Extraction of plant material

Table 16.2 Examples of recent developments in use of plant materials or extract of plant material for protection of processed food against oxidation... 

Farr, D. R. and Horman, I., Treatment of an aqueous extract of plant material for reducing the content of caffeine and/or chlorogenic acid, Ger. Offen. 2,826,466, 1979. (CA90 166789x)... 

Classically, the procedure for the isolation of xylan consists in the extraction of plant material with alkaline solutions. Because of the... 

These plants, with the greatest number of industrial application so far, are used mainly for the extraction of plant materials such as spices and herbs. The extraction volumes are in the range of 200 to 800 1 in which, in most cases, cascade-mode operation with 2 to 4 extractors is applied. The design pressure-range is up to 550 (800) bar. Fig. 8.1-2 illustrates a multipurpose extraction unit for spices and herbs. 

In an extract of plant material containing carotenoids (x + c = xanthophylls and carotenes) in addition to Chls, A470 (the carotenoid region) is determined as the sum of specific... 

Bradfield and Cooke [13] give details of a procedure for the determination of chloride (as well as nitrate phosphate and sulfate) in aqueous extracts of plant materials by an ion chromatographic technique with indirect ultraviolet detection. Recoveries ranged from 84 to 108%. This technique is discussed in further detail in Sect. 10.11. 

Tetrandrine TV-2 -monoxide is a specific isomer, rather than the indiscriminate mixture expected for an artifact of aerial oxidation. In addition, extraction of plant material with petroleum ether rather than ether (a potential source of oxidiz-... 

Concretes are the waxy or fatty extract produced by solvent extraction of plant material with an organic solvent after the solvent has been recovered. They contain compounds of all molecular sizes and are usually solids containing natural wax, essential oil and pigments from the plant. 

Resinoid The purified, viscous, highly scented material produced by extraction of plant material with hydrocarbon solvents, e.g. benzoin. 

The South American Indian arrow and dart poisons known as curares are all concentrated aqueous extracts of plant materials, usually prepared according to well-established ritual. All are powerful poisons which cause rapid paralysis of voluntary muscle. The fascination of this subject is well presented in a monograph by McIntyre (1) on the history, preparation,... 

Supercritical fluid extraction (SEE) has become a method of choice for the extraction of plant material [14]. It represents an interesting alternative technique compared to conventional liquid-solid extraction, with lower solvent consumption and working temperature. The free bases of hyoscyamine and scopolamine are extractable with... 

Analysis of taxanes in biological samples and plant extracts is performed, mainly by reversed phase HPLC. Separation of paclitaxel from cephalomannine, baccatin III, and other taxanes is often performed with phenyl columns (especially for plant material analysis). Eor less complex biological samples, Cig columns are preferred because they give shorter analysis times. Extraction of plant material or cell cultures is often performed by water-dichloromethane partitioning, but lately, the application of SPE has become a basic step in order to obtain cleaner samples, higher extraction recovery, better chromatographic resolution, and longer column lifetime. Detection of taxanes is performed, in most cases, at 227-228 nm. 

Extraction of Tobacco. Methoprene is used on tobacco against the cigarette beetle and the tobacco moth. Methoprene-treated tobacco samples were extracted following a procedure for the extraction of plant materials for determining methoprene residues by GC (21). Known amounts of methoprene in 1 mL methanol were added to 1 g portions of shredded tobacco, mixed well and allowed to thoroughly air dry. The spiked tobacco was then stirred with a 25 mL mixture of acetonitrile/water/Celite 45 (250 mL/30 mL/10 g). The mixture was filtered by suction and the filter cake was washed with acetonitrile/water. The filtrate was extracted with ether, distilled water, and sodium chloride. Ether extracts were combined and washed three times with distilled water, dried, filtered and the solvent removed. The residue was taken up into methanol (1 mL) and applied to the pre-coated microtiter plates (5 jxL methanol/well), followed by the anti-methoprene antibody as described above. 

Many phytochemicals and nutraceutical ingredients are derived from botanicals. In the manufacture of many of these nutraceuticals, processes begin with the extraction of plant materials using a suitable solvent. Many technologies and types of equipment exist to achieve this solid-liquid extraction. To successfully choose and operate the proper equipment for producing the desired product in an economic manner, the fundamentals of equilibrium and mass transfer must be understood. Once these fundamentals are understood, they can be applied to the botanical raw material of interest and the chemical properties of the desired phytochemical to select and operate the most cost-effective extraction equipment. 

Sample Aqueous/methanol extract of plant materials. 

Figure 3. Equipment for routine application of ELISA extraction of plant material with a Pollahne press and transfer of samples from tubes to corresponding wells in an ELISA microtitre plate with an 8-channel pipet.

Methods for alkaloid isolation in Australian laboratories have in general followed classical lines, but the literature contains some useful modifications of standard procedures that were designed to facilitate the extraction of plant material and the recovery and purification of the alkaloids present, and to overcome various types of problems involved in the processes. 

Krukonis, V. J., A. R. Branfman, and M. G. Broome. 1979. Supercritical fluid extraction of plant materials containing chemotherapeutic drugs. Paper presented at the AIChE Meeting, Boston, MA, August. 

Tetrafluoroethane (hydrofluorocarbon-134a or HFC-134a, b.p. -25°C), which was developed as a replacement for the chlorofluorocarbons that were banned because of ozone-depleting effects, is approved in the UK for the production of natural food flavor extracts. It can be applied to optimize the extraction of plant materials and provides an environmental advantage, as well as health and safety benefits [55,56]. 

The overall procedures for the extraction of plant material during a phytochemical investigation consist of a series of apparently simple steps. However, the ultimate success of this type of research project depends on the care devoted to each individual aspect of the work. 

Analysis by the uv absorption of citrate buffered solutions enables the I anthocyanin to be determined from the maximum at 520nm. The distribution of component anthocyanins can be found by TLC on cellulose with various strongly acidic solvents (eg. cone HCl, formic acid, water, 19 19.5 61.5) of extracts of plant material obtained with 1% hydrochloric acid in methanol. The Rf values found for 3-monoglucosides of the anthocyaninidins of Vitis vinifera were, for the petunidin compound (0.13), for that of malvidin (0.22) and of peonidin (0.25) (ref. 11). ... 

Since ABA is a minor component in crude extracts of plant material, extensive purification is necessary prior to identification and quantification [8,31]. The definitive method for identifying ABA as its methyl ester. Me-ABA, is combined gas chromatography-mass spectrometry (GC-MS). Negative chemical ionization causes very little fragmentation, so that the molecular ion is the base peak. This technique has been used extensively in studies with 0-labeled ABA to determine the location of the atoms within the ABA molecule [32]. GC-selected ion monitoring (SIM) is a very sensitive method for quantifying ABA, but requires ABA labeled with a stable isotope, usually H, as internal standard to compensate for losses. 

Efficient extraction of high quality RNA from a variety of plant tissues is an important first step in many procedures, such as analysis of gene expression, cDNA library construction, and in vitro translation. This procedure, which is essentially as described in Draper et al. (1), involves grinding and phenol extraction of plant material followed by differential precipitation of RNA with sodium acetate. The protocol has been successful with leaf material and cultured cells from a large number of species, however, slight adjustments may be necessary to optimize extraction from other tissues. 

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