EFFECTS OF LYE-TREATMENT ON THE NUTRITIONAL AND MICROSTRUCTURAL CHARACTERISTICS OF TABLE OLIVES (OLEA-EUROPAEA L)

Fruits of olive tree of some Italian cultivars (Olea europaea L.) were submitted to chemical debittering treatment with NaOH aqueous solutio n (lye) at different concentrations to study the effect on the chemica l/nutritional and structural composition. Based on the concentration u sed, the results obtained showed that the lye brings about rather note worthy modifications in the fruit as well as the loss of some organic constituents which are essential for the quality of the finest table o lives. Notable modifications were registered in both the sugar and pro tein contents while the oil content remains substantially unchanged. A t a microstructural level, the lye causes a noticeable thinning of the normal pecto-cellulosic thickness of the cell walls, breakage and dis ruption of the cell structure with negative effects on the consistency of the finished product. In the olive with a tender pulp (tender-pulp olive), such alterations can be critical and may compromise the marke tability of the product. Therefore, the optimisation of the process pa rameters and particularly of the concentration of lye is essential for the obtainment of table olives having high quality.