COMPOSITION OF FRUITS, YEARBOOK OF DEPT. OF AGRICULTURE, 1915.
(C. J. LANGWORTHY).
Kind of Fruit. Nitrogen- Carbo- Fuel
Ether free hy- Crude value
Water. Protein. extract extract. drates. fiber. Ash. per lb.
Fresh Fruits. Per ct. Per ct. Per ct. Per ct. Per ct. Per ct. Per ct. Cal.
Apples 84.6 0.4 0.5 13.0 … 1.2 0.3 290
Apricots 85.0 1.1 … … 13.4 … .5 270
Avocado 81.1 1.0 10.2 … 6.8 … .9 512
Bananas 75.3 1.3 .6 21.0 … 1.0 .8 460
Blackberries 86.3 1.8 1.0 8.4 … 2.5 .5 270
Cactus fruit 79.2 1.4 1.3 11.7 … 3.7 2.7 375
Cherries 80.9 1.0 .8 16.5 … .2 .6 365
Cranberries 88.9 .4 .6 8.4 … 1.5 .2 215
Currants 85.0 1.5 … … 12.8 … .7 265
Figs 79.1 1.5 … … 18.8 … .6 380
Gooseberries 85.6 1.0 … … 13.1 … .3 255
Grapes 77.4 1.3 1.6 14.9 … 4.3 .5 450
Guava 82.9 1.3 .7 8.0 … 6.6 .5 315
Huckleberries 81.9 .6 .6 … 16.6 … .3 345
Lemons 89.3 1.0 .7 7.4 … 1.1 .5 205
Mango 87.4 .6 .4 9.9 … 1.2 .5 220
Muskmelons 89.5 .6 … 7.2 … 2.1 .6 185
Nectarines 82.9 .6 … … 15.9 … .6 305
Olives 67.0 2.5 17.1 5.7 … 3.3 4.4 407
Oranges 86.9 .8 .2 … 11.6 … .5 240
Peaches 89.4 .7 .1 5.8 … 3.6 .4 190
Pears 80.9 1.0 .5 15.7 … 1.5 .4 163
Persimmons (Japanese) 80.2 1.4 .6 15.1 … 2.1 .6 174
Pineapples 89.3 .4 .3 9.3 … .4 .3 200
Plums 78.4 1.0 … … 20.1 … .5 395
Pomegranates 76.8 1.5 1.6 16.8 … 2.7 .6 461
Prunes 79.6 .9 … … 18.9 … .6 370
Raspberries (red) 85.8 1.0 … 9.7 … 2.9 .6 255
Rhubarb stalks 94.4 .6 .7 2.5 … 1.1 .7 105
Strawberries 90.4 1.0 .6 6.0 … 1.4 .6 180
Watermelons 92.4 .4 .2 … 6.7 … .3 140
With the exception of smoked bacon, there is no flesh food which even approaches the nut in nutritive value, and bacon owes its high value to the fact that it consists almost exclusively of fat.
That the nut is appreciated as a dainty is attested by the frequency with which it appears as a desert and the extensive use of various nuts as confections. That nuts do not hold a more prominent place in the national bill of fare is due chiefly to two causes; first, the popular idea that nuts are highly indigestible, and second, their comparatively high price.
The notion that nuts are difficult of digestion has really no foundation in fact. The idea is probably the natural outgrowth of the custom of eating nuts at the close of a meal when an abundance, more likely a superabundance, of highly nutritious foods has already been eaten and the equally injurious custom of eating nuts between meals. Neglect of thorough mastication must also be mentioned as a possible cause of indigestion following the use of nuts. Nuts are generally eaten dry and have a firm hard flesh which requires thorough use of the organs of mastication to prepare them for the action of the several digestive juices. Experiments made in Germany showed that nuts are not digested at all but pass through the alimentary canal like foreign bodies unless reduced to a smooth paste in the mouth. Particles of nuts the size of small seeds wholly escaped digestion.
Having been for more than fifty years actively interested in promoting the use of nuts as a staple food, I have given considerable thought and study to their dietetic value and have made many experiments. About twenty-five years ago it occurred to me that one of the above objections to the extensive dietetic use of nuts might be overcome by mechanical preparation of the nut before serving so as to reduce it to a smooth paste and thus insure the preparation for digestion which the average eater is prone to neglect. The result was a product which I called peanut butter. I was much surprised at the readiness with which the product sprang into public favor. Several years ago I was informed by a wholesale grocer of Chicago that the firm's sales of peanut butter amounted on an average to a carload a week. I think it is safe to estimate that not less than one thousand carloads of this product are annually consumed in this country. The increased demand for peanuts for making peanut butter led to the development of "corners" in the peanut market and more than doubled the price and must have had an equally marked influence upon the annual production.
I am citing my experience with the peanut not for the purpose of recommending this product, for I am obliged to confess that I was soon compelled to abandon the use of peanut butter prepared from roasted nuts, for the reason that the process of roasting renders the nut indigestible to such a degree that it was not adapted to the use of invalids, but simply as an illustration of the readiness with which the public accepts a new dietetic idea when it happens to strike the popular fancy. Ways must be found to render the use of nuts practical by adapting them to our culinary and dietetic customs and to overcome the popular objections to their use by a widespread and efficient campaign of education.
Attention has already been called to the superior nutritive value of the nut. It has other excellencies well worthy of consideration; for example, the protein of nuts is of the very choicest character. Recent investigations by Rubner, Osborne, Mendel, and others have shown that every plant produces its own special varieties of proteins. There is indeed a wide difference even between the proteins of various cereals and the proteins of many vegetables differ so widely in character from those of the human body that it is doubtful whether to any extent they can be utilized for human nutrition. Fortunately the potato is in this regard an exception and furnishes a very excellent type of protein. This objection does not apply to nuts. The proteins of nuts are in fact so very closely allied to those of the animal body that food chemists of a generation ago referred to the protein of nuts as vegetable casein because of its exceedingly close resemblance to the protein of milk.