engleski

Solid hydrodistillation residues of bay laurel, rosemary and sage as a source of polyphenols

Solid hydrodistillation residues produced in parallel with essential oils of bay laurel, rosemary and sage are much less explored or even considered waste despite rich polyphenolic content. Prior to hydrodistillation, plant material is often treated with ultrasound, microwaves or enzymes, in order to disrupt the cell wall and improve the access of solvent to the cell content, thus enhancing the release of bioactive compounds. When comparing different extraction procedures used to process solid hydrodistillation residues like enzyme assisted or reflux extraction, ultrasound application is considered gentler in comparison with other extraction procedures, working at lower temperature and for shorter time, which makes it more suitable to preserve polyphenols from thermal degradation. HPLC analysis showed that the solid hydrodistillation residues of all plants were richest in polyphenols. In bay laurel solid hydrodistillation residues extract, procyanidins represented the dominant components, with procyanidin trimer, dimer and tetramer as major compounds. Among other components, epicatechin, epicatechin-hexoside and epicatechingallate were also detected in significant quantities. In sage solid hydrodistillation residues extract, salvianolic acid I and K were major compounds, followed by luteolin-3-O-glucuronide. Finally, in rosemary solid hydrodistillation residues extract, rosmarinic acid was the most represented component. Applied solvents didn’t show significant variations (p<0.05) in polyphenolic composition resulting in considerable concentrations of polyphenols in the final bay laurel, rosemary and sage extracts. In general, the pretreatments didn’t significantly affect the polyphenolic composition of solid hydrodistillation residues (p<0.05), i.e. the composition was comparable to the no- pretreatment control, as confirmed by Spearman ´s test. Our results point out that solid residues remaining after hydrodistillation can also be exploited as secondary raw material for obtaining different polyphenolic compounds using ultrasound assisted extraction with different solvents and obtained plant extracts are valuable source of polyphenolic compounds and can find their application in many fields of food industry.

bay laurel ; hydrodistillation ; hydrolates ; monoterpenes ; rosemary ; sage ; sesquiterpenes

nije evidentirano