18.1 Fruits 821(18.7)Important phenolic acids, dealt with in Sec-
tion 18.1.2.5.1, are quinic, caffeic, chlorogenic
and shikimic acids. Galacturonic and glucuronic
acids are also found.
Tartaric acid biosynthesis inVitis spp. starts
from glucose or fructose and probably proceeds
through 5–oxogluconic acid or ascorbic acid
respectively: