Natural aroma chemicals for use in foods and beverages - Natural Food Additives, Ingredients and Flavourings - page 215

[10.18] [10.19] [10.20]

Less obvious, but also of great importance, is the isolation from 'off-gases'. Since
aroma chemicals are, by their nature, volatile components of food, it should be no
surprise that, when food and related natural materials are processed, useful
materials are lost and that unless trapped or in some way 'scrubbed' from the
effl uent gasses, they would fi ll the surrounding area with an unwanted 'miasma'!
Those of us who have lived, or worked, near to a brewery know the strength of
aromas given off during fermentation. Since this process is also used in the
production of fuel alcohol, a lot of such effl uent gas is produced.
Trapping the volatiles, either cryogenically or by means of activated charcoal,
both reduces the nuisance value of such odours and provides a feedstock for
natural aroma chemicals, most especially dimethyl sulfi de [10.1], which was
mentioned earlier. Other examples are 2-methyltetrahydrofuranone [10.21],
commonly known as coffee furanone from, most appropriately, the effl uent gases
from coffee roasting, and trans -2- trans -4-decadienal [10.22], which is produced
during the deodorisation of vegetable oils.

[10.1] [10.21] [10.22]

There is, perhaps, a limit to this approach. Certain materials, which are both food
by-products and a waste stream, could in theory be processed to yield natural skatole
[10.23], a material of interest for fl avours of the camembert cheese type, with their
goaty-indolic notes. It must be admitted, however, that the marketing of such a
material would perhaps provide a challenge above and beyond the call of duty . . . .

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[10.23]

10.5 Natural aroma chemicals by traditional food
preparation processes: cooking chemistry
One of the classic insults thrown at chemistry students, usually by physics
undergraduates, is that 'chemistry is just cooking'. The correct riposte to this is,