可见/近红外漫反射与漫透射检测脐橙可溶性固形物的对比研究

Contrast of Vis/NIR Reflection and Diffuse Transmission in Detecting the SSC of Ganan Navel Oranges

研究了可见／近红外漫反射与漫透射两种检测方式对赣南脐橙的可溶性固形物含量检测结果的影响．采用波长范围为350～1800nm的QualitySpec型光谱仪采集196个脐橙样品的可见／近红外漫反射和漫透射光谱，取其中148个样品作为建模集用来建模，剩余48个样品作为预测集用于预测模型．用多种预处理结合偏最小二乘回归法分别建立两种检测方式下单次光谱及三次光谱并求平均，得到光谱相对应的脐橙可溶性固形物预测模型，对比该模型可知漫透射方式明显优于漫反射方式；最优结果为漫透射三次光谱求平均所得光谱结合多元散射校正预处理建立的赣南脐橙的可溶性固形物含量预测模型，其校正模型及预测模型的相关系数分别为0．980和0．949，均方根误差分别为0．230°Brix和0．374°Brix．由此得出近红外漫透射光谱更适合用于检测脐橙的可溶性固形物含量．

The impact of using visible/near infrared reflection and diffuse transmission spectra to detect the soluble solids content of Gannan navel oranges was studied. Vis/NIR reflection and diffuse transmission spectra of 196 Gannan navel orange samples were acquired by using a QualitySpec spectrometer in the wavelength range of 350 - 1 800 nm. Regarding these 196 samples, 147 samples were used as the calibration set to build calibration model, and balance ~9 samples were used as the prediction set to validate model. Then a variety of pretreatment methods combined with partial least squares regression was used to develop the prediction models of SSC of navel oranges corresponding to a single spectrum and an average of three times spectra for Vis/ NIR reflection and diffuse transmission spectra respectively. It is found that the diffuse transmission spectra prediction model is much better than the models of a single spectrum and an average of three times spectra. The partial least squares regression prediction model of Gannan navel orange based on the average of three times diffuse transmission spectra combined with multiplicative scattering correction pretreatment method performs the best, and the correlation coefficient and the root mean square errors in the calibration and prediction model are 0. 980, 0. 230°Brix and 0. 949, 0. 374°Brix respectively. So the average of multiple diffuse transmission spectra is more suitable for detecting the SSC of navel oranges.