Gossypol isolation

Use of some oilseed proteins in foods is limited by flavor, color, and flatus effects. Raw soybeans, for example, taste grassy, beany, and bitter. Even after processing, residues of these flavors may limit the amounts of soybean proteins that can be added to a given food (87). The use of cottonseed and sunflower seed flours is restricted by the color imparted by gossypol and phenoHc acids, respectively. Flatus production by defatted soy flours has been attributed to raffinose and stachyose, which are removed by processing the flours into concentrates and isolates (88). 

The seven major flavonoids in these flours were isolated and identified as 3-0-glycosides of kaempferol and quercetin. The marked brown discoloration observed when LCP glanded cottonseed flour is used in a food product is caused by bound gossypol and at least two bound gossypol-like pigments. The brown color observed when glandless cottonseed flour is used in food is believed to be due to other phenolic constituents that are either insoluble polymers or are bound to the insoluble plant polysaccharides. 

Gossypol has been isolated from the roots, stems, and seeds of the cotton plant and reported as a COX inhibitor based on in vitro assay in neutrophils [165] and an inhibitor of LOX and prostaglandin synthase from rat basophilic leukemia cells [166]. Gossypol showed as a potent inhibitor of leukotrienes B4 and D4 production and also reduced PTF-induced contraction of guinea-pig lung parenchyma [167]. 

Gossypol was first discovered and isolated as a crude pigment by Longmore (1886) from cottonseed oil foot, a mixture of precipitated soaps and gums produced in the refining of crude cottonseed oil with... 

Trischitta, F. and Faggio, C. (2008). Gossypol affects ion transport in the isolated intestine of the seawater adapted eel, Anguilla anguilla. Comp. Biochem. Physiol. A Mol. Integr. Physiol. 151, 139-143. 

Phytochemistry Gossypol has been isolated from the seeds (Schmidt and Wells 1990). The main fatty acids isolated from the seed oil were linoleic acid (63.61 %), hexadecanoic acid (16.72 %), oleic acid (12.30 %), stearic acid (2.23 %), and the total content of the unsaturated fatty acids was 79.11 % (Hu et al. 2006). 

Initially, gossypol is in the free state, but in the course of the heat treatments involved in conventional oilseed processing it binds irreversibly with protein. The situation can be appreciated by observing the effect of heat and/or added gossypol (G) on the digestibility of prepared protein isolates (see Table 1). 

The insoluble digest residue is polymeric in character and cannot be hydrolysed, even by strong hydrochloric acid. More information about the gossypol-protein interaction can be obtained by comparing the amino-acid profiles of high- and low-gossypol protein isolates (Table 2). 

ESSENTIAL AMINO-ACIDS OF COTTONSEED FUNCTIONAL PROTEIN ISOLATES AS AFFECTED BY THE PRESENCE OF BOUND GOSSYPOL (G) ... 

---