Food Chemistry

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 dehy-
drated 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 jel-
lies, and for improving cheese texture. It is syn-

thesized from phenol or cyclohexane (cf. Reac-

tions 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 preser-

vatives (e. g. benzoic acid), and as an additive pro-

moting gel setting. Fumaric acid is synthesized

via maleic acid anhydride which is obtained by

catalytic oxidation of butene or benzene (cf. Re-

action 8.23) or is produced from molasses by fer-

mentation usingRhizopus spp.