Applications of natural plant extracts in soft drinks - Natural Food Additives, Ingredients and Flavourings - page 342

Active circulation of the solvent is used for some processes. When liquid carbon
dioxide (CO 2 ) is used the equipment must be capable of withstanding the pressures
involved. Some extractions are carried out with subcritical CO 2 and others with
supercritical CO 2 . Extracts with very different properties are obtained by the
different conditions that apply.
Following the period of infusion, solvent is removed and evaporated leaving
the resulting extract which is usually a viscous resin. Solvent residues must be
carefully considered, although with both ethanol and water, the levels are not
critical. In this respect carbon dioxide is particularly attractive as, although it
needs to be recovered from the processing operation for economic reasons, any
residue in the fi nished extract evaporates rapidly. An added attraction of the use of
CO 2 is its low toxicity and ready removal at low temperature, which minimises
any heat damage to the extract. In this respect aqueous extracts are probably least
favoured because of the relative diffi culty and cost of evaporating water and the
thermal effect on the residual extract.
Extracts sometimes require standardisation before being used.

15.4.2 Manufacture of particular solvent extracts and their use

in soft drinks

Extracts produced using carbon dioxide
Depending on the material used and the solvent employed, extracts may contain
some essential oils and thus have the potential to deliver signifi cant aroma
characteristics to the product in which they are used. Liquid CO 2 extracts of
substances such as ginger root will frequently contain essential oil components as
well as the non-volatile substances that contribute heat to the end product. Most
extracts produced by solvent extraction are used in fl avourings or fl avouring
preparations rather than directly into the soft drink formulation, and although the
amounts used are very small, they contribute key characteristics to the end
product.
To demonstrate this point, solvent extracts of both ginger and capsicum may be
used in the manufacture of ginger fl avours which, in turn, are used to fl avour soft
drinks. A typical level of fl avouring in a soft drink is likely to be around 0.1% by
volume and the respective levels of capsicum and ginger extracts in the fl avour
are likely to be within the range of 3-10% by weight depending on the strength of
the extract used. Thus the level of these extracts in the fi nal product is likely to be
about 0.003-0.01% w/w.
Most fl avourings are prepared in a solvent permitted for use in foods. These
include relatively polar solvents such as ethyl alcohol, monopropylene glycol and
glyceryl triacetate. Even with these solvents it is often diffi cult to solubilise
oleoresins, which may have been prepared by the use of more polar solvents.
A technique that may be employed, if the end product is to be cloudy in
appearance, is to incorporate the resinous material as part of an oil-in-water
emulsion. Such emulsions are widely used as clouding agents and it is often much

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