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The combined effect of calcium chloride (CaCl 2 ) (20–100 mM) and high pressure processing (HPP, 200 MPa) on the solubility of myofibrillar proteins (MP) was investigated under sodium-reduced conditions (0.3 M sodium chloride). The results revealed that HPP combined with low concentrations (<40 mM) of CaCl 2 synergistically increased the solubility of MP, but an antagonistic effect occurred when a high concentration (100 mM) of CaCl 2 was present. This synergistic effect could be attributed to a mildly destabilized conformation of myosin, an increased surface hydrophobicity and the decreased total sulfhydryl group content of MP. However, CaCl 2 at 100 mM destabilized myosin to a larger extent and induced non-disulfide covalent cross-linking of S-1 subfragment in pressurized MP, thus attenuating the solubilizing effect of HPP on the myosin heavy chain, resulting in the antagonistic effect. Therefore, HPP in combination with low-level CaCl 2 (<40 mM) may improve the functional properties of sodium-reduced meat products. [ABSTRACT FROM AUTHOR]

The effects of resistant corn starch (RCS) (0.1–0.6% w/w) on the water-holding capacity (WHC) and gel strength of chicken breast myosin were investigated. The results showed that RCS could successively increase the WHC and gel strength of myosin-RCS gels (P < 0.05) with an elevating concentration of 0.1–0.6% RCS. The hydrophilicity of RCS and the shrinking mobility of inner water in the gels were responsible for increased WHC. The swelling-induced active filling and the enhanced cross-linking between the myosin tail and RCS could promote the formation of a continuous, compact and homogeneous gel network with elevated RCS (0.2–0.6%), as well as increased storage modulus (G ′), thus resulting in reinforced gel strength. The heat-induced conformational transition from β -sheet to α -helix could also improve the WHC and gel strength. It is promising to use RCS as a fat substitute in the development of novel low-fat meat products with potential physiological benefits in industry. Image 1 • RCS (0.1–0.6% w/w) successively improved the WHC and strength of myosin-RCS gels. • The hydrophilicity of RCS and a lower relaxation lead to a higher WHC. • The active filling and enhanced cross-linking result in a stronger gel strength. • It is promising to use RCS for developing low-fat meat product with healthy function. [ABSTRACT FROM AUTHOR]

Abstract: The effects of high pressure processing (HPP) (0–400 MPa for 10 min, 0–20 min under 300 MPa) on the water holding capacity (WHC) and gel strength of chicken breast myosin containing 0.225% κ-carrageenan (W/V, 2.25 g/L relative to myosin solution) (myosin-K) and the thermal gelling mechanism were investigated. The results revealed that HPP at 100–400 MPa could significantly increase the WHC of myosin-K gels while decreasing the gel strength (P < 0.05). The turbidity, surface hydrophobicity and reactive sulfhydryl contents of the pressurized myosin-K increased significantly at 200–400 MPa (P < 0.05). Dynamic rheological measurements indicated that the thermal gelling ability of the pressurized myosin-K matrix gradually decreased as the pressure increased (100–400 MPa). Low-field nuclear magnetic resonance data suggested that HPP at 100–400 MPa might shorten the water relaxation time of the gel. The Fourier transform infrared spectroscopy data revealed that the hydrogen bonding interactions in the gels might weaken when subjected to 100–300 MPa but could be enhanced at 400 MPa. The scanning electron microscopy images revealed that HPP (300 MPa, 10 min) produced a dense, networked myosin-K gel structure with small cavities and thin cross-linked strands. Moreover, pressure levels were responsible for the above results. The protein in myosin-K could denature, unfold and aggregate under HPP (100–400 MPa), thus decreasing the thermal gelling ability of myosin-K matrix. The high WHC of the pressurized myosin-K gel was attributed to the enhanced hydrogen bonding and hydrophobic interactions, as well as the uniform and dense networked structure; the low gel strength might be ascribed to the low thermal gelling ability of pressurized myosin-K. [Copyright &y& Elsevier]