Effects of Horseradish Oil and Eight Isothiocyanates Vapour Treatment on Postharvest Disease Control and Their Efficacy as Preservatives of Mature Green Tomato

This study evaluated the potential of horseradish (Armoracia rusticana) oil (ARO) and eight isothiocyanates (propyl ITC [ProITC], isopropyl ITC [IsoproITC], n-butyl ITC [n-BuITC], 3-butenyl ITC [3-BeITC], phenyl ITC [PhITC], benzyl ITC [BzITC], 2-phenyl-ethyl ITC [PhEITC], and allyl ITC [AITC]) as preservatives and antifungal agents for postharvest tomato disease control. Results showed that ARO and eight ITCs demonstrated antifungal activities against Botrytis cinerea, Alternaria alternata, Rhizopus stolonifer, and Geotrichum candidum, which can cause the decay of mature green tomato during storage. Allyl-ITC (AITC) had the lowest EC₅₀ values of mycelia growth suppression, with 0.18, 0.44, 0.29, and 0.43 μg/ml air for B. cinerea, A. alternata, R. stolonifer, and G. candidum, respectively. ARO, 2-PhEITC, BzITC, and AITC exhibited better efficacy as preservatives of mature green tomato than other ITCs on the basis of some parameters, such as low decay rate, slow reduction in weight loss, slight change in hardness, slow decrease in acidity, and total soluble solid content of treated tomatoes. GC-MS revealed that 2-PhEITC (77.78%) and AITC (15.87%) were the major components of ARO. These results can be used as a basis to develop preservative products composed of ITCs.

Keywords: Armoracia rusticana oil; antifungal; isothiocyanates; preservation; tomato.