STARCH-Making from Cull Sweetpotatoes is Placed on Commercial Basis

The process devised by the Bureau of Chemistry and Soils* for production of starch of high quality from cull sweetpotatoes is now being placed on a commercial basis and it is anticipated that a new starch industry will be developed in this country as a result. The Federal Emergency Relief Administration is financing a sweetpotato-starch factory at Laurel, Miss., to provide employment. This factory will be operated in the interest of a cooperative association of sweetpotato growers and, after setting aside necessary reserves, profits will be distributed to growers on a pro-rata basis. Selection and installation of equipment, as well as initial operation of the factory, are under the technical supervision of the Bureau of Chemistry and Soils. The capacity of this factory is about 2,000,000 pounds of starch annually.

Sweetpotato starch has been tested in several cotton mills and found to be satisfactory for the sizing of warp yarn and for finishing. It gives fully as good results as imported potato starch and also is an advantage in economy in quantity required. All but a small proportion of the potato starch imported into the United States is used in cotton mills.

Dextrine prepared from sweetpotato starch has been tested by the Bureau of Engraving and Printing, and on the basis of both laboratory and machine tests, has been found to be equal to the dextrine made from imported cassava starch which is now used as an adhesive for stamps and for similar purposes. Sweetpotato-starch dextrine is the first domestic product which has met the requirements of the Bureau of Engraving and Printing for this purpose.  Under the law requiring the Government to purchase products of domestic origin whenever feasible, it is anticipated that a market will be afforded sweetpotato-starch dextrine for use on postage stamps, envelops, etc., produced or used by the Government.

As a byproduct of starch production there is obtained a residual pulp which after drying can be sold at a profit to feed mixers. The dried pulp can be mixed advantageously with cottonseed meal so as to produce a better balanced ration for cattle feed. Experiments are being made on the possibility of also adding to this feed ground, dried sweetpotato vines which by analysis are not greatly inferior to alfalfa in feeding value.

Transportation Costs

Low transportation costs are an important factor in the success of any industry. The prospective sweetpotato-starch industry will, in general, have minimum transportation costs. Sweetpotatoes are available in large quantities in areas contiguous to southern cotton mills which are expected to use a substantial proportion of the starch.  Cottonseed meal is produced in the same areas and the feed will be utilized locally, sales being effected through local feed mixers.

This industry is being developed primarily to afford a market for cull sweetpotatoes, which constitute a large proportion of the field-run crop and which are now largely unremunerative. However, under some conditions it may be both profitable and economically advisable to use field-run sweetpotatoes for starch production. This new industry may contribute to a solution of the problem of utilization of cut-over pineland in the South, particularly in the coastal plains section, which is especially suitable for growing sweetpotatoes.  Sweetpotatoes are particularly adapted to newly cleared lands such as cut-over pinelands in the South (U. S. Department of Agriculture Farmers’ Bull. 999, Sweetpotato Growing, p. 2). It has been suggested that a feasible means of handling this cut-over land problem is partial reforestation (utilizing turpentine and rosin to cover carrying charges until the trees reach lumber size) together with the growing of sweetpotatoes and other suitable crops. This new industry is expected to provide a market for considerable quantities of sweetpotatoes.

*See Yearbook of Agriculture, 1932, p. 522; 1933, p. 362.

H. S. PAINE, Bureau of Chemistry and Soils.