The influence of extraction techniques on the yield, kinetics and composition of aqueous extracts from dill fruit (Anethi fructus)

Abstract

University of Niš, Faculty of Technology, Leskovac, Serbia The influence of operational extraction conditions (hydromodule and temperature) and extraction techniques (maceration, Soxhlet, Tillepape, extraction with reflux and ultrasonic extraction) on the yield, composition and kinetics of total extrac­tive matter from dill fruits (Anethi fructus) was investigated. Optimal operational extraction conditions by maceration of total extractive matter were defined (hydro­module 1:20 m/v and solvent boiling point). Two extraction kinetics models (model Ponomaryov and non-stationary diffusion model) were applied for modeling the extraction kinetics of total extractive matter. Total phenolic content (Folin-Ciocalteu assay) and total flavonoids content (assay with AlCl3) in the extracts, obtained by different extraction techniques were measured spectrophotometrically. The yield, extraction kinetics and composition of the obtained extracts (the content of total phenols and flavonoids) of dill fruit depend on applied extraction techniques. The highest yield of total extractive matter was achieved by Soxhlet extraction, in the period of 240 minutes. The ultrasound has a positive effect on the extraction process duration (30 minutes for ultrasonic extraction versus 180 minutes for macera­tion). The aqueous extract from dill fruit had a high phenolic content, while the con­tent of total flavonoids was significantly lower. The highest content of total phenolic compounds (573.81 mg GAE/g dry extract) and flavonoids (12.96 mgRE/g dry extract) was determined in the extract obtained by Soxhlet extraction.