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

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

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

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

Protective mechanisms of three antioxidants against T-2 toxin-induced muscle protein deterioration in shrimp.

BACKGROUND: Quercetin (Q), tea polyphenols (TP), and rutin (R) are widely used plant-derived active ingredients. They possess antioxidant, anti-inflammatory, and anti-tumor properties, and can reduce the muscle damage caused by mycotoxins. However, few studies have examined the protective mechanisms of quercetin, tea polyphenols, and rutin on muscle quality. To elucidate their protective mechanisms, shrimp were exposed to both T-2 toxin and these three antioxidants for 20 days in a dose-escalating trial. The changes in the protein composition of shrimp muscle were measured. The target proteins associated with T-2 and antioxidants were screened and identified by non-labeled quantitative proteomics. RESULTS: The T-2 toxin induced abnormal expression of 21 target proteins, leading to the deterioration of muscle proteins in shrimp. The three antioxidants ameliorated the T-2 toxin-induced damage to muscle proteins by increasing the sarcoplasmic and myofibrillar protein content and decreasing the alkali-soluble protein content. Quercetin had the strongest protective effect. The protective processes of these antioxidants involved the upregulation of target proteins involved in carbohydrate metabolism (enolase, malate dehydrogenase), protein translation (elongation factor 1-alpha and eukaryotic translation initiation factor 2 subunit alpha), and cytoskeleton component (actin 2, fast-type skeletal muscle actin 1). Quercetin regulated the largest number of target proteins, making it the best protective agent against T-2 toxin. CONCLUSION: The T-2 toxin (4.80-24.30 mg/kg feed) induced changes in target proteins and muscle composition of shrimp, leading to a deterioration in muscle proteins. Quercetin (2.00-32.00 g/kg feed) had significant protective effects against this deterioration in muscle protein in shrimp. © 2022 Society of Chemical Industry.

Myofibrillar protein composite gels: effect of esterified potato starch, lard and peanut oil on the gel properties.

BACKGROUND: Heat-induced composite gels were prepared with 20 g kg-1 myofibrillar protein (MP) sol, 20 g kg-1 modified starch and 100 g kg-1 lipid pre-emulsified by MP in 0.6 mol L-1 NaCl, at pH 6.2. The effects of esterified potato starch (EPS) and emulsified lipid (lard or peanut oil) on the rheology, texture properties and nuclear magnetic resonance characterization of MP gel were evaluated. RESULTS: The addition of starch and lipid significantly improved the gel strength and water holding capacity (WHC) of the MP gel. Analysis of the relaxation time compared with the WHC tests showed that the variation range of the transverse T22 relaxation time of a gel was positively proportional to changes in WHC of the composite gel, and the lower the T22 relaxation time, the better the WHC of composite gel. Moreover, MP gel with starch and emulsified lard added at the same time has the lowest T2 relaxation time, and also the best WHC of the gel. Environmental scanning electron microscopy showed that emulsified oil droplets embedded the gaps in the protein network, and the gelatinized starch contributed to restrict the oil droplet size, resulting in thicker MP gel. CONCLUSION: Emulsified lipid and modified starch have an important influence on the rheology and microstructure of MP gels, indicating the subtle interaction between starch, lipid and protein. The results suggest the potential feasibility of modified starch and vegetable oil to improve the textural properties in comminuted meat products. © 2021 Society of Chemical Industry.

Development and characterization of fish myofibrillar protein/chitosan/rosemary extract composite edible films and the improvement of lipid oxidation stability during the grass carp fillets storage.

Biofilm composition from fish myofibrillar protein (FMP) and chitosan solution (CS) incorporated with rosemary extract (RE) was developed and applied to monitor the freshness of fish fillets. The effects of different concentrations of RE as well as physical, mechanical, structural and functional properties of FMP/CS films were investigated. Films containing RE showed reduced water solubility and water vapor permeability and enhanced tensile strength and elongation at break. Results also showed good compatibility of the components and good dispersion of RE in the matrix. However, the content of RE (0.2%, v/v) added in the composite films produced aggregations and had negative effects on their film-forming properties. The antioxidant capacity of composite films was related to the level of RE and demonstrated by the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay. Chilled grass carp fillets wrapped with different films to evaluate the preservative effect. Results of thiobarbituric acid reactive substances, pH value, Free amino acid and total volatile basic nitrogen indicated that FMP/CS/RE composite film could protect the fish fillet well and inhibit the lipid oxidation. The developed FMP/CS/RE composite films possess the potential to be applied as edible films in the food packaging industry and food cold chain transportation.

Synergistic effects of UVA irradiation and phlorotannin extracts of Laminaria japonica on properties of grass carp myofibrillar protein gel.

BACKGROUND: Oxidized phlorotannin can be used as a protein crosslinking agent to produce high-quality fish gel products. Phlorotannin can be easily induced to form quinone compounds in an oxidizing environment, while o-quinone has been proven to be a reactive, electrophilic intermediate that easily reacts with proteins to form rigid molecular crosslinking networks. The objective of this study was to investigate the synergistic effects of ultraviolet A (UVA) irradiation (1 h, 15 W m-2 ) and various concentrations of Laminaria japonica phlorotannin extracts (PTE) on the gel properties of grass carp myofibrillar protein (MP). RESULTS: UVA treatment and PTE could synergistically improve the MP gel properties more than PTE alone (P < 0.05). At 625 mmol kg-1 MP PTE alone, the gel strength and cooking yield reached 3.10 ± 0.16 g cm and 47.45 ± 0.35%, respectively, while with the same level of PTE plus UVA they became 4.26 ± 0.19 g cm and 53.89 ± 1.54%, respectively. The three-dimensional network structure of the gel (with PTE + UVA) showed higher connectivity and tightness than that of the control group (no treatment). CONCLUSIONS: The synergistic effects of PTE and UVA could effectively induce crosslinking of grass carp MP, which could lead to an improvement of MP gel quality. These findings would provide a new technical approach to produce high-quality protein gel products in the fish processing industry. © 2020 Society of Chemical Industry.

The mechanistic effect of bromelain and papain on tenderization in jumbo squid (Dosidicus gigas) muscle.

Jumbo squid (Dosidicus gigas) muscle is rather hard and tough, which directly affects consumer acceptance. In this study, the tenderization effect of bromelain and papain on squid muscle during enzymolysis is examined and compared with an untreated control and water-treated sample. Squid mantle were incubated with different solutions (water, bromelain, and papain solution) for 40 min in a 30 °C water bath. Then, the mantle samples were subjected to water holding capacity (WHC) analysis, texture evaluation, biochemical determination, and histological observations. The results revealed that bromelain and papain disadvantageously decrease the water holding capacity when compared to the control and water-treated samples. Furthermore, following tenderization with bromelain or papain, muscle hardness, shear force, myofibrillar protein content, and Ca2+ ATPase activity were all significantly decreased. Additionally, some essential amino acids were released following tenderization. When examining the myofibrillar fragmentation index (MFI), bromelain and papain were shown to cause high levels of hydrolysis in myofibrillar and sarcoplasmic proteins. Moreover, microstructural imaging indicated that the tenderization treatments disrupted myofibrils and generated a larger number of small fragments in the muscle tissues, subsequently decreasing microstructure stability and integrity. SDS-PAGE analysis confirmed that bromelain and papain have a high proteolytic activity, with some small peptides and/or short fragments detected post-tenderization. The results presented herein demonstrated that bromelain and papain improved squid muscle tenderness and can be utilized to ensure a more desirable squid product.

Influence of sodium pyrophosphate on the physicochemical and gelling properties of myofibrillar proteins under hydroxyl radical-induced oxidative stress.

Porcine myofibrillar proteins (MP) with or without sodium pyrophosphate (PP) were oxidatively stressed in hydroxyl radical (˙OH)-generating systems (10 µM FeCl3, 100 µM ascorbic acid, and 0, 0.5, 3, 10 mM H2O2) at 4 °C for 12 h. The results showed significant protein oxidation under the ˙OH stress, indicated by the modification of amino acid side chain groups and the aggregation of MP, which led to losses in gelling properties of MP especially at high dosages of H2O2 (3-10 mM). The PP addition effectively suppressed ˙OH induced lipid oxidation (as evidenced by TBARS values) in MP, but the inhibitory effect on protein oxidation was limited. In fact, the PP treatment with a high level of H2O2 (10 mM) tended to promote protein unfolding and aggregation in the tested systems. However, a significantly (P < 0.05) improved protein solubility was found in all tested systems with added PP. The PP treated MP gels exhibited a more compact and orderly microstructure, which may explain the reduced cooking loss and improved gel strength.

Effect of typical starch on the rheological properties and NMR characterization of myofibrillar protein gel.

BACKGROUND: Composite gels were individually prepared from 20 g kg-1 myofibrillar protein (MP) imbedded with typical native starch (potato, tapioca, rice or corn starch) in 0.6 mol L-1 NaCl at pH 6.2. The gel strength, water holding capacity, rheological properties and microstructure of the obtained myofibrillar protein-starch composite gels were evaluated. RESULTS: Tapioca starch improved (P < 0.05) gel strength and water holding capacity of MP composite gel at 80 °C. Rheological properties of MP-starch composites differed significantly with the addition of different types of native starch. Additionally, the promoting effect of starch on the storage modulus of the composite gels positively correlated with the gelatinization properties of different typical starch. Environmental scanning electron microscopy showed that the filling effect of starch on the composite gel was related to the pasting temperature and particle size of typical starch, with almost no particles forming at 80 °C. Moreover, the addition of starch changed the relaxation peak area and increased the relaxation time in nuclear magnetic resonance tests, which suggested that starch could improve the water holding capacity of MP-starch composite gels. CONCLUSION: Different typical native starch has varied impacts on the gel strength, water holding capacity, rheological properties and microstructure of MP gels, indicating the potential and feasibility of these typical native starches as an addition agent to modify the textural properties in comminuted meat products. © 2019 Society of Chemical Industry.

Antioxidant Effect of Extracts from Native Chilean Plants on the Lipoperoxidation and Protein Oxidation of Bovine Muscle.

The present study investigated the antioxidant potential and the ability to inhibit lipid and protein oxidation in bovine meat of four native Chilean species: canelo (Drimys winteri), nalca (Gunnera tinctoria), tiaca (Caldcluvia paniculata), and ulmo (Eucryphia cordifolia). Phenolic acids (gallic, chlorogenic, caffeic, and coumaric) and flavonoids (catechin, epicatechin, and rutin) were identified and quantified by HPLC-MS/MS. Drimys winteri extract exhibited the highest antioxidant capacity evaluated by oxygen radical absorption capacity-red pyrogallol method (ORAC-PGR) and ferric ion reducing antioxidant power (FRAP) assays. All extracts decreased lipid oxidation induced by 2,2'-azo-bis(2-amidinopropane) dihydrochloride (AAPH) derived peroxyl radicals by anywhere between 30% and 50% the. In addition, canelo and nalca extracts decreased spontaneous oxidation by around 57% and 37% in relation to the control group, being even more efficient than butylated hydroxyanisole (BHT) a synthetic antioxidant. Protein oxidation in the myofibrillar proteins was evaluated by the formation of protein carbonyls and loss of protein thiols. The canelo, ulmo, and nalca extracts decreased the formation of carbonyls by around 30%. Plant extracts and BHT did not show an antioxidant effect on protein thiol loss. However, tiaca and ulmo extracts exerted a pro-oxidant effect, favoring the oxidation of sulfhydryl groups. The oxidizing system induced structural changes in myofibrillar protein (SDS-PAGE). A protective effect on protein structure from the canelo extract can be observed during the incubation when compared to samples incubated with AAPH.

Effect of Opuntia dillenii polysaccharide on gelling properties of Trichiurus lepturus myobrilar protein.

In this study, the effects of Opuntia dillenii polysaccharide (ODP) at different concentrations (1%, 3% and 5% wet materials) on the gel properties of Trichiurus lepturus myofibrillar proteins were investigated. ODP was prepared by hot water extraction, consisted of arabinose, xylose, fructose, glucose, galacturonic acid and rhamnose and its molecular weight was 106 kDa. The addition of ODP increased the water holding capacity, sulfhydryl content adhesiveness, cohesiveness, elasticity and overall likeness of T. lepturus myofibrillar proteins gel. However, a high dose (5% wet materials) of ODP could not further increase or decrease its efficiency compared with moderate dose (3% wet materials). Consequently, the addition of ODP increased the gel properties of T. lepturus myofibrillar protein gel and could be used as a myofibrillar protein gel supplement.

Effect of glazing and rosemary (Rosmarinus officinalis) extract on preservation of mud shrimp (Solenocera melantho) during frozen storage.

In this study, glazing with water and rosemary (Rosmarinus officinalis) extract were applied on frozen mud shrimp (Solenocera melantho) and stored at -20 °C for 24 weeks. Quality loss and protein and lipid changes of shrimp were evaluated by total volatile basis nitrogen (TVB-N), drip loss, moisture distribution, sulfhydryl content (SH), disulfide bond, intrinsic fluorescence intensity, lipid content, free fatty acids (FFA), peroxide value (PV), fluorescent compounds and sensory characteristics. Results showed that unglazed mud shrimp exhibited significant quality decline after 16 weeks of frozen storage. Glazing treatment significantly reduced quality loss, protein degradation, and lipid oxidative damage of shrimp during the 24 weeks of frozen storage, compared to the unglazed control sample. Glazing with rosemary extract was more effective in controlling quality changes in frozen mud shrimp with lower TVB-N, drip loss, PV, FFA and higher lipid content and sensory scores.

Impact of the calcium form of ß-hydroxy-ß-methylbutyrate upon human skeletal muscle protein metabolism.

BACKGROUND & AIMS: ß-hydroxy-ß-methylbutyrate (HMB) is purported as a key nutritional supplement for the preservation of muscle mass in health, disease and as an ergogenic aid in exercise. Of the two available forms of HMB (calcium (Ca-HMB) salt or free acid (FA-HMB)) - differences in plasma bioavailability have been reported. We previously reported that ∼3 g oral FA-HMB increased muscle protein synthesis (MPS) and reduced muscle protein breakdown (MPB). The objective of the present study was to quantify muscle protein metabolism responses to oral Ca-HMB. METHODS: Eight healthy young males received a primed constant infusion of 1,2 13C2 leucine and 2H5 phenylalanine to assess MPS (by tracer incorporation in myofibrils) and MPB (via arterio-venous (A-V) dilution) at baseline and following provision of ∼3 g of Ca-HMB; muscle anabolic (MPS) and catabolic (MPB) signalling was assessed via immunoblotting. RESULTS: Ca-HMB led a significant and rapid (<60 min) peak in plasma HMB concentrations (483.6 ± 14.2 µM, p < 0.0001). This rise in plasma HMB was accompanied by increases in MPS (PA: 0.046 ± 0.004%/h, CaHMB: 0.072 ± 0.004%/h, p < 0001) and suppressions in MPB (PA: 7.6 ± 1.2 µmol Phe per leg min-1, Ca-HMB: 5.2 ± 0.8 µmol Phe per leg min-1, p < 0.01). Increases in the phosphorylation of mTORc1 substrates i.e. p70S6K1 and RPS6 were also observed, with no changes detected in the MPB targets measured. CONCLUSIONS: These findings support the pro-anabolic properties of HMB via mTORc1, and show that despite proposed differences in bioavailability, Ca-HMB provides a comparable stimulation to MPS and suppression of MPB, to FA-HMB, further supporting its use as a pharmaconutrient in the modulation of muscle mass.

Effects of (-)-epigallocatechin-3-gallate incorporation on the physicochemical and oxidative stability of myofibrillar protein-soybean oil emulsions.

The dose-dependent effects of (-)-epigallocatechin-3-gallate (EGCG; at 0, 50, 100, 200, 500, and 1000 mg/L) on the physical, chemical, and oxidative stability of porcine myofibrillar protein (MP)-soybean oil emulsion systems were investigated. The results showed EGCG at all levels effectively suppressed lipid oxidation in MP emulsion composite gels during the entire chill storage (at 4 °C for 0, 3, or 7 days). The incorporation of EGCG at higher concentrations (>100 mg/L) promoted the loss of sulfhydryls, reduction of surface hydrophobicity, and aggregation and cross-linking of MP. As a result, high concentrations of EGCG (500 and 1000 mg/L) hampered emulsification and gel formation of MP. However, EGCG at lower concentrations (50-200 mg/L) improved the oxidative stability of meat emulsions without jeopardizing the textural stability.

Protective effects of Momordica grosvenori extract against lipid and protein oxidation-induced damage in dried minced pork slices.

The experiment was conducted to assess the protective effects of Momordica grosvenori extract (MGE) against lipid and protein oxidation-induced damage in vacuum-packed dried minced pork slices stored at room temperature for 21days. Antioxidant activity of MGE was evaluated by measuring its radical scavenging activities and reducing power with progressive concentrations from 40 to 200g/L. MGE was added to the dried minced pork slices at 7, 10 or 15g/100g. Results showed that inclusion of MGE in dried minced pork slice significantly delayed the formation of hexanal, thiobarbituric acid-reactive substances and carbonyls and reduced the sulfhydryl loss in a dose-dependent manner (P<0.05), indicating that MGE exerted a protective effect against lipids and protein oxidation. Concomitantly, an intense increase of redness and loss of lightness and yellowness was found to take place (P<0.05), though it exhibited little negative effects on the sensory properties of slices. Mogrosides, the main bioactive components in M. grosvenori, decreased primarily during processing while they were relatively stable during storage under vacuum condition, room temperature. All these results demonstrated MGE had great potential as a natural antioxidant used in meat products.

The influence of peri-conception and first trimester dietary restriction of protein in cattle on meat quality traits of entire male progeny.

Primiparous Santa Gertrudis heifers were used to evaluate the effects of gestational dietary protein content on meat quality traits of 20month old bull progeny (n=40). At -60d before AI, heifers were randomly allocated to HIGH or LOW protein diet (HPERI and LPERI). From 24dpc, half of each treatment group changed to an alternative post-conception HIGH or LOW protein diet (HPOST and LPOST). LPERI and LPOST diets resulted in higher shear force of the semitendinosus muscle than HPERI (P=0.053) and HPOST (P=0.003), respectively. Heat-soluble collagen in the semitendinosus muscle was lower (P=0.019) for LPERI than HPERI. Collagen and tenderness of the longissimus muscle were not affected by dam nutrition (P>0.05). Color, pH, sarcomere length, cooking loss, compression values, desmin and troponin-T degradation, fiber type, intramuscular fat and polyunsaturated fatty acid content were not affected by dam nutrition during the peri-conception and first trimester gestational period (P>0.05).

The effectiveness of clove extracts in the inhibition of hydroxyl radical oxidation-induced structural and rheological changes in porcine myofibrillar protein.

Oxidation is a major cause of protein quality deterioration during the storage and processing of food. This study investigated the effects of clove extract (CE) on structural and rheological changes in porcine longissimus myofibrillar proteins (MP) and the effects of oxidizing radicals produced by a Fenton reaction system (FRS). Increased oxidation time was accompanied by increased carbonyl content, reduced Ca-ATPase activity, decreased enthalpy of denaturation, decreased thermal transition temperatures (P<0.05), and increased protein susceptibility to thermal aggregation. The addition of CE significantly inhibited carbonyl formation (P<0.05), enhanced solubility and thermal stability, and improved the gel formation ability (storage modulus, loss modulus) of MP. The protective effect of CE on protein denaturation was demonstrated by its efficacy in maintaining Ca-ATPase activity and decreasing the degree of protein aggregation. Overall, the hydroxyl radical-induced loss of the structural and functional properties of MP was significantly reduced by the presence of CE.

Role of interfacial protein membrane in oxidative stability of vegetable oil substitution emulsions applicable to nutritionally modified sausage.

The potential health risk associated with excessive dietary intake of fat and cholesterol has led to a renewed interest in replacing animal fat with nutritionally-balanced unsaturated oil in processed meats. However, as oils are more fluid and unsaturated than fats, one must overcome the challenge of maintaining both physical and chemical (oxidative) stabilities of prepared emulsions. Apart from physical entrapments, an emulsion droplet to be incorporated into a meat protein gel matrix (batter) should be equipped with an interactive protein membrane rather than a small surfactant, and the classical DLVO stabilization theory becomes less applicable. This review paper describes the steric effects along with chemical roles (radical scavenging and metal ion chelation) of proteins and their structurally modified derivatives as potential interface-building materials for oxidatively stable meat emulsions.

LuciPHOr2: site localization of generic post-translational modifications from tandem mass spectrometry data.

UNLABELLED: We present LuciPHOr2, a site localization tool for generic post-translational modifications (PTMs) using tandem mass spectrometry data. As an extension of the original LuciPHOr (version 1) for phosphorylation site localization, the new software provides a site-level localization score for generic PTMs and associated false discovery rate called the false localization rate. We describe several novel features such as operating system independence and reduced computation time through multiple threading. We also discuss optimal parameters for different types of data and illustrate the new tool on a human skeletal muscle dataset for lysine-acetylation. AVAILABILITY AND IMPLEMENTATION: The software is freely available on the SourceForge website http://luciphor2.sourceforge.net. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

The N- and C-terminal autolytic fragments of CAPN3/p94/calpain-3 restore proteolytic activity by intermolecular complementation.

CAPN3/p94/calpain-3, a calpain protease family member predominantly expressed in skeletal muscle, possesses unusually rapid and exhaustive autolytic activity. Mutations in the human CAPN3 gene impairing its protease functions cause limb-girdle muscular dystrophy type 2A (LGMD2A); yet, the connection between CAPN3's autolytic activity and the enzyme's function in vivo remain unclear. Here, we demonstrated that CAPN3 protease activity was reconstituted by intermolecular complementation (iMOC) between its two autolytic fragments. Furthermore, the activity of full-length CAPN3 active-site mutants was surprisingly rescued through iMOC with autolytic fragments containing WT amino acid sequences. These results provide evidence that WT CAPN3 can be formed by the iMOC of two different complementary CAPN3 mutants. The finding of iMOC-mediated restoration of calpain activity indicates a novel mechanism for the genotype-phenotype links in LGMD2A.