Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/6/2009
Publication Date: 4/2/2009
Citation: Harry O Kuru, R.E., Mohamed, A. 2009. Processing scale-up of sicklepod (Senna obtusifolia L.) seed. Journal of Agricultural and Food Chemistry. 57(7):2726-2731. Interpretive Summary: New domestic markets could be created for sicklepod, facilitating its commercialization as an alternative crop for farmers, by separating the components of the seed. Sicklepod is a weed species in soybean and other crop fields in the Southeastern United States. This weed is prolific, producing an abundance of seed per acre even for volunteer stands. Its eradication effort adds to the cost of farming faced by the farmer. Yet, seeds of this plant are currently imported for use as a unique flour already in the market as an important ingredient in pet food formulations. Additionally, the seed contains polysaccharides and other non-food components with potential industrial applications. In this project, we separated the proteins, carbohydrates and phenolic components of the sicklepod seed into clean characterizable classes, opening the potential to create new domestic markets for its use.
Technical Abstract: Sicklepod (Senna obtusifolia L) is an invasive weed species primarily impacting 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 agricultural prudence calls for taping the potential of this weed as an alternative economic crop in the affected region. Pursuant to this, in laboratory-scale work, we have shown the feasibility of separating the components of sicklepod seed. However, at kilogram and higher processing quantities, exigencies arise leading to the 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 0.5M 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 0.1N 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°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.