Detection and classification of volatile compounds emitted by three fungi-infected citrus fruit using gas chromatography-mass spectrometry

[Display omitted] •Volatile compounds of flesh and peel tissues of citrus fruit were detected.•PCA and PLS-DA were applied to classify the volatile compounds.•Eight volatile compounds as biomarkers were identified in stem-end rot fruit.•The alpha-guajene as biomarker was screened in green mold rot fruit. Citrus fruit produced some characteristic volatile compounds when infected by fungi compared with the healthy fruit. In the present study, volatile metabolites of postharvest citrus fruit with three different diseases including stem-end rot, blue mold and green mold were detected. Multivariate analysis such as principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were employed to classify the volatile compounds between the infected and non-infected citrus fruit. The results indicated that volatile compounds of unrotten, unrotten-rotten junction, and rotten tissues were successfully classified. Importantly, eight volatile compounds as biomarkers for stem-end rot and one biomarker for green mold of citrus were screened to discriminate the infected citrus fruit. This study offers the application potential of odor profiling of volatile compounds for detecting the fungi infection in postharvest citrus fruit.