Identification and characterisation of phenolic compound extracted from tunisian olive mill wastewater (OMWW) among different varieties, regions and industrial model extraction process

The study explores the influence of industrial extraction methods and olive varieties on the phenolic content and composition of Tunisian olive mill wastewater (OMWW). Two extraction techniques, maceration and liquid-liquid extraction, were employed along with various industrial procedures, including mechanical extraction and modern techniques such as two-phase and three-phase decanter systems. Notably, the industrial three-phase methods (e.g. Pieralisi, Alphalaval, Amenduni) yielded significantly higher phenolic concentrations, ranging from 0.15 to 2.80 g/L, in comparison to traditional processes, which produced lower levels of phenolics (0.06-0.77 g/L). The choice of olive variety was another determining factor, with the Pitchoulini variety displaying the highest phenolic concentration at 2.80 g/L. Through GC-MS analysis, key bioactive compounds were identified, including hydroxytyrosol, ferulic acid, tyrosol, and syringic acid. Overall, hydroxytyrosol and tyrosol were the most prominent phenolic compounds, with higher concentrations found in Pitchoulini and Koroneiki varieties.