Small scale degumming techniques for oil entering the
Nick Fox and Greg Austic
Piedmont Biofuels LLC
Interest in small scale processing of oilseeds is rising in the United States. A variety of
processors of boutique oils, vertically integrated small cooperatives, and small agribusiness
entrepreneurs are interested in smaller scale (less than 1 million gallons per year) oilseed crushing
plants which do not use solvents. Each small processor is different and has different requirements for
both the oil and the crush. As a result, specialized processes informed by the product markets,
feedstock, infrastructure, and cash availability are needed.
In the case studied in this paper, a small scale (1 million gallon per year capacity) soybean,
sunflower, and canola crushing facility wanted to improve the quality of their finished product through
degumming. Their product market was mainly to biodiesel producers which helped define an
acceptable level of gums and metals removal, and their desired capital investment was relatively small.
After testing a variety of methods with crude soybean oil which could be applied to their scale, the
most cost effective method for achieving oils for the biodiesel market was determined to be simple
water degumming. Crude Canola, however, may require more testing to ensure that water degumming
achieves low enough levels of metals for the biodiesel industry.
Gums in vegetable oils refer to a variety of compounds which are generally removed during the
refining process, including hydratable and non-hydratable phosphatides, lecithin, and other impurities.
Gums vary significantly between oil types, and some oils will naturally drop gums out of solution after
pressing. However, significant amounts of gums can remain, specifically the non-hydratable type
which are soluble in the oily layer1. This material is removed during the chemical refining process
which usually includes an acid addition step (phosphoric, oxalic, or citric acids) and