Enrichment of bioactive phenolic compounds from aqueous solution by foam separation
Olive mill wastewater (OMWW) is an abundant source of polyphenols . Due to their different bioactivities, OMWW would be a worthwhile source of highly valuable compounds for pharmaceutical and food industry. However, a simple and cost-effective extraction technique has still to be found. The present study aimed to evaluate foam separation for the isolation of phenolic compounds from OMWW. Thereby, surface-active substances can be enriched in an up-rising foam produced by introducing gas in an aqueous solution . Running the process with inert gas at room temperature provides a mild technique for heat- and oxygen-sensitive substances. Aqueous solutions of phenolic acids (vanillic acid, 4-hydroxybenzoic acid, 4-hydroxyphenylacetic acid, 4-hydroxybenzoic acid, protocatechuic acid), all found in OMWW, were used as simple models of OMWW. The added cetyltrimethylammonium bromide (CTAB) acted as a foaming agent and as an anion-collector for the deprotonated reference substances. Enrichment factors (concentration in the collected foam relative to the concentration in the feed solution verified via HPLC analaysis) for the phenolic acids were optimized by varying important process parameters like pH, CTAB concentration, biophenol concentration, and gas flow rate. As a result, enriched extracts were obtained for all tested substances.
Acknowledgement: This work was funded by the Bundesministerium für Bildung und Forschung, Bio-Disc.
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