Influence of Xanthan Gum on the Structural Characteristics of Myofibrillar Proteins Treated by High Pressure

Combined effect of ultrasound treatment and κ-carrageenan addition on the enhancement of gelling properties and rheological behavior of myofibrillar protein: An underlying mechanisms study

This work aimed to investigate the combined effect of ultrasound (US) treatment and κ-carrageenan (KC) addition on the gelling properties and rheological behaviors of myofibrillar protein (MP). Without US treatment, the KC incorporation promoted the gel strength and water-holding capacity (WHC) of MP gels. These properties were further improved by 20 min US treatment with gel strength of 98.61 g and WHC of 79.87 %, which was mainly attributed to changes associated with hydrophobic interactions and disulfide bonds and the transformation from α-helix to β-sheet in MP gels. In addition, US treatment for 20 min effectively resulted in a more homogeneous polymer distribution of the MP-KC mixed system, leading to lower particle size and the largest G' and G″ values of the MP-KC mixed gels. However, longer US treatment times (30, 40 and 50 min) rendered lower gel strength, WHC, storage modulus and loss modulus of MP-KC mixed gels, which was mainly due to the formation of loose and disordered gel structures. Our present results indicated that the application of US to MP for an intermediate treatment time (20 min) combined with KC provides a potential and novel strategy to promote the gel qualities of heat-induced MP gels.

Effects of hydrocolloids as fat-replacers on the physicochemical and structural properties of salt-soluble protein isolated from water-boiled pork meatballs

Konjac glucomannan (KGM), xanthan gum (XG), guar gum (GG), and κ-carrageenan (KC), as substituent, are commonly used in ground pork products. Here, the content of these (0.5, 1.0, 1.5, and 2.0%, w/w) on the gel properties, thermal properties, and interaction forces of salt-soluble protein (SSP) isolated from water-boiled pork meatballs were investigated. We found 1.0% KGM, 0.5% XG, 0.5-2.0% GG, and 0.5-2.0% KC to water-boiled pork meatballs exerted a positive effect on the denaturation temperature, hydrogen bonds, hydrophobic interactions, disulfide bonds, α-helix, and β-sheet content of SSP, as well as the strength and storage modulus of the modified protein gel. The addition of these hydrocolloids with the addition of 1.0% aggregated myosin and actin, led to the enhancement of the bands corresponding to myosin heavy chain and actin. The prediction model of gel strength showed that the gel strength was negatively correlated with Tpeak1, Tpeak2, and ionic bond. This study provides theoretical guidance for improving the application of hydrocolloids in pork-based foods.

Effects of combined chickpea protein isolate and chitosan on the improvement of technological quality in phosphate-free pork meat emulsions: Its relation to modifications on protein thermal and structural properties

The effects of combined chickpea protein isolate (CPI, 1%, w/w) and chitosan (CHI, 1%, w/w) on the technological, thermal, and structural properties of phosphate-free pork meat emulsions (PPMEs) were investigated. The results showed that CPI + CHI significantly improved the emulsion stability (P < 0.05), synergistically elevated the hardness and chewiness, and did not negatively impact the color attributes, which endowed the PPMEs with similar or even better technological performances compared to the high-phosphate control. These alterations were related to the reduced myosin enthalpy values, the rearrangement of free water into immobilized water, the synergistic reduction in α-helical structure and increase in β-sheet structure, the increased trans-gauche-trans SS conformation intensity of the Raman bands, and the formation of interactive protein gel networks where small-sized fat particles were evenly dispersed in the protein matrix. Therefore, combined CPI and CHI shows promise as a phosphate replacer for meat products.

High-pressure processing influences the conformation, water distribution, and gel properties of pork myofibrillar proteins containing Artemisia sphaerocephala Krasch gum

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Artemisia sphaerocephala Krasch gum could improve WHC and gel strength.

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HPP (≤200 MPa) induced high immobilized water proportion and a dense, uniform microstructure of MP-AG gels.

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HPP (>200 MPa) decreased surface hydrophobicity and storage modulus of MP-AG solutions.

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HPP (>200 MPa) increased particle size and amount of reactive sulfhydryl group of MP-AG solutions.

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The results have great potential for developing reduced-sodium meat products.

The effect of high-pressure processing (100–4 00 MPa) on conformation, water distribution, and gel characteristics of reduced-sodium (0.3 M NaCl) myofibrillar protein containing 0.15% Artemisia sphaerocephala Krasch gum (AG) was investigated. The addition of AG resulted in the increase of WHC, proportion of immobilized water, and gel strength. Then, the WHC, proportion of immobilized water, and gel strength peaked after 200 MPa treatment, attributed to increased solubilization and zeta potential of MP, decreased particle size of MP, exposure of intrinsic tryptophan residues and the partial transformation of α-helix into β-sheet in MP. Moreover, 300 and 400 MPa induced decreases in surface hydrophobicity, solubility and storage modulus, resulting in the formation of loose and disordered gel structures with attenuated WHC. These results suggest that application of moderate HPP (200 MPa) combined with AG could provide a novel approach to improve the WHC and gelation properties of reduced-sodium meat products.

Effects of three treatments on protein structure and gel properties of Perccottus glenii myofibrillar protein

In order to improve Perccottus glenii myofibrillar protein (MP) gel properties, three treatments were evaluated: ultrasonic, transglutaminase (TGase) and combined ultrasonic-transglutaminase treatments. Combined ultrasonic-transglutaminase treatment altered protein structure and gel properties most dramatically. As compared with untreated control group protein, treated protein gels possessed decreased sulfhydryl group content and increases in water holding capacity, whiteness value and hydrophobic interactions that increased gel strength value by up to 3.79 times that of untreated protein gel. Protein structural and Differential scanning calorimetry (DSC) analyses revealed that combined ultrasonic-TGase treatment increased both protein thermal denaturation temperature and UV absorbance (as compared to control and other treatment groups) that supported formation of MP gels with desirable characteristics. These results provide a theoretical basis for development of superior MP gels to promote greater utilization of this fish protein resource by the food industry.

Effects of high-pressure processing on the functional properties of pork batters containing Artemisia sphaerocephala krasch gum

Here, the effect of high-pressure conditions (0.1-400 MPa) on the water-loss, texture, gel strength, color, dynamic rheological property, and water migration of pork batters containing 0.1% (W/W) Artemisia sphaerocephala krasch gum (PB-AG) is studied. Results indicated that the cooking yield, water-holding capacity, texture, gel strength, L^* values, and G' values increased with the increase in pressure (0.1-300 MPa) (p < 0.05). Dynamic rheological results (G') revealed that the thermal gelling ability of the PB-AG gel gradually increased with pressure (0.1-300 MPa). The minimum of T₂₂ content was observed and the proportion of immobilized water decreased at 300 MPa by low-filed nuclear magnetic resonance. However, excessive high-pressure processing treatments (400 MPa) resulted in lower gel strength, WHC, texture, and G'. The scanning electron microscopy results shown that a denser network structure with small cavities was observed at 300 MPa. Therefore, moderate pressure treatment (≤300 MPa) may improve gelation properties of PB-AG gel, while excessive pressure treatment (400 MPa) may weaken the gelation properties. PRACTICAL APPLICATION: High-pressure processing combining Artemisia sphaerocephala krasch gum could enhance the gelation properties of pork batters. To do so, establishing knowledge on gelation properties of pork batters with Artemisia sphaerocephala krasch gum at different pressure levels treatment would be of paramount importance, because this contributes furnishing engineering data pertinent to the technical progress for the processing of emulsion-type meat with high quality.

Effects of High Hydrostatic Pressure on the Conformational Structure and Gel Properties of Myofibrillar Protein and Meat Quality: A Review

In meat processing, changes in the myofibrillar protein (MP) structure can affect the quality of meat products. High hydrostatic pressure (HHP) has been widely utilized to change the conformational structure (secondary, tertiary and quaternary structure) of MP so as to improve the quality of meat products. However, a systematic summary of the relationship between the conformational structure (secondary and tertiary structure) changes in MP, gel properties and product quality under HHP is lacking. Hence, this review provides a comprehensive summary of the changes in the conformational structure and gel properties of MP under HHP and discusses the mechanism based on previous studies and recent progress. The relationship between the spatial structure of MP and meat texture under HHP is also explored. Finally, we discuss considerations regarding ways to make HHP an effective strategy in future meat manufacturing.

Structural basis for high-pressure improvement in depolymerization of interfacial protein from RFRS meat batters in relation to their solubility

High-pressure processing (HPP) can modify the construction of interfacial proteins (IPs) to improve the properties of reduced-fat and reduced-salt (RFRS) meat batters. In this study, the relationship between the construction of IPs and their solubility at fat droplet/water interface in RFRS meat batters with HPP treatments was investigated. When 200 MPa for 2 min was applied, the IPs exhibited the highest solubility due to a high concentration of absorbed myosin with the content of random coil 65.62%, but the particle diameter was in reverse. The microscopy revealed the depolymerization of IPs occurred at low pressure, while macromolecular aggregates were produced as the cross-linking of IPs to some degree at pressure ≥ 200 MPa. This phenomenon was supported by the result of SDS-PAGE and the sulfhydryl of IPs. In conclusion, the HPP induced solubility alteration of IPs was achieved by modifying their construction through adjusting the secondary structures and regulating bond interactions.