430 
Journal of Agricultural Research 
Vol. XXVIII, No 5. 
polysaccharides, while the amounts present in the field varieties are very small, 
usually less than 1 per cent. The water soluble portion seemed so important 
that it was thought worth while to learn something more about its chemical 
nature. 
Dextrin was reported by Salisbury [54) as occurring in a number of varieties of 
maize. He found that nearly half of the total polysaccharides of sweet corn was 
dextrin, while the field corn showed but a small amount; and he attributed the 
wrinkled condition of mature corn to the shrinkage of the kernels through the 
loss of water from the solution of dextrins and albumins which they contained. 
The proportion of starch to the dextrin was found to be greater in the early stage 
of development which he considered as evidence that starch is formed first and 
is later changed to dextrin. Correns [20) also reported the presence of dextrin 
in sweet corn and pointed out its significance in maize crosses. Atwater (5) did 
not determine definitely whether dextrin was present in sweet corn but came to 
the conclusion that it was absent. Harper [28) stated that the wrinkled char¬ 
acter of sweet corn was due to the larger proportion of sugar, dextrin, and gums 
present. Weatherwax [71) reported the presence of dextrin in waxy maize but 
was not able to determine definitely whether it was present in sweet corn. ‘ 
A complete chemical examination of the cold water soluble portion of the 
polysaccharides was not attempted in this work, but a number of experiments 
were performed which yielded significant results. The residue after extraction 
with 70 to 80 per cent alcohol dissolves partially in cold water giving an opalescent 
or milky white solution which is very difficult to filter. If allowed to stand for 
several hours and the supernatant liquid then filtered, there is obtained a faint 
to distinct blue color when a drop of very dilute iodin solution is added. If a 
drop of 1 per cent solution of iodin is added a characteristic red is usually instantly 
obtained. Results vary somewhat with the different corns and their degree of 
maturity. It is apparent that both dextrin and soluble starch are present. 
An attempt was made to separate the dextrin and the soluble starch quan¬ 
titatively by precipitating the soluble starch with basic lead acetate, determining 
the dextrin directly and obtaining the figure for soluble starch by subtracting 
this from the total water soluble polysaccharides, but when basic lead acetate 
was added to the sample it became more turbid and the small amounts of precip¬ 
itate settled out very slowly and filtration was difficult. Owing to this, clear- 
cut separations could not be made and duplicate determinations did not check 
closely. However, the figures obtained in this way for the different varieties 
showed 1 to 3 per cent less dextrin than the total amount of water soluble mate¬ 
rial. It seems apparent from this and other qualitative tests that the varieties 
differ considerably in the proportion of dextrin to soluble starch. By allowing 
the solutions to stand for several weeks after the addition of the basic lead acetate, 
filtering the supernatant portion, and removing the lead, a product was obtained 
which gave only the red color characteristic of dextrin. This substance was not 
precipitated by half saturation with ammonium sulphate, was precipitated by 
alcohol, had adhesive properties, and on hydrolysis yielded reducing sugars. 
In the 5 and 10 day samples nearly all the water soluble portion was pre¬ 
cipitated by basic lead acetate, and since the aqueous extract rarely gave a blue 
color with iodin it was concluded that the water soluble portion in the very early 
stages of development of the kernel was made up principally of pentosans or 
gums. 
In the two field corns the water soluble portion gave a blue color with iodin, 
and was precipitated by basic lead acetate, and also by half saturation with am¬ 
monium sulphate thus indicating soluble starch; and in the later stage of maturity 
the water soluble polysaccharides in the field varieties appeared to consist en¬ 
tirely of starch. 
