Beta-glucan products and extraction processes from cereals

Abstract

A process of obtaining β-glucan from cereal by extracting with water and without deactivation of enzymes associated with the cereal. A process for controlling the average molecular weight of β-glucan extracted from cereal by controlling the extraction time. A process fro recovering -glucan from an aqueous solution of β-glucan comprising freezing the solution, allowing the solution to thaw and separating solids from the resultant suspension. A β-glucan produced by any of these processes. A β-glucan which forms a gel when a heated solution of the β-glucan cools. The use of β-glucan in treating various health disorders, as an additive in cosmetics and foods, and as a film forming agent. A cereal from which b-glucan has been extracted for use as animal feed or in brewing processes.

1 . A process for obtaining β-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 β-glucan and a solid residue such that the β-glucan is partially hydrolysed by one or more enzymes associated with the cereal to give a β-glucan having a lower average molecular weight than in its native state,  
 separating the aqueous solution from the solid residue, and  
 recovering the β-glucan from the aqueous solution,  
 wherein there is no step of deactivation of the one or more enzymes during the process.  
 
     
     
         2 . A process as claimed in  claim 1  wherein the aqueous solution separated from the solid residue is cooled to a temperature between approximately 0° C. and 10° C. so that a gel forms and the β-glucan is recovered from the gel.  
     
     
         3 . A process as claimed in  claim 1  wherein the cereal is a processed form or fraction of the cereal grain or cereal plant material.  
     
     
         4 . A process as claimed in  claim 1  wherein the cereal is mixed with water at a temperature in the range of approximately 0-80° C.  
     
     
         5 . A process as claimed in  claim 1  wherein the temperature is in the range of approximately 45-60° C.  
     
     
         6 . A process as claimed in any one of the preceding claims wherein the cereal is mixed with water at a pH in the range of approximately 1-10.  
     
     
         7 . A process as claimed in any one of the preceding claims further comprising the step of adding one or more enzymes to the slurry or to the aqueous solution obtained from the separation step to assist the partial hydrolysis of the β-glucan.  
     
     
         8 . A process as claimed in any one of the preceding claims further comprising the step of adding acid to the slurry or to the aqueous solution obtained from the separation step to assist the partial hydrolysis of the β-glucan.  
     
     
         9 . A process as claimed in any one of the preceding claims further comprising treating the slurry or the aqueous solution obtained from the separation step with an arabinoxylan degrading enzyme or a starch degrading enzyme so that the β-glucan obtained has reduced amounts of arabinoxylan or starch impurities.  
     
     
         10 . A process as claimed in  claim 9  wherein the arabinoxylan degrading enzyme is xylanase.  
     
     
         11 . A process as claimed in  claim 9  wherein the starch degrading enzyme is an amylase.  
     
     
         12 . A process as claimed in any one of the preceding claims wherein the average molecular weight of the β-glucan is less than approximately 1.5×10 6 .  
     
     
         13 . A process as claimed in any one of the preceding claims wherein the average molecular weight of the β-glucan is less than approximately 6.0×10 5 .  
     
     
         14 . A process as claimed in any one of the preceding claims wherein the average molecular weight of the Z-glucan is less than approximately 3.0×10 5 .  
     
     
         15 . A process as claimed in any one of the preceding claims wherein the average molecular weight of the β-glucan is in the range of approximately 5×10 3  to 5×10 4 .  
     
     
         16 . A process for recovering β-glucan from an aqueous solution of β-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 β-glucan.  
 
     
     
         17 . A process as claimed in  claim 16  wherein the solution is frozen at a temperature between approximately −20° C. and 0° C.  
     
     
         18 . A process as claimed in  claim 16  wherein the solution is thawed at a temperature of approximately 15-25° C.  
     
     
         19 . A process as claimed in  claim 16  wherein the precipitate is separated from the water by filtration or centrifugation and is then dried.  
     
     
         20 . A process as claimed in  claim 16  further comprising redissolving in water the precipitate recovered from the water and repeating the freezing, thawing and separating steps.  
     
     
         21 . A process as claimed in  claim 16  wherein the precipitate is again frozen and then thawed to further remove water from the precipitate.  
     
     
         22 . A process as claimed in any one of  claims 16  to  21  wherein the β-glucan is greater than approximately 30% by weight of the total precipitate.  
     
     
         23 . A process as claimed in any one of  claims 16  to  21  wherein the β-glucan is greater than approximately 70% by weight of the total precipitate.  
     
     
         24 . A process as claimed in any one of  claims 16  to  21  wherein the β-glucan is greater than approximately 90% by weight of the total precipitate.  
     
     
         25 . A process as claimed in  claim 16  wherein an arabinoxylan degrading enzyme or a starch degrading enzyme is added to the aqueous solution containing β-glucan prior to freezing the solution so that undesired arabinoxylans or starch are degraded and the solids recovered from the suspension have reduced amounts of arabinoxylan or starch impurities.  
     
     
         26 . A process as claimed in  claim 16  wherein the solids recovered from the suspension are redissolved in water and treated with an arabinoxylan degrading enzyme or a starch degrading enzyme followed by repeating the freezing, thawing and separating steps to give a precipitate having reduced amounts of arabinoxylan or starch impurities.  
     
     
         27 . A process as claimed in  claim 25  or  claim 26  wherein the arabinoxylan degrading enzyme is xylanase.  
     
     
         28 . A process as claimed in  claim 25  or  claim 26  wherein the starch degrading enzyme is an amylase.  
     
     
         29 . A process as claimed in any one of the preceding claims wherein the cereal is barley, oats, rice, rye, triticale, maize or wheat.  
     
     
         30 . A β-glucan obtained by the process of any one of the preceding claims.  
     
     
         31 . A β-glucan extracted from cereal wherein the β-glucan forms a gel when dissolved in water at a temperature of greater than approximately 45° C. and then allowed to cool.  
     
     
         32 . A β-glucan as claimed in  claim 30  or  claim 31  which has an average molecular weight of less than approximately 1.5×10 6 .  
     
     
         33 . A β-glucan as claimed in  claim 30  or  claim 31  which has an average molecular weight of less than 6.0×10 5 .  
     
     
         34 . A β-glucan as claimed in  claim 30  or  claim 31  which has an average molecular weight of less than 3.0×10 5 .  
     
     
         35 . A β-glucan as claimed in  claim 30  or  claim 31  which has an average molecular weight in the range of approximately 1.5×10 6 .  
     
     
         36 . A β-glucan as claimed in  claim 31  which forms a gel at a concentration above approximately 0.5% by weight in the water.  
     
     
         37 . A β-glucan as claimed in  claim 31  wherein the water is heated to above approximately 60° C. to dissolve the β-glucan.  
     
     
         38 . A composition for use as a hypocholesterolemic agent containing β-glucan as claimed in any one of  claims 30  to  37  together with an acceptable carrier.  
     
     
         39 . A composition for use in treating or preventing constipation containing β-glucan as claimed in any one of  claims 30  to  37  together with an acceptable carrier.  
     
     
         40 . A composition for use in the regulation of bowel activity containing β-glucan as claimed in any one of  claims 30  to  37  together with an acceptable carrier.  
     
     
         41 . A composition for regulation of glycaemic response containing β-glucan as claimed in any one of  claims 30  to  37  together with an acceptable carrier.  
     
     
         42 . A method of treating hypercholesterolemia in a patient in need comprising administering to the patient an effective amount of β-glucan as claimed in any one of  claims 30  to  37 .  
     
     
         43 . A method of treating or preventing constipation in a patient in need comprising administering to the patient an effective amount of β-glucan as claimed in any one of  claims 30  to  37 .  
     
     
         44 . A method of regulating bowel activity in a patient in need comprising administering to the patient an effective amount of β-glucan as claimed in any one of  claims 30  to  37 .  
     
     
         45 . A method of regulating glycaemic response in a patient in need comprising administering to the patient an effective amount of β-glucan as claimed in any one  claims 30  to  37 .  
     
     
         46 . The use of a β-glucan as claimed in any one of  claims 30  to  37  as a food ingredient.  
     
     
         47 . The use of a β-glucan as claimed in any one of  claims 30  to  37  as an additive in cosmetic compositions.  
     
     
         48 . The use of a β-glucan as claimed in any one of  claims 30  to  37  as a film forming agent in wound dressings and in food coatings.  
     
     
         49 . The use of a β-glucan as claimed in any one of  claims 30  to  37  as a matrix for the slow release of an agent carried in the matrix.  
     
     
         50 . The use of a β-glucan as claimed in any one of  claims 30  to  37  for the modification of the properties of other polysaccharides.  
     
     
         51 . The use of a β-glucan as claimed in any one of  claims 30  to  37  as an inhibitor of ice crystal formation in the preparation of frozen foods.  
     
     
         52 . An animal feed consisting of cereal from which β-glucan has been extracted according to the process of any one of  claims 1  to  29 .  
     
     
         53 . An animal feed as claimed in  claim 52  wherein at least approximately 30% of the β-glucan has been extracted from the cereal.  
     
     
         54 . An animal feed as claimed in  claim 52  wherein at least approximately 50% of the β-glucan has been extracted from the cereal.  
     
     
         55 . An animal feed as claimed in  claim 52  wherein at least approximately 80% of the β-glucan has been removed.  
     
     
         56 . A cereal for use in brewing processes wherein the β-glucan has been extracted from the cereal according to the process of any one of  claims 1  to  29 .  
     
     
         57 . A cereal as claimed in  claim 56  wherein at least approximately 30% of the β-glucan has been extracted from the cereal.  
     
     
         58 . A cereal as claimed in  claim 56  wherein at least approximately 50% of the β-glucan has been extracted from the cereal.  
     
     
         59 . A cereal as claimed in  claim 56  wherein at least approximately 80% of the β-glucan has been extracted from the cereal.  
     
     
         60 . A process for obtaining β-glucan from cereal substantially as herein described with reference to any one of Examples 1 to 11.  
     
     
         61 . A process for recovering β-glucan from an aqueous solution of β-glucan substantially as herein described with reference to any one of Examples 1 to 11.  
     
     
         62 . A β-glucan product obtained by a process as claimed in any one of  claims 1  to  29  substantially as herein described with reference to any one of Examples 1 to 11.  
     
     
         63 . The use of β-glucan substantially as herein described with reference to any one of Examples 12 to 16.