陇西腊肉加工过程中蛋白质降解规律的研究

Study on protein degradation during the processing of Longxi bacon

为明确陇西腊肉加工过程中蛋白质的降解规律,该文以猪后腿肉为研究对象,分别从原料肉、腌制中期、腌制末期、晾晒中期和成品5个加工阶段进行取样,测定腊肉加工过程中总氮、非蛋白氮、蛋白质降解指数、三氯乙酸(trichloroacetic acid,TCA)-可溶性肽、多肽和游离氨基酸的变化情况。结果表明,陇西腊肉加工过程中,总氮含量先稍降低后显著增加,非蛋白氮含量和蛋白质降解指数显著增加(P<0.05),在成品腊肉中达到最大值,且原料肉比成品腊肉分别低76.8%和74.24%;TCA-可溶性肽含量从原料肉中的5.79μmol Tyr/g增加到成品腊肉的19.11μmol Tyr/g。根据液相色谱-质谱联用仪鉴定发现,总肽段数的变化呈先上升后下降的趋势,腊肉降解产生的多肽主要来源于肌球蛋白、伴肌动蛋白、肌钙蛋白和肌动蛋白。另外,陇西腊肉加工过程中总游离氨基酸含量显著增加(P<0.05)。综上,陇西腊肉加工过程中非蛋白氮、蛋白质降解指数、TCA-可溶性肽和总游离氨基酸含量显著增加;总肽段数先上升后下降,多肽主要来源于肌球蛋白、伴肌动蛋白、肌动蛋白和肌钙蛋白,蛋白质的降解可为风味物质的形成提供理论依据。

To clarify the protein degradation during the processing of Longxi bacon,the hind leg meat of a pig was taken as the research object,the changes of total nitrogen,non-protein nitrogen,protein degradation index,trichloroacetic acid(TCA)-soluble peptide,peptides,and free amino acid in five different processing stages were determined.Results showed that the total nitrogen content first decreased slightly and then increased significantly during the processing of Longxi bacon,but the non-protein nitrogen content and protein degradation index increased significantly(P<0.05),reaching a maximum in the finished bacon,and the raw meat were 76.8% and 74.2%lower than the finished bacon,respectively.The content of TCA-soluble peptide during the processing of Longxi bacon increased from 5.79μmol Tyr/g in the raw meat to 19.11μmol Tyr/g in the finished bacon.According to the identification by liquid chromatograph mass spectrometer(LC-MS/MS),the number of total peptides increased first and then decreased,and the main peptides produced by the degradation of bacon were myosin,nebulin,troponin,and actin.In addition,the content of total free amino acids increased significantly during the processing of Longxi bacon(P<0.05).In conclusion,the non-protein nitrogen,protein degradation index,TCA-soluble peptide,and total free amino acid content increased significantly during the processing of Longxi bacon,the total number of peptides first increased and then decreased,and the peptides were mainly derived from myosin,nebulin,troponin,and actin,which could provide a theoretical basis for the formation of flavor substances.