基于气相色谱-离子迁移谱结合化学计量学分析大鲵肉冷藏期间挥发性成分

Analysis of volatile components in giant salamander meat during cold storage based on gas chromatography-ion mobility spectrometer and chemometrics

为探究大鲵肉冷藏期间品质和挥发性成分变化,该研究对大鲵肉冷藏过程中(4℃,0、2、4、6和8 d)定期进行感官评价和挥发性盐基氮(total volatile base nitrogen,TVB-N)测定,并采用气相色谱-离子迁移谱(gas chromatograph-ion mobility spectrometer,GC-IMS)分析挥发性气味物质。结果显示,随着冷藏时间的延长,感官品质逐渐下降,从第6天感官上不可接受;TVB-N含量呈上升趋势,在第6天判定为不新鲜(>20 mg/100g)。通过GC-IMS从不同冷藏时间大鲵肉中鉴定出46种挥发性化合物,包括13种酯类、12种醛类、10种酮类、6种醇类、3种醚类和2种酸类。主成分分析表明,前2个主成分累计贡献率达到78.32%,能够解释样品大部分信息。采用正交偏最小二乘法判别分析构建了稳定性和预测能力较好的模型,依据变异权重投影(variable importance in projection,VIP)筛选出15种潜在的气味标记物(VIP>1),其中2-甲基丁酸乙酯、异丁酸乙酯、丙酸乙酯、乙酸乙酯、2-丁酮、乙醇、苯乙醛单体、丙醇的相对含量随着冷藏时间的延长总体呈上升趋势;丁酸乙酯二聚体、正己醛、丙酸相对含量总体呈下降趋势;异戊醛单体、丙酮、异戊醇单体和烯丙基甲基硫醚相对含量在第2、4天达到最大后呈下降趋势。相关性分析表明,异丁酸乙酯、丙酸乙酯、2-甲基丁酸乙酯相对含量与冷藏过程中感官评分和TVB-N值显著相关(P<0.05),可作为大鲵肉冷藏期间腐败变质潜在标志物。该研究为大鲵肉冷藏期间新鲜度评价及其品质控制提供了参考。

To investigate the changes in giant salamander meat quality and volatile components during cold storage,sensory evalua-tion and total volatile base nitrogen(TVB-N)determination were carried out regularly during cold storage(4℃,0,2,4,6,and 8 d).A gas chromatograph-ion mobility spectrometer(GC-IMS)was used to analyze volatile odors.Results showed that the sensory quality de-creased gradually with the extension of cold storage time,and the sensory quality was unacceptable from the sixth day.The TVB-N content showed an increasing trend and was considered to be stale on the 6th day(>20 mg/100g).Forty-six volatile compounds were identified by GC-IMS,including 13 esters,12 aldehydes,10 ketones,6 alcohols,3 ethers,and 2 acids.Principal component analysis(PCA)showed that the accumulative contribution rate of the first two principal components reached 78.32%,which could explain most of the in-formation in the samples.The orthogonal partial least squares-discriminant analysis(OPLS-DA)was used to construct a model with good stability and predictive ability.Totally 15 potential odor markers were screened based on variable importance in projection(VIP>1).The relative contents of ethyl 2-methylbutyrate,ethyl 2-methylpropanoate,ethyl propanoate,ethyl acetate,2-butanone,ethanol,benzene acet-aldehyde-monomer and 1-propanol increased with the extension of cold storage time.The relative contents of ethyl butyrate-dimer,hex-anal,and propanoic acid decreased.The 3-methylbutanal-monomer,acetone,3-methylbutan-1-ol-monomer,and 1-propene-3-methylthio showed a decreasing trend after reaching the maximum value on the 2nd and 4th days.Pearson correlation analysis showed that ethyl 2-methylpropanoate,ethyl propanoate,and ethyl 2-methylbutyrate had a significant correlation with sensory score and TVB-N value during cold storage(P<0.05),which could be a potential marker of deterioration of giant salamander meat during cold storage.This study pro-vides a reference for the freshness evaluation and quality control of giant salamander meat during cold storage.