air/water interface properties demonstrated a notable enhancement. The functional properties of the complexes were demonstrably enhanced following the application of an OH treatment. The aforementioned statement provided a theoretical foundation for the implementation of OH treatment.

Ultrasound-assisted low-sodium salt curing to modify the quality characteristics of beef for aging

Meat products for elderly people are high in sodium content and hardness. Thus, the aim of this study is to explore how ultrasound-assisted low-sodium salting improves meat quality and determine the conditions that result in meat tenderness ideal for people aged 65-74 years. The ultrasound-assisted treatment of bovine hip muscle with non-sodium salt (CaCl2 and C6H10CaO6) was adopted, followed by sous vide (SV) cooking (65 ℃ for 8-12 h). Results showed that ultrasound-assisted low-sodium salt curing can considerably reduce the shear force and hardness of beef (P < 0.05), promote the diffusion of Na+ (P < 0.05), and increase water content (P < 0.05), consistent with the water mobility results of low-field nuclear magnetic resonance. The tenderized effects were examined by Raman spectroscopy, which showed that the ordered α-helix and β-fold contents of the meat proteins decreased, and disordered β-turn and random coil contents increased after heat treatment with ultrasound-assisted low-sodium salt curing. Scanning electron microscopy revealed that the degree of muscle fiber destruction by ultrasound-assisted low-sodium salt curing combined with heat treatment was higher than that observed after traditional cooking with high amounts of sodium. With regard to tenderness, beef marinated with ultrasound-assisted C6H10CaO6 and subjected for 10 h was preferred by people aged 65-74 years. Ultrasound-assisted low-sodium salt curing can improvements on simultaneously reduce the sodium content and enhance the tenderness of meat products for elderly people, and provides an ultrasonic scheme for meat processing using non-sodium salt.

Effect of ultrasound-assisted Maillard reaction on functional properties and flavor characteristics of Oyster protein enzymatic hydrolysates

To address the delamination phenomenon during storage and flavor characteristics of Oyster protein hydrolysates (OPH). In this study, xylo-oligosaccharides (XOS) were selected to covalently graft with OPH through ultrasound-assisted Maillard reaction, and the effect of ultrasound-assisted Maillard reaction on the structure, functional properties, and flavor characteristics of OPH were investigated. The results revealed that the ultrasound treatment led to a 1.46-fold increase in the degree of grafting compared with the conventional wet-heat Maillard reaction methods. Structural analyses at various levels indicated substantial alterations in the OPH structure following the ultrasound-assisted Maillard reaction. More ordered α-helical secondary structures were shifting to random coiling, the tertiary structure showed more stretching changes, and the surface structure was characterized by loose and porous features. Compared with OPH, the solubility of the ultrasound-assisted Maillard reaction products (OPH-U-M) increased from 54.67% to 70.14%, leading to a notable enhancement in storage stability. Flavor profile analysis demonstrated a decrease in unsaturated aldehydes and ketones presenting fishy and bitter aromas, while an increase in presenting meat aroma compounds was observed in OPH-U-M. Furthermore, OPH-U-M exhibited superior antioxidant properties with DPPH and ABTS radical scavenging abilities enhancing 46.05% and 42.09% in comparison with OPH, respectively. The results demonstrated that covalently binding with XOS under ultrasonication pretreatment endowed OPH with superior functional properties (including solubility, storage stability, and antioxidant activity), and the improvement of flavor profile. This study can provide theoretical guidance and practical implications for promoting the processing applications of oyster protein.

Improving the emulsifying properties and oil-water interfacial behaviors of chickpea protein isolates through Maillard reaction with citrus pectin

The limited adsorption capability of chickpea protein isolates (CPI) at the oil-water interface restricts its application in emulsions. This study aimed to improve the emulsifying properties and interfacial behaviors of CPI through Maillard reaction with citrus pectin (CP). The research findings showed that the covalent linking of CP with CPI caused the unfolding of the molecular structure of CPI, exposing more hydrophobic groups. Consequently, the CPI-CP conjugates exhibited improved emulsifying properties. Emulsions stabilized by CPI-CP conjugates after 12 h of glycosylation demonstrated the smallest droplet sizes (1.73 μm) and the highest negative zeta potentials (-54.7 mV). Glycosylation also improved the storage and environmental stability of these emulsions. Interfacial adsorption kinetics analysis revealed the lower interfacial tension (13.94 mN/m) and faster diffusion rates of the CPI-CP conjugates. Furthermore, interfacial dilatational rheology analysis indicated that the CPI-CP conjugates formed an interfacial layer with a higher viscoelastic modulus (33.214 mN/m) and predominant elastic behavior. The interfacial film of CPI-CP conjugates showed excellent resistance to amplitude and frequency variations, enhancing emulsion stability. Thus, this study demonstrates that moderate glycosylation enhances interfacial performances and improves emulsion stability of CPI, providing new insights into the mechanisms by which CPI stabilizes emulsions.

Study on the Structural Characteristics and Foaming Properties of Ovalbumin-Citrus Pectin Conjugates Prepared by the Maillard Reaction

This study explored the structural features and foaming properties of ovalbumin (OVA) and its glycosylated conjugates with citrus pectin (CP) formed through the Maillard reaction. The results demonstrated that OVA and CP were successfully conjugated, with the degree of grafting increasing to 43.83% by day 5 of the reaction. SDS-PAGE analysis confirmed the formation of high-molecular-weight conjugates. Fourier-transform infrared (FT-IR) and fluorescence spectroscopy further revealed alterations in the secondary and tertiary structures of OVA, including an enhanced β-sheet content, a reduced β-turn content, and the depletion of tryptophan residues. Moreover, the surface hydrophobicity of the OVA-CP conjugates significantly increased, enhancing foaming properties. Furthermore, the analysis of foaming properties exhibited that the Maillard reaction improved the foaming capacity of OVA to 66.22% and foaming stability to 81.49%. These findings highlight the potential of glycosylation via the Maillard reaction to significantly improve the foaming properties of OVA, positioning it as a promising novel foaming agent.

Effect of glycation with three polysaccharides on the structural and emulsifying properties of ovalbumin

Herein, three types of ovalbumin (OA)-polysaccharide conjugates were prepared with three polysaccharides (XG: xanthan gum; GG: guar gum; KGM: konjac glucomannan) for the fish oil emulsion stabilization. The glycation did not change the spectra bands and secondary structure percentages of OA, whereas it decreased the molecular surface hydrophobicity of OA. The initial emulsion droplet sizes were dependent on the polysaccharide types, OA preparation concentrations, polysaccharide: OA mass ratios, and glycation pH. The emulsion stability was mainly dependent on the polysaccharide types, polysaccharide: OA mass ratios, and glycation pH. However, it was minorly dependent on the OA preparation concentrations. The emulsions stabilized by conjugates with high polysaccharide: OA mass ratios (e.g., ≥3:5 for OA-GG) or appropriate glycation pH (e.g., 5.0-6.1 for OA-XG) showed no obvious creaming during the room temperature storage. This work provided basic knowledge on the structural modification and functional application of a protein.

Comparative study of Maillard reaction and blending between soybean protein isolate and soluble soybean polysaccharide: Physicochemical, structure and functional properties

Soybean protein isolate-soluble soybean polysaccharide (SPI-SSPS) complexes and mixtures with varying SPI/SSPS concentration ratios (1: 1, 2:1, 4:1, 8:1) were prepared by Maillard reaction and blending, respectively, and their physicochemical, structure, and functional properties were compared studied. The physical stability of SPI-SSPS complex, which consisted of CN and CS bonds, was better than that of the SPI/SSPS mixture with electrostatic interactions and hydrogen bonds, and both were superior SPI alone. The complex with SPI/SSPS concentration ratio of 8:1 had the highest grafting degree (33.25 %) and a more ordered structure, making its solubility and emulsifying property lower than the SPI/SSPS mixture; however, the physical and thermal stability of the SPI-SSPS complex was higher than that of the SPI and SPI/SSPS mixture. In particular, the SPI-SSPS complex with a high grafting degree showed a higher thermal denaturation temperature (194.06 °C). This study aimed to provide effective modification methods to utilize soybean processing by-products by modifying soybean protein isolate with soluble soybean polysaccharide.

Biochemical insights into tea foam: A comparative study across six categories

Tea foam properties, crucial indicators of tea quality, have gained renewed interest due to their potential applications in innovative beverages and foods. This study investigated the foaming properties and chemical foundations of six major tea categories through morphological observations and biochemical analyses. White tea exhibited the highest foaming ability at 56.28%, while black tea showed the best foam stability at 84.01%. Conversely, green tea had the lowest foaming ability (10.83%) and foam stability (54.24%). These superior foaming characteristics are attributed to the relatively low lipid content and acidic pH values. Surprisingly, no significant correlation was found between tea saponin content and foaming properties. Instead, specific amino acids (including Tyr, Gaba, Phe, Ile, and Leu) and catechins (GA and CG) were identified as potential contributors. These results deepen our understanding of tea foam formation and offer insights into utilizing tea-derived plant-based foams in food products.

Effect of pH-Shift Treatment on IgE-Binding Capacity and Conformational Structures of Peanut Protein

Hypoallergenic processing is an area worthy of continued exploration. In the treatment of the peanut protein (PP), pH shift was applied by acidic (pH 1.0-4.0) and alkaline (pH 9.0-12.0) treatment, after which the pH was adjusted to 7.0. Following pH-shift treatment, PP showed a larger particle size than in neutral solutions. SDS-PAGE, CD analysis, intrinsic fluorescence, UV spectra, and surface hydrophobicity indicated the protein conformation was unfolded with the exposure of more buried hydrophobic residues. Additionally, the IgE-binding capacity of PP decreased after pH-shift treatment on both sides. Label-free LC-MS/MS results demonstrated that the pH-shift treatment induced the structural changes on allergens, which altered the abundance of peptides after tryptic digestion. Less linear IgE-binding epitopes were detected in PP with pH-shift treatment. Our results suggested the pH-shift treatment is a promising alternative approach in the peanut hypoallergenic processing. This study also provides a theoretical basis for the development of hypoallergenic food processing.

Structural and functional properties of lactoferrin modified with carboxymethyl chitosan: Physical mixing and transglutaminase glycosylation

Protein-polysaccharide combinations frequently demonstrate functional attributes that surpass those of the individual biopolymers. This study aimed to elucidate the physicochemical, structural, and functional properties of two types of lactoferrin (LF)-carboxymethyl chitosan (CMCS) complexes formed by physical mixing and enzymatic glycosylation. LF and CMCS interactions were characterized using phase behavior, particle size, and zeta-potential analysis. The results indicated the formation of an electrostatic complex with a size of <150 nm at pH 8. SDS-PAGE and Fourier transform infrared spectroscopy confirmed that TGase catalyzed the cross-linking and glycosylation of LF, with the extent of glycosylation dependent on the concentration of CMCS. The introduction of CMCS has been observed to result in alterations to the secondary, tertiary, and microstructure of LF, which impact the functional characteristics of LF. The incorporation of CMCS markedly enhances the thermal stability of LF, with a denaturation temperature of 126.66 °C. The addition of CMCS (0.5 wt%) to LF resulted in a significant (P < 0.05) improvement in the emulsifying activity of LF, but it did not improve its foaming properties. This study offers novel ideas and approaches for developing protein and polysaccharide complexes with improved functional properties, thereby expanding the potential applications of edible proteins.

Agar-gelatin Maillard conjugates used for Pickering emulsion stabilization

A few protein- and polysaccharide-based particles have shown promising potential as stabilizers in multi-phase food systems. By incorporating polymer-based particles and modifying the wettability of colloidal systems, it is possible to create particle-stabilized emulsions with excellent stability. A Pickering emulsifier (AGMs) with better emulsifying properties was obtained by the Maillard reaction between acid-hydrolysed agar and gelatin. Laser confocal microscopy imaging revealed that AGMs particles can be used as solid emulsifiers to produce a typical O/W Pickering emulsion, with AGMs adsorbing onto the droplet surface to form a dense interfacial layer. Cryo-scanning electron microscopy analysis showed that AGMs self-assembled into a three-dimensional network structure, which prevented droplets aggregation through strong spatial site resistance, contributing to emulsion stabilization. These emulsions exhibited stability within a pH range of 1 to 11, NaCl concentrations not exceeding 300 mM, and at temperatures below 80 °C. The most stable emulsion oil-water ratio was 6:4 at a particle concentration of 0.75 % (w/v). AGMs-stabilized Pickering emulsion was utilized to create a semi-solid mayonnaise as a replacement for hydrogenated oil. Rheological analysis demonstrated that low-fat mayonnaise stabilized with AGMs exhibited similar rheological behavior to traditional mayonnaise, offering new avenues for the application of Pickering emulsions in the food industry.

Preparation, characterization and functional evaluation of soy protein isolate-peach gum conjugates prepared by wet heating Maillard reaction

This study was conducted to formulate a conjugate of soy protein isolate (SPI) and peach gum (PG) with improved functional properties, interacting at mass ratios of 1:1, 1:2, 1:3, 2:1, and 2:3 by Maillard reaction via wet heating method. Conjugation efficiency was confirmed by grafting degree (DG) and browning index (BI). Results indicated that DG increased with increasing concentration of PG, and decreased with increasing pH, whereas no remarkable change was observed with increasing reaction time. The conjugates were optimized at a ratio of 1:3. SDS-PAGE confirmed conjugate formation, Fourier transform infrared spectroscopy (FTIR) and circular dichroism (CD) verified conjugate secondary structural changes, and scanning electron microscopy (SEM) indicated significant overall structural changes. The functional properties, solubility, emulsifying stability, water holding, foaming, and antioxidant activity were significantly improved. This study revealed the wet heating method as an effective approach to improve the functional properties of soy protein.

Modification of casein with oligosaccharides via the Maillard reaction: As natural emulsifiers

In the present study, different oligosaccharides (fructooligosaccharide (FOS), galactooligosaccharide (GOS), isomaltooligosaccharide (IMO), and xylooligosaccharide (XOS)) were modified on casein (CN) via Maillard reaction. The CN-oligosaccharide conjugates were evaluated for modifications to functional groups, fluorescence intensity, water- and oil-holding properties, emulsion foaming properties, as well as general emulsion properties and stability. The results demonstrated that the covalent combination of CN and oligosaccharides augmented the spatial repulsion and altered the hydrophobic milieu of proteins, which resulted in a diminution in water-holding capacity, an augmentation in oil-holding capacity, and an enhancement in the emulsification properties of proteins. Among them, CN-XOS exhibited the most pronounced changes, with the emulsification activity index and emulsion stability index increasing by approximately 72% and 84.3%, respectively. Furthermore, CN-XOS emulsions have smaller droplet sizes and higher absolute potential values than CN emulsions. Additionally, CN-XOS emulsions demonstrate remarkable stability when ion concentration and pH are varied. These findings indicate that oligosaccharides modified via Maillard reaction can be used as good natural emulsifiers. This provides a theoretical basis for using oligosaccharides to modify proteins and act as natural emulsifiers.

Enhancing the functionality of pea proteins by conjugation with propylene glycol alginate via transacylation reaction assisted with ultrasonication

Pea proteins lack the desirable functional characteristics for food and beverage applications. In this study, transacylation reaction assisted with ultrasonication was used to glycate pea proteins with propylene glycol alginate to enhance their functional properties. The reaction was carried out at pH 11.0 for different pea protein isolate: propylene glycol alginate mass ratios and time durations in a sonic bath at 40 °C. Glycation was confirmed in gel electrophoresis, and ultrasonication enhanced the glycation, with optimal degrees of glycation observed at 45 min reaction time and mass ratios of 2:1 (37.73%) and 1:1 (35.96%). The transacylation reaction increased random coil content of pea proteins by 28% and enhanced their solubility by 2.02 times at pH 7.0, water holding capacity by >50% at pH 7.0, foaming properties, emulsifying properties, and heat stability. This study offers a novel approach that can enhance functionality and applicability of pea proteins.

Enhancing the emulsion properties and bioavailability of loaded astaxanthin by selecting the reaction sequence of ternary conjugate emulsifiers in nanoemulsions

This study investigated the effects of the conjugate reaction sequences of whey protein concentrate (WPC), epigallocatechin gallate (EGCG) and dextran (DEX) on the structure and emulsion properties of conjugates and the bioaccessibility of astaxanthin (AST). Two types of ternary covalent complexes were synthesised using WPC, EGCG and DEX, which were regarded as emulsifiers of AST nanoemulsions. Results indicated that the WPC-DEX-EGCG conjugate (referred to as 'con') exhibits a darker SDS-PAGE dispersion band and higher contents of α-helix (6%), β-angle (24%) and random coil (32%), resulting in a greater degree of unfolding structure and fluorescence quenching. These findings suggested WPC-DEX-EGCG con had the potential to exhibit better emulsification properties than WPC-EGCG-DEX con. AST encapsulation efficiency (76.22%) and bioavailability (31.89%) also demonstrated the superior performance of the WPC-DEX-EGCG con emulsifier in nanoemulsion delivery systems. These findings indicate that altering reaction sequences changes protein conformation, enhancing the emulsification properties and bioavailability of AST.

Modification mechanism of soybean protein isolate-soluble soy polysaccharide complex by EGCG through covalent and non-covalent interaction: Structural, interfacial, and functional properties

Soybean protein isolate was modified with polysaccharides and polyphenols to prepare a natural emulsifier with antioxidant capacity. Physicochemical, structural, interfacial, and functional properties of SPI-SSPS complex were investigated after covalent and non-covalent interacted with EGCG. SPI-SSPS-EGCG ternary complex with low EGCG concentrations (0.0625 and 0.125 mg/mL) showed a significant increase in absolute potential value and a decrease in turbidity. EGCG destroyed the original rigid structure of SPI-SSPS complex, and the covalent complexes had an ordered structure, while the non-covalent interaction resulted in disordered. The ternary complex with high EGCG concentrations (0.25 and 0.5 mg/mL) exhibited stronger EGCG binding capacity and lower surface hydrophobicity, which in turn affected its interfacial properties. The EAI and ESI of SPI-SSPS-EGCG covalent complex increased significantly, while the non-covalent complex had a significant change in EAI but no significant change in ESI with increasing EGCG concentration. The ternary complex showed significantly enhanced antioxidant capacity. The SPI-SSPS-EGCG ternary complex, with excellent antioxidant capacity and emulsifying property, making it suitable for emulsion delivery systems.

Effect of glycosylation modification on structure and properties of soy protein isolate: A review

Soybean protein isolate (SPI) is a highly functional protein source used in various food applications, such as emulsion, gelatin, and food packaging. However, its commercial application may be limited due to its poor mechanical properties, barrier properties, and high water sensitivity. Studies have shown that modifying SPI through glycosylation can enhance its functional properties and biological activities, resulting in better application performance. This paper reviews the recent studies on glycosylation modification of SPI, including its quantification method, structural improvements, and enhancement of its functional properties, such as solubility, gelation, emulsifying, and foaming. The review also discusses how glycosylation affects the bioactivity of SPI, such as its antioxidant and antibacterial activity. This review aims to provide a reference for further research on glycosylation modification and lay a foundation for applying SPI in various fields.

Effect of succinylation-assisted glycosylation on the structural characteristics, emulsifying, and gel properties of walnut glutenin

In this study, we examined the effects of various sodium alginate (ALG) concentrations (0.2%-0.8%) on the functional and physicochemical characteristics of succinylated walnut glutenin (GLU-SA). The results showed that acylation decreased the particle size and zeta potential of walnut glutenin (GLU) by 122- and 0.27-fold, respectively. In addition, the protein structure unfolded, providing conditions for glycosylation. After GLU-SA was combined with ALG, the surface hydrophobicity decreased and the net negative charge and disulfide bond content increased. The protein structure was analyzed by FTIR, Endogenous fluorescence spectroscopy, and SEM, and ALG prompted GLU-SA cross-linking to form a stable three-dimensional network structure. The results indicated that dual modification improved the functional properties of the complex, especially its potential protein gel and emulsifying properties. This research provide theoretical support and a technical reference for expanding the application of GLU in the processing of protein and oil products.

Preparation and functional properties of rice bran globulin-chitooligosaccharide-quercetin-resveratrol covalent complex

BACKGROUND

As the major protein (approximately 36%) in rice bran, globulin exhibits excellent foaming and emulsifying properties, endowing its useful application as a foaming and emulsifying agent in the food industry. However, the low water solubility restricts its commercial potential in industrial applications. The present study aimed to improve this protein's processing and functional properties.

RESULTS

A novel covalent complex was fabricated by a combination of the Maillard reaction and alkaline oxidation using rice bran globulin (RBG), chitooligosaccharide (C), quercetin (Que) and resveratrol (Res). The Maillard reaction improved the solubility, emulsifying and foaming properties of RBG. The resultant glycosylated protein was covalently bonded with quercetin and resveratrol to form a (RBG-C)-Que-Res complex. (RBG-C)-Que-Res exhibited higher thermal stability and antioxidant ability than the native protein, binary globulin-chitooligosaccharide or ternary globulin-chitooligosaccharide-polyphenol (only containing quercetin or resveratrol) conjugates. (RBG-C)-Que-Res exerted better cytoprotection against the generation of malondialdehyde and reactive oxygen species in HepG2 cells, which was associated with increased activities of antioxidative enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) through upregulated genes SOD1, CAT, GPX1 (i.e. gene for glutathione peroxidase-1), GCLM (i.e. gene for glutamate cysteine ligase modifier subunit), SLC1A11 (i.e. gene for solute carrier family 7, member 11) and SRXN1 (i.e. gene for sulfiredoxin-1). The anti-apoptotic effect of (RBG-C)-Que-Res was confirmed by the downregulation of caspase-3 and p53 and the upregulation of B-cell lymphoma-2 gene expression.

CONCLUSION

The present study highlights the potential of (RBG-C)-Que-Res conjugates as functional ingredients in healthy foods. © 2024 Society of Chemical Industry.

Whey protein isolate and inulin-glycosylated conjugate affect the physicochemical properties and oxidative stability of pomegranate seed oil emulsion

Glycosylated protein was obtained by the reaction of whey protein isolate(WPI) with inulin of different polymerization degrees and was used to stabilize a pomegranate seed oil emulsion. The physicochemical and antioxidative properties of the emulsions were assessed, and the impacts of accelerated oxidation on pomegranate seed oil were examined. The interfacial tension of WPI and short-chain inulin (SCI)-glycosylated conjugate (WPI-SCI) gradually decreased with increasing glycosylation reaction time. Emulsions stabilized by WPI-SCI (72 h) were the most stable, with a thick interfacial film on the surface of the droplets. After accelerated oxidation for 72 h, WPI-SCI inhibited the oxidation of oil in the emulsion. GC-IMS results showed that the production of harmful volatile components in oil was inhibited, and the peroxide strength was less than 30 mmol/kg oil. This study contributes to understanding of stable storage of lipids.

Advance in Hippophae rhamnoides polysaccharides: Extraction, structural characteristics, pharmacological activity, structure-activity relationship and application

Hippophae rhamnoides (Sea buckthorn) is an excellent medicinal and edible plant owing to its high nutritional and health-promoting properties. As an important bioactive component, H. rhamnoides polysaccharides (HRPs) have aroused wide attention due to their various pharmacological activities, including hepatoprotective, immuno-modulatory, anti-inflammatory, anti-oxidant, anti-tumor, hypoglycemic, anti-obesity, and so on. Nevertheless, the development and utilization of HRP-derived functional food and medicines are constrained to a lack of comprehensive understanding of the structure-activity relationship, application, and safety of HRPs. This review systematically summarizes the advancements on the extraction, purification, structural characteristics, pharmacological activities and mechanisms of HRPs. The structure-activity relationship, safety evaluation, application, as well as the shortcomings of current research and promising prospects are also highlighted. This article aims to offer a comprehensive understanding of HRPs and lay a groundwork for future research and utilization of HRPs as multifunctional biomaterials and therapeutic agents.

Enhanced functional properties of pea protein isolate microgel particles modified with sodium alginate: Mixtures and conjugates

Protein microgels are emerging as versatile soft particles due to their desirable interfacial activities and functional properties. In this study, pea protein isolate microgel particles (PPIMP) were prepared by heat treatment and transglutaminase crosslinking, and PPIMP were non-covalently and covalently modified with sodium alginate (SA). The effects of polymer ratio and pH on the formation of PPIMP-SA mixtures and conjugates were investigated. The optimal ratio of PPIMP and SA was found to be 20:1, with the optimal pH being 7 and 10, respectively. PPIMP-SA conjugates were prepared by Maillard reaction. It was found that ultrasound (195 W, 40 min) enhanced the degree of glycation of PPIMP, with a highest value of 37.21 ± 0.71 %. SDS-PAGE, browning intensity and FTIR data also confirmed the formation of PPIMP-SA conjugates. Compared with PPIMP and PPIMP-SA mixtures, PPIMP-SA conjugates exhibited better thermal stability, antioxidant, emulsifying and foaming properties, which opens up opportunities for protein microgel in various food applications.

Effect of ultrasound-assisted Maillard reaction on glycosylation of goat whey protein: Structure and functional properties

Goat whey protein (GWP) has a rich amino acid profile and good techno-functional attributes but still has limited functional performance for certain applications. This study introduces an innovative ultrasound-assisted Maillard reaction to enhance GWP's functional properties by conjugating it with either gum Arabic (GA) or citrus pectin (CP). Sonication accelerated the Maillard reaction, and the glycosylation of GWP was significantly enhanced after optimization of the conjugation conditions. Gel electrophoresis examination verified the creation of GWP-polysaccharide conjugates, while scanning electron microscopy analysis revealed structural modifications caused by polysaccharide grafting and sonication. The use of ultrasound in the Maillard reaction notably enhanced the solubility, foaming capacity, and emulsifying attributes of the GWPs. Among the conjugates, the GWP-GA ones exhibited the best functional properties. Our findings suggest that this approach can notably improve the functional attributes of GWPs, thus broadening their potential uses in the food sector and beyond.

Pea protein-inulin conjugate prepared by atmospheric pressure plasma jet combined with glycosylation: structure and emulsifying properties

Pea protein is one of plant proteins with high nutritional value, but its lower solubility and poor emulsifying properties limit its application in food industry. Based on wet-heating glycosylation of pea protein and inulin, effects of discharge power of atmospheric pressure plasma jet (APPJ) on structure, solubility, and emulsifying ability of pea protein-inulin glycosylation conjugate were explored. Results indicated that the APPJ discharge power did not affect the primary structure of pea protein. However, changes in secondary and spatial structure of pea protein were observed. When APPJ discharge power was 600 W, the solubility of glycosylation conjugate was 75.0% and the emulsifying stability index was 98.9 min, which increased by 14.85 and 21.95% than that of only glycosylation sample, respectively. These findings could provide technical support for APPJ treatment combination with glycosylation to enhance the physicochemical properties of plant-based proteins.

Insights into Cold Plasma Treatment on the Cereal and Legume Proteins Modification: Principle, Mechanism, and Application

Cereal and legume proteins, pivotal for human health, significantly influence the quality and stability of processed foods. Despite their importance, the inherent limited functional properties of these natural proteins constrain their utility across various sectors, including the food, packaging, and pharmaceutical industries. Enhancing functional attributes of cereal and legume proteins through scientific and technological interventions is essential to broadening their application. Cold plasma (CP) technology, characterized by its non-toxic, non-thermal nature, presents numerous benefits such as low operational temperatures, lack of external chemical reagents, and cost-effectiveness. It holds the promise of improving proteins' functionality while maximally retaining their nutritional content. This review delves into the pros and cons of different cold plasma generation techniques, elucidates the underlying mechanisms of protein modification via CP, and thoroughly examines research on the application of cold plasma in augmenting the functional properties of proteins. The aim is to furnish theoretical foundations for leveraging CP technology in the modification of cereal and legume proteins, thereby enhancing their practical applicability in diverse industries.

Soybean isolate protein complexes with different concentrations of inulin by ultrasound treatment: Structural and functional properties

The effects of ultrasound and different inulin (INU) concentrations (0, 10, 20, 30, and 40 mg/mL) on the structural and functional properties of soybean isolate protein (SPI)-INU complexes were hereby investigated. Fourier transform infrared spectroscopy showed that SPI was bound to INU via hydrogen bonding. All samples showed a decreasing and then increasing trend of α-helix content with increasing INU concentration. SPI-INU complexes by ultrasound with an INU concentration of 20 mg/mL (U-2) had the lowest content of α-helix, the highest content of random coils and the greatest flexibility, indicating the proteins were most tightly bound to INU in U-2. Both UV spectroscopy and intrinsic fluorescence spectroscopy indicated that it was hydrophobic interactions between INU and SPI. The addition of INU prevented the exposure of tryptophan and tyrosine residues to form a more compact tertiary structure compared to SPI alone, and ultrasound caused further unfolding of the structure of SPI. This indicated that the combined effect of ultrasound and INU concentration significantly altered the tertiary structure of SPI. SDS-PAGE and Native-PAGE displayed the formation of complexes through non-covalent interactions between SPI and INU. The ζ-potential and particle size of U-2 were minimized to as low as -34.94 mV and 110 nm, respectively. Additionally, the flexibility, free sulfhydryl groups, solubility, emulsifying and foaming properties of the samples were improved, with the best results for U-2, respectively 0.25, 3.51 μmoL/g, 55.51 %, 269.91 %, 25.90 %, 137.66 % and 136.33 %. Overall, this work provides a theoretical basis for improving the functional properties of plant proteins.

Molecular modification of low-dissolution soy protein isolates by anionic xanthan gum, neutral guar gum, or neutral konjac glucomannan to improve the protein dissolution and stabilize fish oil emulsion

Herein, the effects of anionic xanthan gum (XG), neutral guar gum (GG), and neutral konjac glucomannan (KGM) on the dissolution, physicochemical properties, and emulsion stabilization ability of soy protein isolate (SPI)-polysaccharide conjugates were studied. The SPI-polysaccharide conjugates had better water dissolution than the insoluble SPI. Compared with SPI, SPI-polysaccharide conjugates had lower β-sheet (39.6 %-56.4 % vs. 47.3 %) and α-helix (13.0 %-13.2 % vs. 22.6 %) percentages, and higher β-turn (23.8 %-26.5 % vs. 11.0 %) percentages. The creaming stability of SPI-polysaccharide conjugate-stabilized fish oil-loaded emulsions mainly depended on polysaccharide type: SPI-XG (Creaming index: 0) > SPI-GG (Creaming index: 8.1 %-21.2 %) > SPI-KGM (18.1 %-40.4 %). In addition, it also depended on the SPI preparation concentrations, glycation times, and glycation pH. The modification by anionic XG induced no obvious emulsion creaming even after 14-day storage, which suggested that anionic polysaccharide might be the best polysaccharide to modify SPI for emulsion stabilization. This work provided useful information to modify insoluble proteins by polysaccharides for potential application.

Study on the structural characteristics and emulsifying properties of chickpea protein isolate-citrus pectin conjugates prepared by Maillard reaction

Chickpea protein isolate (CPI) typically exhibits limited emulsifying properties under various food processing conditions, including pH variations, different salt concentrations, and elevated temperatures, which limits its applications in the food industry. In this study, CPI-citrus pectin (CP) conjugates were prepared through the Maillard reaction to investigate the influence of various CP concentrations on the structural and emulsifying properties of CPI. With the CPI/CP ratio of 1:2, the degree of graft reached 35.54 %, indicating the successful covalent binding between CPI and CP. FT-IR and intrinsic fluorescence spectroscopy analyses revealed alterations in the secondary and tertiary structures of CPI after glycosylation modification. The solubility of CPI increased from 81.39 % to 89.59 % after glycosylation. Moreover, freshly prepared CPI emulsions showed an increase in interfacial protein adsorption (70.33 % to 92.71 %), a reduction in particle size (5.33 μm to 1.49 μm), and a decrease in zeta-potential (-34.9 mV to -52.5 mV). Simultaneously, the long-term stability of the emulsions was assessed by employing a LUMiSizer stability analyzer. Furthermore, emulsions prepared with CPI:CP 1:2 exhibited excellent stability under various environmental stressors. In conclusion, the results of this study demonstrate that the glycosylation is a valuable approach to improve the emulsifying properties of CPI.