基于电子鼻检测香红梨腐烂程度

目的 为监测贮藏、运输过程中香红梨（Pyrus communis L. cv. Xianghong）的腐烂情况，确定腐烂果的特征传感器。方法 利用电子鼻技术对按腐烂点直径划分的3个等级香红梨的挥发性气体进行测定，同时比较了贮藏初期和后期果实挥发性气体的差异。采用主成分分析（PCA，principal components analysis）、线性判别分析（LDA，linear discriminant analysis）和载荷分析（LA，loading analysis）对电子鼻响应信号值进行分析。结果 电子鼻传感器W5S、W1S、W1W、W2S、W2W是检测香红梨挥发性气体的特征传感器。贮藏期间，氮氧化合物、甲烷、硫化物和萜烯类、醇类和部分芳香族化合物释放量逐渐增加。果实腐烂使硫化物和萜烯类（W1W）、甲烷（W1S）、氮氧化合物（W5S）挥发性物质进一步积累释放，传感器响应值比贮藏初期（P）分别提高了7.7、4.6、4.5 倍。通过监测W5S传感器响应值变化可判断果实的腐烂情况。LDA分析对不同贮藏时期和不同腐烂程度香红梨的区分能力更好。结论 电子鼻传感器W5S、W1S、W1W、W2S、W2W可灵敏反应香红梨的挥发性气体，其中W5S、W1S、W1W为果实腐烂特征性传感器，其响应值可区分果实腐烂程度。本结果为果实采后贮藏保鲜的无损检测技术及果实品质评价提供理论参考。

Detection of decay degree of Xianghong pear based on electronic nose

Objective To monitor the decay of Xianghong pear (Pyrus communis L. cv. Xianghong) during storage and transportation and to determine the characteristic sensor of the decayed fruit. Methods The electronic nose technology was used to measure the volatile gas of three grades of Xianghong pear according to the diameter of the decay point. Meantime, the difference of volatile gas in early and late storage period was compared. Principal component analysis (PCA), linear discriminant analysis (LDA) and loading analysis (LA) were used to analyze the response signal values. Results W5S, W1S, W1W, W2S, W2W are characteristic sensors for detecting the volatile gas of Xianghong pear.During storage, the release of nitrogen oxides, methane, sulfides and terpenes, alcohols and some aromatic compounds gradually increased. The rot of Xianghong pear further accumulated and released volatile substances such as sulfides and terpenes (W1W), methane (W1S) and nitrogen oxides (W5S), the sensor response value was increased by 7.7, 4.6 and 4.5 times respectively compared with the initial storage period (P). It could be judged by monitoring the changes of sensors response values ( W5S). The LDA analysis had better distinguishing ability for different storage periods and different degrees of rot. Conclusion The electronic nose sensors W5S, W1S, W1W, W2S, W2W could sensitively respond to the volatile gas of the pear. Among them, W5S, W1S, W1W were characteristic sensors of fruit decay, and their response values could distinguish the degree of fruit decay. This study provided a theoretical reference for the non-destructive testing technology and quality evaluation of fruit after storage and preservation.