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United States Department of Agriculture

Agricultural Research Service

Research Project: Improvement and Utilization of Natural Rubber- and Castor Oil-producing Industrial Crops

Location: Crop Improvement & Utilization Research

Title: Reducing the toxicity of castor seed meal through processing treatments

Authors
item McKeon, Thomas
item Shim, Kang Bo -
item He, Xiaohua

Submitted to: Biocatalysis and Agricultural Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 8, 2012
Publication Date: December 9, 2012
Citation: McKeon, T.A., Shim, K., He, X. 2012. Reducing the toxicity of castor seed meal through processing treatments. Biocatalysis and Agricultural Biotechnology. doi.org/10.1016/j.bcab.2012.12.001.

Interpretive Summary: Castor oil is a very important chemical feedstock, used in production of greases, coatings, high-value polymers and plasticizers. One acre of castor can produce the equivalent of 6 barrels of petroleum and be used for products equal or superior to similar products currently derived from petroleum. However, the toxic protein ricin in the seed is a significant impediment to cultivation and processing of the castor plant for castor oil production. the research described in this paper tests two approaches to detoxify the ricin and make it safe to produce castor oil domestically. Because castor grows productively with limited agricultural inputs such as water and fertilizer, it can be grown on agricultural set-aside and marginal lands, and not displace food crops. By helping to make castor a safe crop, this work can expand the availability of this valuable renewable resource that displaces petroleum-derived products.

Technical Abstract: The castor plant produces a seed that is high in oil content and composed of approximately 90% ricinoleate. Due to the numerous uses of castor oil and ricinoleate, the oil is in high demand. However, the presence of a protein toxin in the seed meal is a key concern about processing the castor seed to obtain the oil and to utilize the meal. We have addressed this issue by identifying approaches for reducing or eliminating toxin activity during seed processing through proteolytic treatment or microwave pretreatment. While treatment with the protease papain apparently eliminates Coomassie stainable proteins corresponding to ricin bands, ricin detectable by immunoblotting remains present. Microwave pretreatment to heat seeds internally reduces the ricin activity present by 86%.

Last Modified: 10/1/2014
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