Study of the debitering? s changes that take place during the elaboration of green table olives

M. B. MALDONADO; PEREZ RAUL CESAR

International Journal of Food and Biosystems Engineering

Technological Educational Institute of Thessaly, The Technological Research Center of Thessally and the Laboratory of the Food and Biosystems Engineering of TEI of Thessaly

Lugar: Tesally; Año: 2017 vol. 5 p. 45 - 52

ABSTRACTThe first step in the processing of fermented green olives is a lye treatment known as debittering. The lye treatment gives rise to complex chemical and physical changes in the olives, and its extent also affects the subsequent diffusion of salt and the progress of the lactic fermentation. The main objectives of this operation are to eliminate the bitter taste conferred by the glycoside oleuropein and to increase the permeability of the fruit. The skin is a natural barrier to the penetration of NaOH and other solutes to the interior of the olives. Its permeation is a function of the treatment conditions such as lye concentration and temperature, along with olive variety and maturity. The diffusion of solutes in food products plays an important role during the debittering. Different models have been consistent in order to determinate the order magnitude of the effective diffusion coefficient; we can mention the thin plate model, the hollow cylinder and the hollow sphere models and in elliptical coordinates, too.Nevertheless, none of them fit exactly the geometry of the fruit. During the debittering there are dynamic changes of ionic charges between sodium and calcium, principally. This phenomenon occurs while appears swelling and weight gain by water intake, loss of sugars, polyphenol outlet, unwinding of the pectin structure, and other reactions that allow the lactic fermentation. This parameters and variables were measured and explain in part the significant changes that take place during this important step. The comprehension of these changes can help to understand the behavior of olives during and after process and the quality of final product and it can help by understanding the management of effluents and their possible biodegradation.KEY WORDS: green olives, debittering, diffusion, mathematical modeling, phenomena swelling, chemical and physical changes, effluent management