Ripe olives. Comparative study of three procedures for the previous conservation of gordal (O. europaea regalis)

Abstract

This paper shows the physico-chemical and microbiological results of the brines from three procedures of previous conservation of Gordal cultivar olives and its effects on the main quality attributes of the final product: colour and texture. Two of them have used low NaCl levels and initial pH correction to facilitate the growth of lactic bacteria. The other has consisted of a solution highly acidified with acetic. In all procedures, a fermentation process has been found. During it the growth of lactic bacteria, mainly Lactobacillus plantarum and Pediococcus (that has predominated in some cases) and yeats, which have coexisted with the previous mentioned microorganisms thought the whole conservation period, has been detected. The evolution of the physico-chemical characteristics has been different in the three processes, however they have not had any influence on the elaborated final product. For industrial work, the aerobic system is recommended due to its CO₂ purging action which could have a favorable effect on shriveling. It would consist of putting the olives in a 6% NaCl brine, with the initial pH corrected with acetic to 4.00 units and bubbling air throughout the column at a rate of 0.3 l/h.l.c. during 8 h/day. The salt percentage should be raised to 8% once the lactic fermentation has finished.