A New Natural Processing System Based on Slight Carbon Dioxide Pressure for Producing Black Table Olives with Low Salt Content

Abstract

Naturally fermented black table olives are usually processed in brine with low pH and high NaCl content. Because salt is responsible for several cardiovascular problems, methods are needed to decrease the salt (NaCl) content in olive pulp. This study investigated a new natural processing system wherein microorganism growth is inhibited by slight pressure of CO2 (spCO2), in addition to low pH and NaCl, in brine with decreased salt content. The fermentation performed under spCO2 with a low-salt brine with 6% (w v−1) NaCl and 0.5% (w v−1) citric acid, unlike the traditional system, inhibited the growth of bacteria and fungi and decreased the concentration of yeasts. Processing tests with spCO2 in the presence of different salt and citric acid concentrations indicated a slight decrease in yeasts in brines containing 6% (w v−1) NaCl and 0.6% (w v−1) citric acid but not after inoculation of the same brines with Saccharomyces cerevisiae. In contrast, in the presence of 11% (w v−1) NaCl and 0.3% or 0.6% (w v−1) citric acid, the inhibitory effect of brines was greater compared to those with low-salt and it was also confirmed in the same brines inoculated with S. cerevisiae.