Effects Of Sodium Bicarbonate On The Processing Properties Of PSE Myofibrin

The meat is rapidly glycolysis within 40 min after the death of pigs.When carcass muscles after slaughter are exposed to high temperature(?38 ?),which the pH is rapidly reduced,the myosin denaturation and the water retention decreases,resulting in PSE meat.PSE(Pale,Soft,and Exudative)meat has many defects,such as pale surface,lack of elasticity,serious juice loss and so on.As a result,the sensory characteristics and quality characteristics of the produced meat products are far lower than those of normal meat.The aqueous solution of sodium bicarbonate is weakly alkaline,which can relax the molecular network structure of muscle protein by changing the pH of PSE pork,so as to the serious problem of meat water loss improved and the processing performance improved.Therefore,this article studied the effects of sodium bicarbonate on the structure and conformation of PSE meat myofibrillar protein,and observed the effects of sodium bicarbonate on the gel properties of PSE meat myofibrillar protein,and revealed the effects of different amounts of sodium bicarbonate on PSE meat quality,so as to provide a theoretical basis for improving the quality of PSE pork meat.The research contents and results are as follows:1.Effects of sodium bicarbonate on the techno-functional and rheology properties of PSE meat battersIn this study,the changes of salt-soluble protein content,gel property,rheological characteristic,and microstructure attributes of PSE meat batters with various amounts of added sodium bicarbonate(0%-0.6%)were investigated.The results showed that with the increase of sodium bicarbonate,the pH,b* value,salt-soluble protein content,cooking yield,hardness,springiness,cohesiveness,chewiness,emulsion stability,and G? values at 72 ? were significantly increased(P < 0.05),except the texture properties and G? values at 72 ? of the samples with 0.4% and 0.6% sodium bicarbonate.Meanwhile,the a* value was significantly decreased(P < 0.05).The microstructure of cooked PSE meat batters showed that the sample with 0% and 0.2% sodium bicarbonate had a dense structure,and the sample with 0.4% and 0.6% had some larger caves.In conclusion,the use of sodium bicarbonate could improve the techno-functional and rheology property of PSE meat batters,through increasing the pH,salt-soluble protein content,and emulsifying stability.2.Effect of sodium bicarbonate on the aggregation and conformation of PSE meat myofibrillar proteinIn order to investigate the effect of sodium bicarbonate(0%-0.6%)on aggregation and emulsion properties of PSE meat myofibrillar protein,the changes in pH,turbidity,particle size,active sulfhydryl,surface hydrophobicity,emulsifying ability and emulsion stability were studied.The pH,solubility,active sulfhydryl,surface hydrophobicity,emulsifying ability and emulsion stability were significantly increased(P < 0.05)with the increase of sodium bicarbonate from 0% to 0.6%,opposte,the Zeta potential,turbidity,particle size were significant decreased(P < 0.05).In a word,the result showed that added sodium bicarbonate increased the solubility of PSE meat myofibrillar protein,led to more sulfhydryl and hydrophobic groups were exposed,and formed the smaller aggregations,enhanced the emulsion properties.3.Effect of sodium bicarbonate on gel properties of PSE meat myofibrillar proteinsTo study the effects of sodium bicarbonate(0.2%-0.6%)on the pale,soft and exudative(PSE)pork myofibrillar proteins(MPs)gel,the changes in whiteness,cooking yield,texture properties,rheological property and water distribution were investigated.The results showed that with the increase of sodium bicarbonate,the cooking yield,hardness,springiness,cohesiveness and chewiness of PSE pork MPs gel were significantly increased(P < 0.05),and the whiteness value was significantly decreased(P <0.05).The results of dynamic rheology show that with the increase of sodium bicarbonate,the G' values of all samples the maximum were heated to 80 ?,and which was the G' value of T1 the maximum.Compared with T1,the initial relaxation time of T2 b,T21 and T22 from T2,T3 and T4 was advanced,and the peak ratios of P2 b were not significantly different(P > 0.05),but the peak ratios of P21 were significantly increased(P < 0.05),the peak area ratio of P22 was significantly decreased(P < 0.05).Overall,added sodium bicarbonate could improve the gel properties of PSE meat myofibrillar proteins(MPs).