近红外漫反射用于检测苹果糖度及有效酸度的研究

提出了应用近红外漫反射光谱技术并结合光纤传感技术快速检测苹果糖度和有效酸度的新方法。以傅里叶变换光谱仪（12500-4000cm^-1）为试验仪器，以120个红富士苹果为标准样品并结合偏最小二乘法，建立了苹果糖度、有效酸度的定量预测数学模型。试验结果为：样品预测值和真实值之间的相关系数分别为0.970，0.906，标准校正误差（SEC）分别为0．261，0．0562，标准预测误差（SEP）分别为0．272，0．0562．偏差（Bias）分别为0．011，0．0115。通过本研究表明：应用近红外光谱漫反射技术在10341～5461cm^-1光谱波长范围内对苹果糖度的无损检测和在10341-3818cm^-1有效光谱范围内对有效酸度的无损检测具有可行性。

Study on Predicting Sugar Content and Valid Acidity of Apples by Near Infrared Diffuse Reflectance Technique

The nondestructive method for quantifying sugar content(SC) and available acid (VA) of intact apples using diffuse near infrared reflectance and optical fiber sensing techniques were explored in the present research.The standard sample sets and prediction models were established by partial least squares analysis(PLS).A total of 120 Shandong Fuji apples were tested in the wave number of 12 500-4 000 cm~(-1) using Fourier transform near infrared spectroscopy.The results of the research indicated that the nondestructive quantification of SC and VA,gave a high correlation coefficient 0.970 and 0.906,a low root mean square error of prediction(RMSEP) 0.272 and 0.056 2,a low root mean square error of calibration(RMSEC) 0.261 and 0.067 7,and a small difference between RMSEP and RMSEC 0.011 and 0.011 5.It was suggested that the diffuse near infrared reflectance technique be feasible for nondestructive determination of apple sugar content in the wave number range of 10 341-5 461 cm~(-1) and for available acid in the wave number range of 10 341-3 818 cm~(-1).