Accelerated Solvent Extraction for the Determination of Flavonoids in Apple

ALONSO-SALCES, R. M.; CORTA, E.; BAKKALI, A.; BARRANCO, A.; BERRUETA, L. A.; GALLO, B.; VICENTE, F.

Lisboa (Portugal)

Conferencia; EUROANALYSIS XI, European Conference of Analytical Chemistry; 2000

Portuguese Chemical Society, Federation of European Chemical Societies Division of Analytical Chemistry (FECS), EURACHEM and Institute for Reference Materials and Measurements (IRMM)

Flavonoides have an important role in the nutritional, organoleptic and commercial properties ofagricultural foodstuffs, since they contribute to their sensory properties such as color [I],astringency, bitterness and flavour [2].The methodology used to extract flavonoids in apples generally includes extractions withsolvents, such as methanol, ethanol, acetone or mixtures of these with water [3], cleanup andfurther fractionation by liquid-liquid extraction (LLE) [4], usually with ethyl acetate, or columnchromatography (CC) [5].Sample extraction procedures are often regarded as bottlenecks in analytical methods.Moreover, classical sample preparation techniques are both time and solvent consuming. Inaddition, this step accounts for at least one-third of the error generated by the analytical method[b]. Therefore, the importance of sample preparation in analytical chemistry cannot beoveremphasised These facts have led to develop new sample preparation techniques whichallow to reduce the volume of extraction solvent required, shorten the analysis time anddecrease the handling to produce more precise results.Accelerated solvent extraction (ASE) is a new extraction technique that uses organic solvents athigh pressures and temperatures above their boiling point. With ASE, a solid sample is packedinto a stainless steel extraction cell and extracted with a suitable solvent under elevatedtemperature (40-200°C) and pressure (500-3000psi) conditions for short periods of time (5-15min). The sample extract is purged into a collection vial with compressed gas.In this job, the optimisation of the flavonoid extraction ftom apple peel and pulp using ASE isreported. The effects of various experimental parameters, such as solvent composition,temperature, pressure and static time on the ASE efficiency are systematically investigated.Once the optimum conditions were established the reproducibility of the extraction yield wastested by means of repeated analysis on different samples.