Effect of heat treatments on biomolecular profile of Sardinian apple cultivars.

Postharvest heat treatments (hot water or hot air treatment) may be applied to horticultural crops to control fungal diseases, insect infestation and to reduce chilling injury in cultivars susceptible to low storage temperatures. The present study investigated the influence of hot water (53 degrees C for 60s) and hot air treatment (38 degrees C for 24h) applied to two typical Sardinian apple varieties, cvs. Miali and Caddina, on the composition of the lipophilic extracts of the peel as well as on the antioxidant activity of ethanolic extracts of both peel and pulp. The lipophilic extracts of the peel of the two varieties were almost similar and resulted to be dominated by the presence of triterpenes being ursolic and oleanoic acids the main metabolites in both analysed fruits. The chemical analysis of the extracts obtained from the different heat-treated samples for each variety revealed no significant difference in the relative distribution of triterpene components with respect to untreated control samples. This strongly suggested that heat treatment does not affect the composition of terpene metabolite profile of the fruit peel. On the other hand, the antioxidant activity of the ethanolic extracts of the peel and the pulp of heat treated was significantly different from that of control In particular, on Caddina variety the antioxidant activity levels of the peel were consistently higher than in the pulp and were affected by storage conditions. Differently, on Miali variety the antioxidant activity of heat-treated samples was higher than control sample in both peel and pulp.