Food Chemistry

5.5 Natural and Synthetic Flavorings 393

Table 5.38.Binding of aroma compounds by proteins
(0.4% solutions at pH 4.5)

Aroma Total binding constant
compound K′· 103 (lmol−^1 )

Bovine serum Soya protein

albumin

20 ◦C60◦C20◦C60◦C

Butanal 9 .765 11.362 10.916 9. 432
Benzaldehyde 6.458 6.134 5.807 6. 840
2-Butanone 4 .619 5.529 4.975 5. 800
1-Butanol 2 .435 2.786 2.100 2. 950
Phenol 3 .279 3.364 3.159 3. 074
Vanillin 2 .070 2.490 2.040 2. 335
2,5-Dimethyl
pyrazine 0. 494
Butyric acid 0.

increasing molecular weight of alkyl alcohols,
but it is still larger within the helix than on the
outer surface. Altogether, it should be concluded
that, within a helix, the trapped compound cannot
fulfill an active role as an aroma constituent.
An unlimited number of binding sites exist in pro-
teins dissolved or dispersed in water (case b).K′
values for several aroma compounds are given in
Table 5.38. The value of the constant decreases in
the order of aldehydes, ketones, alcohols, while
compounds such as dimethylpyrazine and butyric
acid are practically unable to bind. In the case of
aldehydes, it must be assumed that they can react
with free amino- and SH-groups. The high values
ofK′can reflect other than secondary forces.
Bovine serum albumin and soya proteins are prac-
tically identical with regard to the binding of
aroma compounds (Table 5.38). Since both pro-
teins have a similar hydrophobicity, it is apparent

that hydrophobic rather than hydrophilic interac-
tions are responsible for aroma binding in pro-
teins.

5.5 NaturalandSyntheticFlavorings

Aromatized food has been produced and con-
sumed for centuries, as exemplified by confec-
tionery and baked products, and tea or alcoholic
beverages. In recent decades the number of aro-

Table 5.39.Use of aromas in the production of foods

Product group Percentage (%)a

Non-alcoholic beverages 38

Confectionery 14

Savoury productsb, snacks 14

Bread and cakes 7

Milk products 6

Desserts 5

Ice cream 4

Alcoholic beverages 4

Others 8

aApproximate values.

bSalty product line like vegetables, spices, meat.

matized foods has increased greatly. In Germany,

these foods account for about 15–20% of the total

food consumption. A significant reason for this

development is the increase in industrially pro-

duced food, which partly requires aromatization

because certain raw materials are available only

to a limited extent and, therefore, expensive or be-

cause aroma losses occur during production and

storage. In addition, introduction of new raw ma-

terials, e. g., protein isolates, to diversify or ex-

pand traditional food sources, or the production

of food substitutes is promising only if appro-

priate aromatization processes are available. This

also applies to the production of nutraceuticals

(cf. 19.1.3).

Aroma concentrates, essences, extracts and in-

dividual compounds are used for aromatization.

They are usually blended in a given proportion by

a flavorist; thus, an aroma mixture is “composed”.

The empirically developed “aroma formulation”

is based primarily on the flavorist’s experience

and personal sensory assessment and is supported

by the results of a physico-chemical aroma anal-

ysis. Legislative measures that regulate food

aromatization differ in various countries.

At present, non-alcoholic beverages occupy the

first place among aromatized foods (Table 5.39).

Of the different types of aroma, citrus, mint and

red fruit aromas predominate (Table 5.40).

5.5.1 RawMaterialsforEssences...............................

In Germany, up to about 60% of the aromas used

for food aromatization are of plant origin and,