Use of high-intensity ultrasound to improve emulsifying properties of chicken myofibrillar protein and enhance the rheological properties and stability of the emulsion

Effect of different ultrasound powers on the stability of native/thermally denatured myofibrillar protein-inulin emulsion

The study examined the stability of emulsions made from native and thermally denatured myofibrillar proteins with inulin, using ultrasound treatments ranging from 200 to 800 W. After ultrasound treatment, the droplet size decreased, especially the particle size of MPs-600 W-inulin emulsion reached 1 μm. In addition, by measuring the oxidation stability of oil, it was found that ultrasound could inhibit emulsion oxidation, and the PV of MPs-600 W droplets reached 5.37 ± 0.18 mmol/Kg and TBARS reached 2.37 ± 0.19 μmol/Kg. However, at the same ultrasound power, the dispersion of TMPs-inulin droplets is not as good as that of MPs-inulin droplets, indicating that thermal denaturation is not conducive to emulsion stability. Therefore, the introduce of ultrasound to ameliorate the stability of MPs/TMPs-inulin emulsion is effective, especially at 600 W ultrasound, the emulsion showed good stability.

Effects of ultrasound-induced structural modifications on the emulsifying properties of Tenebrio molitor proteins

Ultrasonication has emerged as a promising technique for modifying physicochemical properties of proteins, enhancing their functionality in food applications. This study evaluated the effects of ultrasonic treatment on the structural and functional properties of mealworm-derived proteins (MPs) and their potential as emulsifiers. Dynamic light scattering revealed a significant reduction in MP particle size from 3464.3 nm (untreated) to 115.5 nm (30 min sonication), along with increased zeta potential, indicating improved colloidal stability. Sonication enhanced oil-holding capacity and solubility, suggesting improved interfacial adsorption and emulsification. Circular dichroism and FT-IR spectroscopy confirmed structural modifications, including increased α-helix content and enhanced hydrogen bonding interactions. Free sulfhydryl content and surface hydrophobicity analyses indicated ultrasound-induced unfolding, exposing functional groups that contribute to emulsifying properties. Sonicated MPs demonstrated superior emulsion stability under varying temperature, pH, and ionic conditions. Furthermore, digestibility analysis showed improved gastric digestion (72.7 % to 82.8 %) and enhanced lipid digestion in the small intestine (36.2 % to 47.9 %), suggesting greater bioavailability. These physicochemical modifications highlight the feasibility of using sonicated MP as natural emulsifiers with enhanced functionality. This study underscores their potential in food formulations, particularly for nutritionally fortified emulsions, contributing to sustainable and functional food ingredient development.

Antioxidant and antimicrobial PSE-like chicken protein isolate films loaded with oregano essential oil nanoemulsion for pork preservation

The oregano essential oil (OEO) nanoemulsion was prepared, and the effects of different added amounts of OEO nanoemulsion on the mechanical and antibacterial properties of PSE-like chicken protein isolate (PPI) film were investigated. Results revealed that the nanoemulsion containing 12 % Tween 80 and 6 % OEO had the smallest particle size (82.46 nm) and the best stability. Compared to the control group, the film of the PPI/OEO-2.5 % treatment group demonstrated superior mechanical properties. With the increase of the concentration of OEO nanoemulsion, the UV transmittance and water contact angle of the films decreased gradually (more hydrophilic), the opacity and water vapor permeability significantly increased, while the thermal stability, antioxidant properties (DPPH scavenging activity, 17.07 % ∼ 56.00 %), and antibacterial properties were markedly enhanced. The PPI/OEO-2.5 % treated film was applied to the preservation of pork, extending the shelf life by 2-4 days. These findings suggested that PPI had great application potential in bioactive packaging materials.

Optimizing the myofibrillar-plant proteins emulsion by ultrasound techniques: Improvements in structural and functional properties

BACKGROUND

The integration of myofibrillar proteins with plant proteins has gained substantial consideration in the food industry for producing healthier and more sustainable food products. However, achieving the desired properties of these protein emulsions remains challenging. High-intensity ultrasound treatment has emerged as a promising method to enhance the structural and functional properties of emulsions. We have explored the previously unexamined potential of ultrasonication with respect to improving the stability of animal-plant-based protein emulsions, providing new insights into the interactions of novel protein combinations.

RESULTS

Ultrasonication improved the stability of the myofibrillar protein-soybean protein isolate (MS), myofibrillar protein-pea protein (MP) and myofibrillar protein-hydrolyzed wheat protein (MW) emulsions. Interestingly, the particle size of MS, MP and MW emulsions was significantly reduced with ultrasound treatment for 20 min. Among the three protein combinations, MW presented better stability, as indicated by the higher zeta potential, lower particle size and turbidity values. Moreover, the stability of MW was increased with an increasing ultrasound time.

CONCLUSION

The stability of MW was significantly improved after 10 min of ultrasound treatment as a result of improving the zeta potential, particle size and turbidity values, changing the secondary structure and microstructure of the emulsion. © 2025 Society of Chemical Industry.

New insights into the interactions between the antibiotic enrofloxacin and fish protein by spectroscopic, thermodynamic, and theoretical simulation approaches

In this study, myofibrillar proteins (MPs) from crucian carp were utilized as a model to investigate the binding mechanism between fish proteins and antibiotic residues. Fluorescence quenching confirmed the static quenching (Ksv = 1.89 × 104 M-1 s-1, Kq = 1.89 × 1012 M-1 s-1) and effective binding (Kb = 5.66 × 106 M-1) of Enrofloxacin (ENRO) to MPs. Fourier-transform infrared spectroscopy and circular dichroism spectroscopy revealed that ENRO binding altered the secondary structure of MPs. The interaction mechanism, primarily driven by hydrogen bonding, electrostatic, and hydrophobic interactions (ΔH0 < 0, ΔS0 > 0), was elucidated using isothermal titration calorimetry. The ΔH0, -TΔS0 and ΔG0 values of the binding reaction between MPs and ENRO were -5.98 kJ/mol, -32.57 kJ/mol and -38.55kJ/mol. Molecular docking further verified the interaction forces, identifying key amino acid residues (Phe-40, His-93, and Lys-42) involved in ENRO binding. Additionally, protein carbonylation results demonstrated that even at maximum residue limits, ENRO accelerated MPs oxidation, further confirming the binding of the two. This study can provide theoretical support for the research of the dissipation fate of bound state residues in aquatic products.

Effects of ultrasound-assisted punicalagin binding on the allergenicity reduction of soybean protein 7S

Punicalagin (PUN) is the predominant polyphenol in pomegranate peels, and it has antioxidant property. This study aimed to explore the potential of PUN binding in reducing the allergenicity of soybean protein 7S (a major soy allergen). Ultrasound pretreatment (U7S) was used to enhance the availability of PUN binding sites. After PUN binding, the U7S conformation became more disordered, and the surface hydrophobicity was reduced. The molecular docking results indicated that the formation of the U7S-PUN complexes mainly depended on hydrogen bonding interactions. The phenolic hydroxyl group from PUN endowed U7S with high antioxidant properties, which were retained after digestion in the gastrointestinal tract. At a molar ratio of 1:50, U7S-PUN complexes reduced the IgG binding capacity by approximately 58.05 % and increased the rate of degranulation inhibition to about 35.87 %. This research offers a theoretical foundation for the use of PUN in the production of hypoallergenic plant-based protein products.

Insights into myofibrillar protein denaturation during freezing: The impact of ice-water interface area

This study investigated the impact of the ice-water interface area on the denaturation of myofibrillar protein (MP) over 1, 3, and 5 freeze-thaw cycles. Experimental systems designed to generate ice-water interfaces with two distinct surface areas were established by employing rapid freezing at -80 °C and slow freezing at -25 °C, resulting in surface areas of 64.63 m2/100 mL and 54.05 m2/100 mL, respectively. Following three freeze-thaw cycles, the process of rapid freezing, characterized by formation of a larger ice-water interface area, was found to significantly influenced the functional properties of MP. The impact was evidenced by a reduction in solubility, total sulfhydryl content, and thermal denaturation temperature. Structural modifications in MP suggested that the larger ice-water interface led an accelerated rate of protein unfolding during freezing. Interfacial pressure and confocal laser scanning microscopy (CLSM) results demonstrated that the larger ice-water interface area could be more able to reduce protein interfacial adsorption and enhanced protein emulsion aggregation. The addition of 0.1 % surfactant Tween 80 prior to freezing markedly enhanced protein stability throughout both the freezing and subsequent freeze-thaw cycles. The findings suggested that to further inhibit MP frozen denaturation, it is important to consider limiting the expansion of ice-water interface area.

Antioxidant, Polyphenol, Physical, and Sensory Changes in Myofibrillar Protein Gels Supplemented with Polyphenol-Rich Plant-Based Additives

BACKGROUND

Plant-based additives such as blackcurrant juice and pomace, as well as herbal extracts from Melissa officinalis and Centella asiatica, possess well-established health-promoting properties. This study aimed to investigate how the incorporation of polyphenol-rich plant-based additives into a myofibrillar protein matrix could enhance the nutritional value, antioxidant potential, and sensory quality of novel food gels.

METHODS

Myofibrillar protein gels were enriched with selected plant-based additives. Antioxidant properties were assessed using the ABTS radical cation decolorization assay, DPPH radical scavenging assay, and the Ferric Reducing Antioxidant Power (FRAP) assay. Polyphenol profiles were determined with emphasis on flavonols, flavan-3-ols, and chlorogenic acids. Physicochemical properties including pH, color, texture, energetic value, dry matter, and ash contents were measured. Sensory evaluation was conducted using consumer preference tests and descriptive sensory profiling.

RESULTS

Enriched gels contained bioactive compounds such as catechins, procyanidins, chlorogenic acids, and anthocyanins, whose presence correlated with distinct antioxidant activities. Blackcurrant pomace significantly elevated both total polyphenol content and antioxidant capacity, imparting a vivid red-purple color that influenced consumer perception. Melissa officinalis extract enhanced antioxidant potential and introduced a mild, pleasant aroma. Centella asiatica extract further improved the nutritional profile and oxidative stability of the gels, demonstrating additive and synergistic effects in both functional and sensory dimensions.

CONCLUSIONS

Polyphenol-rich plant-based additives, particularly blackcurrant pomace and extracts from M. officinalis and C. asiatica, markedly improve the antioxidant capacity, nutritional value, and sensory appeal of myofibrillar protein-based food gels. These findings support their potential application in the development of functional food products tailored to consumer expectations.

Effect of selenium, sonication, and combination of selenium and sonication treatments on potassium bromate, alloxan, and titanium dioxide in bread

Improvers such as potassium bromate, titanium dioxide, and bleaching agents are used in breadmaking despite existing bans. This research aimed to detect potassium bromate, alloxan (a by-product of bleaching agents), and titanium dioxide in bread samples from local automated and traditional bakeries. Bread samples prepared from local durum wheat flour underwent treatments (sonication, selenium, and selenium with sonication). X-ray Fluorescence (XRF) did not detect titanium dioxide, while potassium bromide (a reduced form of potassium bromate) was detected in all samples. UV-visible spectroscopy detected alloxan in 37.5 % of bakeries. Among all treatments, selenium and sonication effectively reduced potassium bromide, alloxan, and titanium dioxide concentrations in spiked (10,000 μg/g) bread samples. Dynamic Light Scattering (DLS) showed particle sizes over 100 nm in all treated samples, and Scanning Electron Microscopy (SEM) revealed the surface morphology structure of rough, flaky surfaces with compact particles for all treated prepared, and spiked samples, indicating no nanoparticle formation.

Ultrasonication improved myofibrillar protein-stabilized emulsions: Oil/water interface adsorption behavior and rheological behavior

This study systematically investigated the ultrasonic enhancement of myofibrillar protein (MP)-stabilized emulsions, with emphasis on interfacial adsorption behavior and rheological properties. High-intensity ultrasonication (20 kHz, 500 W, 15 min) induced a 77.5 % reduction (p < 0.05) in MP particle size and a 61.0 % increase in solubility at pH 7.0, accompanied by the exposure of latent hydrophobic domains and free sulfhydryl groups. These structural modifications significantly enhanced the interfacial adsorption capacity of MPs. Actin was identified as the dominant interfacial-binding protein through SDS-PAGE analysis. Rheological characterization revealed pseudoplastic behavior in MP-stabilized emulsions, where 15-min ultrasonication markedly reinforced emulsion network structures. Intriguingly, while prolonged ultrasonication (15 min) exhibited the strongest correlation (p < 0.05) with emulsion stabilization efficacy, optimal functional performance was achieved at 10-min treatment. This study provides a robust theoretical basis and strong technical support for the application of ultrasonication in optimizing the emulsifying properties of proteins.

Influence of Interactions Between Drawing Soy Protein and Myofibrillar Proteins on Gel Properties

Drawing soy protein (DSP) exhibits a well-defined fibrous structure, conferring significant market potential. This study investigates the interactions between DSP and myofibrillar proteins (MP) and their effects on gel properties. Porcine myofibrillar protein (MP) was used as the raw material, and mixed systems were prepared by incorporating different concentrations of DSP at 0%, 2%, 4%, 6%, and 8% to evaluate their physicochemical properties and gel characteristics. The results demonstrated that the addition of DSP enhanced the gel strength, hardness, and water-holding capacity (WHC) of MP, thereby improving the overall properties and water retention of the gels. Among them, the trend of change was most obvious when the addition amount was 6%. The gel strength increased by 196.5%, the water retention capacity improved by 68.3%, and the hardness rose by 33.3%. Furthermore, as the addition amount of DSP increases, the total thiol content decreases, the hydrogen bond content increases, and the surface hydrophobicity enhances. This leads to a more compact arrangement of protein molecules, which is conducive to a denser and more stable solution and improves the stability of the protein solution. The α-helical structures in the proteins progressively transformed into β-turn structures, exposing more amino acid side chains and inducing conformational changes in MP, resulting in denser and more uniform gel network structures. The most pronounced changes were observed at a 6% addition level. These findings contribute to diversifying meat products and provide a theoretical basis for improving the WHC and yield of emulsified meat products in pork processing.

Effects of Flammulina velutipes powder on the emulsion properties of chicken myofibrillar protein under low-salt conditions

This study aimed to investigate the influence of varying concentrations of Flammulina velutipes powder (FVP) (0, 4, 8, 12, 16, and 20 g L-1, based on FVP weight per liter of emulsion) on the stability, rheological properties, microstructure, and interfacial protein content of chicken myofibrillar protein (MP) emulsions under low-salt conditions. Visual assessment and the Turbiscan stability index revealed that the stability of MP emulsions improved with increasing FVP concentration. The greatest stability was achieved when the FVP concentration was 16 gL-1. The incorporation of FVP enhanced the elasticity and viscosity of the emulsions by forming a dense three-dimensional network structure. The droplet size of the emulsions initially decreased and then increased with increasing FVP concentration. The addition of FVP increased the amount of protein absorbed by the emulsion layer. Flammulina velutipes powder is promising as a stabilizer that could improve the emulsifying and functional properties of low-salt myofibrillar protein emulsions. © 2024 Society of Chemical Industry.

Physicochemical characteristics and anti-inflammatory properties of Zophobas morio (super mealworm) protein extracted by different methods

In this study, Zophobas morio protein (ZMP) was extracted via combining alkaline extraction with ultrasound-assisted (AE-UAE) or microwave-assisted (AE-MAE) extraction in comparison with their respective single extraction methods and conventional method. AE-UAE and AE-MAE exhibited a higher extraction yield (40.68 % and 36.80 %, respectively) than single methods and conventional method (29.19 %-35.89 %). SDS-PAGE showed AE-UAE and AE-MAE induced new formation of smaller molecular weight proteins. Moreover, the hybrid methods decreased α-helix content, whereas increased β-sheet by unfolding the structure of ZMPs. ZMPs demonstrated significant anti-inflammatory properties by ameliorating LPS-induced macrophage activation and subsequent excessive expression of immune modulators in RAW264.7 cells. Notably, at 200 μg/mL, AE-UAE protein reduced approximately 65 % of nitric oxide and 85 % of iNOS expression, decreased TNF-α secretion by 35 % and IL-6 secretion by 68 %, and decreased CD80 expression by 50 %. In conclusion, the proposed hybrid methods are applicable for efficient extraction of ZMP with improved biological activities.

Enhancing the Functional and Emulsifying Properties of Potato Protein via Enzymatic Hydrolysis with Papain and Bromelain for Gluten-Free Cake Emulsifiers

In recent years, plant-derived food proteins have gained increasing attention due to their economic, ecological, and health benefits. This study aimed to enhance the functional properties of potato protein isolate (PPI) through enzymatic hydrolysis with papain and bromelain, evaluating the physicochemical and emulsifying characteristics of the resulting potato protein hydrolysates (PPHs) for their potential use as plant-based emulsifiers. PPHs were prepared at various hydrolysis times (0.25-2 h), resulting in reduced molecular weights and improved solubility under acidic conditions (pH 4-6). PPHs exhibited higher ABTS radical-scavenging activity than PPI. The foaming stability (FS) of bromelain-treated PPI was maintained, whereas papain-treated PPI showed decreased FS with increased hydrolysis. Bromelain-treated PPHs demonstrated a superior emulsifying activity index (EAI: 306 m2/g), polydispersity index (PDI), higher surface potential, and higher viscosity compared to papain-treated PPHs, particularly after 15 min of hydrolysis. Incorporating PPHs into gluten-free chiffon rice cake batter reduced the batter density, increased the specific volume, and improved the cake's textural properties, including springiness, cohesiveness, and resilience. These findings suggest that bromelain-treated PPHs are promising plant-based emulsifiers with applications in food systems requiring enhanced stability and functionality.

Synergistic effects of pulsed electric field and NaCl on myofibrillar proteins and flavor of marinated pork

Marinating is a crucial stage in meat processing. However, traditional marinating takes a long time and is prone to nutrient loss. Pulsed electric field (PEF) technology, an innovative non-thermal processing method, has been shown to improve the efficiency of meat marinating. Myofibrillar proteins (MPs) are essential components of meat and play a key role in determining meat quality. This study investigated the effects of PEF-assisted marination on pork MPs and aldehyde compounds at various PEF frequencies (110.6, 141.2, and 173.6 Hz). PEF pretreatment altered the structure of MPs, leading to an increase in surface hydrophobicity, carbonyl content, and free sulfhydryl groups. Conversely, solubility, total sulfhydryl content, and particle size decreased compared to the control group. These structural changes were linked an increase in NaCl content in the pork following PEF treatment. Additionally, PEF improved the emulsifying properties and digestibility of the pork. Regarding flavor, PEF treatment enhanced both the diversity and concentration of aldehyde compounds in the marinated pork. This study demonstrates that PEF not only improves the functional properties of MPs but also positively affects the flavor profile of marinated meat.

Ultrasound-assisted fermentation effectively alleviates the weakening of wheat gluten network caused by long-chain inulin and the underlying mechanism

The main objective of the article is to elucidate the effects of ultrasonic treatment with different ultrasonic power (0 W, 200 W, 250 W, 300 W, 400 W and 500 W) on the rheology, water distribution, sulfhydryl disulfide bond content, microstructure, and gluten properties of FXL (Long-chain inulin) dough. When the ultrasonic power is 300 W, the protein polymerization can be promoted, thus improving the gluten network. The mechanical action and cavitation induced by ultrasound changed the water distribution of FXL dough and promoted the transition from weakly bound water to tightly bound water. The T21 value (tightly bound water relaxation time) was shortened from 0.25 to 0.16 and the A21 (tightly bound water content) was reduced from 6.35 to 5.18, an improvement of 22.6 %, at a power of 300 W. Ultrasound decreased the enthalpy of FXL dough, and increased the particle size and potential of gluten protein. The introduction of ultrasound increased the content of β-sheets structure (40.85) at 250 W. The microstructure of the FXL dough revealed that ultrasonic treatment induced a continuous tight membrane-like gluten network, while the application of 500 W ultrasonic power resulted in the exposure and depression of starch particles.

Ultrasound-induced food protein-stabilized emulsions: Exploring the governing principles from the protein structural perspective

Consumers' growing demand for healthy and natural foods has led to a preference for products with fewer additives. However, the low emulsifying properties of natural proteins often necessitate the addition of emulsifiers in food formulations. Consequently, enhancing the emulsifying properties of proteins through various modification methods is crucial to meet modern consumer demands for natural food products. High-intensity ultrasound offers a green, efficient processing technology that significantly improves the emulsifying properties of proteins. This study explores how ultrasound treatment enhances the stability of protein-based emulsions by modifying protein structures. While ultrasonic treatment does not significantly affect the primary structure of proteins, it influences the secondary, tertiary, and quaternary structures depending on the type of protein, ultrasound parameters (type, intensity, and time), and treatment conditions. The results suggest that ultrasound treatment reduces α-helix content, decreases protein particle size, and increases β-sheet content, surface hydrophobicity, free sulfhydryl groups, and zeta potential, leading to a more stable protein-based emulsion. The reduced particle size and increased flexibility of proteins induced by ultrasound enable more rapid protein adsorption at the oil-water interface, resulting in smaller emulsion droplets. This contributes to the emulsion's improved stability during storage. Future research should focus on the large-scale application of ultrasonic treatment for protein modification to produce high-quality, natural foods that meet the evolving needs of consumers.

Role of Medium-Chain Triglycerides on the Emulsifying Properties and Interfacial Adsorption Characteristics of Pork Myofibrillar Protein

Medium-chain triglycerides (MCTs) have been known to have multiple health benefits in treating metabolic disorders and reducing the incidence of obesity. In the present study, the partial replacement of lard with MCTs assisted by ultrasound treatment on the emulsifying stability and adsorption behavior of myofibrillar protein (MP) was investigated. The results revealed that ultrasound-assisted MCT emulsion had better emulsifying activity and emulsion stability than other groups. MCTs with ultrasound treatment considerably lowered the particle size, facilitated the formation of much smaller and more homogeneous emulsion droplets, and enhanced the oxidative stability of the emulsion. The emulsion had a pseudo-plastic behavior determined through static and dynamic rheological studies, and the MCT emulsion exhibited a larger viscosity and a greater storage modulus (G') compared with the lard emulsion. MCTs could promote protein adsorption levels at the O/W interface, forming a dense interfacial protein film. The surface hydrophobicity and reactive sulfhydryl content increased, accompanied by the transformation of α-helix and β-turn structure to β-sheet and random coil structure, indicating MCTs combined with ultrasound-induced unfolding and crosslinking of MP at the interface. The results suggested that MCTs may have the potential to enhance emulsifying properties in emulsion-type meat products.

Effects of plasma-activated water on structural and functional properties of PSE-like chicken protein isolate

Pale, soft and exudative (PSE)-like chicken meat is rich in high-quality proteins, however, due to the properties of PSE-like meat, the functional characteristics of PSE-like chicken meat protein isolate (PPI) are affected. The present investigation aimed to improve the functional properties of PPI by employing plasma activation water (PAW), with the ultimate goal of enhancing its utility in various applications. The effects of PAW on the structure and function of PPI were evaluated. PAW treatment induced the protein structure to change from random coil to α-helix, which made the protein conformation more stable. PAW caused the hydrophobic residues to be exposed, thereby effectively enhancing their surface hydrophobicity. Dynamic rheology revealed the storage modulus of PPI gradually raised with increasing of PAW activation time. The scanning electron microscopy (SEM) showed that PAW promoted PPI to form a rough surface. When PAW activation time increased to 40 s, the foaming ability of PPI was raised by 77.84%, the emulsifying activity index was increased to 20.94 m2/g, the emulsion stability index was improved by 20.40%, and the in vitro digestibility was increased by 25.15% (P < 0.05). The above results showed PAW could modify the structural properties, and effectively improve the emulsifying and foaming properties of PPI, and increase the in vitro digestibility of PPI.

The dual role of mannosylerythritol lipid-A: Improving gelling property and exerting antibacterial activity in chicken and beef gel

Gel meat products are important in the meat market. To develop high-quality meat gel products, mannosylerythritol lipid-A (MEL-A) was added to chicken and beef gels, and their physicochemical and biological properties of the composite gel formed by heating were determined in this study. The results of texture analysis showed that MEL-A could significantly improve the hardness, gumminess and chewiness of meat gels and reduce water loss (P < 0.05). In addition, rheological and differential scanning calorimetry (DSC) analysis showed that MEL-A not only improved the rheological properties of meat gel, but also improved its thermal stability. The results of dynamic rheological analysis also showed that MEL-A improved the gel strength of meat gel, and the gel strength of chicken was the highest after adding 1.5 % MEL-A while the gel strength of beef was the highest after adding 2 % MEL-A. The image of scanning electron microscopy (SEM) and protein molecular weight distribution measurement indicated that MEL-A induced protein aggregation, resulting in fewer pores in the meat gels and a more compact network structure. These results suggest that different meat gels show good gel properties, so MEL-A has a lot of potential for gel product development.

Effects of mixing ratio on physicochemical, structural properties and application in lycopene-loaded emulsions of blends of whey protein and pea protein

Physicochemical, structural properties and application in lycopene-loaded emulsions of blends of whey protein isolate (WPI) and pea protein isolate (PPI) at varying mass ratios (100/0, 75/25, 50/50, 25/75, 0/100) were investigated. Data indicated that the mass ratios affected the physical, chemical and storage stability of the emulsion by influencing the particle size, zeta-potential, surface hydrophobicity, free sulfhydryl content, and secondary structure of the blends. Particularly, emulsion with a mixing ratio of 75/25 exhibited superior physical stability against salt concentrations (200 and 500 mM), better chemical stability against UV light and heat, and maintained stability over a 30-day storage period. Emulsions stabilized by blends of different ratios exhibited similar digestion behavior, with no significant differences observed in lycopene's transformation stability and bio-accessibility. Data indicated that substitution of whey protein by pea protein is effective in term of emulsifier application and replacement ratio is an important factor need to be considered.

High-intensity ultrasound-modified Jerusalem artichoke leaf protein for stabilizing corn oi-in-water emulsion and Enhacing curcumin delivery

Jerusalem artichoke leaf protein (JALP) has limited applications because of its dark color, even though Jerusalem artichoke is a cash crop. This study utilized high-intensity ultrasound (HIUS) (≤ 600 W) to modify the physicochemical characteristics and functional properties of JALP. Compared with the JALP, all the HIUS-treated JALP (UJALP) samples had a lighter brown color, higher absolute ζ-potential value, lower Z-average size, higher surface hydrophobicity, higher water solubility, lower turbidity, more -SH group, and higher water-holding, oil-holding, emulsifying and foaming capacities. The HIUS treatment disrupted certain non-covalent and SS bonds, promoted protein depolymerization, change protein secondary structures, causing partial unfolding of protein and exposure of some charged groups, hydrophobic groups and chromophores (like tryptophan and tyrosine). The UJALP-stabilized corn oil-in-water emulsions (UJALPEs) were more stable than the JALP-stabilized emulsion (JALPE). The bioaccessibility of curcumin in the JALPE (56.38 %) was significantly lower than in the UJALPE-600 W (64.59 %).

Impact of egg white protein on mycoprotein gel: Insights into rheological properties, protein structure and Molecular interactions

The mechanisms behind Mycoprotein (MYC) formation, especially the interactions with egg white proteins (EWP), are not fully understood despite the widespread use of fungal proteins. This study investigates the formation of MYC-EWP composite gels using physicochemical and structural analyses, supported by molecular simulations. At pH 7, EWP adsorbs onto the MYC mycelium surface via hydrogen bonding and electrostatic interactions, with a binding energy of -21.97 kcal/mol. Increasing EWP concentration enlarges particle size in the suspension. Upon heating, the gel's microstructure shows irregular fibrous structures with EWP filling the spaces within the mycelium. The texture properties improve with higher EWP levels, resulting in a denser gel structure. These findings offer key insights into MYC-EWP interactions, clarifying the gelation process and providing valuable guidance for optimizing fungal protein products.

Impacts of kappa-selenocarrageenan on the muscle quality of pork: Novel insights into myofibrillar protein and lipid oxidation

Excessive oxidation of protein and lipids in pork leads to quality degradation and loss of nutrients. Kappa-selenocarrageenan (Se-K) can not only be used as a selenium enhancer but also as an antioxidant. To explore potential antioxidants that could be applied to pork, the effect of Se-K on myofibrillar protein (MP) and lipid oxidation was investigated. The results demonstrated that Se-K could scavenge hydroxyl radicals, DPPH radicals, and ABTS radicals. It was found that Se-K inhibited the formation of carbonyls and decreased the loss of sulfhydryl groups of MP. Se-K also inhibited cross-linking, aggregation, unfolding, and structural transformation of MP and repressed the increase in surface hydrophobicity. Additionally, Se-K enhanced the emulsibility, textural properties, and water-holding capacity of MP. We also found that Se-K delayed the increase in acid value, peroxide value, and thiobarbituric acid reactive substances value. Furthermore, Se-K inhibited the degradation of unsaturated fatty acids, especially linoleic acid. Overall, Se-K was effective in inhibiting MP and lipid oxidation and could be a potential antioxidant for pork.

Effect of ultrasound on the functional properties and structural changes of chicken liver insoluble proteins isolated by isoelectric solubilization/precipitation

The studies investigated the effects of different ultrasonic powers (180, 360 and 540 W) on the functional properties and structural changes of chicken liver insoluble proteins (CLIPs) isolated by isoelectric solubilization/precipitation (ISP) (with alkaline solubilization at pH 11.0 and pH 12.0 respectively, and acid precipitation at pH 5.5). Results indicated that ultrasonic significantly increased the solubility of ISP-isolated CLIPs, and narrowed the particle size distribution of D3,2 and D4,3 (P < 0.05). The highest solubility was observed at pH 11.0 and 360 W ultrasound treatment, reaching 77.26 %. The ultrasonic with 360 W exhibited higher shear stress and apparent viscosity. Spectroscopy revealed that compared to without ultrasonic treatment, there was an increase in β-sheet and random curling content accompanied by a decrease in β-turn and α-helix structure when ultrasonication. Ultrasound altered the tyrosine hydrophobic residues to be exposed to the surface of the ISP-isolated CLIPs, thus improving the hydrophilicity. Overall, ultrasound combined with ISP treatment effectively improved the functional properties of CLIPs, and it might be a potential, safe and efficient method for improving the processing properties and broadening the application of insoluble animal-derived proteins.

Systematic free energy insights into the enhanced dispersibility of myofibrillar protein in low-salt solutions through ultrasound-assisted enzymatic deamidation

This work aimed to investigate the effects of ultrasound assisted enzymatic deamidation by protein-glutaminase (PG) on the dispersion of myofibrillar protein (MP) in low-salt solutions. The solubility, structural characteristics, transmission electron microscopy, asymmetric-flow field-flow fractionation, steady shear rheological property and multiple light scattering of MP deamidated by PG (MP-PG) and MP pretreated with ultrasound followed by PG deamidation (MP-U-PG) were determined. Molecular docking and molecular dynamics (MD) simulations were used to estimate the interaction between PG and MP. Under ultrasound assistance, the MP deamidated for 16 h (MP-U-PG16) showed the highest solubility (80.1 %) in low-salt conditions, which is attributed to its highest absolute zeta potential and smallest particle size. Although secondary structure analysis showed that MP-PG and MP-U-PG had an increased α-helix ratio and a decreased β-sheet ratio, ultrasonic treatment had a significantly influence on the MD results. The results manifested that hydrogen bond was the primary forces driving the binding between PG and MP, and the hydrogen bond and hydrophobic interaction were the dominant forces responsible the binding between PG and MP pretreated with ultrasound. According to the energy landscapes theory, ultrasound could overcome the energy barriers through external force input and find the best pathway to achieve the final lowest energy state. Our research contributed to the improvement of the colloidal dispersibility of MPs under low-salt conditions and the regulation of protein interaction by ultrasound assistance.

Study on the regulation of tea polyphenols on the structure and gel properties of myofibrillar protein from Neosalanx taihuensis

Neosalanx taihuensis (N. taihuensis) is an important freshwater fish species, rich in nutrients and proteins. However, myofibrillar proteins (MPs), as the major component of muscle, are prone to oxidative denaturation. Tea polyphenols (TPs), as natural antioxidants, have broad applications in the area of aquatic product manufacturing. The research examined the impacts of three typical catechins, namely epicatechin (EC), epigallocatechin (EGC), and epigallocatechin gallate (EGCG), on the structure and gel characteristics of MP from N. taihuensis under oxidative treatment conditions. In comparison to the oxidized group, all three TP compounds notably slowed down the oxidation process of MP and decreased the production of oxidative products. Additionally, TP addition induced changes in the MP structure, with further exposure of hydrophobic regions. Furthermore, TP treatment notably enhanced the functional properties of MP gels, including optimized gel strength, improved water holding capacity (WHC), and altered rheological properties. Among the three TP compounds, EGCG, due to its higher number of phenolic rings, formed complexes with MP that exhibited greater antioxidant activity. The research results indicated that the WHC of the EGCG group had increased by 17.06 % compared to the oxidized group, and the decrease in amino content reached as much as 40.09 %. Finally, molecular docking simulations were performed to explore the ways in which TP and MP interact. This study not only uncovers the relationship between polyphenol types and MP structure, but also confirms the enormous potential of TP as antioxidants in the improvement of N. taihuensis surimi products.

Encapsulation of Lactiplantibacillus plantarum with casein-gellan gum emulsions to enhance its storage, pasteurization, and gastrointestinal survival

Probiotics serve a very important role in human health. However, probiotics have poor stability during processing, storage, and gastrointestinal digestion. The gellan gum (GG) is less susceptible to enzymatic degradation and resistant to thermal and acidic environments. This study investigated the effect of casein (CS)-GG emulsions to encapsulate Lactiplantibacillus plantarum CICC 6002 (L. plantarum CICC 6002) on its storage stability, thermal stability, and gastrointestinal digestion. L. plantarum CICC 6002 was suspended in palm oil and emulsions were prepared using CS or CS-GG complexes. We found the CS-GG emulsions improved the viability of L. plantarum CICC 6002 after storage, pasteurization, and digestion compared to the CS emulsions. In addition, we investigated the influence of the gellan gum concentration on emulsion stability, and the optimal stability was observed in the emulsion prepared by CS-0.8% GG complex. This study provided a new strategy for the protection of probiotics based on CS-GG delivery system.

Effect of ultrasound combined with plasma protein treatment on the structure, physicochemical and rheological properties of myofibrillar protein

This study aimed to investigate the effect of ultrasound combined with plasma protein (UPP) treatment on the structure, physicochemical and rheological properties of myofibrillar protein (MP). The results indicated that the UPP group caused changes in the secondary structure, increased fluorescence intensity and enhanced surface hydrophobicity of MP. Then, UPP significantly decreased the content of free and total sulfhydryl group, and high molecular weight protein contents were observed in MP. These findings implied moderate cross-linking and aggregation between plasma protein and MP in this ultrasound treatment. Furthermore, the physical characteristics, stability and rheological properties of MP were improved in UPP, as evidenced by increased storage modulus and decreased loss angle tangent. Therefore, this study suggested that the combined treatment not only had the potential to enhance the product quality in the process of ground meat, but also improved the utilization rate and added value of plasma proteins.

Application of Ultrasound to Animal-Based Food to Improve Microbial Safety and Processing Efficiency

Animal-based foods such as meat, dairy, and eggs contain abundant essential proteins, vitamins, and minerals that are crucial for human nutrition. Therefore, there is a worldwide growing demand for animal-based products. Since animal-based foods are vital resources of nutrients, it is essential to ensure their microbial safety which may not be ensured by traditional food preservation methods. Although thermal food preservation methods ensure microbial inactivation, they may degrade the nutritional value, physicochemical properties, and sensory qualities of food. Consequently, non-thermal, ultrasound food preservation methods are used in the food industry to evaluate food products and ensure their safety. Ultrasound is the sound waves beyond the human audible range, with frequencies greater than 20 kHz. Two types of ultrasounds can be used for food processing: low-frequency, high-intensity (20-100 kHz, 10-1,000 W/cm2) and high-frequency, low-intensity (>1 MHz, <1 W/cm2). This review emphasizes the application of ultrasound to improve the microbial safety of animal-based foods. It further discusses the ultrasound generation mechanism, ultrasound technique for microbial inactivation, and application of ultrasound in various processing operations, namely thawing, extraction, and emulsification.

pH-induced interface protein structure changes to adjust the stability of tilapia protein isolate emulsion prepared by high-pressure homogenization

The pH is a crucial external factor affecting the structure and emulsification characteristics of proteins. The current study aimed to reveal the correlation between the secondary structure changes and tilapia protein isolate (TPI) emulsion stability under different pH (3.0-10.0) prepared by high-pressure homogenization. The results showed that TPI with significantly increased solubility and emulsifying properties when the pH keep away from the isoelectric point (pH 5.0). Meanwhile, TPI emulsions presented significantly enhanced stability (with decreased particle size, increased zeta potential, creaming index close to 0, and uniform dispersion of droplets) at pH 3.0 and 10.0. Interface-adsorbed protein mainly consists of a myosin-heavy chain and actin, and the secondary structure was significantly influenced by pH and high-pressure homogenization. The α-helix will be transformed into β-sheet and β-turn when pH is closer to pH 5.0. However, the high-pressure homogenization induced α-helix conversion to β-sheet. The correlation analysis revealed that emulsion stability is positively correlated with α-helix and negatively correlated with β-sheet. This work provides a deep insight into the correlation between secondary structure changes and the stability of TPI emulsion as affected by pH to offer an alternative way to enhance TPI emulsion stability.

Ultrasonic treatment of emulsion gels with different soy protein-hemp protein composite ratios: Changes in structural and physicochemical properties

To improve the emulsion gel system of single soybean isolate protein (SPI) and to broaden the application field of hemp protein isolate (HPI), ultrasonic treatment and HPI were introduced to improve the properties of SPI emulsion gel and to explore the mechanism. The results showed that the gel strength (218.6 g) and water-holding capacity (86.24 %) of the emulsion gels were improved under ultrasonic treatments when the ratio of SPI:HPI was >6:4, and the reticulation structure of the gels was enhanced. When the ratio of SPI:HPI was <6:4, the gel structure was loose and formless. Ultrasonic treatment has a significant effect on the emulsion gel with the ratio of SPI:HPI was >6:4. Appropriate ultrasonic treatment (400 W) changed the protein structure, improved the rheological properties of emulsion gels to form the protein-oil-coated network structure. However, excessive ultrasonic treatment (600 W) will destroy the conformation of the protein, reducing the stability of the structure. The effect of ultrasonic treatment on emulsion gels with the ratio of SPI:HPI was <6:4 is low, but improved the gel protein digestibility. This study provides a theoretical basis for the application of ultrasonic in composite protein emulsion gels systems and the development and application of HPI.

The influence of pH-ultrasonic-induced myofibrillar protein conformation of Penaeus vannamei (Litopenaeus vannamei) on emulsification and digestion characteristics of fish oil oleogel-based emulsions

pH-induced and ultrasound treatment can both adjust spatial conformation to improve the interfacial stability, and fish oil oleogel could be used to enhance oil binding capacity. The relationship between stabilization mechanism and lipid digestion was revealed, considering the protein conformation and interfacial characteristics. The results showed that pH-ultrasonic-induced myofibrillar proteins (MPs) at pH 7.0 had higher interfacial adsorption capacity and surface hydrophobicity as well as more stable secondary structures, which lowered the particle size and enhanced the interfacial stability. In the stomach, the particle size increased along with the decrease in electrostatic repulsion, and β-sheets significantly increased, which promoted aggregation and flocculation. In the small intestine, the reduction of β-sheets favored the interfacial replacement and facilitated the lipid digestion. Therefore, pH-ultrasonic-modified method improved the structure and function of MPs, facilitated the interfacial stability and intestinal digestion.

Ultrasound treatment improved gelling and emulsifying properties of myofibrillar proteins from Antarctic krill (Euphausia superba)

Antarctic krill is a promising source of marine proteins with abundant biomass and excellent nutritional profile, but has poor technological properties. Ultrasonic treatment at power levels of 0, 100, 200, 300, 400 and 500 W was applied to improve the technological properties of Antarctic krill meat, and the changes in physicochemical properties of myofibrillar proteins (MPs) were investigated. The results indicated that proper ultrasonic treatment significantly improved the gelling properties of Antarctic krill meat, in terms of a more uniform and stable gel texture and better water holding capacity, which were related to better cross-linking of MPs. Ultrasonic treatment promoted the conversion of MPs' secondary structures from α-helix and random coil to β-sheet and β-turn, thereby making the molecular structure soft and loose. In addition, at tertiary structure level, ultrasonic treatment exposed the hydrophobic groups and sulfhydryl groups within MPs, thereby improving the emulsifying properties by changing the intermolecular interactions and interface properties. Furthermore, the particle size of MPs decreased and exhibited a more uniform distribution, aligning with the enhanced interactions observed between MPs and oil. These results provide an insight into the efficient development of Antarctic krill by elucidating how the ultrasonic treatment improves the gelling and emulsifying properties based on structure modulation of myofibrillar proteins.

Assessment of the impact of whey protein hydrolysate on myofibrillar proteins in surimi during repeated freeze-thaw cycles: Quality enhancement and antifreeze potential

The quality of surimi, widely used in processed seafood, is compromised by freeze-thaw cycles, leading to protein denaturation and oxidative degradation. The objective of this study is to explore the effects of adding natural whey peptide hydrolysate (WPH) on the myofibrillar proteins of repeatedly freeze-thawed surimi. Results indicated surimi treated with 15% WPH exhibited only a 128% increase in surface hydrophobicity and a maximum peroxide value of 7.84 μg/kg, significantly lower than the control group. Additionally, salt-soluble protein content, emulsification activity, and stability decreased with the increase in freeze-thaw cycles. With a 15% WPH offering the most significant protective effect, evidenced by reductions of only 25.02%, 42.52% and 37.02% in salt-soluble protein content, emulsification activity, and stability, respectively. These outcomes demonstrate that WPH effectively reduces protein denaturation during repeated freeze-thaw processes. Future research should explore the molecular mechanisms underlying WPH's protective effects and evaluate their applicability in other food systems.

Amelioration of myofibrillar protein emulsion gel properties by mildly oxidized sunflower oil

Different oxidation states of oil affect the emulsion stablility and gel properties of emulsified meat products. Emulsified chicken gels were prepared using sunflower oil (SFO) with different oxidation levels (0, 20, 40, and 60 min, 120 °C). The pre-oxidation treatment of oils was investigated for emulsification and gelation of myofibrillar protein (MP). The results showed that MP emulsion gels with mildly oxidized (20 min) SFO had higher elastic modulus (G') and more homogeneous water distribution, which were due to increased hydrophobic interactions between MP and lipids, and improved emulsification stability. However, the addition of highly oxidized (60 min) SFO resulted in aggregation of proteins, increased emulsion particle size, significantly reduced hardness and chewiness (P > 0.05), and exhibited large pores in the network microstructure. The results suggested that mildly oxidized SFO has an ameliorating effect on MP emulsion gelation, which facilitates better comprehension of the protein oxidation process in oil-loaded meat systems.

Is it still meat? The effects of replacing meat with alternative ingredients on the nutritional and functional properties of hybrid products: a review

Consumer interest in a shift toward moderating animal products in their diets (flexitarian) is constantly increasing. One way to meet this consumer demand is through hybrid meat products, defined as those in which a portion of the meat is substituted by plant protein. This review article aims to analyze literature regarding the impact of replacing meat proteins with other alternative proteins on the functional and nutritional properties of hybrid products. Different food matrices created by hybrid products have impact on the digestive processes and outcomes in vitro and in vivo, and the bioavailability of protein, lipid, and mineral nutrients is modified, hence these aspects are reviewed. The functional properties of hybrid products change with regard to type of alternative protein source used. In hybrid products, deficiencies in amino acids in alternative proteins are balanced by amino acids from meat proteins, resulting in wholesome products. Additionally, animal protein degrades into peptides in the gut which bind non-animal iron and increase the availability of iron from the alternative protein material. This relationship may support the development of hybrid products offering products with increased iron bioavailability and a previously unseen beneficial nutritional composition. The effects of alternative protein addition in hybrid meat products on protein and mineral digestibility remains unclear. More research is required to clarify the interaction of the protein-food matrix as well as its effects on digestibility. Very little research has been conducted on the oxidative stability and microbiological safety of hybrid products.

Improvement on gel properties of chicken myofibrillar protein with electron beam irradiation: Based on protein structure, gel quality, water state

This study aimed to investigate the effects of electron beam (E-beam) irradiation at different doses (0-15 kGy) on the solubility, rheological properties, emulsification characteristics, and moisture distribution of chicken myofibrillar proteins (MPs). Irradiation treatment notably increased the solubility, surface hydrophobicity, emulsification properties, and apparent viscosity of MPs, based on conformational changes caused by irradiation-induced oxidative denaturation of proteins. However, high doses of irradiation (15 kGy) induced in excessive cross-linking and aggregation of proteins, reducing the solubility, emulsification properties, and shear stress. Degradation of myosin heavy and light chains in irradiated MPs increased the content of β-turns and random coils. Additionally, the initial relaxation times of T21 and T22 in irradiated protein gels were reduced, and the peak value of P21 was increased, which improved the water-capturing ability of protein gels. Altogether, these results findings suggest that electron beam irradiation can be applied as a potential technique for modifying muscle proteins.

Effect of chitosan oligosaccharides with different molecular weight in alleviating textural deterioration of chicken myofibrillar protein gel with high-temperature treatment

The molecular weight (MW) of oligosaccharides on gel properties of myofibrillar protein (MP) at high temperature remains unclear. In this study, it was found that chitosan oligosaccharides (CO) with different MW all significantly alleviated the textural deterioration of MP gel with high-temperature treatment. Moreover, MP-CO gel with the largest MW had the highest breaking force and the lowest cooking loss. Low-field NMR results further indicated that MP-CO gel with larger MW of CO had gradually increased relaxation rate, thus binding water more tightly. Rheological and microrheological tests suggested the addition of CO with larger MW resulted in much tighter gel network. These results indicated that CO with larger MW improved the quality of MP gel more effectively, which was because CO with larger MW inhibited aggregation of MP to a larger extent, resulting in smaller MP aggregates. Then MP-CO gel with much denser and more homogeneous structure was formed. Besides, MP-CO gel with larger MW of CO had higher content of β-sheet, resulting in MP gel with more ordered structure and better gel quality. Therefore, this study provided theoretical guidance for choosing the appropriate CO in improving texture of high temperature meat products.

Advances in Research on the Improvement of Low-Salt Meat Product Through Ultrasound Technology: Quality, Myofibrillar Proteins, and Gelation Properties

The high sodium content in meat products poses health risks to consumers and does not align with modern green and healthy living standards. Current strategies for directly reducing the sodium content in meat products are limited by their negative impact on the sensory or quality attributes of the products. In recent years, there has been great interest in applying ultrasound technology to reduce sodium content. This paper discusses the advantages and disadvantages of current mainstream strategies for reducing the sodium content in meat products, as well as the potential mechanisms by which ultrasound-assisted marination improves the quality of low-salt meat products. The main findings indicate that ultrasound, through its cavitation and mechanical effects, facilitates the transition of proteins from stable insoluble aggregates to stable soluble complexes, exposing more hydrophilic groups and, thus, enhancing protein solubility. At the same time, ultrasound promotes a greater number of proteins to participate in the formation of interfacial layers, thereby increasing emulsifying activity. Furthermore, ultrasound treatment promotes the interaction between proteins and water, leading to partial unfolding of protein chains, which allows polar residues to more readily capture water in the gel, thereby improving the water-holding capacity of the gel. These effects will contribute to the formation of high-quality low-salt meat products. However, variations in the frequency, intensity, and duration of ultrasound treatment can lead to differing effects on the quality improvement of low-salt meat products.

Modulation of the conformation, water distribution, and rheological properties of low-salt porcine myofibrillar protein gel influenced by modified quinoa protein

High-pressure homogenization modified quinoa protein (HQP) was added to porcine myofibrillar proteins (MP) to study its the influence on protein conformation, water distribution and dynamical rheological characteristics of low-salt porcine MP (0.3 M NaCl). Based on these results, the WHC, gel strength, and G' value of the low-salt MP gel were significantly improved with an increase in the added amount of HQP. A moderate amount of HQP (6%) increased the surface hydrophobicity and active sulfhydryl content of MP (P < 0.05). Moreover, the addition of HQP decreased particle size and endogenous fluorescence intensity. FT-IR results indicated that the conformation of α-helix gradually converted to β-sheet by HQP addition. The incorporation of HQP also shortened the T2 relaxation time and enhanced the proportion of immobile water, contributing to the formation of a compact and homogeneous gel structure. In conclusion, the moderate addition of HQP can effectively enhance the structural stability and functionality of low-salt MP.

Insighting the effect of ultrasound-assisted polyphenol non-covalent binding on the functional properties of myofibrillar proteins from golden threadfin (Nemipterus virgatus)

In this study, the effect of ultrasound-assisted non-covalent binding of different polyphenols (tannins, quercetin, and resveratrol) on the structure and functional properties of myofibrillar proteins (MP) from the golden threadfin (Nemipterus virgatus) was investigated. The effect of ultrasound-assisted polyphenol incorporation on the structure and properties of MP was evaluated by multispectral analysis, interfacial properties, emulsification properties and antioxidant properties et al. The results revealed that the protein-polyphenol interaction led to a conformational change in the microenvironment around the hydrophobic amino acid residues, resulting in an increase in the equilibrium of the MP molecules in terms of affinity and hydrophobicity. Ultrasound assisted polyphenols addition also led to a significant decrease of the oil/water interfacial tension (from 21.22 mN/m of MP to 8.66 mN/m of UMP-TA sample) and a significant increase of the EAI (from 21.57 m2/g of MP to 28.79 m2/g of UMP-TA sample) and ES (from 84.76 min of MP to 124.25 min of UMP-TA). In addition, ultrasound-assisted polyphenol incorporation could enhance the antioxidant properties of MP, with the DPPH and ABTS radical scavenging rate of UMP-TA increase of 47.7 % and 55.2 % in comparison with MP, respectively. The results demonstrated that the noncovalent combination with polyphenols under ultrasound-assisted conditions endowed MP with better functional properties, including solubility, emulsification, foaming, and antioxidant properties through structure change. This study can provide innovative theoretical guidance for effectively preparing aquatic protein-polyphenol non-covalent complexes with multiple functions and improving the processing and utilization value of aquatic proteins.

Effects of ultrasonic treatment on the structure and functional characteristics of myofibrillar proteins from black soldier fly

In the process of utilizing black soldier fly larvae (BSFL) lipids to develop biodiesel, many by-products will be produced, especially the underutilized protein components. These proteins can be recycled through appropriate treatment and technology, such as the preparation of feed, biofertilizers or other kinds of bio-products, so as to achieve the efficient use of resources and reduce the generation of waste. Myofibrillar protein (MP), as the most important component of protein, is highly susceptible to environmental influences, leading to oxidation and deterioration, which ultimately affects the overall performance of the protein and product quality. For it to be high-quality and fully exploited, in this study, black soldier fly myofibrillar protein (BMP) was extracted and primarily subjected to ultrasonic treatment to investigate the impact of varying ultrasonic powers (300, 500, 700, 900 W) on the structure and functional properties of BMP. The results indicated that as ultrasonic power increased, the sulfhydryl content and turbidity of BMP decreased, leading to a notable improvement in the stability of the protein emulsion system. SEM images corroborated the changes in the microstructure of BMP. Moreover, the enhancement of ultrasound power induced modifications in the intrinsic fluorescence spectra and FTIR spectra of BMP. Additionally, ultrasonic treatment resulted in an increase in carbonyl content and emulsifying activity of BMP, with both peaking at 500 W. It was noteworthy that BMP treated with ultrasound exhibited stronger digestibility compared to the untreated. In summary, 500 W was determined as the optimal ultrasound parameter for this study. Overall, ultrasound modification of insect MPs emerges as a dependable technique capable of altering the structure and functionality of BMP.

Utilizing ultrasound combined with quinoa protein to improve the texture and rheological properties of Chinese style reduced-salt pork meatballs (lion's head)

This study aimed to investigate the effect of ultrasound treatment times (30 min and 60 min) and levels of quinoa protein (QPE) addition (1 % and 2 %) on the quality of Chinese style reduced-salt pork meatballs, commonly known as lion's head. The water-holding capacity (WHC), gel and rheology characteristics, and protein conformation were assessed. The results indicated that extending the ultrasound treatment time and elevating the quinoa protein content caused conspicuous improvements (P<0.05) in the cooking yield, WHC, textural characteristics, color difference, and salt-soluble protein (SSP) solubility of the meatballs. Furthermore, the structural alterations induced by the ultrasound treatment combined with quinoa protein addition included enhancement in β-sheet, β-turn, and random coil structure contents, along with a red-shift in the intrinsic fluorescence peak. Additionally, the storage (G') and loss modulus (G'') of the raw meatballs significantly enhanced (P<0.05), indicating a denser gel structure in parallel with the microstructure. In conclusion, the findings demonstrated that ultrasound combined with quinoa protein enhanced the WHC and texture properties of Chinese style reduced-salt pork meatballs by improving SSP solubility.

Investigating the impact of ultrasound on the structural, physicochemical, and emulsifying characteristics of Dioscorin: Insights from experimental data and molecular dynamics simulation

This study investigated the impact of ultrasound treatment on dioscorin, the primary storage protein found in yam tubers. Three key factors, namely ultrasound power, duration, and frequency, were focused on. The research revealed that ultrasound-induced cavitation effects disrupted non-covalent bonds, resulting in a reduction in α-helix and β-sheet contents, decreased thermal stability, and a decrease in the apparent hydrodynamic diameter (Dh) of dioscorin. Additionally, previously hidden amino acid groups within the molecule became exposed on its surface, resulting in increased surface hydrophobicity (Ho) and zeta-potential. Under specific ultrasound conditions (200 W, 25 kHz, 30 min), Dh decreased while Ho increased, facilitating the adsorption of dioscorin molecules onto the oil-water interface. Molecular dynamics (MD) simulations showed that at lower frequencies and pressures, the structural flexibility of dioscorin's main chain atoms increased, leading to more significant fluctuations between amino acid residues. This transformation improved dioscorin's emulsifying properties and its oil-water interface affinity.

Advances of protein-based emulsion gels as fat analogues: Systematic classification, formation mechanism, and food application

Fat plays a pivotal role in the appearance, flavor, texture, and palatability of food. However, excessive fat consumption poses a significant risk for chronic ailments such as obesity, hypercholesterolemia, and cardiovascular disease. Therefore, the development of green, healthy, and stable protein-based emulsion gel as an alternative to traditional fats represents a novel approach to designing low-fat food. This paper reviews the emulsification behavior of proteins from different sources to gain a comprehensive understanding of their potential in the development of emulsion gels with fat-analog properties. It further investigates the emulsifying potential of protein combined with diverse substances. Then, the mechanisms of protein-stabilized emulsion gels with fat-analog properties are discussed, mainly involving single proteins, proteins-polysaccharides, as well as proteins-polyphenols. Moreover, the potential applications of protein emulsion gels as fat analogues in the food industry are also encompassed. By combining natural proteins with other components such as polysaccharides, polyphenols, or biopolymers, it is possible to enhance the stability of the emulsion gels and improve its fat-analog texture properties. In addition to their advantages in protecting oil oxidation, limiting hydrogenated oil intake, and delivering bioactive substances, protein-based emulsion gels have potential in food 3D printing and the development of specialty fats for plant-based meat.

Emulsifying properties of egg proteins: Influencing factors, modification techniques, and applications

As an essential food ingredient with good nutritional and functional properties and health benefits, eggs are widely utilized in food formulations. In particular, egg proteins have good emulsification properties and can be commonly used in various food products, such as mayonnaise and baked goods. Egg protein particles can act as stabilizers for Pickering emulsions because they can effectively adsorb at the oil-water interface, reduce interfacial tension, and form a stable physical barrier. Due to their emulsifying properties, biocompatibility, controlled release capabilities, and ability to protect bioactive substances, egg proteins have become ideal carriers for encapsulating and delivering functional substances. The focus of this review is to summarize current advances in using egg proteins as emulsifiers. The effects of influencing factors (temperature, pH, and ionic strength) and various modification methods (physical, chemical, and biological modification) on the emulsifying properties of egg proteins are discussed. In addition, the application of egg proteins as emulsifiers in food products is presented. Through in-depth research on the emulsifying properties of egg proteins, the optimization of their applications in food, biomedical, and other fields can be achieved.

Insight into the mechanisms of combining direct current magnetic field with phosphate in promoting emulsifying properties of myofibrillar protein

This study investigated the combined effects of direct-current magnetic field (DC-MF, 9.5 mT) and tetrasodium-pyrophosphate (TSPP, 1-5 g/L) on emulsified gel properties of porcine myofibrillar protein (MP). Results showed that MP at DC-MF and 3 g/L TSPP had decreased spectrum intensity of UV and fluorescence compared to that without DC-MF, owing to the changes of MP tertiary structure caused by DC-MF, especially tryptophan and tyrosine. The emulsion treated with DC-MF behaved better emulsifying activity and stability than that without DC-MF under such condition. And emulsion had lower creaming index and better storage stability. Gels prepared by this MP emulsion had low porosity and stable structure, accompanying with smaller size and more uniform distribution of oil droplets. Microstructure images showed that gels were covered with microporous structure, which was conducive to the good WHC of the emulsified gels (97.12%). These results showed the feasibility of DC-MF and TSPP in improving MP emulsion/emulsified gel.

Alkali-Induced Protein Structural, Foaming, and Air-Water Interfacial Property Changes and Quantitative Proteomic Analysis of Buckwheat Sourdough Liquor

In this study, the protein structural, foaming, and air-water interfacial properties in dough liquor (DL) ultracentrifugated from buckwheat sourdough with different concentrations of an alkali (1.0-2.5% of sodium bicarbonate) were investigated. Results showed that the alkali led to the cross-linking of protein disulfide bonds through the oxidation of free sulfhydryl groups in DL. The alterations in protein secondary and tertiary structures revealed that the alkali caused the proteins in DL to fold, decreased the hydrophobicity, and led to a less flexible but compact structure. The alkali accelerated the diffusion of proteins and decreased the surface tension of DL. In addition, the alkali notably improved the foam stability by up to 34.08% at 2.5% concentration, mainly by increasing the net charge, reducing the bubble size, and strengthening the viscoelasticity of interfacial protein films. Quantitative proteomic analysis showed that histones and puroindolines of wheat and 13S globulin of buckwheat were closely related to the changes in the alkali-induced foaming properties. This study sheds light on the mechanism of alkali-induced improvement in gas cell stabilization and the buckwheat sourdough steamed bread quality from the aspect of the liquid lamella.

Effects of high-intensity ultrasound on physicochemical and gel properties of myofibrillar proteins from the bay scallop (Argopecten irradians)

Myofibrillar proteins (MPs) have a notable impact on the firmness and flexibility of gel-based products. Therefore, enhancing the gelation and emulsification properties of scallop MPs is of paramount significance for producing high-quality scallop surimi products. In this study, we investigated the effects of high-intensity ultrasound on the physicochemical and gelation properties of MPs from bay scallops (Argopecten irradians). The carbonyl content of MPs significantly increased with an increase in ultrasound power (150, 350, and 550 W), indicating ultrasound-induced MP oxidation. Meanwhile, high-intensity ultrasound treatment (550 W) enhanced the emulsifying capacity and the short-term stability of MPs (up to 72.05 m2/g and 153.05 min, respectively). As the ultrasound power increased, the disulfide bond content and surface hydrophobicity of MPs exhibited a notable increase, indicating conformational changes in MPs. Moreover, in the secondary structure of MPs, the α-helix content significantly decreased, whereas the β-sheet content increased, thereby suggesting the ultrasound-induced stretching and flexibility of MP molecules. Sodium-dodecyl sulfate-polyacrylamide gel electrophoresis and scanning electron microscopy analysis further elucidated that high-intensity ultrasound induced MP oxidation, leading to modification of amino acid side chains, intra- and intermolecular cross-linking, and MP aggregation. Consequently, high-intensity ultrasound treatment was found to augment the viscoelasticity, gel strength, and water-holding capacity of MP gels, because ultrasound treatment facilitated the formation of a stable network structure in protein gels. Thus, this study offers theoretical insights into the functional modification of bay scallop MPs and the processing of its surimi products.