Applications of natural plant extracts in soft drinks - Natural Food Additives, Ingredients and Flavourings - page 341

new sources of botanical material for levels of both permitted and non-permitted
substances and then to carry out occasional spot checks on future deliveries.
In addition to the use of these substances during the growing and harvesting
operations, some botanicals from some geographical sources may be treated, after
loading into containers, with substances that generate phosphine gas to exterminate
warehouse moths. This substance is both very toxic and reactive, and relatively
little is known about its interaction with active ingredients.
Selected raw materials are then usually subject to a grinding or kibbling process
where the mass of botanical is broken up to allow access from the solvent. In most
instances the raw material will not be fi nely powdered to avoid blocking screens
and fi lters.

Principles of solvent extraction
The choice of solvent is made primarily on technical grounds depending on the
botanical and the type of extract to be prepared. However, increasingly, the range
of solvents permitted for extracts to be used in 'food' (the statutory defi nition
includes beverages in many countries) becomes more restricted and the issue of
residues in the extract must also be considered. In the EU, the list of permitted
solvents under the Annex to Directive 88/344/EEC is shown in Table 15.4. In
practice, the most widely used solvents for the production of extracts for use in
fl avourings for use in soft drinks are carbon dioxide, ethanol and water.
Material to be extracted is placed in an appropriate vessel, solvent is added and
the process of infusion is allowed to take place. For some botanicals, the process
is carried out at ambient temperature and for others at elevated temperature.

Table 15.4 Annex to Directive 88/344/EEC showing extraction solvents

Annex Extraction solvents

Part 1
May be used in compliance with GMP
for all uses *

Propane
Butane
Ethyl acetate
Ethane

Carbon dioxide
Acetone †
Nitrous oxide

￿ ￿ ￿ ￿ ￿

Hexane ‡
Methyl acetate
Ethylmethylketone

Part II
Conditions of use are specifi ed in the
directive (extracted foodstuff/ingredient)

Dichloromethane
Methanol
Propan-2-ol

Part III Diethyl ether Butan-2-ol

Conditions of use are specifi ed in the
directive (preparation of fl avourings)

Hexane
Cyclohexane
Methylacetate
Butan-1-ol

Ethylmethylketone
Dichloromethane
Propan-1-ol
1,1,1,2-tetrafl uroethane

Notes:
* Extraction solvent is considered as being used in compliance with Good Manufacturing Practice
(GMP) if its use results only in the presence of residues and derivatives in technically unavoidable
quantities presenting no danger to human health.
† Use is forbidden in the refi ning of olive-pomace oil.
‡ The combined use of hexane and ethylmethylketone is forbidden.