PROXIMATE COMPOSITION OF FRESH FRUITS 3 
AVERAGES AND VARIATIONS 
Averages are arithmetical means of individual values as given in 
percentage of the edible portion except in a few stated cases. In 
these few instances averages were taken on a water-free basis and 
calculated back to the fresh, at the average water content. Probable 
error, indicated as P. E., has been given to indicate variation in 
individual determinations and is the standard deviation xX 0.6745. 
In cases where part of the source material was given only as averages, 
estimates have been made by allowing for variation within the group 
averaged. 
WATER 
Water content refers to the loss in weight from drying or the differ- 
ence between the weight of the total solids and the fresh substance. 
In some cases the material was air dried at 100° C. and in others it 
was dried in vacuum at lower temperatures. Probably the errors 
due to method are greater in the determination of this constituent 
than in any of the others. 
PROTEIN, FAT, AND ASH 
Protein was calculated as N <6.25, the nitrogen being determined 
by the Kjeldahl method or one of its modifications. Fat was deter- 
mined as ether extract, and it includes therefore other ether-soluble 
substances such as plant pigments. Ash is the residue from burning 
the dry substance until it is free from carbon. When determinations 
of fat content were lacking, a figure was sometimes assumed to 
admit of calculations of fuel value. In a single case, also, such an 
assumption was made for protein. All assumptions were made on 
the basis of analyses of similar substances and may be in error by 
several tenths of a per cent, but these errors would hardly be sig- 
nificant in dietary calculations. 
TOTAL CARBOHYDRATES 
The term “total by difference including fiber” under carbohydrates 
refers to solids other than protein, fat, and ash. Like nitrogen-free 
extract it includes organic acids and undetermined solids as well as 
the substances properly classed as carbohydrates. It is numerically 
equal to the sum of nitrogen-free extract and fiber. It is apparent 
that any errors in the determination of water, protein, fat, or ash 
will be reflected in this quantity and that it is therefore less reliable 
than a direct determination. No indication of the variation in this 
quantity is given since individual calculations of it were not recorded, 
but it can be assumed that the variation in this eroup of substances 
would be of about the same order as that of the water content. 
FIBER 
Fiber is the loss in weight from incinerating the residue obtained 
by successive treatments of the fat-free dry substance with dilute 
sulphuric agus and dilute sodium hydroxide. 
SUGARS 
The term “sugars as invert” refers to total sugars, and the quantity 
is given asin the other constituents, in percentage of the fresh edible 
substance. ‘They were determined in the majority of cases on the 
