2009_Book_FoodChemistry

8.10 Acids 447
Table 8.13. (Continued)
8.10.3 Succinic Acid Anhydride
This is the only acid anhydride used as a food
additive. The hydrolysis proceeds slowly, hence
the compound is suitable as an agent in baking
powders and for binding of water in some dehydrated
food products.
8.10.4 Adipic Acid
Adipic acid (pK 1 = 4.43; pK 2 = 5.62) is used
in powdered fruit juice drinks, for improving the
gelling properties of marmalades and fruit jellies,
and for improving cheese texture. It is synthesized
from phenol or cyclohexane (cf. Reactions
8.22).
8.10.5 Fumaric Acid
Fumaric acid (pK 1 = 3.00; pK 2 = 4.52) increases
the shelf life of some dehydrated food products
(e. g. pudding and jelly powders). It is also used to
lower the pH, usually together with food preservatives
(e. g. benzoic acid), and as an additive promoting
gel setting. Fumaric acid is synthesized
via maleic acid anhydride which is obtained by
catalytic oxidation of butene or benzene (cf. Reaction
8.23) or is produced from molasses by fermentation
using Rhizopus spp.