Sugar and polyol compositions of some European olive fruit varieties (Oleaeuropaea L.) suitable for table olive purposes

An experimental investigation was carried out on olive fruits of Douro, Hoj iblanca, Cassanese, Taggiasca and Thasos cultivars, to assess free sugar an d polyol compositions and their changes during ripening and processing. TMS ethers of sugars from olive pulp were analysed by GC and GC-MS and identif ication of each sugar component was obtained by comparison of retention rim es and mass spectra with those of authentic compounds. Quantitation of suga rs was performed on mixture whose tautomeric equilibria were stable. Glucos e, fructose and galactose were the main sugars found in olive pulp. Appreci able quantities of mannitol were also present. Sucrose and inositol were pr esent in very low concentrations. A significant correlation (r=0.941) betwe en mannitol and oil contents was found. Sugar content decreased from green to cherry and black colour, according to the stage of ripeness of fruits. I n processed olive-fruits, sugar contents varied among olive cultivars accor ding to processing conditions. (C) 2001 Elsevier Science Ltd. All rights re served.