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 l i 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 mucji 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. 



