Scale-Up of Sicklepod Processing

Sicklepod (Senna obtusifolia L., Fabaceae) is a leguminous plant that thrives unwanted in crop fields such as soybean farms and is therefore described as a weed especially in many Southeastern States in the US. Although the recent introduction of “round-up-ready” soybeans mitigates infestation of the beans by sicklepod, the latter is so prolific that even volunteer stands yield over a 1120 kg/ha. The composition of sicklepod seed has been reported to include mainly: anthraquinones 1%–2%, fats 5%–7%, proteins 14%–19%, and carbohydrates 66%–69% (Khanna and Gupta 1967; Varshney et al. 1973; Crawford et al. 1990; Abbott et al. 1998). Sicklepod flour from Indian seed is in the market as a hydrocolloid additive in pet foods because of its unique galactomannan ratio which enhances flexibility in the range of formulation compositions (Bayerlein et al. 1989). In a previous report we have shown a laboratory-scale process for partitioning the crushed seed components in order to separate the three classes of compounds in the seed (Harry-O’kuru et al. 2005). To effect a scale-up of that process beyond a hundred gram level, cost as well as technical considerations have resulted in the development of a two-pronged approach for enhanced isolation of the different seed components into their corresponding classes. In both approaches, water is the principal solvent used except for defatting the meal. To isolate the various proteins, we have used solubility as a guiding principle (Osborne 1895; Csonka and Jones 1927). And traditional saline treatment has been applied to sicklepod defatted seed meal to allow for solubilization of water soluble proteins. For non water-soluble proteins, alternative aqueous based techniques were used to effect complete extraction. This paper reports scaled-up procedures for the extraction of sicklepod seed components mainly proteins and carbohydrates.