from three to five grams and more. A large portion of the
phosphate compounds of white bread is present in organic combinations,
as lecithin and nucleated proteids, which are the most available forms,
and more valuable for purposes of nutrition than the mineral phosphates.
In the case of graham and entire wheat flours, a proportionally smaller
amount of the phosphates are digested and assimilated than from the
finer grades of flour.

192. Comparative Digestibility of New and Old Bread.--With healthy
persons there is no difference whatever in the completeness of
digestibility of old and new bread; one appears to be as thoroughly
absorbed as the other. In the case of some individuals with impaired
digestion there may be a difference in the ease and comfort with which
the two kinds of bread are digested, but this is due mainly to
individuality and does not apply generally. The change which bread
undergoes when it is kept for several days is largely a loss of moisture
and development of a small amount of acid and other substances from the
continued ferment action.

193. Different Kinds of Bread.--According to variations in method of
preparation, there are different types and varieties of bread, as the
"flat bread" of Scandinavian countries, unleavened bread, Vienna bread,
salt rising bread, etc. Bread made with baking powder differs in no
essential way from that made with yeast, except in the presence of the
residue from the baking powder, discussed in Chapter XII. Biscuits,
wheat cakes, crackers, and other food materials made principally from
flour, have practically the same food value as bread. It makes but
little difference in what way flour is prepared as food, for in its
various forms it has practically the same digestibility and nutritive
value.

194. Toast.--When bread is toasted there is no change in the
percentage of total nutrients on a dry matter basis. The change is in
solubility and form, and not in amount of nutrients available. Some of
the starch becomes dextrine, which is more soluble and digestible.[5]
Proteids, on the other hand, are rendered less soluble, which appears to
slightly lower the digestion coefficient. They are somewhat more readily
but not quite so completely digested as those of bread. Digestion
experiments show that toast more readily yields to the diastase and
other ferments than does wheat bread. Toasting brings about ease of
digestion rather than increased completeness of the process.