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.

Individual and combined effects of postharvest dip treatments with water at 50 degrees C, soy lecithin and sodium carbonate on cold stored cactus pear fruits.

Objective of this study was to evaluate the effect of prestorage dip treatments at 20 degrees C or 50 degrees C alone or with sodium carbonate (SC) and soy lecithin (LEC), either individually or in combination, on weight losses, peel disorders, overall appearance and decay of cactus pears. Fruits were subjected to a simulated Mediterranean fruit fly (medfly) disinfestation by cold quarantine at 2 degrees C for 21 days followed by one week of shelf-life at 20 degrees C. Hot water alone was very effective in reducing peel disorders and decay both during cold storage and shelf-life. SC applied at 20 degrees C showed a weak control of decay and chilling injury, while its effectiveness significantly increased when the solution temperature was set to 50 degrees C. LEC was more effective in preserving freshness during cold storage, but after shelf-life decay incidence in fruit dipped in LEC at 20 degrees C or 50 degrees C was higher than in those dipped in water at 20 degrees C or 50 degrees C, respectively. Significant but moderate differences were detected among treatments in weight loss. After shelf-life, fruit dipped in the heated mixture of SC and LEC showed the lowest incidence of peel disorders and the highest percentage of marketable fruit, although decay incidence was slightly higher than in fruit treated with SC at 50 degrees C. SC and LEC used in combination at 50 degrees C improved fruit tolerance to chilling injury and reduced decay.

Influence of post-harvest treatments with fludioxonil and soy lecithin co-application in controlling blue and grey mould and fludioxonil residues in Coscia pears.

The residue levels of fludioxonil (FLU) were determined in Coscia pear following a 1-, 2- or 4-min dip in an aqueous mixture of FLU containing 300 or 100 mg l(-1) (active ingredient, a.i.) at 20 and 50 degrees C, respectively, with or without 2% soy lecithin. The efficacy of heat treatment with water and FLU mixtures was investigated on artificially inoculated pears for the control of post-harvest decay caused by blue (Penicillium expansum Link) and grey (Botrytis cinerea Pers. ex Fr.) mould. Treatment with 300 mg l(-1) FLU at 20 degrees C increased residues significantly when treatment time rose from 1 to 2 min; no further increase was recorded when dip time raised from 2 to 4 min. FLU residue rates were unaffected by treatment time when 300 mg l(-1) a.i. was applied in combination with lecithin at 20 degrees C. While treatment with 100 mg l(-1) a.i. at 50 degrees C for 1 and 2 min resulted in similar residue levels, significantly higher residues were detected when dip time increased from 1 to 4 min. Co-application of lecithin significantly decreased FLU residues with respect to fruit treated with FLU alone. Treatments with FLU at 20 or 50 degrees C effectively controlled decay over 10 days of incubation. While co-application of lecithin did not affect the efficacy of FLU at 300 mg l(-1)and 20 degrees C, treatment efficacy decreased when lecithin was applied in combination with 100 mg l(-1) FLU and 50 degrees C for 4 min and to a greater extent when dip time was 1-2 min.