近红外透射光谱法快速测定瓶装醋中挥发酸含量的研究

采用近红外光谱直接对瓶装醋进行透射检测。结果发现，玻璃包装对入射光源强度影响很大。采用室内外置光源解决此问题，在850～2000nm的波长范围内，采用偏最小二乘方法（PLs）对醋中的挥发酸含量进行了定量预测。结果表明，原始光谱结合PLs方法可以很好地预测瓶装醋中的挥发酸含量，校正样本和预测样本的相关系数分别为0．98、0．97；校正样本和预测样本的标准偏差分别为o．776、0．878。此外，对挥发酸含量起主要作用的波段主要集中在900nm和1100nm左右。

Rapid Determination of Volatile Acid Content in Bottled Vinegar with Near Infrared Reflectance Spectroscopy

To evaluate the applicability of non-invasive Near Infrared Reflectance （NIR） spectroscopy for detecting the bottled vinegar, the transmission spectra of 240 bottled vinegar samples were tested by using ASD-Handheld Field Spec3 spectrometer. The results showed that, absorhance peak was obviously influenced by the glass bottle when the intensity of light source was less strong which could be improved by using external light source with Lowell pro lam 14.5V Bulb/128690 tungsten halogen bulb. Partial Least Square （PLS） analysis was used to build the prediction model of volatile acid content. The results indicated that the correlation coefficient and root mean standard error of calibration samples are 0.98 and 0. 776, respectively, while, the correlation coefficient and root mean standard error of prediction samples are 0.97 and 0. 878, respectively. The sensitive bands of volatile acid were centered between 900 and 1100 nm.