Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Preparing compound containing saccharide radical
Reexamination Certificate
1999-05-20
2002-07-30
Prats, Francisco (Department: 1651)
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Preparing compound containing saccharide radical
C435S101000, C435S093000, C435S072000, C426S028000, C536S123120, C536S123100, C536S128000, C514S054000
Reexamination Certificate
active
06426201
ABSTRACT:
FIELD OF INVENTION
This invention relates to novel substances which can be extracted from cereals, novel extraction procedures, and the use of the products as therapeutic agents, biocompatible films and as additives in food and cosmetics.
BACKGROUND
&bgr;-Glucan polysaccharides present in cereals comprise D-glycopyranosyl units. The units are linked together by (1→3) or (1→4) &bgr;-linkages, &bgr;-Glucans of this type comprise up to approximately 15% of the solids in oats and barley cereals. They typically have a molecular weight of around 2.5 million.
&bgr;-Glucans are useful as soluble dietary fibre. Soluble fibre remains undigested except by colonic microflora in the lower intestines. This enhances the growth of bacteria beneficial to health. Soluble dietary fibre is believed to have a role in the prevention of certain diseases including colonic cancer and diseases associated with high serum cholesterol levels. Soluble fibre can be used for the treatment and prevention of constipation, for the improvement of bowel regularity, and for the regulation of the glycaemic response associated with the digestion of many substances.
&bgr;-Glucans are considered to have hypocholesterolemic activity. &bgr;-Glucans are also useful as food ingredients. They have neutral flavours and provide bulk in addition to having desirable mouthfeel and texture characteristics. In this context, &bgr;-glucans are known as fat replacements in some foods.
The reported methods of extracting &bgr;-glucans from cereal involve a number of steps. First, the milled cereal is treated to deactivate enzymes associated with the cereal. Then the &bgr;-glucan is extracted from the cereal into warm water after which the solids are removed from the solution.
Large quantities of water-miscible organic solvents are added to the solution to precipitate the &bgr;-glucan, generally along with other polysaccharides. The &bgr;-glucan is of low purity and of generally high molecular weight. It is also known to carry out the enzyme deactivation step after the water extraction rather than as a first step. The deactivation step inhibits hydrolysis of the &bgr;-glucan thereby maintaining a high average molecular weight of the &bgr;-glucan.
Aqueous solutions of the &bgr;-glucan obtained via the known methods have minimal functionality with respect to temperature. They are generally high molecular weight gums and form viscous aqueous solutions although they do not dissolve in water easily.
The &bgr;-glucans obtained by the reported methods can contain arabinoxylans and starch. These impurities can be responsible for the formation of viscous aqueous solutions during extraction which are difficult to process. Gummy or tacky solids can result when the solids are recovered as a dry product. These products are difficult to redissolve, even at high temperatures.
The known methods of recovering &bgr;-glucan from the aqueous solution include precipitation of the &bgr;-glucan by the addition of a water miscible organic solvent (such as ethanol) followed by filtration, and spray- or freeze-drying of the precipitate.
The extraction procedures suggested by the prior art have limited commercial potential in view of the number of steps and hence the cost involved.
SUMMARY OF INVENTION
It is an object of this invention to provide a &bgr;-glucan product and a simple and effective method of extracting &bgr;-glucan, or to at least provide the public with a useful alternative.
In a first aspect of this invention there is provided a process for obtaining &bgr;-glucan, having a lower average molecular weight than in its native state, from cereal comprising:
mixing the cereal with water to form a slurry of an aqueous solution of &bgr;-glucan and a solid residue such that the &bgr;-glucan is partially hydrolysed by one or more enzymes associated with the cereal to give &bgr;-glucan having a lower average molecular weight than in its native state,
separating the aqueous solution from the solid residue, and
recovering the &bgr;-glucan from the aqueous solution,
wherein there is there is no step of deactivation of the one or more enzymes during the process.
In accordance with a second aspect of this invention there is provided a process for recovering &bgr;-glucan from an aqueous solution of &bgr;-glucan comprising:
freezing the solution,
thawing the solution to give a precipitate in water, and
separating the precipitate from the water,
wherein the major non-aqueous component of the precipitate is &bgr;-glucan.
The invention provides a &bgr;-glucan produced by any of the processes of the first and second aspects of the invention.
The invention also provides a &bgr;-glucan extracted from cereal which forms a gel when dissolved in heated water and then allowed to cool.
In accordance with a further feature of the invention there is provided a composition containing &bgr;-glucan for use as a hypocholesterolemic agent. A composition containing &bgr;-glucan is also provided for use in treating or preventing constipation, for regulating bowel activity, or for regulating glycaemic response.
The invention also provides a method of treating hypercholesterolemia in a patient in need comprising administering to the patient an effective amount of &bgr;-glucan.
The invention further provides a method of treating or preventing constipation, a method of regulating bowel activity and a method of regulating glycaemic response, each method comprising administering to a patient in need an effective amount of &bgr;-glucan.
The invention provides the use of a &bgr;-glucan as a food ingredient, as an additive in cosmetic compositions, as a film forming agent in wound dressings and in food coatings, as a matrix for the slow release of an agent carried in the matrix, and for the modification of the properties of other polysaccharides.
The invention also provides an animal feed consisting of cereal from which &bgr;-glucan has been extracted to a substantial extent. The invention further provides a cereal for use in brewing processes wherein &bgr;-glucan has been extracted from the cereal.
DETAILED DESCRIPTION
The cereal used in this invention may be any &bgr;-glucan containing grain or plant material including, but not limited to, barley, oats, rice, rye, triticale, maize and wheat. The preferred cereal is barley. In addition, waxy cereals have the advantage over non-waxy cereals that less leeching of amylose from the starch granules into the extraction solution occurs.
The physical properties of &bgr;-glucans depend largely on their average molecular weight. The expression “high molecular weight &bgr;-glucan” as used herein means &bgr;-glucan having an average molecular weight substantially similar to the average molecular weight of &bgr;-glucan found in the cereal (typically 2×10
6
to 3×10
6
). The expression “low molecular weight &bgr;-glucan” as used herein means &bgr;-glucan having a lower average molecular weight (5×10
3
to 1.5×10
6
) relative to the average molecular weight of &bgr;-glucan found in the cereal.
The average molecular weight of the &bgr;-glucan extracted from the cereal is a function of the amount of time the &bgr;-glucan is in contact with one or mole hydrolase enzymes associated with the cereal. Thus, when the cereal is mixed with water, the one or more hydrolase enzymes are believed to become activated with respect to reaction with the &bgr;-glucan. A portion of the &bgr;-glucan molecules are hydrolysed to smaller units leading to &bgr;-glucan recovered from the extraction process having low molecular weight.
The hydrolase enzymes associated with the cereal include enzymes endogenous to the cereal and also enzymes present in, or produced by, microorganisms which may have adhered to the cereal.
The average molecular weight of &bgr;-glucan obtained by aqueous extraction of cereal, without deactivation of hydrolase enzymes, can be controlled by controlling the time of the extraction. In the process of the first aspect of the invention cereal is mixed with water to form a slurry so that &bgr;-glucan is extracted from the cere
Gracelinc Limited
Prats Francisco
LandOfFree
&bgr;-glucan products and extraction processes from cereals does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with &bgr;-glucan products and extraction processes from cereals, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and &bgr;-glucan products and extraction processes from cereals will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2820441