Effects Of MgCl₂ On The Thermal Gelling Properties Of Two Kinds Of Myofibrillar Protein Including κ-carrageenan

Low-fat and sodium-reduced meat products are an important direction of meat industry product. Based on the compensation of KCG （ic-carrageenan） and physiological function of magnesium ions, the effects of MgCl₂ （0～12mM） on the gel properties （water holding capacity, WHC and gel hardness） of KCG-MP （myofibrillar protein） and SKCG-MP （w/w,15:85） were investigated in order to improve the gel properties of the meat products, and their mechanism were also explored with sol molecular properties, physicochemical properties, gel microstructure, intermolecular forces of KCG-M and SKCG-M gel, respectively. The main results showed as follows:（1） The addition of 6～10mM MgCl₂ could significantly increase the WHC of KCG-MP gel and decreased gel hardness （P<0.05）. Meantimes, the WHC was initially increased by MgCl₂ （≤10 mM）, then delined rapidly with additional MgCl₂ to 12nM.（2） The addition of MgCl₂ could promote to unfold M in low-salt KCG-M system, increase hydrophobic effect and turbidity; weakened the thermal stability （Tpeakl reduced） and thermal gel ability （G’ reduced） of the KCG-M hybrid sol system by weakening the molecular interaction of KCG-M, M-M, and forming dense three-dimensional network structure of gels. These changes induced a high WHC and a reduced hardness of the KCG-M gel, which contribute the properties of KCG-MP gel.（3） The addition of 2-12mM MgCl₂ could significantly decrease the WHC gel and the hardness of KCG-MP gel （P<0.05）. Meanwhile, the gel hardness was initially decreaed by MgCl₂, then follow by a "back-up" increase with further addition of MgCl₂.（4） The addition of MgCl₂ could promote to unfold M in low-sodium SKCG-M system, increase hydrophobic effect; weaken the thermal stability （Tpeakl reduced） and thermal gel ability （G’reduced） of the SKCG-M hybrid sol system by weakening the superposition effect between KCG and M, molecular interaction of M-M, and forming loose, uniform three-dimensional gels network structure that was not conducive to improve the WHC and gel hardness. These changes reduced the WHC and the hardness of low-sodium SKCG-M gel, which contribute the properties of SKCG-MP.（5） These results will provide possibility to develop low-fat and salt （sodium）-reduced, low-hardness, juicy, magnesium-strengthened meat products that are suitable for consumption in certain people including the elderly.