Exploring enzyme and microbial technology for the preparation of green table olives

The aim of this work is to study alternative biotechnological procedures to prepare green table olives. Specifically, by working on laboratory-scale system and under controlled conditions, the technological potential of enzymes from olive leaf and/or Lactobacillus plantarum strain (TB38) isolated from wine were assayed on green olives in comparison with spontaneous fermentation and 3 % NaOH treatment. The fermentation process (microbial count, pH, ethyl alcohol and the lactic and acetic acids, in the cover liquid medium) and the changes of phenolic fraction (total phenols, oleuropein and hydroxytyrosol, in the olive fruits) were checked weekly for 30 days. In the first week, olive leaf enzymes showed to be very effective in degrading the oleuropein; conversely, their action showed a decline in the subsequent days. Also the TB38 LAB strain showed a good oleuropeinolytic activity and acidifying capacity. However, the presence of undissolved olive leaf solid residue inhibited clearly the metabolism of LAB.