Food scientists have found some jellies and jams made with a common fruit-juice (apple) labeled differently, though varied only by different flavors, natural or artificial; and others of gelatin similarly flavored and sweetened with glucose instead of sugar; and even some entirely alike also labeled differently.

Preserving fruit adds sugar, usually pound for pound. This makes such foods highly heat-energy-giving, so cold-weather foods, while fresh fruit is refreshing food of value in summer. Living quality and freshness of food cannot be overvalued.

Starch changes to sugar as fruit ripens, and acid lessens. (See p. 39.) Cooking unripe fruit changes starch thus, too, so makes it digestible as it is not when raw.

Vegetables develop starch as they mature; fruits, sugar. Fruits contain organic acids (1 - 50% of their solids). Fruits have also very complex oils and aromatic substances in small quantities which give them their characteristic flavors. Fruits also contain some gums (pectin or pectose), to the presence of which is due the congealing of fruit-juices when boiled with sugar. Pectin is more abundant in unripe than in ripe fruit.

Digestibility Of Fruits (After Dr. Gilman Thompson)