Insight into the mechanism of physicochemical influence by three polysaccharides on myofibrillar protein gelation

Deciphering the structure-function-quality improvement role of starch gels by wheat bran insoluble dietary fibers obtained from different fermentation patterns and its potential mechanisms

Insoluble dietary fiber (IDF) isolated through co-fermented bran from probiotics may improve starch gel-based foods. This work aimed to elucidate the comprehensive impact of different IDF samples (CK, unfermented; NF, natively fermented; YF, yeast fermented; LF, Lactobacillus plantarum fermented; and MF, mix-fermented) and their addition ratios (0.3-0.9%) on gel structure-property function. Results indicated that IDF introduction altered the starch pasting behavior (decreased the viscosity and advanced the pasting time). Also, YF, LF, and MF showed less effect on gel multiscale morphology (SEM and CLSM); however, their excessively high ratio resulted in network structure deterioration. Moreover, FT-IR, XRD, and Raman characterization identified the composite gels interaction mechanisms mainly by hydrogen bonding forces, van der Waals forces, water competition, and physical entanglement. This modulation improved the composite gel water distribution, rheological/stress-strain behavior, textural properties, color, stability, and digestive characteristics. The obtained findings may shed light on the construction and development of whole-grain gel-based food products with new perspectives.

Mechanistic insights into combined effects of continuous microwave heating and tremella powder addition on physiochemical properties of Nemipterus virgatus surimi gel

The physicochemical properties of Nemipterus virgatus surimi gel were investigated, with tremella powder (TP) at concentrations ranging from 0 to 0.5% (w/w) combined with continuous microwave heating (CMH) using water-bath heating (WBH) as control. Results showed that TP addition (0.1%-0.3%, w/w) could significantly enhance the water holding capacity and reduce whiteness and cooking loss, attributed to the changed lateral relaxation time of water distribution. Notably, at 0.3% TP and 80 °C, the gel strength significantly increased by 96.84%, and the hardness, chewiness, and adhesiveness improved, but the quality of surimi decreased above 0.3% TP. The gel network structure was influenced by protein secondary structure composition, especially for increasing β-sheet in Raman spectra, thus promoting the gel microstructure density and uniform protein distribution. These findings offer insights for enhancing surimi gel quality and broadening tremella application in product processing.

Impact of konjac glucomannan with varied deacetylation degrees on plant-based meat analogue: Study on the gel properties, digestibility, and microstructure

Polysaccharides are widely used to improve the quality of plant-based meat analogue (PMA). In this study, four kinds of konjac glucomannan (KG) with different deacetylation degrees (DD) were prepared, namely KG1 (native KG, DD = 0.00 %), KG2 (DD = 41.40 %), KG3 (DD = 80.01 %) and KG4 (DD = 89.07 %), and their effects on the quality of PMA were studied. Results manifested that KG3 improved the hardness (from 3017.16 g to 3307.16 g) and protein digestibility (from 49.65 % to 53.01 %) of PMA without reducing the P21, KG2 and KG4 were less effective than KG3, while KG1 led to a significant decline in the hardness and protein digestibility of PMA. The rheological properties and intermolecular force analysis showed that the partially deacetylated KG was more conducive to improving the G' of the protein system during heating and the proportion of covalent bonds in PMA. These findings suggested that partially deacetylated KG was more promising than native or highly deacetylated KG in PMA. Furthermore, scanning electron microscopy revealed that the morphology of KG gradually changed from fine filaments, to coarse filaments, short filaments and granules as DD increased. This study provides a theoretical basis for the application of partially deacetylated KG in PMA.

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.

Preparation and characterization of a new food-grade Pickering emulsion stabilized by mulberry-leaf protein nanoparticles

BACKGROUND

Food-grade Pickering particles, particularly plant proteins, have attracted significant interest due to their bio-based nature, environmental friendliness, and edibility. Mulberry-leaf protein (MLP) is a high-quality protein with rich nutritional value and important functional properties. It has special amphoteric and emulsifying characteristics, making it valuable for use in Pickering emulsions. This study aimed to investigate the feasibility of using MLP nanoparticles as solid particles to stabilize Pickering emulsions.

RESULTS

The particle size of MLP nanoparticles was less than 300 nm under neutral and alkaline conditions. At pH 9, the zeta potential value reached -34.3 mV, indicating the electrostatic stability of the particles. As ion concentration increased, the particle size of MLP nanoparticles increased, and the zeta potential decreased. Throughout the storage process, no obvious aggregation or precipitation was observed in the dispersion of MLP nanoparticles, indicating strong stability. The particle size of the Pickering emulsion decreased with the increase in protein concentration. When the protein concentration was low, the particles on the oil-water interface became sparse, resulting in poor stability of the prepared emulsion and making it susceptible to aggregation and thus larger particle sizes. Increasing the oil-phase ratio to 70% (v/v) promotes the formation of Pickering emulsions, which exhibit exceptional stability when MLP nanoparticles are fixed at a concentration of 20 mg mL-1.

CONCLUSION

The overall findings indicated that MLP nanoparticles have potential as food-grade materials for Pickering emulsions, marking a novel application of these nanoparticles in the food industry. © 2024 Society of Chemical Industry.

Impact of Flammulina velutipes polysaccharide on properties and structural changes of pork myofibrillar protein during the gel process in the absence or presence of oxidation

The present study aimed to investigate the impact of Flammulina velutipes polysaccharide (FVSP) on the rheological properties and structural alterations of myofibrillar protein (MP) and oxidized MP (OMP), utilizing techniques such as rhehometer, fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). In the unoxidized system, the addition of 5.00% FVSP significantly improved (p < 0.05) the storage and loss moduli of the composite gel and promoted the α-helix to β-sheet transformation. These effects enhanced the protein's gel strength and water-holding capacity (WHC). In the oxidation system, 5.00% FVSP had significant effects (p < 0.05) on repair and improvement of the oxidized MP. These effects inhibited the cross-linking aggregation and degradation of the protein. In addition, the addition of FVSP significantly improved the gel properties of MPs after oxidation (p < 0.05), hindered fracture of the protein gel network structure. In summary, polysaccharides have a substantial effect on the functional characteristics of MP, and FVSP could potentially be applied in meat products.

Effect of sanxan as novel natural gel modifier on the physicochemical and structural properties of microbial transglutaminase-induced mung bean protein isolate gels

Mung bean protein isolate (MBPI) has attracted much attention as an emerging plant protein. However, its application was limited by the poor gelling characteristics. Thus, the effect of sanxan (SAN) on the gelling behavior of MBPI under microbial transglutaminase (MTG)-induced condition were explored in this study. The results demonstrated that SAN remarkably enhanced the storage modulus, water-holding capacity and mechanical strength. Furthermore, SAN changed the microstructure of MBPI gels to become more dense and ordered. The results of zeta potential indicated the electrostatic interactions existed between SAN and MBPI. The incorporation of SAN altered the secondary structure and molecular conformation of MBPI, and hydrophobic interactions and hydrogen bonding were necessary to maintain the network structure. Additionally, in vitro digestion simulation results exhibited that SAN remarkably improved the capability of MBPI gels to deliver bioactive substances. These findings provided a practical strategy to use natural SAN to improve legume protein gels.

Effect of deacetylated konjac glucomannan on the 3D printing properties of minced pork

BACKGROUND

The influences of deacetylated konjac glucomannan (DKGM) at different condition levels (0.0%, 0.5%, 1.0%, 1.5%, 2.0%) on the 3D printing feasibility, printing properties, and the final gel characteristics of minced pork were investigated.

RESULTS

As the DKGM content increased, the printing accuracy and stability initially increased and then declined, and the printing stability and accuracy increased to their highest levels (98.16% and 98.85%) with a 1.5% addition of DKGM. Furthermore, the addition of DKGM significantly enhanced the texture of 3D-printed meat after heat treatments. When the DKGM content reached 1.5%, the hardness and springiness were 1.19 and 1.06 times higher than those of the control group. The results of low-field nuclear magnetic resonance and Raman spectra revealed that DKGM enhanced the amount of bound water in 3D-printed meat and encouraged changes in protein structure. After the addition of DKGM at 1.5%, the contents of bound water and β-sheets were 7.67% and 12.89% higher than those of the control group, respectively, facilitating the development of a better gel network of minced meat during heating.

CONCLUSION

The results indicate that a concentration of 1.5% DKGM is the ideal setting for obtaining the desired rheological properties and textural characteristics (printability) of 3D-printed minced meat products compared to other samples. In addition, the results showed that the addition of DKGM at 1.5% promotes the transition from α-helix to β-folding of proteins during heating, which facilitates the formation of gels. The results of the study contribute to the application potential of minced meat in the field of 3D food printing. © 2024 Society of Chemical Industry.

Rheological, thermal, and structural properties of heat-induced gluten gel: Effects of starch with varying degrees of debranching

This study evaluated the effects of starch with varying degree of debranching on the rheological, thermal, and structural properties of heat-induced gluten gel. As the duration of starch debranching treatment increased from 0 to 8 h, the viscoelasticity of the gel containing debranched starch (DBS) improved. Compared with the gluten gel (G), the gel strength of the G + DBS (8 h) sample increased by 65.2 %. The degradation temperature of gluten was minimally affected by DBS, while the weight loss rate increased by 4.4 %. Furthermore, the α-helical structure of gluten decreased, concomitant with an increase in β-sheet content. Notably, DBS treated for 8 h exhibited more hydrogen bonds with the tyrosine of gluten and triggered disulfide bridge conformation to transition from g-g-g to t-g-g, thereby reducing the stability of the molecular conformation of gluten proteins, as evidenced by the decreased height and width of the molecular chains observed in atomic force microscopy images. Overall, the composite gel structure induced by DBS exhibited a more continuous and homogeneous owing to the improved compatibility between DBS and gluten proteins, favoring the formation of a robust gel. These findings provide valuable insights for utilizing DBS to enhance gluten gel properties.

Effects of Gnaphalium affine Extract on the Gel Properties of •OH-Induced Oxidation of Myofibrillar Proteins

This study aimed to investigate the effect of Gnaphalium affine extract (GAE) (0.04, 0.2 and 1 mg/g protein) on the gel properties of porcine myofibrillar proteins (MPs) in a simulated Fenton oxidation system, using tea polyphenols (TPs) at similar concentrations of 0.04, 0.2, and 1 mg/g protein, respectively, as a contrast. The findings revealed that as the TP concentration increased, the water retention of MP gels decreased significantly (p < 0.05). In contrast, MP gels containing medium and high concentrations of GAE exhibited significantly higher water retention than those with low concentrations of GAE (p < 0.05). When the concentration of GAE was increased to 1 mg/g protein, the strength of MP gels was significantly reduced (p < 0.05) by 33.32% compared with the oxidized control group, suggesting that low and medium GAE concentrations support MP gel formation. A texture profile analysis indicated that an appropriate GAE concentration improved gel structure and texture. Dynamic rheological characterization revealed that low concentrations of TP (0.04 mg/g protein) and low and medium concentrations of GAE (0.04 and 0.2 mg/g protein) strengthened the protein gel system. Conversely, high concentrations of TP and GAE (1.0 mg/g protein) damaged the protein gel system or even promoted the collapse of the gel system. Scanning electron microscopy revealed that higher TP concentrations disrupted the gel, whereas low and medium GAE concentrations maintained a more continuous and complete gel network structure compared with the oxidized control group. This indicates that an appropriate GAE concentration could effectively hinder the destruction of the gel network structure by oxidation. Therefore, based on the obtained results, 0.2 mg/g protein is recommended as the ideal concentration of GAE to be used in actual meat processing to regulate the oxidization and gel properties of meat products.

Gel Properties and Protein Structures of Minced Pork Prepared with κ-Carrageenan and Non-Meat Proteins

Problems with minced pork include water release and low gel strength. This study aimed to investigate the effect of treatments with κ-carrageenan (κ-CAR), egg white powder (EWP), wheat gluten (WG), soy isolate protein (SPI), and a combination of these treatments on the gel properties and protein structures of minced pork. The cooking loss and trapped water within minced pork increased when additives were incorporated; in particular, the SPI group reached 1.31 ± 0.01% and 91.42 ± 0.20%. The hardness and chewiness of minced pork reached their maximum values (38.91 ± 0.80 N, 14.73 ± 0.41 N) when the WG was added. The κ-CAR/WG-minced pork gel network structure was the densest and most stable, characterized by increased hydrophobic interactions, disulfide bonds in the mince gel, and enthalpy value. The α-helix content with κ-CAR/WG treatment decreased from 27% to 7.8%, transforming into other secondary structures. This suggests that the addition of κ-CAR/WG can be a more effective combination for improving the quality of minced pork.

Design of colloid structure to realize gel salt reduction: a review

Excessive consumption of salt is associated with increased incidence of cardiovascular diseases, hypertension, diabetes, and other health issues. However, it is challenging to find appropriate strategies that balance sensory qualities while achieving sodium reduction as salt plays a crucial role in providing desired appearance, texture, and taste. The impact of hydrocolloid properties (addition and type) on saltiness perception were reviewed. Additionally, considering the interactions between food components, both covalent and noncovalent, we propose designing specialized colloidal structures capable of binding sodium ions to enhance salt-taste perception. The effects of hydrocolloids on the physicochemical, structural, and sensory qualities of gel foods are then discussed. Finally, by addressing current issues with low-salt foods and consumer demands, we provide a future outlook for low-salt food development. The selection of suitable hydrocolloids and precise control of the addition are crucial considerations for achieving salt reduction. The interaction between hydrocolloids and other food components can be utilized to design specialized colloidal structures, thereby accomplishing gel-based salt reduction and enhancing properties. This review serves as a theoretical reference for developing healthy, nutritious, and flavorful low-salt foods that can aid in the prevention and mitigation of diseases associated with excessive salt consumption.

Metal cation-induced conformational changes of soybean protein isolate/soybean soluble polysaccharide and their effects on high-internal-phase emulsion properties

BACKGROUND

Metal ions commonly inevitably appear in food products and have adverse effects on high-internal-phase emulsions (HIPEs) foods, but conformational conversion of soybean protein isolate (SPI)/soybean soluble polysaccharide (SSPS) on the interface layer of HIPEs influenced by different metal ions has rarely been reported.

RESULTS

Here, the conformational conversion of SPI/SSPS induced by Na+ , K+ , Ca2+ , Mg2+ and Fe3+ ions and its effects on HIPEs were investigated. After adding the ions to SPI and SPI/SSPS dispersions, the particle size and zeta potential results showed different degrees of flocculation; the zeta potential and Fourier transform infrared spectra indicated that SPI and SPI/SSPS changes in structure involve electrostatic interactions and hydrogen bonding. Moreover, Raman spectra showed that the content of β-sheet of SPI/SSPS HIPEs increased with the addition of Ca2+ , Mg2+ and Fe3+ , suggesting that SPI molecules at the interface formed a more orderly structure. The ultraviolet and fluorescence results showed that the hydrophobic environment of tryptophan and tyrosine residues inside protein molecules played a vital role in the emulsifying stability of SPI.

CONCLUSION

These findings suggested that the SPI/SSPS complexes for food applications were not susceptible to ions, thus ensuring complex stability, showing potential for commercial application in the production of emulsions. © 2023 Society of Chemical Industry.

Phase behavior of the gelation process of myofibrillar protein-curdlan blended system: Discussion based on rheology and gel properties

The phase behavior in protein-polysaccharide blended systems is the main factor affecting the physical properties of composite gels; however, the phase behavior at room temperature and during heated gelation is lacking discussion. In this research, extracted grouper myofibrillar protein (MP) and curdlan (CUR) were used as models for the MP-CUR blended system. The phase behavior of the MP-CUR blended system was analyzed using rheology and microstructure analysis, and the accuracy of the phase behavior analysis was verified by measuring the physical indices such as gel properties of the MP-CUR composite gels. At room temperature, MP and CUR showed good co-solubility, so the blended system with 0.8% CUR content obtained the best apparent viscosity, structural recoverability, and other rheological properties. After heating gelation, MP and CUR had strong thermodynamic unaffinity leading to phase separation, and the best storage modulus was obtained for the MP-CUR blended system with 0.6% CUR content. Therefore, it is concluded that 0.6% CUR content is the critical concentration for the MP-CUR blended system. The results were also confirmed by the best gel properties of 0.6% CUR composite gel when the physical properties of the composite gel were determined. The phase behavior evaluation was used to determine the appropriate polysaccharide concentrations as a means to improve the physicochemical properties of the composite gels and to exploit the value of polysaccharides in protein-based food applications.

Exploring the versatility of carbohydrates in surimi and surimi products: novel applications and future perspectives

Carbohydrate is one kind of the most important additives in the production of surimi and surimi products, mainly due to its wide range of sources and superior functionality. In recent years, new carbohydrates (oligosaccharides and polysaccharides) have been gradually applied in the production of surimi and surimi products which is mainly driven by consumer requirement on nutritional and the flavors or taste quality and producer requirement on extending the shelf life, like low calorie intake, dietary fiber enrichment, rich taste and improvement of antioxidant properties. Besides anti-freezing and improvement in gelling ability, novel functionalities have been explored such as fat substitution, improving flavor, antibacterial effect, antioxidant effect and improving three-dimensional printability. With an in-depth study of the mechanism of carbohydrate improving the qualities of surimi and surimi products, the application of carbohydrates in surimi would be more effective. Therefore, this review summarizes the new carbohydrates applied in the processing of surimi and surimi products, and their novel functionalities. Additionally, progress of the research on the mechanism of carbohydrate improving the qualities of surimi is also reviewed. © 2023 Society of Chemical Industry.

Comparative analysis of soluble and insoluble dietary fiber on improving the gelation performance and fishy odors of silver carp surimi

This work investigated the effects and mechanisms of soluble and insoluble dietary fiber (SDF and IDF) on the gelation performance and fishy odors of silver carp surimi. The results showed that the gel properties of surimi increased and then decreased with increasing SDF content, and the best gel properties were achieved at 1 wt% SDF. The gel strength, elasticity and deformation resistance of surimi increased in a dose-dependent manner as affected by IDF, but its effect on viscosity and recovery ratio was similar to SDF. Moreover, 2 wt% SDF and 1 wt% IDF reduced the content and odor activity value (OAV) of most fishy compounds in surimi, and the latter was superior to the former. The rheological characteristics indicated that SDF affected the thermal gelation properties of surimi mainly through filling, concentration and volume exclusion, and IDF mainly through filling, concentration and intermolecular interactions between IDF and myofibrillar protein. Additionally, SDF and IDF inhibited the release of fishy odors by improving the gel network structure and their adsorption, but more SDF (2 wt%) promoted the formation of escape channels for odors release. In summary, 1 wt% IDF could simultaneously improve the gelation performance and fishy odors of silver carp surimi.

Electron beam irradiation induced aggregation, structural and functional changes of soybean 11S globulin

This study investigated the effects of different irradiation doses of an electron beam (e-beam) (0, 2, 4, 6, 8, and 10 kGy) on the structure, emulsification, foaming, and rheological and gel properties of soybean 11S globulin. The irradiation treatment at 4 and 6 kGy significantly increased the solubility, surface hydrophobicity, disulfide bonding, and ζ-potential of 11S globulin, decreased the particle size of the protein solution, and effectively improved the emulsifying activity and foaming stability of the protein solution. Moreover, irradiation induced moderate cross-linking and aggregation of the proteins, thereby increasing the apparent viscosity and shear stress of the protein solution. In addition, the low-field NMR and microstructure analysis results revealed that protein gels formed a dense and homogeneous three-dimensional mesh structure after irradiation (6 kGy), along with increased content of bound water (T2b) and water not readily flowable (T21) and a decrease content of free water (T22). Overall, our results confirmed that e-beam irradiation could significantly improve the physicochemical properties of soybean 11S globulin. Our study thus provides a new technical means for the application of electron beam irradiation technology toward protein modification and broadens the high-value utilization of soybean 11S globulin in the food processing industry.

Impact of Corn Starch Molecular Structures on Texture, Water Dynamics, Microstructure, and Protein Structure in Silver Carp (Hypophthalmichthys molitrix) Surimi Gel

This study systematically investigates the impact of corn starch molecular structures on the quality attributes of surimi gel products. Employing molecular analyses to characterize corn starch, three amylopectin fractions (A, B1, and B2), categorized by the degree of polymerization ranges (6 < X ≤ 12, 12 < X ≤ 24, and 24 < X ≤ 36, respectively) were specifically focused on. The surimi gel quality was comprehensively assessed through texture profile analysis, nuclear magnetic resonance, scanning electron microscopy, stained section analysis, and Fourier transform infrared spectroscopy. Results indicated the substantial volume expansion of corn amylopectin upon water absorption, effectively occupying the surimi gel matrix and fostering the development of a more densely packed protein network. Starch gels with higher proportions of A, B1, and B2 exhibited improved hardness, chewiness, and bound water content in the resultant surimi gels. The weight-average molecular weight and peak molecular weight of corn starch showed a strong positive correlation with surimi gel hardness and chewiness. Notably, the secondary structure of proteins within the surimi gel was found to be independent of corn starch's molecular structure. This study provides valuable insights for optimizing formulations in surimi gel products, emphasizing the significance of elevated A, B1, and B2 content in corn starch as an optimal choice for crafting dense, chewy, water-retaining surimi gels.

Effects and mechanisms of different κ-carrageenan incorporation forms and ionic strength on the physicochemical and gelling properties of myofibrillar protein

The present work was aimed to investigate the effects of incorporating κ-carrageenan into myofibrillar protein (MP) as a dry powder (CP) or water suspension (CW) and the ionic strength (0.3 or 0.6 M sodium chloride (NaCl)) on MP physicochemical and gelling properties. The results indicated that incorporation of either CP or CW significantly increased turbidity, surface hydrophobicity, particle size and rheological behaviour of MP. In contrast, the protein solubility and fluorescence intensity of MP decreased when added with each form of κ-carrageenan (P < 0.05). These observed effects improved MP's gelling properties and produced a more compact and homogenous gel network after heating treatment. Moreover, the addition of CW rendered higher gel strength, water holding capacity and intermolecular interactions, such as ionic, hydrogen and disulphide bonds and hydrophobic interactions in MP gel compared with those added with CP, especially for 0.3 M NaCl (P < 0.05). Furthermore, addition of CW significantly decreased the α-helix content of MP gels (P < 0.05), which mainly contributing to the transformation from a random structure to an organised configuration. In addition, a higher NaCl concentration (0.6 M) enhanced the gelling properties of MP gels compared with 0.3 M NaCl concentration in the presence of each form of κ-carrageenan. Therefore, our present study indicated that incorporation form of κ-carrageenan and ionic strength have distinctive effects on regulating physicochemical characteristics and improves gelling properties of MP.

Salmon protein gel enhancement for dysphagia diets: Konjac glucomannan and composite emulsions as texture modifiers

The growing prevalence of dysphagia among the aging population presents a significant challenge. Many highly nutritious foods, like salmon, are often unsuitable for the elderly due to their firm texture when heated. To address this concern, a combination of salmon myofibrillar protein (SMP), Konjac glucomannan (KGM), and different emulsion fillers-such as oil droplets, octenyl succinic anhydride (OSA)-modified potato starch emulsion, and high methoxylated pectin (HMP) emulsions-was selected to enhance the network of salmon protein gels with the aims to create potential applications as dysphagia-friendly foods. The International Dysphagia Dietary Standardization Initiative (IDDSI) test indicated that all gel samples were classified as level 5. The OSA-SMP-KGM gel exhibited notably higher cohesiveness (P < 0.05), reduced adhesion, and enhanced mouthfeel. The OSA-SMP-KGM gel exhibited a smooth surface and excellent water retention (92.4 %), rendering it suitable for individuals with swallowing difficulties, particularly those prone to experiencing dry mouth. The yield stress of OSA-SMP-KGM gel was 594.14 Pa and stable structure was maintained during chewing and swallowing (γe/γv = 62.5). This study serves as a valuable reference for developing salmon-based products that are not only highly nutritious but also fulfill the criteria for a desirable swallowing texture.

Promising effects of β-glucans on gelation in protein-based products: A review

Gel property is one of the most important abilities to endow protein-based food products with a unique texture and higher overall acceptability. Cereal β-glucan (BG) is widely applied in protein-based products to improve the stability of the protein gel by increasing water holding capacity, storage modulus (G'), loss modulus (G") and linking with protein through more exposed sites, making it easier to form a stronger three-dimensional gel network. In addition, BG may be cross-linked with proteins, or physically embedded and covered in protein network structures, interacting with proteins mainly through non-covalent bonds including hydrogen bonding and electrostatic interaction. Furthermore, the transition of the α-helix to the β-form in the protein secondary structure also contributes to the stability of the protein gel. The practical applications of BG from different cereals in protein-based products are summarized, and the rheological properties, microstructure of protein as well as the underlying interaction mechanisms between BG and protein are discussed. In conclusion, cereal BG is a promising polysaccharide in developing nutritional protein-based products with better sensory properties.

Effects of konjac glucomannan as a freeze-denaturation inhibitor or binder on the physiochemical properties of heat-induced gel of freeze-dried duck blood

During freeze-drying, the degradation or eutectic melting of duck blood proteins can reduce the quality of duck blood gels. However, the interaction between proteins and polysaccharides during drying can improve protein-based gel quality. Therefore, here, we investigated the physicochemical properties of heat-induced gels of freeze-dried duck blood (FDB) and FDB with different proportions of the polysaccharide konjac glucomannan (KG), which serves as a freeze-denaturation inhibitor agent (FDA) or binder (BG). The pH and water-holding capacity (WHC) of FDB + KG gels were higher than those of FDB gel without KG (control). Especially, the WHC increased from 11.00% for control to 55.65% for FDB gel with 1% KG as a BG. Consequently, cooking loss and texture parameters of FDB + KG gels decreased. The hardness of control was 2.14 kg, which significantly reduced to 0.12-0.87 kg with KG addition. The highest carbonyl content was observed in control gel, and the thiobarbituric acid reactive substance content was reduced by the addition of 1% KG as an FDA (T1) or 0.8% KG as an FDA with 0.2% KG as a BG (T2) (p < 0.05). These changes might be induced by the alteration of tertiary structure and thermodynamic stability of gels. In conclusion, 1% KG can be used as an FDA to improve the quality and physicochemical properties of heat-induced gels of FDB. Optimized FDB gels with KG can be used as an innovative food ingredient to fortify nutrition and develop special dietary purposes.

Effects of Dextran on the Gel Properties of Faba Bean Protein Isolates Prepared Using Different Processes

The properties of faba bean (Vicia faba L.) protein isolate (FPI) gels depend on their starting protein material and can be modulated by the addition of polysaccharides. In order to investigate the interplay between these two factors, commercial FPI (FPI1) and FPI prepared in-house (FPI2) were used to fabricate glucono-delta-lactone-induced gels, with or without dextran (DX) addition. FPI1 exhibited lower solubility in water and a larger mean particle size, likely because it experienced extensive degradation due to the intense conditions involved in its preparation. The FPI1 gel showed a similar water-holding capacity as the FPI2 gel; however, its hardness was lower and viscoelasticity was higher. After DX addition, the hardness of both FPI gels decreased, while their water-holding capacity increased. Interestingly, DX addition decreased the viscoelasticity of the FPI1 gel but enhanced the viscoelasticity of the FPI2 gel. The microstructural analysis demonstrated that the density of the aggregation network decreased in the FPI1 gel after DX addition but increased in the FPI2 gel. This was consistent with the changes observed in the dominant protein interaction forces in these gels after DX addition. Overall, these findings have the potential to guide ingredient selection for the tailored preparation of FPI gels.

Using nanocellulose to improve heat-induced cull cow meat myofibrillar protein gels: effects of particle morphology and content

BACKGROUND

Enhancing protein gel properties is essential to improve the texture of meat products. In this study, the improvement effects of three types of nanocellulose, i.e. rod-like cellulose nanocrystals (CNC), long-chain cellulose nanofibers (CNF) and spherical cellulose nanospheres (CNS) with different concentrations (1, 3, 5, 10, 15 and 20 g kg-1 ), on cull cow meat myofibrillar protein (MP) gel were investigated.

RESULTS

Compared with needle-shaped CNC and spherical CNS, the addition of 10 and 20 g kg-1 long-chain CNF had the most significant improvement effect on gel hardness and water-holding capacity, respectively (P < 0.05), increasing to 160.1 g and 97.8%, respectively. In addition, the incorporation of long-chain CNF shortened the T2 relaxation time and induced the formation of the densest network structure and promoted the phase transition of the gel. However, excessive filling of nanocellulose would destroy the structure of the gel, which was not conducive to the improvement of gel properties. Fourier transform infrared results showed that there was no chemical reaction between the three nanocellulose types and MP, but the addition of nanocellulose was conducive to gel formation.

CONCLUSION

The improvement of MP gel properties by adding nanocellulose mainly depends on its morphology and concentration. Nanocellulose with higher aspect ratio is more beneficial to the improvement of gel properties. For each nanocellulose type, there is an optimal addition amount for MP gel improvement. © 2023 Society of Chemical Industry.

Mechanism on the Synergistic Gelation of the Myofibrillar Protein Composite Gel Enhanced by "Clean-Label" Skin Functional Protein Powders

The concept of healthiness and sustainability has promoted the innovation and development of "clean-label" products. Herein, this study aims to explore the influence mechanism of "clean label" skin protein powder (FPP) on the gelation properties of myofibrillar proteins (MPs). Specifically, the addition of FPP (0.2-4.0%) can improve the water holding capability and texture properties of MP composite gels. When the FPP concentration is over 1.0%, the composite gels exhibit no significant water loss during centrifugation. Dynamic rheology and sodium-dodecyl sulfate-polyacrylamide gel electrophoresis results revealed that FPP can slow the aggregation and denaturation of myosin and promote the formation of disulfide bonds between myofibril proteins, thus forming a stable network structure. Structural observation revealed that FPP can fill into the MP gel and lead to the formation of compact gel structures. Besides, with the increase of FPP concentration, the chemical forces involved in structural stabilization change significantly. Specifically, hydrophobic interaction and hydrogen bonding are the dominant forces at a lower FPP concentration (0.2 and 0.4%), while the ionic bond and disulfide bond are the dominant forces at a higher concentration. Overall, this work demonstrated that FPP can significantly improve the gel functionality of MP by altering the gel structure and strengthening the molecular forces.

Effect of material temperatures on quality of fish vermicelli, a noodle-shaped surimi product

The study investigated the effect of material temperatures (15°C, 20°C, 25°C, 30°C, 35°C, and 40°C) on the quality of fish vermicelli (FV) in terms of morphological, cooking, textural, microstructural, and water distribution properties. Results showed that as the material temperatures increased, the surface smoothness, cooking characteristics, and textural properties of FV significantly increased, followed by a decrease. Especially, when the material temperatures were 25°C and 30°C, the FV samples exhibited denser and more continuous gel networks with more embedded starch particles, resulting in decreased cooking loss and improved tensile strength. However, at material temperatures above 35°C, the continuity of the protein phase was disrupted by overswelling starch granules, leading to the worst cooking characteristics and textural properties. Especially at material temperatures of 40°C, the water holding capacity, hardness, and springiness of FV decreased by 25.59%, 73.48%, and 47.98%, respectively, compared to the samples at 25°C. Additionally, the cooking loss increased by 91.40%. In conclusion, the critical material temperature for the quality deterioration of FV was 35°C, and it was recommended to produce FV below this temperature.

Double network hydrogels: Design, fabrication, and application in biomedicines and foods

Research on the design, fabrication, and application of double network (DN) hydrogels, assembled from pairs of polymers, has grown recently due to their unique structural, physicochemical, and functional properties. DN hydrogels can be designed to exhibit a broader range of functional attributes than single network (SN) ones, which extends their applications in various fields. There has been strong interest in the development of biopolymer DN hydrogels because of their environmental, sustainability, and safety benefits. However, there is limited knowledge on the formation and application of these novel materials. This article reviews the principles underlying the design and fabrication of hydrogels using different crosslinking approaches, including covalent and/or non-covalent bonding, and the formation mechanisms, network structures, and functional attributes of different DN hydrogels. The impact of polymer composition, structural organization, and bonding on the mechanical and functional properties of DN hydrogels is reviewed. Potential applications of these hydrogels are highlighted, including in tissue engineering, biomedicines, and foods. The functional attributes of DN hydrogels can be tailored to each of these applications by careful selection of the biopolymers and crosslinking mechanisms used to assemble them. Finally, areas where further research are needed to overcome the current limitations of DN hydrogels are highlighted.

Modification of low-salt myofibrillar protein using combined ultrasound pre-treatment and konjac glucomannan for improving gelling properties: Intermolecular interaction and filling effect

The quality deterioration of low-salt meat products has been gained ongoing focus of researchers. In this study, konjac glucomannan (KGM) was used to alleviate the finiteness of ultrasound treatment on the quality improvement of low-salt myofibrillar protein (MP), and the modification sequence was also investigated. The results revealed that the single and double sequential modification by utilizing KGM and ultrasound significantly influenced the gelation behavior of low-salt MPs. The uniform MP-KGM mixture formed by a single ultrasound treatment had limited protein unfolding, resulting in relatively weak intermolecular forces in the composite gel. Importantly, ultrasound pre-treatment combined with KGM modification promoted the unfolding and moderate thermal aggregation of proteins and remarkably improved the rheological behaviors and gel strength of the composite gel. This result could also be corroborated by the highest percentage of trans-gauche-trans conformation of SS bridges and maximum β-sheet proportion. Furthermore, molecular dynamic simulation and molecular docking elucidated that the hydrogen bond length between protein and KGM was shortened after ultrasound pre-treatment, which was the molecular basis for the enhanced intermolecular interactions. Therefore, ultrasound pre-treatment combined with KGM can effectively improve the gelling properties of low-salt MPs, providing a practical method for the processing of low-salt meat products.

Effect of Flammulina velutipes polysaccharides on the physicochemical properties of catfish surimi and myofibrillar protein oxidation during frozen storage

This study investigated the effect of Flammulina velutipes polysaccharides (FVPs) on the myofibrillar protein (MP) oxidation protein and physicochemical properties of catfish surimi during 75 days of frozen storage at -18°C. FVP was added to surimi at 1%, 1.5%, and 2%, respectively; the degree of MP oxidation and the physicochemical properties of the surimi were investigated, and the microstructure of the surimi was observed by scanning electron microscopy (SEM). The results showed that the carbonyl content and the thiobarbituric acid reactive substances (TBARS) in the FVP groups were lower than those in the CK group (the blank surimi). In comparison, the total sulfhydryl content, solubility, and Ca2+-ATPase activity were higher than those in the CK group after 75 days of storage. The addition of FVP significantly increased the water-holding capacity (WHC), gel strength, elastic modulus (G'), and loss modulus (G") of surimi, and made the gel of surimi have stronger continuity and a denser structure. Therefore, FVP has a better cryoprotective effect on surimi. It improves the quality of surimi, decreases MP oxidation, and reduces lipid and water loss during frozen storage. The anti-freezing effect of FVP added at 2% was similar to that of commercial protectants (4% sucrose and 4% sorbitol).

Elucidation of interactions between myofibrillar proteins and κ-carrageenan as mediated by NaCl level: Perspectives on multiple spectroscopy and molecular docking

The present study was aimed to investigate the intermolecular interaction between myofibrillar proteins (MP) and κ-carrageenan (KC) as mediated by KC concentration (0.1, 0.2, 0.3, and 0.4 %, w/w) and NaCl levels (0.3 and 0.6 M) based on the multiple spectroscopy and molecular docking. The results showed that the incorporation of KC increased the turbidity, zeta-potential, and surface hydrophobicity of MP-KC mixed sols with a dose-dependent manner, as well as significantly decreasing the protein solubility (P < 0.05), which indicated that the interaction between KC and MP promoted the expansion of protein structure and exposed more hydrophobic groups. Fluorescence spectra result revealed that the interaction between MP and KC was a static quenching in the fluorescence quenching process, which affected the aromatic amino acids residue microenvironment of MP. Moreover, the existence of KC decreased the α-helix contents of MP (P < 0.05), contributing to the transformation from random structure to organized configuration of MP. In addition, molecular forces, the molecular docking and thermodynamic parameters indicated that hydrophobic interactions, van der Waals force, and hydrogen bonding were considered as the main interaction forces between MP and KC. Furthermore, 0.6 M NaCl level rendered higher solubility and particle size, as well as lower turbidity and the surface hydrophobicity of MP-KC mixed sols than those with 0.3 M NaCl level (P < 0.05), which promoted the unfolding of MP molecule and subsequently increased the numbers of binding sites between MP and KC, facilitating the intermolecular interactions between MP and KC in mixed sols.

Discovery of Potential Protein Markers Associated with Quality Characteristics of Antarctic Krill (Euphausia superba) Surimi Gel

Antarctic krill are a consumption resource with great exploitation potential. However, the poor gel properties of Antarctic krill meat seriously limit its high-value application. In the present study, the quality characteristics and proteome changes of the κ-/ι-carrageenan-Antarctic krill surimi gel were systematically analyzed and compared. In addition, the transcriptome sequencing of Antarctic krill was carried out, which filled the gap in the Antarctic krill database. Higher molecular forces (disulfide bond and hydrophobic interaction) and the degree of network cross-linking significantly promoted the formation of κ/ι-carrageenan-Antarctic krill surimi compared to that of Antarctic krill surimi. This is the first study to investigate and map potential protein markers for quality characteristics of Antarctic krill surimi based on mass spectrometry-based label-free quantitative proteomics. The results could provide a theoretical reference for the quality control of Antarctic krill during application.

Insoluble dietary fibers from Lentinus edodes stipes improve the gel properties of pork myofibrillar protein: A water distribution, microstructure and intermolecular interactions study

This paper investigated the effects of Lentinus edodes stipes insoluble dietary fiber (LESIDF, 0%-3.0%) on the quality and microscopic properties of pork myofibrillar protein (MP) gels. The results showed that the water holding capacity and gel strength of composite gels enhanced with increasing LESIDF (1.0%-2.5%), and reached the maximum at the level of 2.5%-3.0%. Disulfide and non-disulfide covalent bonds were major chemical forces maintaining the 3D network of LESIDF-MP composite gels. LESIDF also promoted the formation of ionic and hydrogen bonds, confirmed by the self-assembly of β-sheets to α-helices, leading to a compact gel network structure. The observation of paraffin section revealed that LESIDF could capture more water molecules in gels, which was consistent with the transformation of free water to immobilized water. Overall, the optimal addition of LESIDF was 2.5%-3.0%, which provided a good strategy for LESIDF as an agricultural by-product to improve the quality of gel meat products.

A comparison of the impacts of different polysaccharides on the sono-physico-chemical consequences of ultrasonic-assisted modifications

This study aimed to examine the sono-physico-chemical effects of ultrasound (UND) and its impact on the conjugate rates of morin (MOI) following the addition of polysaccharides in various conditions. In comparison to the control group, the incorporation of quaternary ammonium chitosan decreased the rate of MOI conjugation by 17.38%, but the addition of locust bean gum enhanced the grafting rate by 29.89%. Notably, the highest degree of myofibrillar protein (MRN) unfolding (fluorescence intensity: 114435.50), the most stable state (-44.98 mV), and the greatest specific surface area (393.06 cm2/cm3) were observed in the UMP/LBG group. The outcomes of atomic force microscopy and scanning electron microscopy revealed that the inclusion of locust bean gum led to a different microscopic morphology than the other two polysaccharides, which may be the primary cause of the strongest sono-physico-chemical effects of the system. This work demonstrated that acoustic settings can be tuned based on the characteristics of polysaccharides to maximize the advantages of sono-physico-chemical impacts in UND-assisted MOI processing.

Carboxymethylation modification, characterization of dandelion root polysaccharide and its effects on gel properties and microstructure of whey protein isolate

In the present study, a native polysaccharide (DP) with sugar content of 87.54 ± 2.01 % was isolated from dandelion roots. DP was chemically modified to obtain a carboxymethylated polysaccharide (CMDP) with DS of 0.42 ± 0.07. DP and CMDP were composed of the same six monosaccharides including mannose, rhamnose, galacturonic acid, glucose, galactose, and arabinose. The molecular weights of DP and CMDP were 108,200 and 69,800 Da, respectively. CMDP exhibited more stable thermal performance and better gelling properties than DP. The effects of DP and CMDP on the strength, water holding capacity (WHC), microstructure, and rheological properties of whey protein isolate (WPI) gels were investigated. Results showed that CMDP-WPI gels had higher strength and WHC than DP-WPI gels. With the addition of 1.5 % CMDP, WPI gel had a good three-dimensional network structure. The apparent viscosities, loss modulus (G"), and storage modulus (G') of WPI gels were increased with the polysaccharide addition, the influence of CMDP was remarkable compared to DP at the same concentration. These findings suggest that CMDP may be used as a functional ingredient in protein-containing food products.

Impact of Insoluble Dietary Fiber and CaCl2 on Structural Properties of Soybean Protein Isolate-Wheat Gluten Composite Gel

The effect and mechanism of soybean insoluble dietary fiber (SIDF) (0~4%) and CaCl₂ (0~0.005 M) on the properties of soybean protein isolate (SPI)-wheat gluten (WG) composite gel were studied. It was revealed that the addition of insoluble dietary fiber (1~2%) increased the strength and water-holding capacity (WHC) of the composite gel (p < 0.05) and enhanced the gel network structure compared with the control. WHC and LF-NMR showed that the water-binding ability of the gel system with only 2% SIDF was the strongest. The addition of excessive SIDF increased the distance between protein molecules, impeded the cross-linking of protein, and formed a three-dimensional network with low gel strength. The infrared spectrum and intermolecular force indicated that the interaction between SIDF and SPI were mainly physical, and the hydrophobic interaction and disulfide bond were the main forces in the gel system. The addition of CaCl₂ can increase the critical content of gel texture destruction caused by SIDF, and the gel strength attained its peak at 3% SIDF, indicating that appropriate CaCl₂ improved gel structure weakening caused by excessive SIDF. This study provides insights in enhancing the production of multi-component composite gel systems.

Changes in the Quality of Myofibrillar Protein Gel Damaged by High Doses of Epigallocatechin-3-Gallate as Affected by the Addition of Amylopectin

This work investigated the improvement of amylopectin addition on the quality of myofibrillar proteins (MP) gel damaged by high doses of epigallocatechin-3-gallate (EGCG, 80 μM/g protein). The results found that the addition of amylopectin partially alleviated the unfolding of MP induced by oxidation and EGCG, and enhanced the structural stability of MP. Amylopectin blocked the loss of the free amine group and thiol group, and increased the solubility of MP from 7.0% to 9.5%. The carbonyl analysis demonstrated that amylopectin addition did not weaken the antioxidative capacity of EGCG. It was worth noting that amylopectin significantly improved the gel properties of MP treated with a high dose of EGCG. The cooking loss was reduced from 51.2% to 35.5%, and the gel strength was reduced from 0.41 N to 0.29 N after adding high concentrations of amylopectin (A:E(8:1)). This was due to that amylopectin filled the network of MP gel after absorbing water and changed into a swelling state, and partially reduced interactions between EGCG and oxidized MP. This study indicated that amylopectin could be used to increase the polyphenol loads to provide a more lasting antioxidant effect for meat products and improve the deterioration of gel quality caused by oxidation and high doses of EGCG.

Characteristics and potential application of myofibrillar protein from golden threadfin bream (Nemipterus virgatus) complexed with chitosan

The strategies to broaden the applications of proteins involve their modification with polysaccharides. However, the characteristics and application of myofibrillar proteins (MPs) from golden threadfin bream (Nemipterus virgatus) complexed with chitosan (CS) are still unclear. Therefore, the characteristics of MPs complexed with CS and their application were investigated at different MP/CS ratios (100:0-80:20 (w/w)). The turbidity of MP/CS complexes was small at the MP/CS ratio of 95:5 (w/w). Besides, CS addition induced changes in MP structure to make it hydrophilic. Secondary structure analysis showed that α-helix and β-turn interconverted with β-sheet and random coil after the addition of CS. Additionally, the thermal stability of MP/CS mixtures enhanced after the addition of CS and the MP/CS mixtures at the ratio of 95:5 (w/w) had a relatively compact structure. High internal phase emulsions (HIPEs) prepared at the MP/CS ratio of 95:5 (w/w) were relatively stable compared to those at the other ratios. Consequently, MP/CS mixtures at suitable ratios possess the potential ability to prepare HIPEs. These results exhibit that MP/CS mixtures may be applied for constructing food-graded emulsion delivery systems with a high internal phase in the food industry.

Hybrid Spreadable Cheese Analogues with Faba Bean and Mealworm (Tenebrio molitor) Flours: Optimisation Using Desirability-Based Mixture Design

Hybrid products could help bridge the gap as new alternative diets emerge in response to the demand for less animal protein, while recent studies suggest that the Western population is not yet ready to fully embrace an alternative protein-based diet. This study used a desirability-based mixture design to model hybrid spreadable cheese analogues (SCAs). The design combined milk protein concentrate (MPC), Tenebrio molitor (IF) and faba bean (FBP) flours, representing 7.1% of the formula. Nine SCAs with different MPC/FBP/IF ratios were formulated. Incorporating the IF negatively impacted the desirable texture properties. The FBP flour improved the texture (increasing firmness and stickiness and decreasing spreadability), but only when combined with MPC. Sensory analysis showed that hybrid SCAs (≤50% MPC) C2, C7 and C9 had a more characteristic cheesy flavour than the commercial plant-based reference, and sample C2 had a texture profile similar to the dairy reference. Samples containing IF (C7 and C9) showed a better flavour profile than that without IF (C2). The SCAs had higher protein and lower saturated fat, starch and sugar content than commercial analogues. The study suggests that incorporating alternative proteins in hybrid products can be an effective approach to reduce animal protein content, specifically dairy, in food formulations.

In-Depth Insight into the Mechanism of Incorporation of Abelmoschus manihot Gum on the Enhancement of Gel Properties and In Vitro Digestibility of Frankfurters

This study aimed to investigate the effects of different concentrations (0.1, 0.2, 0.3, 0.4, and 0.5% w/w) of Abelmoschus manihot gum (AMG) on the gel properties and in vitro digestibility of frankfurters. The results indicated that AMG incorporation significantly enhanced the emulsion stability and texture of frankfurters, as well as the dynamic rheological characteristics of raw meat batter, with the optimal concentration being 0.3% (p < 0.05). Furthermore, hydrogen bonds and disulphide bonds were the main molecular forces of the frankfurters in the presence of AMG. Microstructural images showed that more uniform and dense microstructures of frankfurters were formed due to AMG supplementation. In addition, AMG incorporation significantly increased the in vitro protein digestibility of frankfurters as the level of addition increased (p < 0.05). In conclusion, our results provided critical information for the practical application of AMG in the production of emulsified meat products.

Myofibrillar protein can form a thermo-reversible gel through elaborate deamidation using protein-glutaminase

BACKGROUND

Novel thermo-reversible hydrogels that undergo gelation in feedback to external stimuli have numerous applications in the food, biomedical, and functional materials fields. Muscle myofibrillar protein (MP) has long been known for thermally irreversible gelation. Once the reversible gelation of MP is achieved, its scope for research and application will expand.

RESULTS

The work reported here achieved, for the first time, a thermo-reversible MP gelation by elaborate deamidation using protein glutaminase (PG). The protein concentration and PG reaction time within windows of 1.0-2.5% and 8 h or 12 h were observed to be vital for creating thermo-reversible gels. The gel strength increased with protein concentration. The gel displayed a perforated lamellar microstructure, which resulted in a high water-holding capacity. The rheological results revealed the thermo-reversibility of the gel was robust for up to five cycles of heating and cooling. The thermally reversible gelation is closely related to the reversible assembly between individual α-helix and helical coiled coil. Hydrophobic interactions proved to be predominantly involved in the formation and stabilization of the gel network structure.

CONCLUSION

This work increases the scope of research into the thermo-responsive behavior of MP-based gel. It can foster advances in research into the applications of muscle proteins and into the use of PG as a novel ingredient in the food industry. © 2022 Society of Chemical Industry.

Improvement on gel properties of myofibrillar protein from chicken patty with potato dietary fiber: Based on the change in myofibrillar protein structure and water state

Influence of potato dietary fiber (PDF) on myofibrillar protein (MP) structure, aggregation behavior, and gel properties of chicken patty was evaluated. The Raman spectroscopy results indicated that the α-helix content decreased by 21.9 %, while β-sheets content increased by 45.0 % in 3.0 % PDF sample compared with the control (P < 0.05), and aliphatic residues cross-linked. Particle size, turbidity, and the roughness of MP surface morphology increased, whereas the zeta-potential of MPs decreased with PDF increasing. The gelation process of MP with PDF proceeded at a fast rate and their elasticity and viscosity were high as determined by dynamic rheology. Gels with 3.0 % PDF exhibited significantly enhanced gel strength and a high WHC, which increased by 44.20 % and 22.5 %, respectively, compared with the control, PDF inhibited the transformation of immobilized water to free water and eliminated the water channels during heating as well as formed a more uniform and denser microstructure. Therefore, PDF can be a potential ingredient for improving the quality of processed meat products.

Consolidating the gelling performance of myofibrillar protein using a novel OSA-modified-starch-stabilized Pickering emulsion filler: Effect of starches with distinct crystalline types

Starch-stabilized Pickering emulsions were employed as a novel particulate filler in myofibrillar protein (MP)-based gels for improving the gelling characteristics. The role of emulsions prepared by native starches (NS) with distinctive crystalline types (i.e., A-type waxy corn starch, B-type potato starch, and C-type pea starch) and their OSA-modified counterparts (A-OS, B-OS, C-OS) in the gelling performance was evaluated and compared with MP-stabilized-emulsion. Compared with MP-emulsion, starch-emulsion caused substantial increases in the gelling properties, notably for OSA-starch emulsions. Herein, A-OS exhibited up to 1.26-, 5.3-, and 2.9-fold increments in storage modulus, gel strength, and water holding capacity relative to pure MP gel, respectively, higher than B-OS and C-OS. Moreover, light microscopy evinced a more compact gel network filled with smaller and uniform oil droplets when A-OS emulsions were incorporated into the gels. The addition of OSA-starch emulsions, especially A-OS emulsion, facilitated the protein conformational conversion from α-helix to β-sheet and caused a marked reduction of free sulfhydryls in the gels; yet, the chemical forces that stabilized the gels altered, where remarkable reinforcements in hydrogen bond and hydrophobic interaction were detected, in support of the construction of splendid MP gels. Hence, OSA-starch emulsions show promise as functional components in meat products.

Contribution of κ-/ι-carrageenan on the gelling properties of shrimp myofibrillar protein and their interaction mechanism exploration

BACKGROUND

The contribution and mechanism of κ-/ι-carrageenan (CG) with different hydration characteristics on the gelling properties of shrimp myofibrillar protein (MP) gelation was studied.

RESULTS

The gel strength, water-holding capacity and viscoelastic properties of MP gels were significantly enhanced by 1.0% κ-/ι-CG (P < 0.05), but the microstructure showed that excessive carrageenan caused fragmentation of the gel network and a corresponding decrease in gel properties. Compared to MP-ιCG, MP-κCG showed larger breaking force and shorter breaking distance, thus enhancing the hardness and brittleness of the gel, which might be ascribed to a reinforced network skeleton and a tighter binding of κCG-myosin. However, MP-ιCG stabilized more moisture in the gel network, thereby improving the tenderness of the gel, which might be related to the electrostatic repulsion observed between the sulfate groups of ιCG and the myosin observed by molecular docking. In addition, the β-sheet content and intermolecular interactions might be positively correlated with gel properties.

CONCLUSION

In this study, a composite gel system was constructed based on the interaction of MP and CG. The quality differences of two kinds of CG-MP gels were clarified, which will provide guidance for the application of different kinds of carrageenan and the development of recombinant meat products with specific quality. © 2022 Society of Chemical Industry.

Modulating the structure of lamb myofibrillar protein gel influenced by psyllium husk powder at different NaCl concentrations: Effect of intermolecular interactions

In this study, a strategy involving psyllium husk powder (PHP) was proposed to alleviate the textural deterioration of protein gels under low-sodium conditions. Results revealed that myofibrillar protein (MP) in 0.3 M NaCl could accommodate more PHP to achieve better gels properties compared with that of 0.6 M NaCl. The 3 % addition of PHP could lessen the textural deterioration of gels at 0.3 M NaCl because of the insertion of PHP into the hydrophobic cavity of MP. Consequently, the reduction in protein viscoelasticity and the thermal stability of the head and tail of myosin improved. α-Helix structures unfolded, intermolecular forces formed, and proteins aggregated. Molecular docking predicted hydrogen bonds and hydrophobic interactions as the main forces to stabilize the conformation of composites. Experiments further verified that hydrophobic interactions and disulfide bonds were the main forces that stabilized the structure of MP-PHP composite gels.

Effect of Potato Dietary Fiber on the Quality, Microstructure, and Thermal Stability of Chicken Patty

A total of 150 chicken patties containing different concentrations of potato dietary fiber (PDF) (0.0−4.0%) (30 for every treatment) with three replicates were used to access the influence of PDF on their quality, microstructure, and thermal stability. PDF improved the quality of chicken patty, including significantly inhibiting dimensional change and improving water- and fat-binding properties and textural properties (p < 0.05). Moreover, PDF promoted a more homogeneous and dense meat−protein network structure to be formed. The results of thermal stability showed that PDF did not affect the thermal denaturation of proteins (p > 0.05). The samples with PDF (<3.0%) did not have a significant negative effect on sensory properties of chicken patty; meanwhile, there were more abundant nutrients and a lower energy value in samples with PDF compared with the control. Therefore, PDF could be a promising ingredient to improve the properties of chicken patties, which was related to the amount of PDF added and performed best at 3.0% level.

Insight into the mechanism of fracture properties modulated by microstructure in the myofibrillar protein and polysaccharide gel systems

The objective of this study was to investigate the mechanism of fracture properties modulated by microstructure in the myofibrillar protein (MP) and polysaccharides gel systems. Compare to the modified starch, the dietary fiber significantly improved the fracture stress and reduced the fracture strain at same concentration. The treatment with 2% dietary fiber had the highest value of fracture stress and the lowest value of fracture strain, which were 259 g and 1.12 respectively. From the skeleton structure, the Raman spectroscopy result showed that dietary fiber addition significantly reduced the intensity at 2945 cm−1, which suggested that the aggregation of hydrophobic groups was improved. The SEM showed that the treatment with 2% dietary fiber had the highest fractal dimension value of 1.7772 and the lowest lacunary value of 0.258. From the filling structure, the paraffin section showed that the polysaccharides were just simply trapped in MP gel networks and formed numerous large volumes and no-elastic of cavities. The principal component analysis suggested that the compactness of three-dimensional gel networks determined fracture stress of composite gel. The no- no-elastic of cavities formed by modified starch and dietary fiber resulted in the reduction of fracture strain. These results would promote the development of innovative nutritional meat product formulation with satisfied textural property.

Graphical Abstract