生鲜紫薯花青素等多品质参数的可见-近红外快速无损检测

基于实验室自行搭建的可见-近红外光谱系统，以市售生鲜紫薯为研究对象，探讨其花青素、可溶性固形物（soluble solid contents，SSC）以及总糖（total sugars，TS）的同时快速无损检测方法。对紫薯原始光谱进行SG（Savitzky-Golay）平滑、标准正态变量变换以及一阶求导预处理，然后用偏最小二乘回归法进行建模分析。对于花青素和TS，经SG平滑结合一阶求导预处理的模型预测效果最佳；对于SSC，经SNV预处理的模型预测效果最好。针对紫薯各参数最佳预处理光谱采用竞争性自适应加权算法进行波长筛选，再次建立模型。花青素模型预测集的相关系数为0.942 1，预测均方根误差（root mean square error of prediction，RMSEP）为0.225?9?mg/g；SSC模型预测集相关系数为0.943?1，RMSEP为0.878?7?°Brix；TS模型预测集的相关系数为0.925?3，RMSEP为0.244?3%。结果显示，利用可见-近红外光谱可以实现对生鲜紫薯的花青素、SSC以及TS的同时快速无损检测，对生鲜紫薯品质的快速无损检测分选有着重要的实用意义。

Rapid Nondestructive Detection of Multiple Quality Parameters of Fresh Purple Sweet Potato Based on Visible Near Infrared Spectroscopy

This study aimed to simultaneously, rapidly and nondestructively detect anthocyanins, soluble solid content (SSC) and total sugar (TS) in commercial fresh purple sweet potato by visible and near infrared (VIS/NIR) spectroscopy. The infrared spectra of 52 purple potato cultivars were recorded with the VIS/NIR spectroscopy system set up in our laboratory and Savitzky-Golay (SG) smoothing, standard normal variate (SNV) transformation and first derivative (FD) were separately used to preprocess the original spectra. Partial least squares regression (PLSR) models were established. The best predictive model for anthocyanins and TS was obtained with SG smoothing combined with FD, whereas SNV transformation gave the best predictive model for SSC. Furthermore, new models were developed with the selected optimal pretreatments by competitive adaptive reweighed sampling (CARS) algorithm. For anthocyanins, the correlation coefficient of prediction was 0.942 1, and the root mean square error of prediction was 0.225 9 mg/g; for SSC, the correlation coefficient of prediction was 0.943 1, and the root mean square error of prediction was 0.878 7 °Brix; for TS, the correlation coefficient of prediction was 0.925 3, and the root mean square error of prediction was 0.244 3%. These results showed that using visible/near infrared spectroscopy could achieve the simultaneous, rapid and nondestructive detection of anthocyanins, SSC and TS in fresh purple sweet potato, which is of great practical importance for rapid non-destructive quality testing of fresh purple sweet potato.