Preventive antifungal activity of postharvest treatments with SPI (soy protein isolate) −coatings forming solutions against blue mould decay were evaluated on Persian lime (Citrus latifolia Tanaka) artificially inoculated in rind wounds with Penicillium italicum. Stimulatory effects were observed with the use of citral, however with the use of limonene an inhibitory effect was obtained. After 13 d of storage, significant preventive activity against blue mould was observed with a 20% of disease incidence applying SPI-coating forming solutions with limonene added. SEM micrographs showed that limonene could act as an inhibitor of germ tube elongation, delaying the process of infection. Quality parameters like water losses, change in colour and aroma compounds release were assessed on fruit coated. Depending to storage condition, SPI-coating forming solutions were effective to reduce water losses, maintain colour and controlling the liberation of active agent.