Volatile organic compounds (VOCs) are generated in different commodities through various biosynthetic pathways. They act as biomarkers for different infections and metabolisms and can be instrumental in the development of biosensors for monitoring the health of stored horticultural commodities. Healthy onions and samples infected with Pectobacter Erwinia carotovora were stored at different conditions (4 °C, 60 %; 8 °C, 65 %; 15 °C, 75 %; 25 °C, 60–80 %) for 4 weeks and the VOCs were mapped using SPME-GC–MS. The data were analyzed using multivariate data analysis techniques like Principal Component Analysis (PCA), and Partial Least-Squares Discriminant Analysis (PLS-DA), and visualized using a cluster heat map. The number of VOCs was higher in the infected samples, which increased over the storage duration. The predominant class of VOCs at 25 °C are mostly ester and sulfur; and at 15 °C, alkane and ketone groups of VOCs contributed more, during the initial phase of infection. At a lower temperature of 8 °C bacterial metabolic VOCs belonging to alcohol or aldehyde groups could be observed. On the other hand at 4 °C, since the microbial activity is retarded, no such compounds were found. With storage and extent of spoilage, the predominant VOCs belonged to acids and multi-functional group variants for lower temperatures. VOC profile was found to be correlated with storage conditions as well as periods that ultimately had an impact on Erwinia carotovora secondary metabolism. Except for the 4 °C storage temperature, PCA could distinguish and separate the VOCs into clusters for the classification of infected and non-infected samples; however, PLS-DA performed better separation and distinction of VOCs among the groups for all the storage conditions. The dominance of the VOCs with respect to sample type, storage condition, and storage duration was represented through the clustered heat maps.

挥发性有机化合物 (VOC) 是通过各种生物合成途径在不同商品中产生的。它们充当不同感染和新陈代谢的生物标志物，可有助于开发用于监测储存园艺商品健康的生物传感器。健康的洋葱和感染 Pectobacter Erwinia carotovora 的样本在不同条件（4 °C，60 %；8 °C，65 %；15 °C，75 %；25 °C，60–80 %）下储存 4 周，并使用 SPME-GC–MS 绘制 VOC . 使用主成分分析 (PCA) 和偏最小二乘判别分析 (PLS-DA) 等多变量数据分析技术对数据进行分析，并使用聚类热图进行可视化。受感染样品中 VOC 的数量较高，并且随着储存时间的增加而增加。25 °C 时的主要 VOC 类别主要是酯类和硫磺；在 15 °C 时，在感染的初始阶段，VOC 的烷烃和酮基贡献更多。在 8 °C 的较低温度下，可以观察到属于醇或醛基的细菌代谢 VOC。另一方面，在 4 °C 时，由于微生物活动受到阻碍，因此未发现此类化合物。随着储存和腐败程度，主要的 VOC 属于较低温度下的酸和多功能基团变体。发现 VOC 分布与储存条件以及最终影响欧文氏菌次生代谢。除了 4 °C 的储存温度外，PCA 可以将 VOCs 区分和分离成簇，用于感染和未感染样品的分类；然而，PLS-DA 在所有储存条件下对组间 VOC 进行了更好的分离和区分。VOC 在样品类型、储存条件和储存持续时间方面的优势通过聚类热图表示。