Improved gelation functionalities of myofibrillar protein from pale, soft and exudative chicken breast meat by nonenzymatic glycation with glucosamine

Enhancement mechanism of glycation with l-arabinose and xylose on texture properties of silver carp mince gel

BACKGROUND

Glycation is a green processing technology. Based on our previous studies, glycation with l-arabinose and xylose was beneficial to enhance the texture properties of silver carp mince (SCM) gels. However, the possible enhancement mechanism remained unclear. Therefore, in this study, SCM gels with different types of reducing sugar (glucose, l-arabinose, and xylose) were prepared based on our previous study. The possible mechanism of texture enhancement of SCM gels was analyzed by investigating the changes in water distribution, protein structures, and microstructure in the gel system.

RESULTS

The glycation of l-arabinose and xylose enhanced the hardness, cohesiveness, chewiness, and resilience of SCM gels. Hardness increased from 1883.04 (control group) to 3624.54 (l-arabinose group) and 4348.18 (xylose group). Low-field nuclear magnetic resonance (LF-NMR) showed that glycation promoted the tight binding of immobilized water to proteins. Raman spectroscopic analysis showed that glycation increased the surface hydrophobicity and promoted the formation of disulfide bonds. Scanning electron microscopy (SEM) showed that glycation promoted the formation of uniform and dense three-dimensional network structure in SCM gels.

CONCLUSION

In summary, glycation enhanced the binding ability of immobilized water to proteins, improved the surface hydrophobicity, promoted the formation of disulfide bonds, and led to a more uniform and dense gel network structure of proteins, thus enhancing the texture properties of SCM gels. This research provided a theoretical basis for a better understanding of the mechanism of the effect of glycation on the quality of gel products and also provided technical support for the application of l-arabinose and xylose in new functional gel foods. © 2024 Society of Chemical Industry.

Changes in glycated myofibrillar proteins conformation on the formation of Nε-carboxymethyllysine under gradient thermal conditions

N^ε-carboxymethyllysine (CML), a frequently used marker of advanced glycation end products (AGEs) in food, was generated in food processing easily and caused changes in myofibrillar proteins (MPs) characterization. The relevance between glycosylated MPs structure alternation and CML formation under thermal conditions have been reported. However, the correlation mechanism was not clear yet. In this work, the influence of gradient heating (50℃, 60℃, 70℃, 80℃, and 90℃) on the different degrees of glycated MPs, which determined the correlation with CML formation in protein structural changes of MPs. In the rising stage of the CML level, glycation accelerated the fibrillation and aggregation behavior of MPs during heating and increased surface hydrophobicity and particle size. The protein cross-linking affected the protein modification caused by heating and glycation. This work highlights the substantial influences of glycosylation and thermal treatments on MPs, which transformed the MPs structural characteristics and CML level.

Magnetic field-assisted cascade effects of improving the quality of gels-based meat products: A mechanism from myofibrillar protein gelation

Physics-assisted processing technologies have huge potential in the meat processing industry. By modeling two essential procedures (pickling and preheating) of gels-based meat products, this work investigated the cascade effects of a new physical technology (magnetic field) on the conformational structures and gel properties of myofibrillar proteins (MPs). Samples were subjected with four magnetic field (MF)-assisted treatments (group A, both processes without MF; group B, pickling without MF combining with preheating with 4.5 mT MF; group C, pickling with 3.0 mT MF combining with preheating without MF; group D, pickling with 3.0 mT MF combining with preheating with 4.5 mT MF). The result showed that MF-assisted treatments significantly improved water holding capacity (WHC) of MP gels compared with group A (46.9%), reaching the maximum value of 52.1% in group D.According to the low-field nuclear magnetic results, group D decreased the percentages of P₂₂ (6.97%) and increased the percentages of P₂₁ (93%), which showed that water molecules were more tightly bound to each other. Meanwhile, the unfolding of α-helix and the formation of random coil of MF-assisted treatments resulted in more exposure of internal groups, leading to the formation of a dense network. These findings would provide new insights to improve the quality of gels-based meat products via the MF.

Glycosylation modification: A promising strategy for regulating the functionalities of myofibrillar proteins

Myofibrillar proteins (MPs), the most important proteins in muscle, play a vital role in the texture, flavor, sensory and consumer acceptance of final muscle-based food products. Over the past several decades, conjugation of carbohydrates to MPs via glycosylation is of particular interest due to the substantial enhancement in MPs characteristics. Studying the covalent interactions between carbohydrates and MPs under various processing conditions and molecular mechanisms by which carbohydrates affect the functionalities of MPs can introduce new perspectives for design and production of muscle-based foods. However, there is no insightful and comprehensive summary of the structural, physicochemical and functional characteristics changes of MPs induced by glycosylation modification and how these changes can be adopted to potentially promote the science-based development of tailor-made muscle foods. Based on this, the functionalities of MPs as well as their practical limiting issues are initially highlighted. A comprehensive overview of fabrication strategies is then introduced. Additionally, changes in the structural and functional properties of MPs regulated by glycosylation have also been carefully summarized. On this basis, the research limitations to be solved and our perspectives for the future development of muscle-based foods are put forward.

Effects of grafted myofibrillar protein as a phosphate replacer in brined pork loin

For the development of healthier meat products, the grafted myofibrillar protein was evaluated as an ingredient that can substitute phosphate in brined loin. Individual brine solutions, consisting of salt (negative control, NP), salt + sodium tripolyphosphate (positive control, PC), salt + myofibrillar protein without grafting (MP), salt + myofibrillar protein grafted at high concentration (GMP-H), and salt + myofibrillar protein grafted at low concentration (GMP-L), were added to the pork loin by 40% of their weight. Differential scanning calorimetry demonstrated that MP and GMP-H lowered the thermal energy for the transition of myosin and actin, thereby improving the thermal stability of pork loin and increasing protein solubility. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed that thicker protein bands appeared in MP and GMP-H samples while exhibiting increased pH values, moisture content, water holding capacity, and processing yield. Accordingly, the shear force of MP and GMP-H decreased. Lipid oxidation of pork loin was increased in MP, whereas it decreased in GMP-H. Thus, GMP-L is a potential substitute for phosphate since it improves physicochemical properties and prevents the lipid oxidation of pork loin.

Formation of Nε-Carboxymethyl-Lysine and Nε-Carboxyethyl-Lysine in Heated Fish Myofibrillar Proteins with Glucose: Relationship with Its Protein Structural Characterization

The formation of advanced glycation end products (AGEs), including N^ε-carboxymethyl-lysine (CML) and N^ε-carboxyethyl-lysine (CEL), in a fish myofibrillar protein and glucose (MPG) model system at 80 °C and 98 °C for up to 45 min of heating were investigated. The characterization of protein structures, including their particle size, ζ-potential, total sulfhydryl (T-SH), surface hydrophobicity (H₀), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared spectroscopy (FTIR), were also analyzed. It was found that the covalent binding of glucose and myofibrillar protein at 98 °C promoted protein aggregation when compared with the fish myofibrillar protein (MP) heated alone, and this aggregation was associated with the formation of disulfide bonds between myofibrillar proteins. Furthermore, the rapid increase of CEL level with the initial heating at 98 °C was related to the unfolding of fish myofibrillar protein caused by thermal treatment. Finally, correlation analysis indicated that the formation of CEL and CML had a significantly negative correlation with T-SH content (r = -0.68 and r = -0.86, p ≤ 0.011) and particle size (r = -0.87 and r = -0.67, p ≤ 0.012), but was weakly correlated with α-Helix, β-Sheet and H₀ (r² ≤ 0.28, p > 0.05) during thermal treatment. Overall, these findings provide new insights into the formation of AGEs in fish products based on changes of protein structure.

Changes in Gel Characteristics, Rheological Properties, and Water Migration of PSE Meat Myofibrillar Proteins with Different Amounts of Sodium Bicarbonate

The changes in the gel and rheological properties and water-holding capacity of PSE meat myofibrillar proteins with different amounts of sodium bicarbonate (SC, 0−0.6/100 g) were studied. Compared to the PSE meat myofibrillar proteins with 0/100 g SC, the texture properties and cooking yield significantly increased (p < 0.05) with increasing SC; meanwhile, adding SC caused the gel color to darken. All samples had similar curves with three phases, and the storage modulus (G’) values significantly increased with the increasing SC. The thermal stability of the PSE meat myofibrillar proteins was enhanced, and the G’ value at 80 °C increased with the increasing SC. Because water was bound more tightly to the protein matrix, the initial relaxation times of T21 and T22 shortened, the peak ratio of P21 significantly increased (p < 0.05), and the P22 significantly decreased (p < 0.05), which implied that the mobility of the water was reduced. Overall, SC could improve the thermal stability of the PSE meat myofibrillar proteins and increase the water-holding capacity and textural properties of the cooked PSE meat myofibrillar protein gels.

Synergistic effect of preheating and different power output high-intensity ultrasound on the physicochemical, structural, and gelling properties of myofibrillar protein from chicken wooden breast

The effects of preheating to 50 ℃ and the subsequent application of high-intensity ultrasound (HIU, 20 kHz) at 200, 400, 600, and 800 W on the physicochemical, structural, and gelling properties of wooden breast myofibrillar protein (WBMP) were studied. Results suggested that the WBMP structure expanded to the balanced state at 600 W, and rheological properties exhibit that 600 W HIU (P < 0.05) significantly improved the storage modulus (G') of WBMP. Notably, the WBMP gel (600 W) had the best hardness (65.428 ± 0.33 g), springiness (0.582 ± 0.01), and water-holding capacity (86.11 ± 0.83%). Raman spectra and low-field NMR indicated that 600 W HIU increased the β-fold content (37.94 ± 0.04%) and enlarged the immobilized-water proportion (93.87 ± 0.46%). Scanning electron micrographs confirmed that the gel was uniform and dense at 600 W. Therefore, preheating to 50 ℃ followed by HIU (600 W) helped form a superior WBMP gel.

Nano Filling Effect of Nonmeat Protein Emulsion on the Rheological Property of Myofibrillar Protein Gel

Incorporation of vegetable oils through pre-emulsification has received notable attention for delivering polyunsaturated fatty acids to emulsified-type meat products. The two important influencing factors of the rheological property of composite myofibrillar protein (MP) gel are emulsion droplet size and active or inactive interaction between interface and meat proteins. Incorporation of nonmeat protein emulsion (2% protein (w/w), egg-white protein isolate (EPI), porcine plasma protein (PPP), or sodium caseinate (SC)) with different droplet sizes (nano or macro) to a model of 2% MP gel was investigated in this research. The results of drop size measurement showed that 15,000 psi homogenizing could decrease the diameter of emulsion drop from macro- to nanoscale in the range of 324.4−734.5 nm. Active fillers (PPP and EPI emulsions) with nanodroplet size did not influence the viscosity of emulsion-filled composite cold sols but caused positive filling effects on the MP gel matrix after heating, as evidenced by the density microstructure. PPP and EPI nano-emulsion-filled composite MP had a significant high storage modulus enforcement effect, which reached nearly eight times those of other treatments (p < 0.05). Similarly, the results of thermal scanning rheology and a large-deformation mechanical test showed that PPP and EPI emulsions with nanoscale droplets, other than macroscale, had the highest gel strength of heat-induced emulsion-filled composite MP gel (p < 0.05). Overall, these findings will be helpful for selecting the correct pre-emulsified protein and designing the textural properties of foods.

Comparison of two kinds of peroxyl radical pretreatment at chicken myofibrillar proteins glycation on the formation of Nε-carboxymethyllysine and Nε-carboxyethyllysine

During meat processing, two typical advanced glycation end products (AGEs), N^ε-carboxymethyllysine (CML) and N^ε-carboxyethyllysine (CEL), are generated by free radical induction. However, the impact of peroxyl radicals on myofibrillar proteins (MPs) glycosylation and CML and CEL formation is scarcely reported. In this study, two peroxyl radicals called ROO· and LOO· derived from AAPH (2,2'-azobis (2-methylpropionamidine) dihydrochloride) and linoleic acid were exposed prior to the Maillard reaction (glucosamine incubation at 37 °C for 24 h). Levels of AGEs (CML/CEL), protein oxidation (sulfhydryl/carbonyl), free amino group, surface hydrophobicity, zeta potential, particle size, intrinsic fluorescence intensity and secondary structure were determined. Together with Pearson's correlation, the assumption that free radicals promote MPs oxidation and glycation, alter the aggregation behavior and structure modification, leading to AGEs promotion has been built. In addition, the effect of dose-dependency of peroxyl radical on AGEs has also been established with different effects of peroxyl radical induction.

Impact of methylglyoxal modification of chicken sarcoplasmic protein emulsions on emulsifying properties, rheological behavior and advanced glycation end products

BACKGROUND

Protein modification is used to improve emulsion properties. However, there are limited reports on the effect of methylglyoxal (MGO) modification on emulsifying properties and on the production of advanced glycation end-products (AGEs) in chicken sarcoplasmic protein emulsion (SPE). In this study, MGO solution was dispersed into prepared emulsion (17 mg mL^-1 sarcoplasmic-soybean oil (v/v 5:1)) at 0, 0.5, 5, 10, 30 and 50 mmol L^-1 concentrations. Emulsifying activity index (EAI), emulsifying stability index (ESI), Z-average diameter, polydispersity index (PDI), zeta potential, rheological behavior (thermal condensation characteristics and fluidity) and AGEs in different concentrations of MGO SPE were measured. In addition, the effect of MGO on the levels of AGEs, lipid and protein oxidation of the emulsion as well as their relationship has also been analyzed.

RESULTS

Our findings showed that ESI had the lowest value when MGO was added at a concentration of 10 mmol L^-1 , while Z-average, PDI, carbonyl and AGEs had the highest value at the same concentration. Also, 10 mmol L^-1 MGO played an important role in affecting the rheology of the emulsion. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) results showed that the presence of myofibrillar proteins (MPs) in SPE was the main reason for the crosslinking of polymers which could be damaged by high concentration of MGO (>10 mmol L^-1 ).

CONCLUSION

Different concentration of MGO showed varying effects on emulsion properties and on the formation of AGEs in chicken SPE. Pearson's correlation analysis concluded that protein oxidation played a significant positive role during MGO modification. © 2020 Society of Chemical Industry.