UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1158 
Washington, D. C. T July 3, 1923 
PRODUCTION OF SIRUP FROM SWEET POTATOES. 
By H. C. Gore, Chemist in Charge, Fruit and Vegetable Utilization Laboratory, 
H. C. Reese, Assistant Development Engineer, and J. O. Reed, Assistant 
Development Engineer, Office of Development Work, Bureau of Chemistry. 1 
CONTENTS. 
Page. 
Sweet-potato by-products 1 
Commercial possibilities for sweet- 
potato sirup - 3 
Experimental work on sweet-potato 
sirup 4 
Production of sweet-potato sirup on 
commercial scale 20 
Page. 
General properties of sweet-potato 
sirup 32 
('(imposition of sweet-potato sirup — 32 
Composition of sweet-potato pomace. 32 
Summary 33 
SWEET-POTATO BY-PRODUCTS. 
Xo sweet-potato by-products industry exists at present in the United 
States where sweet potatoes rank second in importance of all vegeta- 
bles grown. Consequently a large part of this crop is lost each year 
from decay. When good growing conditions prevail up to harvest 
time, a great many potatoes become overgrown, forming so-called 
" jumbo " potatoes. These oversized potatoes, which often constitute 
40 per cent of the entire crop, have the same composition as roots 
of the standard market sizes, but they are of less value for shipping 
to distant markets and for canning. The development of profitable 
methods for converting such potatoes into useful products is there- 
fore of great importance. While the production of oversized po- 
tatoes is large, the production of undersized potatoes is usually 
small. The small potatoes are used largely for seed purposes. 
Sweet potatoes are richer in carbohydrates, especially starch, than 
any other vegetable commonly grown. For this reason they are a 
possible source of many products containing or derived from starch, 
such as potato flour, dehydrated potatoes, starch, sirup, alcohol. 
1 The work reported in this bulletin was conducted cooperatively by the fruit and vege- 
table utilization laboratory and the office of development work. ' The laboratory process 
for producing sirup from sweet potatoes was worked out by H. C. Gore, who also assisted 
in the production of sirup at the experimental plant installed at Fitzgerald, Ga. The 
equipment for the production of the sirup at Fitzgerald was designed and installed by 
the members of the office of development work, who also determined the production cost 
and the market value of the sirup. This part of the project was conducted under the 
supervision of H. E. Roethe. The Union Cotton Oil Co., Fitzgerald, Ga., gave the use of 
its plant for making the simp on the commercial scale, and C. A. Newcomer, secretary 
and treasurer of the company, cooperated with the investigators during the field work. 
The States Relations Service of the Department of A-griculture and various State exten- 
sion directors submitted helpful comments and tested the sirup produced. Manufacturers 
and jobbers of sirups, confectionery, soft drinks, cookies, biscuits, etc., tested samples of 
sweet-potato sirup and gave their opinions on its quality and possible use. 
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