2009_Book_FoodChemistry

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 ′ · 10 3 (lmol −1 )
Bovine serum Soya protein
albumin
20 ◦ C 60 ◦ C 20 ◦ C 60 ◦ 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 proteins
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
of K ′ can reflect other than secondary forces.
Bovine serum albumin and soya proteins are practically
identical with regard to the binding of
aroma compounds (Table 5.38). Since both proteins
have a similar hydrophobicity, it is apparent
that hydrophobic rather than hydrophilic interactions
are responsible for aroma binding in proteins.
5.5 Natural and Synthetic
Flavorings
Aromatized food has been produced and consumed
for centuries, as exemplified by confectionery
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 products b , snacks 14
Bread and cakes 7
Milk products 6
Desserts 5
Ice cream 4
Alcoholic beverages 4
Others 8
a Approximate values.
b Salty 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 produced
food, which partly requires aromatization
because certain raw materials are available only
to a limited extent and, therefore, expensive or because
aroma losses occur during production and
storage. In addition, introduction of new raw materials,
e. g., protein isolates, to diversify or expand
traditional food sources, or the production
of food substitutes is promising only if appropriate
aromatization processes are available. This
also applies to the production of nutraceuticals
(cf. 19.1.3).
Aroma concentrates, essences, extracts and individual
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 analysis.
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 Raw Materials for Essences
In Germany, up to about 60% of the aromas used
for food aromatization are of plant origin and,