Abstract:

Fenugreek gum was extd. from fenugreek seeds and evaluated for its surface activity. This unique galactomannan has a mannose backbone grafted with galactose units at an av. ratio of one. The purified fenugreek gum was found to reduce surface tension to values lower than guar gum (42 and 55 mN/m, resp.). The interfacial activity was surprisingly better than other galactomannans (interfacial tension was reduced to 2 mN/m in vegetable oils) which led to the formation of oil-in-water emulsions with with small droplet size (2-3 $μ$m) and long-term stability. The fenugreek gum was found to adsorb (or 'ppt.') on the oil interface forming a relatively thick interfacial film. The emulsions are more stable than any equiv. emulsions stabilized by other galactomannan gums. No flocculation was obsd. in emulsions stabilized with fenugreek concns. sufficient for a good coverage of the oil interface as expressed by the coverage index (Rc) correlated to the gum/oil wt. ratio (Rc\textgreater12). [on SciFinder(R)]