近红外漫反射光谱检测损伤猕猴桃内部品质

研究贮藏期间损伤猕猴桃内部品质与其近红外漫反射光谱之间的关系。利用近红外光谱(12000～4000cm-1)技术和多元线性回归(multiple linear regression，MLR)、主成分回归(principal component regression，PCR)和偏最小二乘法(partial least squares，PLS)3种校正方法分别对损伤华优猕猴桃在2℃条件下贮藏4周期间的可溶性固形物含量、pH值和硬度进行定量分析；并对比吸光度原始光谱、一阶微分和二阶微分3种不同预处理方法的PLS模型校正结果。结果表明：一阶微分预处理方法时，应用PLS建立的可溶性固形物含量、pH值和硬度校正模型的效果最佳；预测集样品预测值与测量值之间的相关系数分别为0.812、0.703、0.919，预测均方根误差分别为0.749、0.153、1.700。说明应用近红外漫反射技术检测贮藏期间损伤猕猴桃的内部品质是可行的。

Non-destructive Testing of Internal Qualities of Bruised Kiwi Fruits in Storage by Near-infrared Diffuse Reflectance Spectroscopy

Internal quality characteristics such as soluble solids content (SSC), pH value and firmness of bruised samples of Huayou kiwifruits stored at 2 ℃ for four weeks were quantitatively evaluated by near-infrared (NIR) diffuse reflectance spectroscopy over the range of 12000－4000 cm-1 in combination with each of the three calibration methods multiple linear regression (MLR), partial least squares (PLS) regression and principal component (PCR) regression, respectively. Meanwhile, the results of PLS models based on different pretreatment methods such as the logarithms of the reflectance reciprocal D1 lg(1/R) and its first derivative D1 lg(1/R) and second derivative D2 lg(1/R) were compared. The results indicated the PLS prediction models for SSC, pH and firmness based on D1 lg(1/R) were the most accurate, exhibiting a correlation coefficient between predicted and measured values of 0.812, 0.703 and 0.919 and a root mean square error of prediction of 0.749, 0.153 and 1.700, respectively. Thus, it is feasible to use near-infrared diffuse reflectance spectroscopy to detect internal qualities of bruised kiwifruits such as SSC, pH value and firmness nondestructively.