Ozonation process for the regeneration and recycling of Spanish green table olive fermentation brines

Abstract

Treatment with ozone broke down the most characteristic polyphenols present in the fermentation brines of green table olives. The ozone required for their complete elimination was 15 and 7 mg/L in acidic solutions (pH 4.0) and alkaline conditions (pH 10.0), respectively. The usual microbial population of brines, lactic acid bacteria and yeasts, was simultaneously eliminated in parallel but needed higher ozone levels in acidic conditions. The ozone treated brines were then filtered through a 0.45 μm pore size and diluted (1:1) and re-used as cover brine for plain and pitted olive packing. After 3 months equilibrium, the cover brines from regenerated brines had slighter poorer colour and slightly higher pH. Fruits packed with diluted (1:1) ozonated brines in alkaline conditions had higher firmness and similar organoleptic characteristics to those using fresh brine. The partial regeneration and reuse of fermentation brines may be a cheap and technologically simple alternative for reducing the environmental problems derived from the high polluting charge of green olive fermentation brines.