实验采用SPME-GC-MS结合GC-O技术对25个不同批次的羊肉样本中的挥发性成分进行分析鉴定，共筛选获得32种共有风味物质作为羊肉特征风味评定的关键化合物，以此为分类变量，结合五种常见肉类样品中相对应化合物的种类和含量，构建用于鉴别天然羊肉风味的偏最小二乘回归-判别分析(PLS-DA)模型，所建模型相关系数大于0.90，校正和预测误差均方根均小于0.3，表明所建模型拟合度较好，可以应用于天然羊肉风味的识别。依据所建立的PLS-DA模型，对自制一系列羊肉香精（MPF）风味的天然模拟程度进行评估。结果表明：由不同美拉德反应体系制备的羊肉香精呈现显著差异，整体风味属性依次为MPF5> MPF6-8>MPF2>MPF4>MPF1>MPF3。为了考察所建模型对羊肉风味评定的准确性和可靠性，结合课题组已建立的描述性感官分析方法对所PLS-DA模型评定的结果进行了验证，结果趋势较为一致，表明通过结合PLS-DA模型可以替代传统的描述性感官分析用于羊肉香精风味质量的评定。

The volatile components in twenty-five mutton samples from different batches were analyzed by headspace– solid phase microextraction gas chromatography mass spectroscopy (SPME-GC-MS) and gas chromatography-olfactometry (GC-O). Thirty-two common volatiles were identified as the key compounds for the evaluation of the characteristic mutton flavor. Based on these 32 compounds, the variables were classified, and the partial least squares discriminant analysis (PLS-DA) model was developed for the identification of natural mutton flavor relative to the types and content of the corresponding compounds in five common meat samples. The correlation coefficient of the PLS-DA model was > 0.90, and the root mean square error of calibration (RMSEC) and root mean square error of prediction (RMSEP) were < 0.3, indicating that this model achieved a good fit and could be used for the identification of natural mutton flavor. Subsequently, PLS-DA model was used to evaluate the degree of natural flavor simulation for a series of mutton process flavor (MPF) samples that were prepared in our lab. The results showed that there were significant differences among MPF samples that were prepared by different Maillard reaction systems. The order of the flavor quality for the MPF samples studied was as follows: MPF5 > MPF6-8 > MPF2 > MPF4 > MPF1 > MPF3. In order to validate the accuracy and reliability of the model for the evaluation of mutton flavor, descriptive sensory analysis (DSA), previously established by our group, was used to examine the results obtained from PLS-DA model. The results were consistent, indicating that PLS-DA model can replace the traditional DSA method in the evaluation of the flavor quality of MPFs.

国家自然科学基金(31460408)；师市中小企业创新基金(2015QY11)；石河子大学名校名师结对子项目(SDJDZ201517)