Fruits.
Fruits are composed largely of water, with starches, a vegetable
jelly, pectin, cellulose and organic acids. The most important acids
in fruit are citric, malic and tartaric. Citric acid is found in
lemons, limes and oranges; tartaric acid in grapes; malic acid in
apples, pears, peaches, apricots, gooseberries and currants. Among the
least acid are peaches, sweet apples, bananas and prunes. Strawberries
are moderately acid, while lemons and currants contain the most acid
of all.
Uses of Fruit.
(1) To furnish nutriment; (2) to convey water to the system and
relieve thirst; (3) to introduce various mineral matter (salts) and
acids which improve the quality of the blood; (4) as anti-scorbutics;
(5) as laxatives and cathartics; (6) to stimulate the appetite,
improve digestion and provide variety in the diet. Apples, lemons and
oranges are especially valuable for the potash salts, lime and
magnesia they contain. Fruit as a common article of daily diet is
highly beneficial, and should be used freely in season. Cooked fruit
is more easily digested than raw, and when over-ripe should always be
cooked in order to prevent fruit poisoning.
NUTS.
Nuts contain proteid, with some starch and sugar, but are not
considered valuable as nutrients. Cocoanuts, almonds and English
walnuts are the most nutritious.
Beverages.
TEA.
Tannin is an astringent of vegetable origin which exists in tea, is
also found in coffee and wines, and is very injurious. Tea is a
preparation made from the leaves of a shrub called Thea. The
difference between black and green tea is due to the mode of
preparation, and not to separate species of plant. Green tea contains
more tannin than black. The following table will show the
difference:--
=======================+===================+===================
| GREEN TEA. | BLACK TEA.
-----------------------+-------------------+-------------------
Crude protein | 37.43 | 38.90
Fibre | 10.06 | 10.07
Ash (mineral matter) | 4.92 | 4.93
Theine | 3.20 | 3.30
Tannin | 10.64 | 4.89
Total nitrogen | 5.99 | 6.22
-----------------------+-------------------+-------------------
The stimulating properties which tea possesses, as well as its color
and flavor, depend upon the season of the year at which the leaves are
gathered, the variety of the plant, the age of the leaves, which
become tough as they grow older, and the care exercised in their
preparation. Much depends upon the manner in which tea is infused. (1)
Use freshly boiled water; (2) allow it to infuse only three or four
minutes, in order to avoid extracting the tannin. When carefully
prepared as above, tea is not considered unwholesome for people in
good health.
COFFEE.
Coffee is made from the berries of coffee-arabica, which are dried,
roasted and browned. The following table gives an approximate idea of
the composition of coffee beans (Konig):--
Water 1.15
Fat 14.48
Crude fibre 19.89
Ash (mineral matter) 4.75
Caffeine 1.24
Albuminoids 13.98
Other nitrogenous matter 45.09
Sugar, gum and dextrin 1.66
Coffee is frequently adulterated with chicory, which is harmless.
Coffee should not be allowed to boil long or stand in the coffee pot
over a fire, as the tannin is extracted, which renders it more
indigestible. Much controversy has been indulged in over the effect of
coffee upon the system, but like many other similar questions it has
not reached a practical solution. The general opinion seems to be that
when properly made and used in moderation it is a valuable stimulant
and not harmful to adults.
COCOA.
Cocoa and chocolate contain more food substances than tea or coffee,
although their use in this respect is not of much value. The following
table gives the analysis of cocoa (Stutzer):--
Theobromine 1.73
Total nitrogenous substance 19.28
Fat 30.51
Water 3.83
Ash (mineral matter) 8.30
Fibre and non-nitrogenous extract 37.48
ALCOHOL.
The use of alcohol is wholly unnecessary for the health of the human
organism. (See Public School Physiology and Temperance.)
Condiments.
Condiments and spices are used as food adjuncts; they supply little
nourishment, the effect being mainly stimulating, and are very
injurious when used in excess. They add flavor to food and relieve
monotony of diet. The use of such condiments as pepper, curry,
pickles, vinegar and mustard, if abused, is decidedly harmful. Salt is
the only necessary condiment, for reasons given in the chapter on
mineral matter. The blending of flavors so as to make food more
palatable without being injured is one of the fine arts in cookery.
Some flavors, such as lemon juice, vinegar, etc., increase the solvent
properties of the gastric juice, making certain foods more
digestible.