Changes in flavour influencing parameters of coldstored orange fruit

Orange fruits may undergo changes in sensory quality during prolonged cold storage, probably associated with decreased emission of those volatile compounds characterising aroma profile of fresh fruits, as well as with development of off-flavours.The purpose of this work was to evaluate modifications in aroma of two blood varieties ('Tarocco' and 'Moro') and a blond variety (cv.'Washington navel') of orange fruit [Citrus sinensis (L.) Osbeck] after storage at 6 °C and 90-95 % RH during 60 days.Standard quality parameters (juice yield, TSS, TA, pH, vitamin C) in addition to anthocyanin content, volatile flavour compounds in fruit juice and biogenic amines) were determined during fruit storage.Moreover, the spoilage level was assessed by a sensory panel.GC-MS analysis showed the formation of detrimental volatile components such as p-vinylguaiacol and ethanol in blood varieties.In addition, oxidation products of limonene such as α-terpineol in both blood and blond varieties were identified.The predominant biogenic amine was putrescine in all cultivars.In fruit of the blood varieties its levels increased through storage time, the highest levels being present after 60 days of storage, while in fruit of the blond variety putrescine levels increased more slightly.These results are in accordance with those obtained by sensory evaluation that has shown an increase of off-flavours in the last period of storage for blood orange fruits.