内蒙古自治区阿拉善盟放牧型阿拉善白绒山羊和蒙古羊不同部位羊肉的氨基酸指纹特征分析

Characterization of Amino Acid Profiles in Different Parts of Free-grazing Alagxa White Cashmere Goat and Mongolian Sheep Meat from Alagxa League,Inner Mongolia

[目的]分析内蒙古自治区阿拉善盟放牧型阿拉善白绒山羊和蒙古羊羊肉的氨基酸指纹特征。[方法]从阿拉善盟阿拉善左旗、阿拉善右旗、额济纳旗采集阿拉善白绒山羊和蒙古羊的股二头肌、背最长肌和肋间肌样品共137份,参照《食品安全国家标准食品中氨基酸的测定》(GB 5009.124—2016)中规定的方法测定羊肉样品中17种氨基酸的含量;采用化学计量学判别和描述性统计分析方法,比较不同品种、不同部位羊肉的氨基酸指纹特征。[结果]基于正交信号校正的偏最小二乘判别分析(OPLS-DA)方法对不同品种、不同部位羊肉的氨基酸含量分离效果最好。2个品种羊肉样品中均检测到17种氨基酸,其中,人体必需氨基酸(EAA)7种。17种氨基酸含量在2个品种羊肉间差异均不显著(P>0.05),且2个品种羊肉的总氨基酸(TAA)、EAA和非必需氨基酸(NEAA)含量相近。3个部位羊肉的17种氨基酸含量普遍存在显著(P<0.05)差异,TAA、EAA和NEAA含量也存在显著(P<0.05)差异;肋间肌的特征氨基酸有Gly、Pro和Ala,而His、Tyr、Gly、Lys、Ala、Phe和Met 7种氨基酸在进行羊肉不同部位区分时可能是重要的标志性氨基酸。2个品种和3个部位羊肉的必需氨基酸/总氨基酸(EAA/TAA)均在40%左右,必需氨基酸/非必需氨基酸(EAA/NEAA)均高于60%,符合联合国粮农组织/世界卫生组织(FAO/WHO)发布的理想蛋白质EAA/TAA和EAA/NEAA的推荐值。[结论]初步建立了阿拉善盟放牧型阿拉善白绒山羊和蒙古羊不同部位羊肉的氨基酸指纹特征;2个品种羊肉的氨基酸组成及含量丰富,都具有较高的营养价值。

[Objective]The aim of the present study was to characterize the amino acid profiles in free-grazing Alagxa white cashmere goat and Mongolian sheep meat from Alagxa League,Inner Mongolia.[Method]A total of 137 mutton samples including biceps femoris,longissimus dorsi muscle and intercostal muscle were collected from Alagxa white cashmere goat and Mongolian sheep reared in Alagxa Left Banner,Alagxa Right Banner and Ejin Banner of Alagxa League.The contents of 17 kinds of amino acids in mutton were assessed in accordance with the Determination of Amino Acids in Food in National Food Safety Standards(GB 5009.124—2016).Chemometric discrimination and descriptive statistical analysis methods were applied to compare the differences in amino acid profiles in mutton from different species and parts.[Result]Orthogonal partial least squares discriminant analysis(OPLS-DA)achieved an higher separating capacity in amino acid contents in mutton from different species and parts.The presence of all the tested amino acids were detected in mutton from both species,including 7 kinds of essential amino acid(EAA)for human.There were no significant(P>0.05)differences in the contents of all the tested amino acids between the mutton from the two species,and the similar contents of total amino acid(TAA),EAA and non-essential amino acid(NEAA)were observed within the two species.There were significant(P<0.05)differences in most of the amino acid contents in mutton from the three parts,and significant(P<0.05)differences in the contents of TAA,EAA and NEAA were observed among different parts as well.The characteristic amino acids of intercostal muscle samples were Gly,Pro and Ala,while His,Tyr,Gly,Lys,Ala,Phe and Met were the potentially important marker amino acids for discriminating different parts of mutton.The ratios of EAA to TAA(EAA/TAA)in the mutton from both species and three parts were all around 40%,and those of EAA to NEAA(EAA/NEAA)were all above 60%,which were in line with the recommended EAA/TAA and EAA/NEAA of ideal protein by FAO/WHO.[Conclusion]The amino acid profiles in different parts of free-grazing Alagxa white cashmere goat and Mongolian sheep meat from Alagxa League was preliminarily characterized in this study.Mutton from both species were abundant in amino acid composition and content,and had high nutritional value.