PEOCESS OF KIPENING IN THE TOMATO. 17 



ing. The solution was then neutralized and filtered and 20 c. c. 

 used for reduction. 



Starch. — The residue from the water extraction of the sample used 

 for reducing substances was placed in an Erlenmeyer flask and 

 heated immersed in a boiling water bath for 2\ hours with 150 c. c. 

 of water and 15 c. c. of HC1 (sp. gr. ; 1.125). After cooling and 

 neutralizing to phenolphthalein with NaOH, the mixture was made 

 to 250 c. c. volume at 20° C. and filtered through a dry filter paper; 

 20 and 50 c. c. aliquots of this solution were used for reduction. 



Pentosans. — A quantity of the original alcoholic extract represent- 

 ing one-tenth of the total extract was evaporated nearly to dryness 

 in an Erlenmeyer flask and one-tenth of the original residue added 

 to this. Pentosans were determined by the furfural-phloroglucid 

 precipitate method. The usual procedure is to distill over 360 c. c. 

 and then to make up to 400 c. c. with a phloroglucin solution. It 

 required 480 c. c. of distillate to obtain all of the furfural present, 

 and 40 c. c. of phloroglucin solution were added to this. No correc- 

 tion was made for the additional 120 c. c. distilled o^er. Krober's 

 formulae were used in calculating the pentosan equivalents, as given 

 in the Official and Provisional Methods of Analysis (57). 



Total nitrogen. — Two hundred cubic centimeters of the original 

 alcoholic extract, representing one-tenth of the sample, were intro- 

 duced into a Kjeldahl flask and evaported to dryness on the steam 

 bath, and to this residue one-tenth of the original residue from 

 the original sample was added. The total nitrogen in the aliquot 

 was determined by the Kjeldahl method. 1 



Crude fiber. — A quantity of the residue representing three-twen- 

 tieths of the sample was used for crude-fiber determination, which 

 was made in the usual manner. 



ANALYTICAL DATA CONCERNING PROGRESSIVE CHANGES IN COMPO- 

 SITION DURING RIPENING. 



The data showing progressive changes in composition during the 

 process of ripening are assembled in Table IV. In section A of this 

 table the percentages are referred to the weight of the entire fruit; 

 in section B they are reduced to a basis of dry weight. Each entry 

 in this table is a mean of two determinations, except as indicated by 

 an asterisk (*), which shows that duplicate determinations were not 

 made. 



Although the method of sampling has been described, it may not 

 be amiss to emphasize the fact that each sample was a composite of 

 fruits of the same maturity but of greatly varying sizes. The data 

 with regard to average size and average weight at the various ages 

 are found in Table III. 



1 All determinations of nitrogenreported in this investigation were carried out bylheiSIitrogen Laboratory, 

 Bureau of Chemistry, United States Department of Agriculture. 



175085°— 20— Bull. 859 3 



