Processing scale-up of sicklepod (Senna obtusifolia L.) seed.

Sicklepod (Senna obtusifolia L.) is an invasive weed species especially of soybean and other field crops in the southeastern United States. The seeds contain a small amount (5-7%) of a highly colored fat as well as various phenolics, proteins, and galactomannans. The color of sicklepod seed oil is such that the presence of a small amount of the weed seed in a soybean crush lowers the quality of the soybean oil. Sicklepod is very prolific, and even volunteer stands yield >1000 lb of seed per acre, and prudence calls for tapping the potential of this weed as an alternative economic crop in the affected region. Pursuant to this, we have shown in laboratory-scale work the feasibility of separating the components of sicklepod seed. However, at kilogram and higher processing quantities, difficulties arise leading to modification of the earlier approach in order to efficiently separate components of the defatted seed meal. In a version for cleanly separating the proteins, the defatted meal was extracted with 0.5 M NaCl solution to remove globular proteins. Prolamins were extracted from the pellet left after salt extraction using 80% ethanol, and glutelins were then obtained in 0.1 N alkali from the residual solids left from ethanol treatment. In a pilot-scale version for water-soluble polysaccharides, the defatted meal was stirred with deionized water (DI) and centrifuged. The pooled centrifugates were heated to 92 degrees C (20-25 min), filtered, cooled to room temperature, and passed through a column of Amberlite XAD-4 to separate the polysaccharides from the anthraquinones. Senna obtusifolia L. is a one-stop-shop of a seed (from food components to medicinals).