Characterization of Volatile Organic Compounds Associated with Postharvest Pathogens of Stored Sugarbeet Roots

Postharvest diseases caused by fungal and bacterial pathogens significantly reduce sucrose yield in stored sugarbeet roots in the U.S. and other sugarbeet producing regions. This study investigated volatile organic compounds (VOCs) associated with infections by sugarbeet postharvest pathogens, such as Penicillium expansum, P. paneum, and Leuconostoc suionicum. Root tissues were inoculated in vitro, and VOCs were analyzed after 7, 14, and 21 days at 30°C using solid-phase microextraction coupled with gas chromatography-mass spectrometry. Among 29 VOCs identified, ethanol was most abundant, indicating fermentative activity by inoculated postharvest pathogens. Sugarbeet roots inoculated with the fungal pathogens Penicillium expansum and P. paneum showed elevated ethanol levels, whereas inoculation by the bacterial pathogen L. suionicum produced a distinct profile characterized by the release of ethyl acetate and acetic acid. These compounds represent potential biomarkers for early detection of storage diseases, enabling early interventions to reduce sucrose loss and mitigate economic impacts in postharvest sugarbeet storage.