ARS | Publication request: Detoxification of castor meal through reactive seed crushing

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 9, 2012
Publication Date: May 1, 2013
Citation: Dubois, J., Piccirilli, A., Magne, J., He, X. 2012. Detoxification of castor meal through reactive seed crushing. Industrial Crops and Products. 43(1):194-199.

Interpretive Summary: Castor seed contains about 48% of oil and among it more than 85% is the ricinoleic acid. Ricinoleic acid is a hydroxylated fatty acid (HFA). No other known natural oil contains such a high proportion of HFA. It is this characteristic composition which distinguishes castor oil from any other vegetable oils and gives it its notable physical and chemical properties. The annual worldwide production of castor beans is approximately one million tons. The residual castor meal that is left after oil extraction represents about one half of the weight of the castor bean and it has a protein content of 34-36%, which could be a good source of protein for animals. However, castor meal has not found a place as a protein supplement, mostly because the seed contains a highly toxic protein, ricin, and a group of allergenic compounds named CB-1A. The reactive seed crushing process presented in this study combines seed crushing, solvent extraction, oil refining, esterification and meal detoxification into a single step, thereby reducing the capital cost and increasing the economic value for processing castor seeds. The process also allows destroying “in planta” the ricin toxin and the allergen present in the seeds at the same time, which greatly reduces the risks to the health of the individuals who handle them and enable the use of castor oil cake in animal feed. This is particularly important for the economy of countries that are large producers of castor oil such as India, China, and Brazil. While castor oil has many industrial uses, castor oil cakes have not yet found a use on the industrial scale, in particular owing to the ricin and allergy problems.

Technical Abstract: Non-edible oil crops, such as castor or jatropha, contain several toxic components. Post-harvest treatments should be used to reduce the risks associated with the possible dispersion of toxic compounds in the environment. A new processing technology named Reactive Seed Crushing was developed, which combines in a single process of the seed-crushing, solvent extraction, oil refining, transesterification and meal detoxification. When applied to castor seeds, it was demonstrated that the process produced a detoxified meal and a castor oil methyl ester of acceptable quality for the downstream processing.