Title:  Gel products from plant matter

United States Patent:  6,174,549

Assignee:  EI Du Pont de Nemours and Company (Wilmington, DE)

Filed:  October 4, 1999

Foreign Application Priority Data:  Nov 16, 1991[GB] (9124427); Mar 12, 1992[GB] (9205406); Apr 27, 1992[GB] (9209094); Jul 07, 1992[GB] (9214392)

Gels are produced from an aqueous soluble hemicellulosic starting medium which is free of glucans and obtainable from testaceous plant material. The starting medium is extracted with a non-acidic reagent and reacted with an oxidizing system comprising a peroxide, together with an oxygenase. The gel material is substantially free of glucans and pectins, and comprises a polysaccharide network comprising a matrix of polysaccharide chain segments with a multiplicity of cross-linking ferulate bridges at regularly spaced intervals along the cross-linked chain segments.

SUMMARY OF THE INVENTION

By processing testaceous plant material according to the invention, a gel material with advantageous properties can be produced. The method comprises:

(a) providing a hemicellulosic starting medium which is substantially free of glucans and is obtainable from testaceous plant material;

(b) extracting aqueous soluble material from said starting medium by means of a non-acidic aqueous reagent; and

(c) reacting the extracted material with an oxidizing system comprising at least one peroxide, together with at least one oxygenase (such as a peroxidase).

The soluble hemicellulosic starting medium is typically prepared from testaceous plant material which would otherwise be waste, the plant material containing a significant quantity (such as at least about 10%, such as about 20%) of arabinoxylan or glucuronoarabinoxylan, which is present in nature primarily in the cell wall regions. Examples of preferred such sources include waste materials which are rich in cell walls, such as cereal husk or bran, or legumes (pulses). Typical cereal husk or bran includes maize, barley, wheat, rice or oats, or malt or malt culms (dried germinated barley rootlets).

The gel material according to the invention may have a wide variety of uses, of which the following are exemplary:

1. In medicinal compositions for example as a topical formulation or wound dressing (such as for treatment of burns) or debriding agent, as a carrier for iron or zinc, as a lubricant, or a thickener for parenteral compositions, or as an encapsulating agent, or as a slow release vehicle for drug delivery (either for oral, parenteral or anal delivery), or for use for implants and prosthesis purposes for orthopedic purposes (such as pressure-relief gels), for ocular purposes or suppository uses.

A particularly preferred medicinal application of the gel is for use as a wound dressing, and there is further provided by the present invention a wound dressing having a surface contact region comprising a gel as hereinbefore described. Advantageously, the wound dressing consists essentially of a gel material substantially as hereinbefore described.

2. In foodstuffs or animal feeds, for example, as a cold setting gel for use as a stabiliser for ice cream or the like, as a suspending agent for particles such as coconut, as a glazing agent for meat or the like, as a setting agent for jams, or a thickening agent for gravies, purees, sweets, soups or the like, as a soluble fiber, as a food lubricant, as a viscosity agent for flavors, as a canning gel, functional food or fish bait.

3. In the oil industry, for example, for sealing strata above oil deposits, as an oil drilling sealing agent, as an additive to drilling muds or the like, and for recovery of oil from oil-bearing strata.

4. In the microbiological industry, for example as a gelling agent, a spore biocontainer or a culture biocontainer.

5. In the agricultural industry, as a slow release pesticide biocontainer, a plant culture medium, an anti-drying agent, a silage pit sealing material, or the like.

Gels obtained according to the invention may be prepared such that they eventually break down to the sol form.

Claim 1 of 9 Claims

What is claimed is:

1. A pharmaceutical composition in the form of a gel or viscous solution, said gel or viscous solution comprising a polysaccharide matrix obtained from plant material, said polysaccharide matrix comprising polysaccharide chain segments joined by crosslinking ferulate bridges bonded at regular intervals along said crosslinked segments and said polysaccharide matrix being substantially free of glucans and pectins.

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