Phenolic compounds in Rojo Brillante and Kaki Tipo persimmons at commercial harvest and in response to CO2 and ethylene treatments for astringency removal

The aim of this paper was to investigate the presence of thirty-six analytes among hydroxybenzoic and hydroxycinnamic acids, flavanols, flavonols and dihydrochalcones, accurately quantifying their concentrations in “Rojo Brillante” and “Kaki Tipo” flesh of commercially harvested persimmons, cultivated in the same orchard and under the same cultivation practices (cultivar effect), as well as after postharvest treatments with ethylene or CO2 for astringency removal (postharvest effect). Twenty-nine compounds were determined in at least one of the two untreated varieties, eleven of them for the first time (e.g. ellagic acid). In untreated fruits, gallic and ellagic acid were by far predominant (38–47 and 6 mg/100 g d.w., respectively). The untreated varieties provided different native phenolic compositions, indicating the presence of a cultivar effect. In both varieties, ethylene treatment induced a 40% decline of the sum of individual polyphenols, whereas an 86.3% reduction was observed in “Rojo Brillante”, after CO2 treatment (postharvest effect). The decrease of gallic acid due to CO2 treatment was more than double the one with ethylene. CO2 induced a strong decrease also for ellagic acid, which remained conversely unchanged after ethylene application. Some catechins behaved differently, since they were unchanged by CO2, but increased with the exposure to ethylene.