132 MODERN FRUIT MARKETING 
sponsible for the rapid change in color from white to 
brown in the cut surface of the fresh fruit; also largely 
responsible for the bitter principle contained in fruits be- 
fore they are ripe. Most fruits in the ripening process 
pass through certain chemical and respiratory changes. 
Changes in Ripening.—When a fruit is taken from 
the tree it is not a dead or inert substance, but certain 
chemical changes continue to take place until the fruit 
is finally used or decayed. This process is usually spoken 
of as the ‘‘ripening up’’ of the fruit. The most notice- 
able change is the gradual transformation of the starch 
content to sugar. In this way the fruit becomes sweeter 
and certain aromas or flavors are intensified. The rea- 
son for this is due to the fact that abundance of starch 
is associated with firm, hard fruit. At high temperatures 
the starch changes rapidly to sugar and the low temper- 
atures do not have the same effect upon the cellulose, 
hence they soften much more slowly. 
Changes in Storage.—The greatest influence of cold 
storage upon the chemical changes in fruit is to retard 
them. The fruit kept at a temperature as low as pos- 
sible without freezing will lengthen materially the life 
of the fruit by retarding certain chemical changes. The 
rate of transition of starch to sugar will be much slower 
in the cold storage house. The time of cooling down 
also has a marked influence on fruit. That which is 
cooled down as quickly as possible after being removed 
from the trees will keep much better in storage than 
where from two to four weeks elapse before it is placed 
in the cooling room. With such fruits as plums or apri- 
cots it is absolutely necessary that this cooling be done 
at the earliest possible opportunity after picking. 
