近红外漫反射无损检测梨果糖度及pH值的研究

Study on nondestructive detecting sugar content and pH value of pear by using near infrared diffuse reflectance Spectroscopy

【目的】应用近红外漫反射光谱技术无损检测梨果的糖度和pH值。【方法】采集完整梨果的近红外漫反射光谱（350~1800nm），光谱经移动窗口平滑处理、一阶微分和多元散射校正预处理后，再分别采用多元线性回归、主成分回归和偏最小二乘法，建立梨果糖度和pH值的定量预测数学模型。【结果】采用一阶微分结合偏最小二乘法所建模型的预测效果较好，糖度和pH值定量预测数学模型的相关系数分别为0．9285和0．8584，均方根误差分别为0．4364和0．1205。【结论】近红外漫反射光谱作为一种无损的检测方法，可用于评价梨果的糖度和pH值。

[Objective] The objectives of the study were to predict sugar content and pH value of pear fruit by using the near-infrared diffuse reflectance（NIR） spectra. [Method] After three point windows moving smooth treatment,the first derivative Dllog（1/R） and multivariant scattering correction were used to preprocess the primitive spectrum （350-- 1 800 nm） of pear fruit respectively. Multi-linear regression （MLR）,principal component regression（PCR） and partial least square （PLS） regression were taken to build prediction models which were used to quantitatively analyze sugar content and pH value of pear fruit respectively. [Result] The PLS model with Dllog（1/R） data treatment is prior to the other two ways based on the comparative analysis. The results show that the correlation coefficients of sugar and pH value are 0. 928 5 and 0. 858 4 respectively, and root mean standard error of sugar and pH is 0. 436 4 and 0. 120 5 respectively. [Conclusion] The research indicates that NIR spectroscopy could provide an accurate,reliable and nondestructive method for assessing the internal quality index sugar content and pH value of pear fruit.