Study On The Quality Of Qianbei Ma Goat Meat And Its Neu5Gc Dissociation Based On Electrical Stimulation Effect

N-Glycolylneuraminic acid（Neu5Gc）,a unique non-human sialic acid,is metabolised and absorbed by the body in its’self’form when Neu5Gc-rich red meat is consumed,even though humans cannot synthesise it themselves.The accumulation of Neu5Gc in human cellular expression glycans can contribute to developing chronic inflammation in the body and increase the risk of cancer.The Qianbei ma goat,as one of the three best local goat breeds in Guizhou Province,is a unique genetic resource of goat breeds in the Karst region.It is popular with consumers because of its delicious meat,high protein content and rich nutritional value.However,the endogenous risk substance Neu5Gc was present in the muscle of Qianbei ma goats at levels as high as79.00μg/g,posing a more significant potential threat to human health.Therefore,reducing the Neu5Gc content in Qianbei ma goat meat is essential to enhance its food safety.Electrical stimulation（ES）,a widely used low-carbon,green processing technology in the meat industry,improves the quality of red meat after slaughter and reduces the Neu5Gc content in red meat.In this paper,we investigated the effects of ES on the quality and proteomics of post-slaughter Qianbei ma lamb by applying different current ES treatments,compared the changes of risk substance Neu5Gc content in different parts of lamb,and explored the fragmentation rules of ES on Neu5Gc molecules using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry（UHPLC-Q-TOF-MS）.The content and results of the study are as follows:（1）Effect of ES on the quality of hind leg meat of Qianbei ma goat after slaughter.Changes in the edible quality of Qianbei ma goat after slaughter were investigated by applying 0.2 A,0.5 A and 0.8 A currents to ES for 60 s after storage for 10 d.The results showed that ES accelerated the decrease in p H and glycogen content,which improved the lamb’s tenderness,color,water-holding capacity and chewiness throughout the storage period while increasing the total free amino acid content of the lamb and enhancing its flavour.In addition,ES accelerated the hydrolysis of associated proteins during storage and inhibited the oxidation rate of myoglobin compared to the control group.Therefore,ES can be used as a post-slaughter intervention technique to improve the quality of Qianbei ma goat meat.（2）Effect of ES on the proteomics of post-slaughter Qianbei ma lamb.The changes of ES on the proteome of Qianbei ma lamb were explored using 4D-fast DIA proteomics.3017 proteins were quantifiably compared between the two groups of samples（ES1/NES1）,and a total of 173 differential proteins were found to be expressed,including 34 up-regulated proteins and 139 down-regulated proteins.These differential proteins are associated with biological metabolic activities such as the regulation of biological processes,organic matter metabolism and cellular metabolism in lamb after slaughter;Furthermore,differential proteins are mainly involved in the post-slaughter lamb glycolytic response,ECM receptor interactions,adhesive spots,and phosphatidylinositol 3-kinase/protein kinase signalling pathways.Hence,the protein bioinformatics analysis showed that ES altered the physiological and biochemical response of post-slaughter lamb.Still,the mechanism of ES’s effect on lamb quality needs to be further investigated.（3）Effect of ES on the content of Neu5Gc in different parts of Qianbei ma lamb.The changes of Neu5Gc content in the hind leg,foreleg and tenderloin of Qianbei ma lamb were investigated after applying 0.2 A,0.5 A and 0.8 A currents to ES for 30 s and60 s,respectively,after slaughter.The results showed that the Neu5Gc contents in the three parts of Qianbei ma lamb were significantly different,at 79.00μg/g,74.28μg/g and 63.97μg/g,respectively.The highest dissociation rates of Neu5Gc content in the hind leg,foreleg and tenderloin up to 16.64%,11.46%and 17.86%with different currents（0.2 A,0.5 A,0.8 A）ES 30 s,respectively;When the ES time was increased to60 s for different currents（0.2 A,0.5 A,0.8 A）,the highest dissociation rates up to34.75%,36.87%and 37.02%were achieved for the Neu5Gc content in the three different parts of the lamb.Therefore,current strength and ES time affect the dissociation of Neu5Gc.Furthermore,according to the results of the analysis of Neu5Gc content in the hind leg of Qianbei ma lamb by ES-coordinated conventional cooking processing,the reduction of 0.2 A and 0.5 A current ES-coordinated high-temperature cooking treatment increased by 6.52μg/g and 12.07μg/g,respectively,compared with high-temperature cooking without ES.ES technology can be applied to degrade Neu5Gc,an endogenous risk substance in Qianbei ma lamb,to enhance the safety of lamb for consumption.（4）ES preliminary exploration of the degradation patterns of the Neu5Gc molecule.To investigate the direct degradation effect of ES on Neu5Gc,aqueous solutions of Neu5Gc were subjected to 0.2 A,0.5 A and 0.8 A currents ES for 30 s,60 s,90 s and120 s.The results showed that the degradation of Neu5Gc increased significantly with increasing stimulation time by applying three different intensity currents,with dissociation rates of 82.61%（0.2 A）,80.73%（0.5 A）and 60.26%（0.8 A）at 120 s of stimulation.The 0.5 A degradation effect is more significant than 0.2 A and 0.8 A according to the fitted models y=C₀e^-0.0132t（0.2 A）、y=C₀e^-0.0139t（0.5 A）、y=C₀e^-0.0068t（0.8 A）of the degradation kinetic equation.Moreover,UHPLC-Q-TOF-MS was used to explore the cleavage pattern of the Neu5Gc molecule by ES.The cleavage pathway of Neu5Gc was deduced from the analysis of the intermediate products of the dissociation of the Neu5Gc molecule.This study provides theoretical support for ES’s degradation of Neu5Gc in red meat.