Control of Penicillium expansum and patulin accumulation on apples by the phytoalexins quercetin and umbelliferone

The effectiveness of seven phenolic compounds(esculetin, ferulic acid, quercetin, resveratrol,scopoletin, scoparone and umbelliferone) in controllingPenicillium expansum growth and patulin accumulationwas evaluated by both in vitro and in vivo studies. The invitro screening showed that quercetin and umbelliferonewere the most effective compounds in controlling Penicilliumgrowth and patulin accumulation, respectively.Quercetin and umbelliferone, resulted to be effective alsoin the in vivo screening, were further tested (alone and incombination) on Granny Smith and Golden Deliciousapples. The efficacy in controlling Penicillium growth wasbetter expressed on Golden Delicious than on GrannySmith apples, with quercetin providing a better control ofboth incidence of decay and disease severity as comparedto umbelliferone. Both compounds exerted a considerablecontrol of patulin accumulation on the two apple cultivars.Quercetin and umbelliferone can be considered as naturalcompounds to be used as alternative strategy to chemicalfungicides in postharvest control of P. expansum infectionson apples.