Insights into the trace Sr2+ impact on the gel properties and spatial structure of mutton myofibrillar proteins

Study on the interaction and gel properties of pork myofibrillar protein with konjac polysaccharides

BACKGROUND

Natural myofibrillar protein (MP) is sensitive to changes in the microenvironment, such as pH and ionic strength, and therefore can adversely affect the final quality of meat products. The aim of this study was to modify natural MP as well as to improve its functional properties. Therefore, the quality improvement effect of konjac polysaccharides with different concentrations (0, 1.5, 3, 4.5 and 6 g kg-1 protein) on MP gels was investigated.

RESULTS

With a concentration of konjac polysaccharides of 6 g kg-1 protein, the composite gel obtained exhibited a significant improvement of water binding (water holding capacity increased by 7.71%) and textural performance (strength increased from 29.12 to 37.55 N mm, an increase of 8.43 N mm). Meanwhile, konjac polysaccharides could help to form more disulfide bonds and non-disulfide covalent bonds, which enhanced the crosslinking of MP and maintained the MP gel network structure. Then, with the preservation of α-helix structure (a significant increase of 8.11%), slower protein aggregation and formation of small aggregates, this supported the formation of a fine and homogeneous network structure and allowed a reduction in water mobility.

CONCLUSION

During the heating process, konjac polysaccharides could absorb the surrounding water and fill the gel system, which resulted in an increase in the water content of the gel network and enhanced the gel-forming ability of the gel. Meanwhile, konjac polysaccharides might inhibit irregular aggregation of proteins and promote the formation of small aggregates, which in turn form a homogeneous and continuous gel matrix by orderly arrangement. © 2023 Society of Chemical Industry.

Insight into the effect of large yellow croaker roe phospholipids on the physical properties of surimi gel and their interaction mechanism with myofibrillar protein

BACKGROUND

The present study aimed to investigate the effects of large yellow croaker roe phospholipids (LYCRPLs) on the physical properties of surimi gels and to clarify their interaction mechanism with myofibrillar proteins (MPs) in terms of chemical forces and the spatial conformation.

RESULTS

LYCRPLs could improve the gel strength, textural properties, rheological properties and water-holding capacity of surimi gels. Moreover, the interaction mechanism between LYCRPLs with MPs was revealed through intermolecular forces, Fourier transform infrared spectroscopy and ultraviolet visible absorption spectroscopy. The findings demonstrated that LYCRPLs enhanced the surface hydrophobicity and particle size of MPs, facilitating expansion and cross-linking of MPs.

CONCLUSION

These results provide a theoretical basis for improving the characteristics of surimi gels and thus facilitate the application of LYCRPLs in the aquatic food industry. © 2023 Society of Chemical Industry.

Improving the texture attributes of squid meat (sthenoteuthis oualaniensis) with slight oxidative and phosphate curing treatments

This study aimed to improve the pasty texture of squid meat by oxidative and phosphate curing (OPC) treatment, and elucidate the underlying mechanism. The shear force, springiness, weight gain, water-holding capacity (WHC), color and sensory evaluation of squid meat samples treated with a mild OPC approach (OPC_2, 10 mM H2O2 solution with complex phosphate solution) were significantly improved. However, the samples subjected to over-oxidized (20 and 30 mM H2O2 solution with complex phosphate solution) treatment did not obtain favorable outcomes. Microstructure analysis revealed that muscle fibers aggregated after moderate OPC treatments, leading to an increased spacing between muscle fiber bundles. This gap facilitated a more uniform distribution and restriction of water, according to low-field nuclear magnetic resonance (LF-NMR) results. The results from in vitro simulated oxidation of myofibrillar proteins (MPs) demonstrated that increased H2O2 led to formation of carbonyl groups and decreased sulfhydryl groups, and even secondary structure changes, according to fourier transform infrared spectroscopy (FT-IR). Particle size, zeta potential and sodium dodecyl sulfate-polyacryl amide gel electrophoresis (SDS-PAGE) results showed that oxidation caused protein aggregation into larger molecules. This study presents a novel approach to improve pasty texture of squid meat.

Combination of carrageenan with sodium alginate, gum arabic, and locust bean gum: Effects on rheological properties and quiescent stabilities of partially crystalline emulsions

In the present study, carrageenan (CG) was combined with sodium alginate (SA), gum arabic (GA), and locust bean gum (LBG) to obtain four gum combinations (CG, CG + SA, CG + GA, and CG + LBG). The effects of different combinations on rheological properties and quiescent stabilities of PCEs were systematically investigated through characterization of fresh emulsion related parameters (rheological properties, forces between proteins, zeta potentials, surface tensions, interfacial adsorption properties, and multiple light scattering) and storage related parameters (visual appearance, creaming index, viscosities, particle sizes, and microscopic morphology). Rheological results indicated that CG PCEs had the highest apparent viscosities of 7.77-41.91 Pa·s at 0.01 s-1, followed by CG + SA PCEs (2.35-30.62 Pa·s), CG + GA PCEs (2.37-21.16 Pa·s), and CG + LBG PCEs (2.06-19.93 Pa·s). At low thickener concentration (0.02 %), CG PCE exhibited weak gel structure due to higher G' than G″ at all frequencies, while CG + SA, CG + GA, and CG + LBG PCEs had entangled network due to intersection between G' and G″. After three months of storage, CG + SA PCEs showed the lowest creaming index values (11.47-17.75 %), which were significantly lower than CG PCEs (15.35-20.85 %), CG + GA PCEs (15.97-24.42 %), and CG + LBG PCEs (17.13-21.71 %). Meanwhile, all the samples except for 0.02 % CG + SA PCE completely lost fluidity, and their viscosities were above 14,000 mPa·s. It was further found that CG stabilized emulsions showed severe droplet flocculation induced by hydrophobic interactions among adsorbed proteins. Combination of CG with SA, GA, and LBG, especially CG + SA, formed strong network structure and reduced contribution of hydrophobic interactions, which effectively inhibited flocculation of fat droplets, thereby improving rheological properties and storage stabilities of PCEs.

Research advances of molecular docking and molecular dynamic simulation in recognizing interaction between muscle proteins and exogenous additives

During storage and processing, muscle proteins, e.g. myosin and myoglobin, will inevitably undergo degeneration, which is thus accompanied by quality deterioration of muscle foods. Some exogenous additives have been widely used to interact with muscle proteins to stabilize the quality of muscle foods. Molecular docking and molecular dynamics simulation (MDS) are regarded as promising tools for recognizing dynamic molecular information at atomic level. Molecular docking and MDS can explore chemical bonds, specific binding sites, spatial structure changes, and binding energy between additives and muscle proteins. Development and workflow of molecular docking and MDS are systematically summarized in this review. Roles of molecular simulations are, for the first time, comprehensively discussed in recognizing the interaction details between muscle proteins and exogenous additives aimed for stabilizing color, texture, flavor, and other properties of muscle foods. Finally, research directions of molecular docking and MDS for improving the qualities of muscle foods are discussed.