12 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 
Relatively few investigations have been reported showing the pro- 
gressive changes in composition of the tomato. Differences in com- 
position between green and ripe fruit are given in several instances, 
but the researches of Albahary (2) and Bigelow (11) seem to be the 
only systematic studies of the changes occurring during development. 
Passerini (35) reports a partial analysis of both green and ripe 
fruits of two varieties. The data, which are expressed in terms of wet 
weight, seem to indicate that as the tomato matures there is an in- 
crease in water and sugar and a decrease in total solids and acid. 
Formenti and Scipiotti (19) found that the water content of the entire 
fruit was greater in the ripe fruit than in that half ripe. Thompson 
and TVhittier (51) reported a slightly larger percentage of total 
sugar in ripe than in green tomatoes. 
Congdon (15) reported the specific gravity of ripe and green 
tomatoes as 1.0216 (average of eight) and 1.0230, respectively; also 
the citric acid content as 0.528 (average of eight) for ripe and 0.990 
for green fruit. Bigelow (11) studied the composition of tomatoes 
(expressed juice) at different stages of maturity, but did not arrive 
at any very definite conclusions. He states that in general the per- 
centage of solids and sugars increases and the percentage of acid 
decreases as the tomato becomes more mature. 
Albahary (2) has given the most complete account of the chemical 
transformations in tomatoes during ripening. He used three succes- 
sive stages of ripening: (1) Green fruit before seed development, 
(2) green fruit at the time seeds were completely formed, and (3) 
fruit which was fully ripe, and he concluded that with ripening there 
is a progressive increase in acids, sugars, starch, and nitrogenous 
nonprotein constituents, while proteins and cellulose diminish greatly, 
remaining practically stationary toward the end of ripening. 
From the preceding resume of former work on the chemical com- 
position of the tomato at different stages of its growth, it is seen that 
there is little consistency in the results obtained. 
The red pigment of the tomato is not estimated in any of the 
routine analyses. It has been isolated by several workers, who found 
that the amount recoverable was 0.2 per cent of the dry weight of 
the fruit or less. Its preparation in pure crystalline condition was 
first accomplished in 1876 by Millardet (31), who named it solanoru- 
bin. After it had passed into the synonymy of carotin, it was again 
isolated, in 1903, by Schunck (45), who renamed it lycopin. Mon- 
tanari (32) made the first analysis and proved that it was a hydro- 
carbon. The final identification of lycopin as an isomer of carotin 
was made by Willstatter and Escher (58). In 1913 Duggar (17) 
studied the effect of conditions upon the development of the tomato 
pigmentation and found the color of the ripe fruit to depend (1) 
upon the presence or absence of lycopin in the flesh (in the absence 
of red lycopin the flesh is yellow, due to carotin and possibly xantho- 
