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Abstract Polysaccharides are widely used as quality improvers for meat products. However, the mechanisms of how different ionic polysaccharides regulate the gelling properties of myofibrillar protein (MP) are still unclear. This study aimed to elucidate the contribution of different ionic polysaccharides to MP gelation and its mechanism. The enhancement of hydrogen bond, hydrophobic interaction, and disulfide bond between carboxymethyl cellulose sodium (CMC‐Na, anionic polysaccharide) and MP made them bind tightly, which contributes to the improvement of gel strength, water‐holding capacity, and viscoelasticity. Konjac glucomannan (neutral polysaccharide) mainly relied on physical filling to support the gel network and improve the gel characteristics. The electrostatic attraction between cationic polysaccharides and MP enhanced the binding between them. However, due to the large structure of chitosan (cationic polysaccharide) sugar chain, it can only attach to the surface of protein, which limits the interaction between them. These findings will provide guidance for the application of polysaccharides as food quality improvers or fat substitutes and the design of new low‐fat restructured meat products.

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.

Knowledge regarding the denaturation process and control methods for depolymerized sol-state myofibrillar proteins (MPs) during freezing remains scant. This study investigated the effects of protein cross-linking treatment before freezing on physicochemical and subsequent gelation properties of MPs sol subjected to freeze-thaw (F-T) cycles. Results indicated that after five F-T cycles, cross-linked MPs sols showed increased high molecular weight polymers and bound water (T21a and T21b) mobility, suggesting enhanced protein-protein interactions at the expense of protein-water interactions. Upon heating after F-T cycles, gels formed from cross-linked sols exhibited significantly higher hardness, springiness, and cooking loss (P

The effects of different concentrations of ε-Poly-lysine (ε-PL: 0.005%, 0.01%, 0.02%, 0.04%, and 0.06%) on the marine fish-egg white protein compound gels, treated with 0.4% TGase induced cross-linking were systematically investigated under low salt and phosphorus-free conditions (0.5% NaCl). The results showed the combination of ε-PL and TGase had a synergistic effect on improving sectional gel properties of composite surimi samples. Wherein the rheological, LF-NMR, and SEM results confirmed that the addition of ε-PL based on 0.4% TGase significantly improved the gel strength (to the highest value: 781.63 g·cm), apparent viscosity, and G 'value of the composite surimi sample, as well as reduced the internal water fluidity of surimi, accompanied by the emergence of a more dense and uniform gel network structure. Notably, ε-PL treatment significantly inhibited fat oxidation in the compound surimi gel and the degree of inhibition was proportional to its addition (decreased from 2.03 to 1.67 mg·kg−1). However, the addition of a small amount (0.005%) or an excessive amount (0.06%) of ε-PL on the gel properties of composite surimi samples witnessed the negative effects of the changes in the internal water distribution state and the cooking loss. To sum up, moderate ε-PL (0.04%) treatment combined with TGase induction can maximize the performance of mixed surimi gel and inhibit fat oxidation. The research results supply a diverse perspective and theoretical basis for the development of 'low salt and no phosphorus' surimi product ingredients.

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Summary: This work investigated gelling properties and structural characteristics of fish gelatin (FG) modified by four different molecular weights of γ‐polyglutamic acid (γ‐PGA) with 700, 1000, 2000 and 3000 kDa, respectively. Gelation‐melting transition temperature and gel strength increased with the increase of molecular weight in γ‐PGA. Especially, γ‐PGA in 3000 kDa made gel strength, gelation and melting temperatures reaching to 628.08 g (P < 0.05), 22.30 °C and 30.17 °C (P < 0.05), respectively. Non‐covalent interactions existed in FG and γ‐PGA. Such as, new hydrogen bonds were generated between them. Moreover, γ‐PGA with increased molecular weight enhanced three‐stranded helical structure and microscopic meshwork of FG. Finally, a schematic model was described to illustrate the interaction between FG and γ‐PGA in different molecular weights. On the whole, γ‐PGA with high molecular weight significantly improved gelling properties of FG, and could be a potential modifier of FG in the future. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The influence of ultrasonic processing on the physicochemical characteristics, microstructure, and intermolecular forces of the hybrid gels obtained by heating the mixtures of different ratios of salted ovalbumin (SOVA)-cooked soybean protein isolate (CSPI) was investigated. With the growth of SOVA addition, ζ-potential in absolute value, cohesiveness, water-holding capacity (WHC), surface hydrophobicity, and the content of soluble protein of the hybrid gels decreased (P

This study investigated the effects of ultra-high pressure (UHP) at different levels on the physicochemical properties, gelling properties, and in vitro digestion characteristics of myofibrillar protein (MP) in Tai Lake whitebait. The α-helix gradually unfolded and transformed into β-sheet as the pressure increased from 0 to 400 MPa. In addition, the elastic modulus (G') and viscous modulus (G'') of the 400 MPa-treated MP samples increased by 4.8 and 3.8 times, respectively, compared with the control group. The gel properties of the MP also increased significantly after UHP treatment, e.g., the gel strength increased by a 4.8-fold when the pressure reached 400 Mpa, compared with the control group. The results of in vitro simulated digestion showed that the 400 MPa-treated MP gel samples showed a 1.8-fold increase in digestibility and a 69.6 % decrease in digestible particle size compared with the control group.

To investigate the effects of ultrasound treatment combined with pH adjustment on the gelling properties of composite gels prepared from ginkgo seed protein isolate (GSPI) and whey protein isolate (WPI), the physicochemical properties and molecular behavior of the GSPI and WPI mixture and the texture, water-holding capacity (WHC) and microstructure of the heat-induced gel of the protein mixture were characterized. Results showed that ultrasonic treatment at 25%, 45%, or 65% power alone did not significantly influence protein solubility. However, ultrasonic treatment combined with lower pH (pH 4.0) markedly decreased protein hydrophobicity, and increased surface sulfhydryl group content and the sol’s particle size. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared (FTIR) spectroscopy showed that ultrasonic treatment affected protein structure and aggregation behavior. The heat-induced composite gel formed at lower pH had poor textural properties, whereas the composite gel formed at higher pH (especially at pH 5.0) exhibited improved textural properties and higher WHC. The textural properties and WHC of the composite protein gel were significantly improved with increasing ultrasonic power, which was attributed to the fact that ultrasonic treatment strengthened the interaction between hydroxyl groups in GSPI and WPI, promoting protein aggregation and cross-linking and improving the structural compactness of the composite gel. Overall, ultrasound treatment combined with pH adjustment could be an effective method for improving the functional properties of the composite protein gel.

In order to study the effect of extraction pH on gelling properties and characteristic peptide identification of pigskin gelatin, the molecular mass distribution and gelling properties of pigskin gelatin extracted under different pH conditions were studied by dodecyl sodium sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), a texture analyzer and a rheometer. Moreover, the characteristic peptides were identified by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The results showed that with a decrease in pH, the relative molecular mass of pigskin gelatin initially increased and then decreased, the gel intensity gradually declined, and the gel melting temperature and gelling temperature initial increased and then decreased. Gelatin extracted at pH 1 had the worst gelling properties. HPLC-MS/MS analysis showed that pH significantly affected the traceability of gelatin. In this study, 62, 71, 79 and 76 characteristic peptides were detected from pigskin gelatins extracted at pH 1, 3, 5 and 7, respectively. Among them, 37 characteristic peptides were common to all pigskin gelatins. Compared with our previous research, 17 characteristic peptides were found to be common to pigskin gelatins extracted under different conditions. These stable common characteristic peptides could be used as an important basis for pigskin gelatin traceability with high accuracy.

To improve the gel quality of chicken blood, a by-product of concentrated slaughter, the effects of different concentrations and formulations of xanthan gum (XG) and guar gum (GG) on the gel properties of chicken blood were investigated using the indices of water retention, texture, and rheological properties, as well as analysis of molecular interactions and sensory scores. The results showed that while individual treatment with either XG or GG improved the water-holding capacity of the chicken blood gel, the action of XG was superior. Addition of 4.0 g/L of XG resulted in a cooking loss rate of 10.02%, centrifugation loss of 12.73%, and syneresis rate of 10.96% (at 48 h), while the hardness, cohesiveness, gelation, mastication, and recovery of the gel were decreased. Addition of 6.0 g/L of GG significantly improved the textural properties of the gel, resulting in a hardness of 366.95 N, elasticity of 0.94 mm, cohesiveness of 0.77, adhesiveness of 281.94, masticatory value of 263.72 mJ, and recovery of 0.25. Analysis of dynamic rheology and intermolecular forces showed that the gelation transformation of the chicken blood gel system was mainly determined by the elastic response. The formulation of XG and GG had a synergistic effect in stabilizing the chicken blood gel, with strengthened ionic bonds (from 29.18% to 32.62%) and hydrogen bonds (from 2.48% to 6.43%), reduced hydrophobic force (from 22.68% to 16.28%), increased water-holding capacity of the gel, and enhanced gel stability. The addition of 4.0 g/L of formulated colloid (XG and GG in a ratio of 7:3) to chicken blood resulted in optimal water retention and texture, together with high sensory scores of the gel.

The effect of NaCl concentration on heat-induced gel forming ability of myofibrillar protein from European eel muscle was studied. The turbidity, surface hydrophobicity and reactive sulfhydryl groups of the protein was measured. Meanwhile, the properties of heat-induced gel of myofibrillar protein at 0.1, 0.3 and 0.5 mol/L NaCl concentration were investigated. It was found that turbidity, surface hydrophobicity and reactive sulfhydryl groups began to increase at 30, 35 and 40 ℃, respectively. With the increase of NaCl concentration, the temperature of endothermic peaks of myofibrillar protein decreased, while the storage modulus and loss modulus increased. The breaking strength of heat-induced protein gel prepared with 0.5 mol/L NaCl was 98.81 g, which was higher than that of the heat-induced protein gel prepared with low NaCl concentration. The increased NaCl concentration could promote the interaction between myosin heavy chain and actin according to the electrophoresis analysis. Based on the results of Fourier transform infrared spectra and scanning electron microscopy, heat-induced myofibrillar protein gel with 0.5 mol/L NaCl had a highest Amide II/Amide I intensity ratio and densest network. The result of this study suggested that myofibrillar protein from European eel muscle was prone to denature at above 35 ℃, and the gel strength and network structure of heat-induced myofibrillar protein gels could be improved by increasing the addition of NaCl. The obtained results will provide theoretical guidance for controlling the quality of eel based heat-processed food by using salt concentration and temperature.

Ultrasound-assisted washing had an expectant to increase the concentration of myofibrillar proteins that play an important role in gelling properties of surimi. This work investigated the effect of low-intensity ultrasound-assisted washing on surimi's biochemical and gelling properties from yellowstripe scad. Washed minced fish was obtained by conventional method or washing process through ultrasound at a frequency of 45 kHz with different steps. Physicochemical properties and protein patterns of washed minced and surimi gel were evaluated. Results showed that the washed minced fish treated by ultrasound three times (U-3) showed the highest L* (50.37 ± 0.23) and whiteness (48.69 ± 0.23) (p

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Preserved egg white (PEW) has excellent gelling properties but is susceptible to the freshness of raw eggs. In this study, the correlation between the comprehensive freshness index (CFI) of raw eggs and the gelling properties of alkali-induced egg white gel (EWG) was elucidated. Results showed that the CFI, established by a principal component analysis (PCA) and stepwise regression analysis (SRA) methods, can be used to predict the freshness of duck eggs under storage conditions of 25 °C and 4 °C. A correlation analysis demonstrated that the CFI showed a strong negative correlation with the hardness and chewiness of alkali-induced EWG and a strong positive correlation with resilience within 12 days of storage at 25 °C and 20 days at 4 °C (p < 0.01). It might be due to the decrease in α-helix and disulfide bonds, as well as the hydrophobic interactions showing a first decrease and then an increase within the tested days. This study can provide an important theoretical basis for preserved egg pickling. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: The reduction of protein oxidation is important for maintaining the product quality of reconstituted meat. In this study, the dose‐dependent effects of lentinan (LNT) on gelling properties and chemical changes in oxidatively stressed goose myofibrillar protein were investigated. RESULTS: Myofibrillar protein (MP) with 200 μmol g−1 protein LNT increased gel strength by 87.90 ± 9.26% in comparison with LNT‐free myofibrillar protein after oxidation. Scanning electron microscopy analysis revealed that the gel network containing LNT was compact, with small pores and uniform distribution. The absolute value of the zeta potential reduced significantly following oxidation of LNT with 200 μmol g−1 protein at 4 °C for 12 h compared with the zeta potential without LNT, according to the laser particle size analyzer. The incorporation of LNT increased protein solubility and –SH content, inhibited carbonyl formation, enhanced α‐helix content and tryptophan intrinsic fluorescence intensity, and reduced exposure of hydrophobic groups and protein aggregation. CONCLUSION: The results indicated that adding LNT to myofibrillar protein could improve gel. This is related to its protective effect on conformational changes in the oxidation system. Lentinan is therefore recommended for oxidatively stressed goose meat processing to enhance the MP gelling potential. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Fish gelatin (FG) has multifunctional properties similar to mammalian gelatin (MG), and it has been recognized as the optimal alternative to MG. While its poor surface‐active and gelling properties significantly limit its application values, glycosylation has been successfully used to increase surface‐active properties of FG, but the influence of ultrasonic‐associated glycosylation (UAG) on the gelling and structural characteristics of FG is still rarely reported. This article explores UAG (100–200 W, 0.5–1 h) with κ‐carrageenan (κC) on the functional properties (emulsifying, gelling and rheological properties) and structural characteristics of FG. RESULTS: The longer time and higher power of ultrasonics accelerated the glycosylation reaction with an increase in glycosylation degree and browning index values. Compared with original FG, FG–κC mixture and bovine gelatin, UAG‐modified FG possessed higher emulsification activity index, emulsion stability index, gel strength, hardness and melting temperature values. Among them, gelatin modified by appropriate ultrasonic conditions (200 W, 0.5 h) had the highest emulsifying and gelling properties. Rheological results showed that UAG contributed to the gelation process of gelatin with advanced gelation time and endowed it with high viscosity. Structural analysis indicated that UAG promoted κC to link with FG by the formation of covalent and hydrogen bonds, restricting more bound and immobilized water in the gels, exhibiting higher gelling properties. CONCLUSION: This work showed that UAG with κC is a promising method to produce high gelling and emulsifying properties of FG that could replace MG. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In this paper, the effects of different modification orders of microbial transglutaminase (MTGase) and contents of pectin (0.1–0.5%, w/v) on the gelling and structural properties of fish gelatin (FG) and the modification mechanism were studied. The results showed that the addition of pectin could overcome the phenomenon of high-MTGase-induced lower gelling strength of gelatin gels. At a low pectin content, the modification sequences had non-significant influence on the gelling properties of modified FG, but at a higher pectin content (0.5%, w/v), P0.5%-FG-TG had higher gel strength (751.99 ± 10.9 g) and hardness (14.91 ± 0.33 N) values than those of TG-FG-P0.5% (687.67 ± 20.98 g, 12.18 ± 0.45 N). Rheology analysis showed that the addition of pectin normally improved the gelation points and melting points of FG. The structural results showed that the fluorescence intensity of FG was decreased with the increase in pectin concentration. Fourier transform infrared spectroscopy analysis indicated that the MTGase and pectin complex modifications could influence the secondary structure of FG, but the influenced mechanisms were different. FG was firstly modified by MTGase, and then pectin (P-FG-TG) had the higher gelling and stability properties. [ABSTRACT FROM AUTHOR]

β-glucan from cereals such as wheat, barley, oats and rye are a water-soluble dietary fiber, which are composed of repeating (1→4)-β-bond β-D-glucopyranosyl units and a single (1→3)-β-D-bond separated unit. β-glucan has a series of physicochemical properties (such as viscosity, gelling properties, solubility, etc.), which can be used as a food gel and fat substitute. its structure endows the healthy functions, including anti-oxidative stress, lowering blood glucose and serum cholesterol, regulating metabolic syndrome and exerting gut immunity via gut microbiota. Due to their unique structural properties and efficacy, cereal β-glucan are not only applied in food substrates in the food industry, but also in food coatings and packaging. This article reviewed the applications of cereal β-glucan in hydrogels, aerogels, intelligent packaging systems and targeted delivery carriers in recent years. Cereal β-glucan in edible film and gel packaging applications are becoming more diversified and intelligent in recent years. Those advances provide a potential solution based on cereal β-glucan as biodegradable substances for immune regulation delivery system and intelligent gelling material in the biomedicine field. [ABSTRACT FROM AUTHOR]

Membrane separation technologies allow the implementation of environmentally friendly and cost-effective processes to separate fine particles and molecules. Fractionation process of proteins from tuna skin gelatin was performed in four consecutive filtration steps using four membranes with pore diameters of 800 nm, 100 nm, 50 nm, and 20 nm. The retentates obtained from all membranes exhibited a similar protein size distribution. Gel strength and gelling and melting temperatures did not differ significantly among the tuna skin gelatin and the four retentates (p > .05). The permeate from the 20 nm pore diameter membrane exhibited significantly lower gelling properties than the other fractions (p

In this study, we investigated the effects of different high-intensity ultrasound (HIU) pretreatment times (0–60 min) on the structure of β-conglycinin (7S) and the structural and functional properties of 7S gels induced by transglutaminase (TGase). Analysis of 7S conformation revealed that 30 min HIU pretreatment significantly induced the unfolding of the 7S structure, with the smallest particle size (97.59 nm), the highest surface hydrophobicity (51.42), and the lowering and raising of the content of the α-helix and β-sheet, respectively. Gel solubility showed that HIU facilitated the formation of ε-(γ-glutamyl)lysine isopeptide bonds, which maintain the stability and integrity of the gel network. The SEM revealed that the three-dimensional network structure of the gel at 30 min exhibited filamentous and homogeneous properties. Among them, the gel strength and water-holding capacity were approximately 1.54 and 1.23 times higher than those of the untreated 7S gels, respectively. The 7S gel obtained the highest thermal denaturation temperature (89.39 °C), G′, and G″, and the lowest tan δ. Correlation analysis demonstrated that the gel functional properties were negatively correlated with particle size and the α-helix, while positively with Ho and β-sheet. By contrast, gels without sonication or with excessive pretreatment showed a large pore size and inhomogeneous gel network, and poor properties. These results will provide a theoretical basis for the optimization of HIU pretreatment conditions during TGase-induced 7S gel formation, to improve gelling properties. [ABSTRACT FROM AUTHOR]

There is an emerging consumption of the Antarctic krill (AK) muscle‐based food due to its excellent nutritional value and enormous biomass storage capacity. However, the coarse texture of the muscle and the weak gelling properties of AK protein impede its expansion in surimi‐based products. This investigation successfully prepared heat‐induced gels of AK surimi with desirable textural properties by including Litopenaeus vannamei in varying proportions. Higher concentrations of L. vannamei resulted in improved three‐dimensional printability, greater water‐holding capacity (WHC), larger viscoelastic modulus, and a well‐formed microstructural matrix of AK surimi, due to an increased level of myofibrillar protein. Compared with AK, L. vannamei muscle had double the salt‐soluble protein content, which was corroborated by increased intensity of bands of actin, paramyosin, tropomyosin, and myosin light chains on reducing SDS‐PAGE. DSC results indicated that a high ratio of L. vannamei elevated the denaturation temperature and enthalpy of myosin, sarcoplasmic protein, and actin, suggesting a high degree of cross‐linking. It was also found that when hydroxypropyl cassava starch was added at 0.5% (w/w), WHC and gel strength were further improved with a more compact gel matrix. The successful preparation of unwashed mixed surimi with AK meat fully exploited in this study provides an option for AK surimi‐based product industrialization. [ABSTRACT FROM AUTHOR]

Silver carp (Hypophthalmichthys molitrix) is a potential source for making surimi products. However, it has the disadvantages of bony structures, high level of cathepsines and muddy off-odor which is mainly caused by geosmin (GEO) and 2-methylisoborneol (MIB). These disadvantages make the conventional water washing process of surimi inefficient (low protein recovery rate, and high residual muddy off-odor). Thus, the effect of the pH-shifting process (acid-isolating process and alkali-isolating process) on the cathepsins activity, GEO content, MIB content, and gelling properties of the isolated proteins (IPs) was investigated, comparing it with surimi obtained through the conventional cold water washing process (WM). The alkali-isolating process greatly boosted the protein recovery rate from 28.8% to 40.9% (p < 0.05). In addition, it removed 84% GEO and 90% MIB. The acid-isolating process removed about 77% GEO and 83% MIB. The acid-isolated protein (AC) displayed the lowest elastic modulus (G′), the highest TCA-peptide content (90.89 ± 4.65 mg/g) and the highest cathepsin L activity (65.43 ± 4.91 U/g). The AC modori (60 °C for 30 min) gel also demonstrated the lowest breaking force (226.2 ± 19.5 g) and breaking deformation (8.3 ± 0.4 mm), indicating that proteolysis caused by the cathepsin deteriorated the gel quality of AC. The setting (40 °C for 30 min) considerably increased the breaking force (386.4 ± 15.7 g) and breaking deformation (11.6 ± 0.2 mm) of the gel made from the alkali-isolated protein (AK) (p < 0.05). In AC and AK gel, a clearly visible cross-linking protein band with a molecular weight greater than MHC was seen, demonstrating the presence of endogenous trans-glutaminase (TGase) activity, that improved the gel quality of AK. In conclusion, the alkali-isolating process was an effective alternative method for making water-washed surimi from silver carp. [ABSTRACT FROM AUTHOR]

Effects of the incorporation of ultrasound with varied intensities (0–800 W) into the thermal-induced gelation process on the gelling properties of myofibrillar protein (MP) were explored. In comparison with single heating, ultrasound-assisted heating (

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. [ABSTRACT FROM AUTHOR]

Pasting and gelling behaviors of barley starches isolated from Cinnamon (waxy of 3.3% apparent amylose; WB), Golden Promise (normal of 26.2% amylose; NB), and amylose‐only (high‐amylose of 97.8% amylose; AO) varieties were examined over 95–140 °C cooking. Gelatinization temperatures of AO starch were significantly higher than those of WB and NB, thereby the former displaying negligible pasting viscosity at 95 °C heating. At 140 °C, AO starch was completely gelatinized and able to develop viscosity, particularly at the final pasting stage. Gel hardness of NB gradually decreased with higher cooking temperatures. After 140 °C cooking and storage, only AO starch formed a gel, exhibiting the largest hardness among the studied gels or pastes. Gelation mechanisms of the barley starches at 95—140 °C cooking were elucidated by visualizing their gel/paste microstructures under scanning electron microscopy. The insightful information on the physicochemical properties of the barley starches possessing 3.3–97.8% amylose will be meaningful for their industrial applications. [ABSTRACT FROM AUTHOR]

BACKGROUND: Washing is an essential process in surimi production, from which a large amount of wastewater is generated. Due to the increasing pressure of environmental protection, it is an urgent technical requirement for surimi manufacturers to reduce water usage while maintaining the quality of surimi. In this study, composition, structure and gelling properties of grass carp surimi prepared with a modified washing process (MWP) were investigated. Intermediate dehydration with various compression ratios were utilized between two washing cycles. RESULTS: Water usage and wastewater discharge were reduced significantly by 33% and 38%, respectively, when MWP was applied. As the compression ratio increased, composition of fat, cathepsins, transglutaminase and heme proteins in surimi decreased gradually. Yield, protein content and the major protein pattern of surimi were not changed, but surface hydrophobicity gradually decreased. As the compression rate increased to 1:2.0, textural values and water holding capacity of the corresponding surimi gel decreased gradually, while whiteness increased and then remained unchanged. At a higher compression ratio (>1:1.5), aggregated network and excessive free water were observed in the surimi gel. Composition and gelling properties of the MWP surimi with a compression ratio of 1:1.2–1:1.5 were equal to those of the surimi prepared under conventional three‐cycle washing. CONCLUSION: Results indicated that MWP demonstrated its great potential in surimi production by dramatically reducing the usage of cold water and discharge of wastewater without scarifying surimi quality. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This study investigated the gelling properties, rheological behaviour, and microstructure of heat-induced, low-salt myofibrillar protein (MP) gels containing different levels (2%, 4%, 6%, and 8%, w /w) of cross-linked (CTS) or acetylated (ATS) tapioca starch. The results indicated that either CTS or ATS significantly enhanced the gel strength and water-holding capacity of low-salt MP gels (P < 0.05), an outcome verified by the rheological behaviour test results under different modes. Furthermore, iodine-staining images indicated that the MP-dominated continuous phase gradually transited to a starch-dominated phase with increasing CTS or ATS levels, and 4% was the critical point for this phase transition. In addition, hydrophobic interactions and disulphide bonds constituted the major intermolecular forces of low-salt MP gels, effectively promoting phase transition. In brief, modified tapioca starches possess considerable potential application value in low-salt meat products. [Display omitted] • Low-salt MP gels with cross-linked/acetylated tapioca starch (CTS/ATS) were formulated. • CTS/ATS enhanced the gelling and rheological properties of low-salt MP gels. • Increasing CTS/ATS levels promoted low-salt MP gel phase transition. • Hydrophobic interactions and disulphide bonds mainly led to phase transition. [ABSTRACT FROM AUTHOR]

To verify whether there is a non-thermal effect in the radio frequency (RF) treatment process, it's very important for effectively excluding the thermal effect. Native maize starch (MS) slurry was treated under a specific electric field intensity while maintaining the sample temperature at 25 ± 2 °C for different times (1, 2, 4 and 8 h), which would effectively eliminate the influence of thermal effect on starch. A corresponding low electric field intensity of 3.3–3.4 kV/m was established after adjusting the electrode gap to be 220 mm of the 27.12 MHz RF system. Samples treated without RF-wave for the same time (1, 2, 4 and 8 h) were used as controls. The differences between the effect of these two treatments on the multi-scale structural and gelling properties of starch samples were investigated. Results showed that the low intensity RF-wave treatment enhanced the short-range structural order. A higher degree of order value and the double helical structure were observed from Fourier transform infrared (FTIR) spectra and solid state 13C nuclear magnetic resonance (13C NMR). Moreover, compared to control MS, the crystallinity of low intensity RF-treated starch significantly increased though the crystal pattern remained unchanged. Low intensity RF-wave treated starch had no significant difference in loss modulus, energy and distance of inter-double helices hydrogen bond, and pasting properties (i.e. TV, SB and BD) when compared with control sample. The effect of low intensity RF wave on starch without heating was insufficient to cause macroscopic property changes. These results provide valuable insights into the structural changes of starch treated by low intensity RF-wave and verify that the non-thermal effect of RF waves may be primarily achieved through the dipole polarization mechanism. • Native maize starch slurry was treated by radio frequency (RF) wave at 25 °C of sample. • Low intensity RF-wave treatment enhanced the short-range structural order. • Effect of low intensity RF wave was insufficient to cause macroscopic property changes. • Non-thermal effect of RF waves may be primarily achieved through dipole polarization mechanism. [ABSTRACT FROM AUTHOR]

This study investigates the effect of germination and high-pressure (HP) treatment on the functional and gelling behaviour of red quinoa (RQ) (Chenopodium quinoa). The grains were subjected to germination for 48 h followed by the application of four pressures (200, 300, 400 and 500 MPa) as well as their combinations to germinated quinoa (GQ) samples. The samples were ground, and the flour was analysed for functional, rheological, and microstructural attributes. Germination and HP treatment improved the functional and gelling properties of RQ samples significantly. The degradation of protein, fat, and starch-lipid complex of the flour led to an increase in the swelling capacity of flour. The treatments increased the oil absorption capacity from 50.02 ± 0.47 to 80.86 ± 0.88 % and emulsification capacity from 57.85 ± 0.71 to 64.17 ± 0.53 %. This increase is attributed to the dissociation and unfolding of polypeptides that expose the hydrophobic sites of amino acids. The decrease in least gelling capacity from 18 to 14% signified a decrease in the amount of flour required for the gelation. Rheometric and texture profile analysis demonstrated an improved gel strength. Moreover, the SEM micrographs showed an increased structure density and reduced porosity which further support the improved gel strength. The study would help to widen the scope of accommodating RQ flour as a gelling or thickening agent in the food industries. [Display omitted] • Germination and high-pressure treatment improved functional and gelling properties of red quinoa. • Red quinoa flour can act as a gel-forming or firming agent. • Rheometric and TPA demonstrated an improved gel strength due to treatments. • SEM micrographs showed an increased structure density and reduced porosity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Oxidation and shearing had interactive effect on gel-formation of salt-dissolved MP. • Oxidation caused severe denaturation and aggregation of sol suffering freeze–thaw. • Mild oxidation (≤1 mmol/L) improved unfrozen gel quality with less water loss. • Shearing impaired heat-induced gel quality from frozen sol under oxidation stress. Frozen surimi quality generally correlates with oxidation, but impacts of protein oxidation on salt-dissolved myofibrillar protein (MP) sol in surimi remain unclear. Hence, physicochemical and gelling properties of MP sol with different oxidation degrees were investigated subjected to freeze–thaw cycles. Results showed that mild oxidation (≤1 mmol/L) improved unfrozen MP gel quality with lowest cooking loss (3.29 %) and highest hardness (829.76 N). Whereas, oxidized sol suffering freeze-thawing degenerated severely, showing reduction of 23.85 % of salt soluble protein contents with H 2 O 2 concentrations of 10 mmol/L. Shearing before heating influenced gelling properties of freeze-thawed sol, depending on oxidation levels. Oxidized gel with shearing displayed disorganized network structures, whereas gel without shearing displayed relatively complete appearances without holes under high oxidation condition (10 mmol/L). Overall, freeze–thaw process aggravated denaturation extents of MP sol subjected to oxidation, further causing high water loss and yellow color of heat-induced gel, especially to gel with shearing. [ABSTRACT FROM AUTHOR]

This study investigated the effect of ultrasound (US) combined with pre- and post-addition of κ-carrageenan (KC) on the gelling properties, structural characteristics and rheological behavior of myofibrillar proteins (MP) under low-salt conditions. The results showed that US combined with either pre- or post-addition of KC rendered higher gel strength and water holding capacity (WHC) of MP gels than those treated with US alone and added with KC alone (P < 0.05). US combined with pre-addition of KC facilitated the binding between MP and KC, which enhanced the gel strength and WHC of the mixed MP gels and significantly improved the rheological behavior of MP. This was also confirmed by the highest surface hydrophobicity, disulfide bonds and β-sheet content of the MP gels with US combined with pre-addition of KC. Moreover, microstructural results reflected a denser structure for the pre-addition of KC in combination with US. However, US combined with post-addition of KC resulted in limited MP unfolding and relatively weak hydrophobic interactions in the composite gels, which were less effective in improving the gel properties of the MP gels. This study provides potential strategies for enhancing the gelling properties of low-salt meat products via application of US and KC. • Sequential addition of KC and ultrasound (US) affected low-salt MP gelation. • US combined with pre-addition of KC enhanced interaction between MP and KC. • US combined with pre-addition of KC led to the formation of denser gel matrix. • US combined with post-addition of KC had limited effect on low-salt MP gelation. [ABSTRACT FROM AUTHOR]

Preserved egg white (PEW) has excellent gelling properties but is susceptible to the freshness of raw eggs. In this study, the correlation between the comprehensive freshness index (CFI) of raw eggs and the gelling properties of alkali-induced egg white gel (EWG) was elucidated. Results showed that the CFI, established by a principal component analysis (PCA) and stepwise regression analysis (SRA) methods, can be used to predict the freshness of duck eggs under storage conditions of 25 °C and 4 °C. A correlation analysis demonstrated that the CFI showed a strong negative correlation with the hardness and chewiness of alkali-induced EWG and a strong positive correlation with resilience within 12 days of storage at 25 °C and 20 days at 4 °C (p < 0.01). It might be due to the decrease in α-helix and disulfide bonds, as well as the hydrophobic interactions showing a first decrease and then an increase within the tested days. This study can provide an important theoretical basis for preserved egg pickling.

Plasma is a new technology used to modify myofibrillar proteins (MPs) structure and promote protein aggregation. In order to study the mechanism of plasma modifying MPs thus the effects on qualities of MP gels, MPs were extracted by 0.6 M NaCl solution prepared with plasma-activated water (PAW) at different treatment time (0 s, 30 s, 60 s, 120 s, 240 s). With the prolonged PAW treatment time from 0 to 240 s, the pH values of natural MP solutions decreased significantly from 5.91 to 2.61 (P

This study investigated the changes in conformation and gelling properties of myofibrillar protein (MP) from Penaeus vannamei under various ultrahigh pressure (UHP)-heat assisted technologies. The results indicated that UHP heat-assisted technology enhanced the cross-linking of the gel network by causing a rearrangement of the secondary structure of MP. Microstructural analysis revealed that MP gels treated with UHP heat-assisted technology exhibited a more uniform gel network structure. Additionally, UHP heat-assisted technology improved the binding capacity of water molecules within the gel network, particularly in the two-stage UHP heat-assisted (PBH) condition at 400 MPa. Gels prepared under this condition demonstrated the highest gel strength, measuring 386.4 g·mm. Furthermore, in vitro simulated digestion showed that PBH method significantly improved the digestibility of MP gels, suggesting that the UHP heat-assisted technology had the potential to produce easily digestible MP gel-based aquatic foods., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

The effects of high-intensity ultrasound on the physicochemical and gelling properties of Litopenaeus vannamei (L. vannamei) myofibrillar protein (MP) were investigated. MP solutions were subjected to ultrasound treatment (power 100 W, 300 W, and 500 W). It was found that the carbonyl and free amino contents of MP increased significantly with increasing ultrasound power, accompanied by enhanced emulsification properties. The increase of free radical and carbonyl content indicated that ultrasound induced the oxidation of MP. With the increase of ultrasound power, it was found that the total sulfhydryl content of the shrimp MP decreased, but the surface hydrophobicity increased significantly, which might be closely related to the conformational changes of MP. Meanwhile, a significant increase of β-sheet but a decrease of α-helix in the secondary structure of MP was observed with increasing ultrasound power, indicating that ultrasound treatment induced the stretching and flexibility of MP molecules. SDS-PAGE showed that L. vannamei MP consisted of myosin heavy chain, actin, myosin light chain, paramyosin and tropomyosin. Ultrasound treatment could lead to some degree of oxidative aggregation of MP. The results of rheological properties indicated that ultrasound treatment enhanced the viscoelasticity of MP and further improved the gel strength of MP gel. This study can provide a theoretical basis for the functional modification of shrimp MP and the processing of its surimi products.

In this paper, the effects of different modification orders of microbial transglutaminase (MTGase) and contents of pectin (0.1–0.5%, w/v) on the gelling and structural properties of fish gelatin (FG) and the modification mechanism were studied. The results showed that the addition of pectin could overcome the phenomenon of high-MTGase-induced lower gelling strength of gelatin gels. At a low pectin content, the modification sequences had non-significant influence on the gelling properties of modified FG, but at a higher pectin content (0.5%, w/v), P0.5%-FG-TG had higher gel strength (751.99 ± 10.9 g) and hardness (14.91 ± 0.33 N) values than those of TG-FG-P0.5% (687.67 ± 20.98 g, 12.18 ± 0.45 N). Rheology analysis showed that the addition of pectin normally improved the gelation points and melting points of FG. The structural results showed that the fluorescence intensity of FG was decreased with the increase in pectin concentration. Fourier transform infrared spectroscopy analysis indicated that the MTGase and pectin complex modifications could influence the secondary structure of FG, but the influenced mechanisms were different. FG was firstly modified by MTGase, and then pectin (P-FG-TG) had the higher gelling and stability properties.

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Citrus pectins (CP) are the most common types of commercial pectins, and their gelling properties are of interest in many industrial applications. However, the dynamic changes in the chemical structures and gelling properties of pectins during citrus maturation and storage are poorly understood. This study compared pectins from citrus fruit in terms of different maturity (M1: green citrus; M2: green-yellow citrus; M3: light orange citrus; FM: full maturity citrus) and storage times (S1: 10-day; S2: 20-day; S3: 30-day). All pectin were high-methoxylated polymers, with high content of HG and RG-I domain (about 95.0 mol%). With increasing citrus maturity and storage time, HG content (from 69.0 mol% to 51.9 mol%), the molecular weight and methyl-esterification of pectins continuously decreased, while the RG-I content (from 26.4 mol% to 42.5 mol%) and compact spatial conformation significantly increased. Polygalacturonase, methylesterase, α-arabinofuranosidase, β-galactosidase, and cellulase, induced dynamic variations in the structural characteristics of pectins. The decreases in HG content and the lower molecular weight reduced hydrogen bonding and the hydrophobic interactions, thus weakening the gelling properties. The relatively high RG-I content, the additional hydrogen bonds generated by the free carboxyl groups, and the compact conformation shortened the distances between pectin chains and increased chain entanglement, thereby ensuring that the gel network was stable. Consequently, CP S3 gel exhibited the greatest strength (hardness: 977.0 g, A α : 642.9 Pa sα) and satisfactory extrusion recovery ability (springiness: 95.5%). These results can guide the selection of raw materials that will yield pectins with specific structural characteristics and superior gelling properties. [Display omitted] • The chemical structure and gelling properties of citrus pectin changed dynamically. • Citrus maturity reduced HG ratio and DM of pectins, but increased their compactness. • Endogenous enzymes in citrus fruit accounted for the structural variations of pectin. • Pectins in citrus fruit stored for 30 days had the best gel strength and good stability. • Alterations in the chemical structures of pectins regulated their gelling properties. [ABSTRACT FROM AUTHOR]

Frozen surimi sol incline to protein oxidation, but the quality control strategies based on oxidation remain limited. Hence, the antioxidant and cryoprotective effects of γ-polyglutamic acid (γ-PGA) on freeze-thawed salt-dissolved myofibrillar protein (MP) sol were investigated. Results showed that γ-PGA could effectively regulate protein oxidation of MP sol during freeze-thawing with lower carbonyl contents and less oxidative cross-linking. Meanwhile, γ-PGA primely maintained sol protein structures, showing reduction of 15.28% of salt soluble protein contents at γ-PGA addition of 0.04% under unoxidized condition. Additionally, compared to the control group without oxidation treatment, cooking loss of heat-induced gel with 0.04% γ-PGA decreased by 47.19%, while gel strength obviously increased by 57.22% respectively. Overall, moderate γ-PGA addition (0.04%) could inhibit protein oxidation of sol, further improving frozen stability of sol through hydrogen bonds and hydrophobic interaction, but excessive γ-PGA was adverse to sol quality due to severe cross-linking between γ-PGA and MP. [Display omitted] • γ-polyglutamic acid (γ-PGA) retarded protein oxidation of frozen sol. • Mild γ-PGA inhibited denaturation and oxidative aggregation of frozen sol. • Mild γ-PGA improved gel quality with less water loss and higher gel strength. • Excessive γ-PGA is adverse to frozen stability and gel quality of sol. • γ-PGA bound to myofibrillar protein via hydrogen bonds and hydrophobic interaction. [ABSTRACT FROM AUTHOR]

This study investigated the effects of ultrasound-assisted phosphorylation on gelling properties of fish gelatin (FG). Ultrasound-assisted phosphorylation (UP) for 60, 90, and 120 min resulted in >6.54% increase of phosphorylation degree and decreased zeta potential of FG. Atomic force microscopy revealed that UP-FGs showed larger aggregates than P-FGs (normal phosphorylation FGs). Low frequent-NMR and microstructure analysis revealed that phosphorylation enhanced water-binding capability of FG and improved the gel networks. However, UP60 had the highest gel strength (340 g), gelling (17.96 °C) and melting (26.54 °C) temperature while UP90 and UP120 showed slightly lower of them. FTIR analysis indicated thatβ-sheet and triple helix content increased but random coil content decreased in phosphorylated FGs. Mass spectrometry demonstrated phosphate groups mainly bound to serine, threonine and tyrosine residues of FG and UP-FG exhibited more phosphorylation sites. The study showed that mild phosphorylation (UP60) could be applied to improve FG gel properties. [Display omitted] • Ultrasound assistance increased the phosphorylation degree and sites of FG. • Phosphate group mainly bound to serine, threonine and tyrosine residues of FG. • Moderate phosphorylation increased water binding ability, GS, GT and MT of FG. • Over phosphorylation led to poor gel network and gel properties of FG. [ABSTRACT FROM AUTHOR]

The pectin was extracted using H 2 SO 4 , HNO 3 , and HCl from the pulp of four coffee varieties (Harar, Sidama, Jimma, and Guji) collected from different regions of Ethiopia. The effect of extraction temperature, time, solid-to-liquid ratio, types of acid and coffee varieties on the physiochemical properties and yield of pectin were studied. A maximum pectin yield, which was 12.7 %, was obtained from Harar coffee pulp treated with H 2 SO 4. The equivalent weight of the extracted pectin varied from 1111 to 1667 g/mol. The methoxyl contents of the extracted pectin ranged from 4.23 to 7.13 %. The degrees of esterification and anhydrouronic acid of the pectin ranged from 53 to 68.5 % and 35.5 to 68.8 %, respectively. The results show the yield and physiochemical properties of the coffee pulp pectin depend on extraction parameters, acid types, and coffee varieties. Moreover, the pectin extracted from coffee pulp showed strong gelling properties. [ABSTRACT FROM AUTHOR]

Starch and protein are essential biomacromolecules ubiquitous in foods that contribute to nutritional and textural properties. Understanding the gelling behavior of starch and proteins can help develop texture-modified foods. Herein, composite gels were created with various ratios of rice starch to soybean protein (constant solid content 12%). The International dysphagia diet standardization initiative (IDDSI) levels of rice starch–soybean protein composite gels with various ratios were evaluated. The texture, gelling behavior, rheological properties, and water fixation properties of rice starch–soybean protein gel were characterized. The results showed that soybean protein inhibit the gelatinization of rice starch by reducing the gelatinization viscosity. Rice starch could prevent the denaturation of soybean protein by preventing the structural transformation of protein. Rice starch and soybean protein antagonize each other to inhibit gelation. In addition, rice starch precedes soybean protein gel so that the network formation of rice starch and soybean protein is hindered by each other in the composite system. Obvious phase separation was observed in the rice starch–soybean protein composite gel. Disulfide and hydrogen bonds are affected by the proportions of rice starch and soybean protein and are the main intermolecular forces to maintain structure. Gels prepared with a mixture of rice starch and soybean protein had lower IDDSI levels, gel strength, modulus, and strain compared to single-component gels. All gels exhibit excellent water-holding capacity. Therefore, the rice starch–soybean protein composite gel can be used to prepare soft and moist texture-modified foods to meet the needs of patients with dysphagia. [Display omitted] • Soybean protein hinders the pasting of rice starch. • Rice starch improves the thermal stability of soybean protein. • In the composite system, rice starch gels earlier than soybean protein. • Rice starch-soybean protein composite gel displays the phase separation structure. • The φ P 50 gel has the lowest gel strength. [ABSTRACT FROM AUTHOR]

Ulvan, a sulfated polysaccharide extracted from Ulva spp., has garnered significant attention in the food and pharmaceutical industries due to its potential health benefits. These include immunomodulation, antiviral, anti-inflammatory, anti-hyperlipidemic, and anti-cancer effects. Nonetheless, practical applications in these fields remain limited due to an incomplete understanding of its gelation mechanisms. Additionally, the underlying mechanisms of its gelation have not been completely understood and thoroughly reviewed. The primary objective is to provide current insights into ulvan's gelling mechanisms and potential health impacts. This review also delves into the existing applications of ulvan polysaccharides. By unraveling these aspects, the information provided in this work is expected to deepen our understanding of ulvan's gelation mechanisms and its prospective role in enhancing health, holding promise for advancements in the fields of food science and disease prevention. This work's theoretical insights contribute significantly to a deeper understanding of these aspects, which holds paramount importance in unleashing the full potential of ulvan and elevating its scientific significance. • Ulvan holds potential as a gelling agent offering therapeutic effects. • Gelling and therapeutic effects of ulvan are influenced by its sulfate groups. • Ulvan's molecular weight and structure affect its health-promoting properties • Ulvan solutions can present both shear-thinning and shear-thickening behaviors. [ABSTRACT FROM AUTHOR]

This study investigated the effects of different levels (0, 0.1, 0.3, and 0.5 %, w/w) of microbial transglutaminase (TG) on the gelling properties and in vitro digestibility of heat-induced myofibrillar protein (MP) gels with or without κ -carrageenan (KC, 0.2 %, w/w). The results indicate that the crosslinking degree of MP gels was gradually enhanced with increasing levels of TG alone (P < 0.05). However, regardless of TG level, KC incorporation effectively inhibited TG-induced crosslinking through the steric effect and subsequently promoted the water-holding capacity, gelling properties and rheological characteristics of the MP gels (P < 0.05), as well as led to the development of a more uniform and denser gel network structure. Moreover, compared with the MP gels with TG alone, KC addition increased the presence of hydrogen bonds, hydrophobic interactions, and disulphide bonds among the gels (P < 0.05). Additionally, the existence of KC significantly decreased the in vitro digestibility of TG-mediated MP gels mainly because TG-induced crosslinking promoted physical interaction between KC and MP. Therefore, the present study provides essential information regarding the influence of KC on the gelling properties and in vitro digestibility of heat-induced TG-mediated MP gels. [Display omitted] • Transglutaminase (TG) led to crosslinking of myofibrillar protein (MP) gels. • κ -carrageenan (KC) evidently reduced crosslinking degree of TG-mediated MP gels. • TG-mediated crosslinking enhanced physical interaction between KC and MP. • Combination of TG and KC promoted the gelling properties of heat-induced MP gels. • TG and KC synergistically reduced the in vitro digestibility of MP gels. [ABSTRACT FROM AUTHOR]

Hawthorn fruits (Crataegus pinnatifida) present high content of high-methoxyl pectin, able to gel under high-sugar acidic conditions. In this work, the proximate and phytochemical composition of two cultivars of hawthorn fruit and the gelling ability of their unrefined (not further processed) dried powders and their extracted pectins were evaluated and systematically compared with citrus pectins (CP1 and CP2). Mianqiu (MI), a less known cultivar, showed two-fold higher pectin content and titratable acidity than Dajinxing (DA), one of the most common cultivars. DA showed higher starch, insoluble dietary fiber, pasting viscosity and total and extractable (EPP) phenolic compounds. EPP content was almost two-fold higher in DA than MI, resulting in stronger antioxidant properties. All high-methoxyl sugar acid gels exhibited a predominantly elastic response. MI resulted in hawthorn-powder gels with higher elastic modulus (G′) after gel-making (initially stronger gels), and lower G′ increase during storage (hardening) than DA. Citrus pectins (CP2 > CP1) showed higher gel-strength and faster gelling ability than hawthorn pectin gels (DA > MI) based on the lower G' and lack of gel formation after 90 min of cooling in hawthorn pectin-based gels. The gelation results were closely linked to the starch-to-pectin ratio, purity, and degree of methyl esterification. • Hawthorn fruit from Mianqiu (MI) was richer in pectin than Dajinxing (DA) cultivar. • Flour from DA cultivar had higher starch, total dietary fiber and pasting viscosity. • Extractable phenolics were two-fold higher in DA, with stronger antioxidant capacity. • MI flour formed high-sugar acid gels with higher elastic modulus and less hardening. • Citrus pectins showed faster gelling and higher gel-strength than hawthorn pectins. [ABSTRACT FROM AUTHOR]

[Display omitted] • High-intensity ultrasound led to the unfolding of scallop MP conformation. • High-intensity ultrasound promoted the interaction and aggregation of MP molecules. • High-intensity ultrasound promoted the formation of disulfide bonds. • High-intensity ultrasound improved functional properties of scallop MP. • High-intensity ultrasound improved the strength and WHC of scallop surimi gel. 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. [ABSTRACT FROM AUTHOR]