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The effects of high-pressure processing (HPP) (0-400 MPa for 10 min) on the cooking loss (CL), gel strength, and thermal gelling mechanism of chicken breast actomyosin solution containing 0.5 % ( w/ v) sodium alginate (AS-SA) were investigated. The results showed that HPP could significantly increase ( P < 0.05) the reactive sulfhydryl contents, surface hydrophobicity, and turbidity of the pressurized sample under 200-400 MPa and gradually decrease its thermal gelling ability with an elevating pressure from 100 to 400 MPa. The HPP under 300 MPa for 10 min could enhance the thermal stability of AS-SA and promote the formation of AS-SA gel structure with large pores and thick strands. Those resulted in the increased gel strength and the increased CL of pressurized AS-SA, which were relative to hydrophobic interaction and disulfide bonding. The information could offer certain theoretical foundation to apply HPP technology for developing meat-SA gels with various properties via combinational use of different HPP levels and SA. [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]

• The maximum WHC and gel strength of pressurized MP-Ca occurred at 200 MPa. • HPP (≤200 MPa) increased the solubility and reduced aggregation ability of MP. • HPP (>200 MPa) induced disulfide cross-linking of myosin S-1. • The results are helpful for regulating the properties of reduced-sodium meat gel. The improvement mechanism of high pressure processing (HPP, 100–300 MPa, 10 min) on the gelation properties of reduced-sodium (0.3 M sodium chloride) myofibrillar protein containing 20 mM CaCl 2 (MP-Ca) were explored. The results showed that the water holding capacity (WHC) and strength of MP-Ca gel reached the maximum values under 200 MPa. This was attributed to substantial solubilization of myosin heavy chain and actin, a decreased protein aggregation ability and the exposure of both tyrosine and tryptophan residues resulting from the unfolding of the protein tertiary structure. However, 300 MPa induced the hydrophobic rearrangement of MP and the disulfide cross-linking of the myosin S-1 subfragment, leading to the formation of large protein aggregates and decreased solubility of MP, thus resulting in a weaker gel with a reduced WHC. Therefore, moderate HPP (approximately 200 MPa) and low concentrations of CaCl 2 could potentially improve the gelation properties of reduced-sodium meat products. [ABSTRACT FROM AUTHOR]