DIETETIC VALUE OF FRUITS. 307 



5. Relative economy of fruit and other foods. 



6. Comparative digestibility of raw and cooked fruit. 



7. Probable effect of eating over-ripe and decayed fruit. 



8. Relation of green fruits to illness, especially in children. 



9. Effect of eating unwashed fruits raw. 

 10. Medicinal value of fruits. 



Fresh fruits are dilute foods ; that is, they contain a large amount 

 of water in proportion to the nutritive material present. Fruits 

 which contain eighty per cent or more of water are sometimes called 

 flavor fruits, and those with less water, food fruits. Strawber- 

 ries, raspberries and blackberries belong to the first class and bana- 

 nas, figs and dates to the second. Preserved fruits and raw dried 

 fruits are of course more concentrated than fresh fruits of the same 

 variety. 



Fruits generally contain protein, mineral matter and fats in small 

 amounts, but the bulk of the nutritive material is carbohydrates. 

 The carbohydrates of fruits consist of sugars and so called pectin 

 bodies, with, in the case of some under-ripe fruits, more or less 

 starch. 



Sugar occurs in fruits in three forms, viz., cane sugar, grape 

 sugar, fruit sugar. Grape sugar (glucose) and fruit sugar (levu- 

 lose) usually occur together and in about equal quantities. These 

 are often called invert, or reducing, sugars. The amount of sugar 

 varies with the stage of growth and the degree of ripeness of the 

 fruit. According to a summary published some years ago, invert 

 sugar ranges as follows in the fruits named below (in round num- 

 bers) : from two per cent in large early apricots to fifteen per cent in 

 grapes and a variety of sweet cherries. Strawberries, gooseberries, 

 raspberries and apples are reported as containing about half that 

 quantity. Cane sugar ranges from less than one per cent in lemons 

 to fourteen per cent in a variety of plums, and bananas contain 

 eleven per cent. Cane sugar has been reported as occurring in 

 amounts larger in proportion to the grape sugar in such fruits as 

 sweet apples, sweet pears and some varieties of grapes. The per cent 

 of grape sugar in some grapes, however, has been reported as high 

 as eighteen to thirty per cent. 



The average amount of sugar is higher in dried than in fresh 

 fruits and in some cases has reached thirty-two per cent in prunes, 

 fifty-four per cent in Zante currants, sixty-one per cent in raisins, 48 

 per cent in figs and sixty-six per cent in dates. Fresh fruits are 

 therefore directly comparable with green vegetables as regards food 

 nutrients contained, but as regards flavor they are in a class by 



