Characteristics of oleuropeinolytic strains of Lactobacillus plantarum group and influence on phenolic compounds in table olives elaborated under reduced salt conditions

• Technological characteristics of five oleuropeinolytic strains of the Lactobacillus plantarum group.
• Fermentation of Protected Designation of Origin olives “green olives Chalkidikis” and black “Kalamata olives”.
• Reduced salt brines were used during fermentation.
• Low oleuropein and increased hydroxytyrosol and tyrosol content were detected in elaborated olives.
• The oleuropeinolytic Lactobacillus strains can lead to biological debittering of table olives.

The technological characteristics of five oleuropeinolytic strains of the Lactobacillus plantarum group selected within 135 isolates from table olives were investigated. The metabolism of phenolic compounds during elaboration of green (cv. Chalkidikis) and black (cv. Kalamata) olives under reduced salt conditions was evaluated. Olives of both cultivars were fermented in two different kinds of brine (Brine A containing 2.3% NaCl, 32.3 mM Ca-acetate and 33.9 mM Ca-lactate and Brine B containing 4% NaCl, pH 5.0 in both brines) by five selected strains of L. plantarum group. After 60 days of fermentation, the analysis of phenolic compounds was performed by HPLC and nine compounds were identified and quantified: oleuropein, hydroxytyrosol, tyrosol and vanillin and the phenolic acids protocatechuic, caffeic, p-hydroxybenzoic, vanillic and p-coumaric acid. The study can lead to the development of starter culture potentially active in biological debittering of olives during fermentation in order to unify the debittering and fermentation process during elaboration of table olives.