基于改进偏最小二乘法的甜椒可溶性固形物和总酸的近红外光谱检测

Determination of soluble solids contents and total acidity contents of sweet peppers based on near-infrared diffuse reflectance spectroscopy and improved partial least squares

以黄色甜椒为研究对象,利用改进偏最小二乘法（MPLS）建立其近红外漫反射光谱无损检测可溶性固形物（SSC）和总酸含量的数学模型。在400～2 500 nm以及400～980 nm＋1 108～1 900 nm 2个波长范围内分别建立了甜椒的SSC和总酸质量分数的定标MPLS模型,并用最优模型进行预测。结果表明,最优的预处理是在400～980 nm＋1 108～1 900 nm下建立的模型,SSC采用SNV处理的定标模型较好,交互验证相关系数（RCV）、交互验证标准误差（SECV）分别为0.926 9和0.186 2,预测集的相关系数RP和预测标准误差（SEP）分别为0.924 8和0.158 9;总酸则是采用None处理的模型较好,交互验证相关系数（RCV）、交互验证标准误差（SECV）分别为0.868 0和0.012 5,预测集的相关系数RP预测标准误差（SEP）分别为0.903 8和0.011 1。试验结果说明,基于改进偏最小二乘法对甜椒鲜果SSC和总酸含量的近红外漫反射快速无损检测是可行的,近红外光谱与SSC和总酸含量呈显著相关性。

A nondestructive measurement model for predicting soluble solids contents and total acidity contents of yellow sweet peppers by near infrared spectroscopy and improved partial least squares was designed. Improved partial least squares（ MPLS） calibration model of soluble solids contents and total acidity contents of sweet peppers were established respectively in two wavelength ranges of 400- 2 500 nm and 400- 980 nm ＋ 1 108- 1 900 nm,then the optimal model was used to predict. The results showed that standard normal variate（ SNV） model obtained the best result for soluble solids contents（ SSC） prediction with a correlation of determination of calibration（ RCV） of 0. 926 9and standard error of cross validation（ SECV） of 0. 186 2,and a correlation coefficient of prediction（ RP） of0. 924 8 and standard error of prediction（ SEP） of 0. 158 9. None model obtained the best result for total acidity contents prediction with a correlation of determination of calibration（ RC） of 0. 868 0 and standard error of cross validation（ SECV） of 0. 012 5,and a correlation coefficient of prediction（ RP） of 0. 903 8 and standard error of prediction（ SEP） of 0. 011 1. The results indicated that it was feasible for determination of soluble solids contents and total acidity contents of sweet pepper based on near-infrared diffuse reflectance spectroscopy and improved partial least squares,and the soluble solids and total acidity contents in sweet pepper had a significant correlation with the near infrared spectroscopy.