Fac-simile Scheda Linee di Ricerca - Federalimentare

considered as the most important, due to healthy and sensory properties that characterize most of the compoundsbelonging to this class, such as oleuropein and ligstroside and their aglycon derivatives. Several biological activitieshave been demonstrated, in fact, for, with important repercussions on the prevention of oxidative stressrelatedpathologies; furthermore they are responsible for the bitter taste of olives. The debittering process,strongly modify the final concentration of phenols in brined olives. The factors involved in this modification arestill partially unknown and may include release mechanisms and hydrolysis reactions. In this research olivesfrom Coratina cultivar, harvested at two different ripening stages, were subjected to natural debittering processby controlled lactic fermentation with a selected Lactobacillus strain. Before and after fermentation the phenoliccomposition of olives and brines has been analysed. Processed olives are characterized by low phenolic concentration,consisting mainly in phenyl alcohols, verbascoside, and the dialdehydic form of elenolic acid linked tohydroxytirosol, while high amount of phenols occurs in the brine.Olives before and after the two debittering processes were cryo-fixed, analysed in a frozen-hydrated state bothon surface and along transversal freeze-fracture planes by Cryo-scanning Electron Microscopy and energydispersiveX-ray Microanalysis. These techniques allow to follow the modifications produced by fermentationprocesses inside the tissue cells, both from a structural and microanalitical point of view.5) Servili M., Selvaggini R, Esposto S., Taticchi A., Urbani S., Montedoro GF. (2006) The effectof mechanical extraction process in the phenolic composition of virgin olive oil. Proceedingof the Second international seminar Olivebioteq 2006, “Recent advaces in olive industry”.Mazara del Vallo, 5-10 November 2006, Casusi T., Montisi A., Sebastiani L. ED., pp 339-346.Hydrophilic phenols are the most abundant natural antioxidants of virgin olive oil (VOO), in which, however,tocopherols and carotenes are also present. The prevalent classes of hydrophilic phenols found in VOO are phenolicalcohols, phenolic acids, flavonoids, lignans and secoiridoids. Secoiridoids, that include aglycon derivativesof oleuropein, demethyloleuropein and ligstroside, that are present in olive fruit, are the most abundantphenolic antioxidants of VOO. The technological parameters of oil mechanical extraction process strongly affecttheir concentration in the oil. Higher modification are observed for the secoiridoid derivatives while lignans arelower affected by the oil extraction operative conditions.SISTAL - SOCIETA’ ITALIANA DI SCIENZE E TECNOLOGIE ALIMENTARIDipartimento di Scienze e Tecnologie Agroalimentari, Università degli Studi della TusciaVia San Camillo de Lellis, 01100 ViterboTel.: 0761- 35 74 94/7 , Fax: 0761- 35 74 98, e-mail: mmoresi@unitus.it377