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In this study, silver carp surimi products enriched with Antarctic krill oil high internal phase emulsions (AKO-HIPEs) were cooked using steaming (STE), microwave heating (MIC), and air-frying (AIR), respectively. The gel and flavor properties, lipid quality and stability were investigated. Compared to the MIC and AIR groups, the STE surimi gel added with HIPEs had better texture properties, exhibiting higher water-holding capacity and a more homogeneous structure, while the air-frying treatment resulted in visually brighter surimi products. The degree of lipid oxidation during cooking was in an order of STE < MIC < AIR as determined by electron paramagnetic resonance spectrometer and thiobarbituric acid reactive substances. HIPE-added surimi gels retained more nutrients and flavor when cooked by AIR compared to STE and MIC. Results imply that the texture properties and lipid stability of surimi products fortified with AKO-HIPEs were better than those of the oil group under any cooking method. In conclusion, surimi products added with AKO-HIPEs had better gel properties and retained more fatty acids and flavor than AKO-SO. [ABSTRACT FROM AUTHOR]

Gelling properties are important functional characteristics of fish gelatin, which directly affects its application range and commercial value. Fish gelatin was modified with hyaluronic acid in different molecular weights in this work. The effect of hyaluronic acid on gelling properties and structural characteristics of fish gelatin was studied by rheometer, texture analyzer, infrared spectroscopy, and scanning electron microscope. The findings suggested that hyaluronic acid with different molecular weights decreased gel strength of fish gelatin, but significantly increased gelling temperature, melting temperature, and apparent viscosity of fish gelatin. Moreover, the higher molecular weight of hyaluronic acid, the greater changes in gelling properties of fish gelatin. When the molecular weight of hyaluronic acid was more than 1 800 kDa, gelling temperature, melting temperature, and apparent viscosity (η50) reached respectively 22.32 °C 32.48 °C, and 153 mPa·s, respectively. Hyaluronic acid slightly reduced gel strength of fish gelatin by less than 8.1% . The gelation dynamics analysis showed that regardless of molecular weight, hyaluronic acid could decrease the gel rate of fish gelatin and stabilize the gel network structure of fish gelatin. Infrared spectroscopy showed the FG-HA complex formation was mainly driven by electrostatic interaction, and the complex hindered the formation of hydrogen bond between molecular chains in fish gelatin. The scanning electron microscopy analysis showed that hyaluronic acid could effectively improve gel network structure in the composite colloid. Moreover, the FG-HA > 180W complex showed the most compact microstructure. This paper will provide a theoretical basis for improving functional properties and expanding the application of fish gelatin. [ABSTRACT FROM AUTHOR]

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.

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries 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 gelling properties and flavor quality of preserved eggs are affected by temperature reached during pickling. In response, this study investigates the effects of different temperature-controlled techniques on the gelling properties and flavor quality of preserved eggs. The results show that compared with an overall constant temperature and a two-stage temperature-controlled technique, the P-12–18–30 °C three-stage temperature-controlled pickling model produced the best texture properties of the preserved egg white gel, as further verified by LF NMR and SEM analysis. The results of amino acid analysis also show that the taste intensity of free amino acids in the P-12–18–30 °C group was significantly increased, especially for umami amino acids. In addition, the results of the electronic noise show that the volatile components of preserved eggs subjected to different temperature-controlled pickling techniques were similar, mainly consisting of short-chain alkanes; alcohols, aldehydes, ketones, and some aromatic compounds; long-chain alkane aliphatic groups; and inorganic sulfides, and there was no significant difference in the content of each flavor substance. In conclusion, this study offers theoretical basis for temperature-controlled pickling of preserved egg with better gel quality.

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.

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.

In this study, silver carp surimi products enriched with Antarctic krill oil high internal phase emulsions (AKO-HIPEs) were cooked using steaming (STE), microwave heating (MIC), and air-frying (AIR), respectively. The gel and flavor properties, lipid quality and stability were investigated. Compared to the MIC and AIR groups, the STE surimi gel added with HIPEs had better texture properties, exhibiting higher water-holding capacity and a more homogeneous structure, while the air-frying treatment resulted in visually brighter surimi products. The degree of lipid oxidation during cooking was in an order of STE < MIC < AIR as determined by electron paramagnetic resonance spectrometer and thiobarbituric acid reactive substances. HIPE-added surimi gels retained more nutrients and flavor when cooked by AIR compared to STE and MIC. Results imply that the texture properties and lipid stability of surimi products fortified with AKO-HIPEs were better than those of the oil group under any cooking method. In conclusion, surimi products added with AKO-HIPEs had better gel properties and retained more fatty acids and flavor than AKO-SO.

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.

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

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.)

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.

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.

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.

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.

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

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.)

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]

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.)

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]

The present work mainly investigated the changes of gel characteristics, rheological properties and ultrastructure of myofibrillar protein (MP) gels with varying amounts (2, 4, 6, and 8 %, w /w) of cross-linked tapioca starch (CTS) or acetylated tapioca starch (ATS). The findings showed that CTS or ATS notably improved the gelling characteristics (such as gel strength and water retention) of mixed MP gels in a dose-dependent manner (P < 0.05), which was clearly verified by the results of rheological behavior tests under different modes. Moreover, compared to ATS, CTS rendered higher gel strength and promoted the formation of a more uniform and smoother mixed MP gel matrix, which was mainly attributed to the higher peak viscosity of CTS. Furthermore, the images of iodine staining indicated that in mixed MP gels, the continuous phase supported by MP was gradually transited to being starch supported as the amounts of CTS or ATS increased between 2 % and 8 %. Additionally, hydrophobic interactions and disulfide bonds were the principal chemical forces of mixed MP gels, which could promote the occurrence phase transition. Briefly, our present work provided some vital understanding of the molecular interactions between MP and modified tapioca starches, which could efficiently modulate the quality profiles of meat products. • MP gels with cross-linked/acetylated tapioca starch (CTS/ATS) were prepared. • CTS or ATS promoted the gel and rheological properties of mixed MP gels. • Increasing levels of CTS or ATS led to obvious phase transition of mixed MP gels. • Hydrophobic interactions and disulfide bonds mainly promoted the phase transition. [ABSTRACT FROM AUTHOR]

The effects of κ -carrageenan (KC, 0.2 %, w/w) on the gelling properties and microstructures of heat-treated myofibrillar protein (MP) gels mediated by various levels (0, 0.1, 0.3, and 0.5 %, w/w) of microbial transglutaminase (TG) were investigated. The results revealed that regardless of TG level, the existence of KC significantly promoted the forming of disulphide bonds but limited the generation of large-sized protein polymers in MP gel treated with TG alone, as well as subsequently enhanced the water retention ability and gel strength of mixed MP gel, especially in the sample adding 0.3% TG and 0.2% KC, which was clearly verified by the forming of more denser and continuous gel network. Moreover, TG-induced changes in protein structure led to the alteration in the protein profiles of different MP gels, and an obvious down-regulation trend of myosin (Q9TV63, Q9TV62, P79293, and Q9TV61) was identified in the TG-0.3 group. Furthermore, liquid chromatography–tandem mass spectrometry analysis demonstrated that TG mainly induces protein crosslinking in the light meromyosin domain of the myosin rod. Meanwhile, in the presence of KC, the crosslinking-site percentage of the TG-0.3 group decreased from 37.7% to 36.2%, indicating that KC potentially reduces TG-induced crosslinking in MP gels. Thus, our findings illustrate the critical mechanisms underlying the modulation of KC on the gelling properties of TG-mediated MP gels at the molecular level, which providing potential guideline for the combined applications of TG and KC in the meat industry. [Display omitted] • Transglutaminase (TG) level altered the crosslinking of myofibrillar protein (MP). • TG mainly induced crosslinking in the light meromyosin region of the myosin rod. • κ -Carrageenan (KC) addition enhanced the gelling properties of TG-mediated MP. • Proteomics revealed that KC lowered number of TG crosslinking sites in myosin rod. [ABSTRACT FROM AUTHOR]

Aim of this research was to assess gelling properties and riboflavin delivery capacity of mung bean protein (MBP)-sugar beet pectin (SBP) hydrogels by duo-induction of heat and laccase. The results showed that hydrogel properties were regulated by SBP concentration. When SBP concentration was 0.20%, composite hydrogel had the highest stress (665.27 ± 26.36 Pa), water holding capacity (WHC) (75.68 ± 0.88%), storage modulus (G′) and surface hydrophobicity (H 0) (9550.50 ± 33.86) (P < 0.05). At the same time, network structure of composite hydrogel was the densest and system was the most stable. When SBP concentration was 0.20%, composite hydrogel had better swelling rate, riboflavin encapsulation efficiency (51.81 ± 2.31%), cumulative release rate, biological accessibility (37.83 ± 0.90%) and storage stability (P < 0.05) compared with low concentration SBP. The introduction of SBP triggered the transition of riboflavin release mechanism to non-Fick release mechanism and transported riboflavin to the colon effectively. This study might provide theoretical support for the interaction between proteins and polysaccharides in composite hydrogel system as well as provide theoretical basis for composite hydrogel to be a delivery vehicle for bioactive substances. [Display omitted] • Composite hydrogel was formed by dual induced of heat and laccase. • Sugar beet pectin (SBP) improved the properties of mung bean protein (MBP) hydrogel. • SBP facilitated forming a dense composite hydrogel network structure. • MBP-SBP hydrogel was effective in encapsulating and delivering riboflavin. [ABSTRACT FROM AUTHOR]

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]

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]

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]

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

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 (