This section is from the book "Food And Dietetics", by Alice Peloubet Norton. Also available from Amazon: Food and Dietetics.
New varieties of fruit produced by careful selection and cross fertilization are constantly appearing. Some of the most important changes that have been induced by cultivation have been the lessening of the proportion of cellulose, the production of seedless varieties, the increase in size and the development of fine flavors.

PICKING AND DRYING RAISINS IN CALIFORNIA From Year Book U. S. Department of Agriculture, 1904.
As in the case of vegetables, the digestibility of fruits is largely an individual matter. Bananas may be eaten freely by many, even by children, while others fail to digest even a small portion. Strawberries, generally considered easily digested, are actual poison to some people. The chief benefit of a table of digestibility is as a guide for experimentation. In feeding a child, for instance, one would try first the fruits considered most digestible.
Aside from the personal equation, ease in mastication is one of the important elements in the digestion of fruits, as in the case of other foods. The banana, for instance, easily slips down the throat in large pieces; the blueberry can be swallowed whole, while such a fruit as the apple is naturally more thoroughly masticated, for ease in swallowing, and the orange almost falls apart of itself.
The difference in the digestibility of ripe and unripe fruits is generally attributed to the larger proportion of cellulose in the latter; this and the excess of acids in unripe varieties is held responsible for their ill effects.
Gilman Thomson gives among the commoner fruits easy of digestion: grapes, oranges, lemons, cooked apples, figs, peaches, strawberries and raspberries; while he classifies as somewhat less digestible: melons, prunes, raw apples, pears, apricots, bananas and fresh currants. Dried currants and citron he considers "wholly indigestible," while he gives as the most use ful fruits for invalids: lemons, oranges, baked apples, stewed prunes, grapes, banana meal.
Young children and those of delicate digestion should avoid all skin and seeds of fruit.
Percentage Composition of Edible Portion | ||||||||
Refuse | *Corbohydrates | Fiber | Nitrogenous | Ash | †Calories, per lb. | |||
Bananas.. | 35. | 75.3 | 21.0 | 1.0 | 1.3 | .6 | .8 | 460 |
Grapes.. | 25. | 77.4 | 14.9 | 4.3 | 1.3 | 1.6 | .5 | 450 |
Plums... | 5. | 78.4 | 20.1 | 1 | 1.0 | ... | .5 | 395 |
Cherries... | 5. | 80.9 | 16.5 | .2 | 1.0 | .8 | .6 | 365 |
Huckle berries... | ... | 81.9 | 16.6 | 1 | .6 | .6 | .3 | 345 |
Apples... | 25. | 84.6 | 13.0 | 1.2 | .4 | .5 | .3 | 290 |
Pears ................... | 10. | 84.4 | 11.4 | 2.7 | .6 | 5 | .4 | 295 |
Black berries... | ... | 86.3 | 8.4 | 2.5 | 1.3 | 1.0 | .5 | 270 |
Apricots ................ | 6. | 85.0 | 13.4 | 1 | 1.1 | ... | .5 | 270 |
Peaches... | 6. | 85.0 | 10.5 | ? | .5 | .. | .6 | ... |
Oranges... | 27. | 86.9 | 11.6 | 1 | .8 | .2 | .5 | 240 |
Raspberries (red)...... | 1 | 85.8 | 9.7 | 2.9 | 1.0 | .6 | 255 | |
Cranberries... | ... | 88.9 | 8.4 | 1.5 | .4 | .6 | .2 | 215 |
Lemons... | 30. | 89.3 | 7.4 | 1.1 | 1.0 | .7 | .5 | 205 |
Pineapples... | ... | 89.3 | 9.3 | .4 | .4 | .3 | 3 | 200 |
Muskmellon... | 50. | 89.5 | 7.2 | 2.1 | .6 | ... | .6 | 185 |
Strawberries... | 5. | 90.4 | 6.0 | 1.4 | 1.0 | .6 | .6 | 180 |
Watermelon... | 60. | 92.4 | 6.7 | ? | .4 | .2 | .3 | 140 |
* Not including liber, † Including fiber.
The carbohydrates of fruits are chiefly in the form of sugar. Nearly all contain pectin bodies and these are most abundant in unripe fruit. The acids of the fruits are here included under the carbohydrates. Apples, pears and peaches contain malic acid; lemons and oranges, citric acid; grapes, tartaric acid; rhubarb, oxalic acid, etc.
Percentage Composition of Edible Portion | |||||||
Refuse | Water | *Carbohydrate | Nitrogenous | Fats | Ash | *Calories, per lb. | |
Dates... | 10.0 | 15.4 | 78.4 | 2.1 | 2.8 | 1.3 | 1,615 |
Raisins... | 10.0 | 14.6 | 76.1 | 2.6 | 3.3 | 3.4 | 1,605 |
Currants... | ... | 17.2 | 74.2 | 2.4 | 1.7 | 4.5 | 1,495 |
Figs... | .. | 18.8 | 74.2 | 4.3 | .3 | 2.4 | 1,475 |
Prunes... | 15.0 | 22.3 | 73.3 | 2.1 | .... | 2.3 | 1,400 |
Apples.. | .. | 28.1 | 66.1 | 1.6 | 2.2 | 2.1 | 1,350 |
Apricots... | .. | 29.4 | 62.5 | 4.7 | 1.0 | 2.4 | 1,290 |
* Including fibor.
 
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