Role of Heavy Meromyosin in Heat‐Induced Gelation in Low Ionic Strength Solution Containing l‐Histidine

Abstract

The gelation of myosin has a very important role in meat products. We have already shown that myosin in low ionic strength solution containing L-histidine forms a transparent gel after heating. To clarify the mechanism of this unique gelation, we investigated the changes in the nature of myosin subfragments during heating in solutions with low and high ionic strengths with and without L-histidine. The hydrophobicity of myosin and heavy meromyosin (HMM) in low ionic strength solution containing L-histidine was lower than in high ionic strength solution. The SH contents of myosin and HMM in low ionic strength solution containing l-histidine did not change during the heating process, whereas in high ionic strength solution they decreased slightly. The heat-induced globular masses of HMM in low ionic strength solution containing L-histidine were smaller than those in high ionic strength solution. These findings suggested that the polymerization of HMM molecules by heating was suppressed in low ionic strength solution containing L-histidine, resulting in formation of the unique gel.

l‐histidine improves water retention of heat‐induced gel of chicken breast myofibrillar proteins in low ionic strength solution

“…Myosin in a low ionic strength solution with l ‐His had a longer and more unravelling rod than native one (Hayakawa et al ., ; Chen et al ., ), which might cause changes in the molecular forces of myosin molecules interaction during gelation (Hayakawa et al ., ). It was indicated that heavy meromyosin (HMM) regions of the myosin in low ionic strength solution with l ‐His could not form disulphide bonds between molecules during heating, resulting in low rigidity of the heat‐induced gel of solubilised myosin (Hayakawa et al ., ). As tail–tail interactions is important in forming the strands and cross‐links that stabilised the gel network, the structural change of the rod regions of myosin in 1 m m NaCl containing l ‐His would affect the interaction between rods during heating (Hayakawa et al ., ).…”

“…Similar microstructure was also observed in heat‐induced gel of myosin in a low ionic strength solution with l ‐His (Hayakawa et al ., ). The unique gel was reported as the result of low hydrophobicity and/or to the nondecreasing reactive SH content in myosin head interaction (Hayakawa et al ., ) and structural change in myosin rod portion (Hayakawa et al ., ). Compared to that of MPs in 1 m m NaCl, this sponge‐like network induced by l ‐His might be capable to retain more water and hence induce higher water‐binding capacity (Fig.…”

“…Notably, it was suggested that 5 m m l ‐histidine ( l ‐His) can affect the secondary structure of myosin (Chen et al ., ) and cause elongation of light meromyosin (LMM), enabling solubilisation of 80% chicken breast myosin in a low ionic strength solution (1 m m ) (Hayakawa et al ., , ). Different from thermal gelation already known, it is shown that myosin in low ionic strength solution containing l ‐His can form a transparent gel with fine network structure (Hayakawa et al ., , ). Moreover, l ‐His might contribute to the salty taste of NaCl through interactions between the components (Zhang et al ., ) and has been used as salt substitute components in dry‐cured meat product (Zhang et al ., ).…”

“…To our knowledge, although some pioneering studies on the effects of l ‐His at low ionic strength on the heat‐induced gelation of chicken breast myosin have been conducted by Hayakawa and Nishimura (Hayakawa et al ., , ), there was no literature about the effects of l ‐His on water‐binding capacity and texture property of heat‐induced gel of MPs in high salt or low salt concentration. We hypothesised that MPs in a low ionic strength solution (1 m m NaCl) containing l ‐His might have different gelation properties from that in a high ionic strength solution (0.6 m NaCl), leading to development of novel meat gel‐product with low NaCl content.…”

Emulsion‐forming properties of heat‐induced pork myofibrillar protein affected by NaCl

“…During heating, the content of ɑ‐helix and irregular curl in MPs decreased, the content of β‐sheet increased, hydrophobic residues exposed, and the solubility of MPs gradually decreased. (Shimada et al ., 2015; Hayakawa et al ., 2015). In addition, the thermal aggregation or gelation of MPs is affected by attractive and repulsive forces between proteins, which involve hydrophobic and electrostatic interactions, hydrogen bonds, van der Waal's interactions and covalent bonds (Xiong, 1997; Chi et al ., 2003).…”