基于近红外光谱技术(NIRS)对工夫红茶含水率、游离态氨基酸、茶多酚品质成分评价研究
Research to moisture content,free form amino acids,polyphenols quality ingredients of Congou black tea by near infrared spectroscopy
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摘要: 目的:提出一种利用近红外光谱技术无损快速检测工夫红茶含水率、游离态氨基酸、茶多酚品质的新方法。方法:实验样品共计240个,手动选择180个样品作为校正级,剩余60个样品作为预测集;利用OPUS 7.0软件优化出各模型最佳波数段和最佳预处理方法,平滑点数17,维数1,结合含水率、游离态氨基酸、茶多酚含量建立预测模型,分析预测模型的预测性能。结果:各预测模型预测精准度高,均可用于工夫红茶含水率、游离态氨基酸、茶多酚品质预测。其中,各模型校正相关系数(Rc)为92.76%~99.28%,校正均方根误差(RMSEC)为0.016~0.0437;预测相关系数(Rp)为97.41%~98.46%,预测均方根误差(RMSEP)为0.00915~0.0168。各模型校正集和预测集均有较高的拟合度,模型预测性能游离态氨基酸>含水率>茶多酚。结论:近红外光谱图结合含水率、游离态氨基酸、茶多酚品质含量建立的各预测模型预测性能优,适合工夫红茶品质评价。Abstract: Objective: This paper gave a new method about detecting the moisture content,free form amino acids,polyphenols quality of Congou black tea by near infrared spectroscopy.Methods: There were 240 test samples,180 samples of them used to be a correction stage as the remaining 60 samples a prediction set. Each model is optimized,the best waves of the number of segments and best pretreatment method for modeling use to establish the quantitative prediction model by OPUS 7.0 software.The smooth points were 17 and dimension was 1.Results:The models predicted a high accuracy which can be used to predict the moisture content,free form amino acids,polyphenols quality of Congou black tea. The calibration correlation coefficients( Rc) were 92.76% ~ 99.28%,correcting root mean square errors( RMSEC) were 0.016~0.0437,predictive correlation coefficient( Rp) was 97.41%~98.46%,and the RMSEP was 0.00915~0.0168.Each model calibration set and prediction set had a higher degree of fit,the prediction performance model of free form amino acids > moisture > polyphenols. Conclusion: The combination of near- infrared spectra of each prediction model to predict the performance had an excellent organoleptic results which established for Congou black tea quality evaluation.