1. University of Food Technologies, Department of Organic Chemistry and Microbiology, 26 Maritza Blvd., Plovdiv, Bulgaria
E-mail address: petkovanadejda@abv.bg, denev57@abv.bg
Table 1. Moisture content in the roots and tubers of the medicinal plants
Number Name of the plant Moisture CV, %
Abstract
content ±SD, %
Тhe continuous ethanol and water extractions of medicinal plants Cichorium
1. Inula helenium L. (elecampane) 8,50 ±0,23 0,15
intybus, Inula helenium, Taraxacum officinalis and Helianthus tuberosus
accumulating inulin-type fructans in their underground parts – roots and tubers 2 Cichorium intybus L (common chicory) 7,76±0,38 0,24
were carried out. The extraction efficiency of inulin and oligofructoses was 3 Taraxacum ollicinale Web. (dandelion) 8,46±0,26 0,12
followed by TLC. The amount of extracted fructans was determinated by the 4 Helianthus tuberosus L. (Jerusalem artichoke) 9,66 ±0,3 0,19
spectrophotometric method based on the Seliwanoff reaction with resorcinol as SD – standard error; CV – coefficient of variation
the absorbance of resulting compound was measured at 480 nm. It was obtained
Figure 2. Thin layer chromatography of inulin and FOSs extraction
that the average fructan content was as follows: Cichorium intybus е 33 %, в Helianthus tuberosus L. Inula helenium L. Taraxacum officinale Web.
Inula helenium - 42-44 %, Helianthus tuberosus – 69 % и Taraxacum officinalis – Ethnol extracts Water extracts
Fructose
34 %, which make them rich sources of soluble dietary fiber, when they were Sucrose
used in dietary food products.
Introduction
Inulin is a polydisperse linear polysaccharide, member of fructan family and serves Figure 3. Absorption spectrum of the complex compounds formed by
as a reserve carbohydrate in underground part of plants from the Compositae interaction of fructans with concentration 1 mg/ml with resorcinol
(Astraceae) family such as Cichorium intybus (chicory), Inula helenium (elecampane), Abs
Taraxacum officinalis (dandelion) and Helianthus tuberosus (Jerusalem artichoke). 0,400 THE
FOSs Inulin
Inulin consists mainly of β-(2→1) fructosyl fructose units (Fm), and usually but not 0,350 HTW
always the chain terminate with α-glucopyranose unit (1→2) (GFn) at the reducing end CIE
0,300 CIW
(Figure 1). A small percentage of inulin molecules have a terminal fructoside unit 0,250 TOE
found primarily in the pyranose form in aqueous solution. The degree of 0,200 TOW
polymerization (DP) of inulin varies from 2 to 70 and depends on plant species, 0,150 IHE
harvesting time and post-harvest conditions. Molecules with DP<10 are called
0,100 IHW
oligofructoses or fructooligosaccharides (FOSs) and are a subgroup of inulin. The IHW10
0,050
maximum amount of low- and high-molecular fructans (75-85%) is found in IHE10
topinambur as the greater part of topinambur is a low-molecular fraction. Inulin and (GFm) (Fn) 0,000
320 360 400 440 480 520 560 600 640 680
FOSs are classified as soluble dietary fiber. They act as prebiotic as stimulate growth Figure 1. Chemical structure of Inulin Wavelength, nm
of Bifidobacteria, low glucose blood level, improve mineral absorbtion and possess
Table 2. Fructan content (g/100 g dw) in underground organs of Composite Family (Astraceae) plants
immunomodulation effects. Inulin has been increasingly used in various foods due to
No Species Date of Underground Low molecular High-molecular Fructan,
its beneficial nutritional attributes . Along with positive healthy effect inulin acts as
texture modifier, decreases caloric value and improves nutritional properties of food. taking part fraction (fructose fraction (inulin) g/100 g
samples and FOSs), g/100 g g/100 g
1 Inula helenium L 11.11 rootstock 10,9 ±2,2 32,0±2,0 42,9±2,1
2 Inula helenium L 04.10.10 roots 8,3±1,5 32,7± 0,5 41,0±1,8
Material and methods: 3 Cichorium intybus L. 04.11 - 16,1 ± 0,06
Moisture content of the dried ground tubers and roots were determinated according AOAC 945.32 method as the drying 11.11 roots 12,1±2,5 21,2 ±1,5 33,3 ±2,0
process was carried out at 105 °C for 3 hours..
The extraction process was carried as follows: 0,45 g dry sample (roots or tubers) was extracted three times with 95 %
4 Taraxacum officinale Web. 06.11.11 roots 10,7±0,7 23,9±4,2 34,6±2,4
ethanol (40, 40, 20 ml) to obtain low-molecular fraction composed of fructose and FOSs. High-molecular fraction (inulin)
was then extracted by three following water extraction (40, 40, 20 ml). The extraction level of oligofructoses in the ethanol
5 Helianthus tuberosus L. 06.09.11 tubers 6,4 ±0,4 43,5±2,5 49,9± 1,4
extracts and of inulin in water extracts were monitored by TLC to observe the extraction rate of fructans and to observe
inulin fractions. Thin-layer chromatography (TLC) was performed on silica gel 60 F254 plates (Merck) with: 1) n-
6 Helianthus tuberosus L. 2010 tubers flour 45,4 ±2,2 23,9±1,0 69,3±2,5
BuOH:EtOH:H2O (5:3:2) (v/v) as an eluent and the plates were dipped into a detecting reagent diphenylamine-aniline-
acetone-H3PO4; 2) BuOH:i-PrOH:H2O:CH3COOH (7:5:4:2) (v/v) – mobile phase and detecting reagent – diphenylamine- Conclusion
aniline-H3PO4 acetone (1:1:5:50). Inulin and oligofructoses content in some medicinal plants has been defined by TLC
The fructan content in ethanol and water extracts were analyzed spectrophotometrically at 480 nm by resorcinol- and spectrophotometric methods of analysis. From the obtained results we can
thiourea reagent. conclude that Helianthus tuberosus is the richest source of fructan (50-70 g/100 g),
but the FOSs fractions dominate in the both extracts. Water fractions obtained from
Taraxacum ollicinale consists of short chain-oligofructoses and very small amount of
inulin. The greatest content of high-molecular inulin (40-42 g/100 g) is characteristic
of elecampane. The fructan content in all of the investigated plants increases during
the autumn. The rich content of FOSs and inulin in these plants made them a source of
prebiotics which improve the digestion function and enriches colon with
Bifidobacteria.