Classifications

• • A—HUMAN NECESSITIES
  • A21—BAKING; EDIBLE DOUGHS
  • A21D—TREATMENT, e.g. PRESERVATION, OF FLOUR OR DOUGH, e.g. BY ADDITION OF MATERIALS; BAKING; BAKERY PRODUCTS; PRESERVATION THEREOF
  • A21D13/00—Finished or partly finished bakery products
  • A21D13/02—Products made from whole meal; Products containing bran or rough-ground grain
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
  • A23L7/00—Cereal-derived products; Malt products; Preparation or treatment thereof
  • A23L7/10—Cereal-derived products
  • A23L7/115—Cereal fibre products, e.g. bran, husk
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
  • A23L7/00—Cereal-derived products; Malt products; Preparation or treatment thereof
  • A23L7/10—Cereal-derived products
  • A23L7/117—Flakes or other shapes of ready-to-eat type; Semi-finished or partly-finished products therefor
  • A23L7/135—Individual or non-extruded flakes, granules or shapes having similar size, e.g. breakfast cereals

Definitions

• the present invention relates generally to methods of producing improved bran products from cereals and in particular to an improved oat bran product and its method of production.
• cereals such as oats, barley, wheat, rice, maize and millet are well known.
• One of the key components of cereal that contributes to the nutritional aspects is dietary fibre.
• Foods rich in dietary fibre have been thought to result in benefits ranging from reduction in the risk of cancer to the reduction in cholesterol levels.
• Total dietary fibre comprises both soluble dietary fibre and insoluble dietary fibre and is considered to be the soluble and insoluble components of food that are not digested by enzymes in the human gastrointestinal tract.
• Oats and barley have relatively high levels of soluble fibre which is predominantly in the form of ⁇ -glucan.
• the soluble fibre content of barley is roughly the same as that of oats although: the oat bran fraction is distinctly higher in soluble fibre than barley bran. There has. therefore, been considerable interest in the processing of oats to produce oat bran.
• Oat bran has been defined by the American Association of Cereal
• oat bran fraction is not more than 50% of the starting material, and has a total of ⁇ -glucan content of at least 5.5% (dry weight basis) and a total dietary fibre content of at least 16% (dry weight basis), and such that at least one third of the total dietary fibre is soluble fibre.
• a key characteristic of oat bran is that unlike most other cereal brands, it contains large amounts of adhering endosperm with accompanying significant concentrations of ⁇ -glucan and starch.
• Oat bran is a useful source of complex carbohydrate in the diet and has a specific effect attributable to the soluble fibre, or ⁇ -glucan.
• the commercial oat fraction that is commonly referred to as "bran" consists of the outer layers of the groat (pericarp, seed coat, nucellus and aleurone layers) plus one to several cell thickness of adhering starchy endosperm containing starch, protein and ⁇ -glucan.
• ⁇ -Glucan is found in the seed of cereals and other grasses, but is present in the highest concentrations in oats and barley.
• the ⁇ -glucan content of oats typically falls within the range of 25-60g/kg.
• ⁇ -glucan The highest concentration of ⁇ -glucan is found in the bran fraction, specifically in the aleurone and sub-aleurone cell layers.
• ⁇ -Glucan has recently been recognised as a useful soluble dietary fibre, and as a useful texturing agent for foods.
• oats have been found to be beneficial in the prevention of or amelioration of disease states, including improvements in gastro-intestinal function, modulation of glucose metabolism, and reducing blood cholesterol.
• ⁇ -glucan is the likely active principal in oat bran, there has been a search for technologies that will yield oat bran fractions enriched in ⁇ -glucan.
• Cereal grains such as oats are also rich in essential lipids including monounsaturated and polyunsaturated fats. Such fats are an important requirement in the every day diet of humans and animals. Attempts to produce oat bran in ways analogist to those used for wheat bran have met with limited success. Oats have a soft kernel and a relatively high content of lipid in the endosperm, which leads to the clogging of rollers and sieves. Although many relatively hard-textured cereals (eg wheat, barley, corn, sorghum) can be dry milled to some extent in roller or abrasive mills to produce concentrates of outer grain tissues (eg bran), the soft texture and usual high lipid levels of the oat kernel preclude such manipulations.
• relatively hard-textured cereals eg wheat, barley, corn, sorghum
• endosperm does not easily separate from the outer layers and the lipids contribute to a product that is not easily sieved.
• commercial oat bran products contain large amounts of adhering starchy endosperm.
• Commercial oat bran is therefore not an anatomically pure bran which is a sieved fraction that is enriched in ⁇ -glucan.
• oat bran production remains essentially a dry grinding and sifting operation.
• the process generally begins with the cleaning of the incoming seeds to remove foreign matter, detaching the hull from the groat. subjecting the groats to a process to inactivate enzymes and develop flavour followed by steaming and flaking.
• Groats contain 6 to 9% fat, which is higher than levels found in other commercial cereal grains.
• Lipases catalyse the hydrolysis of triglycerides to free fatty acids which cause the oat products to taste rancid and be unpalatable.
• Whole oats or cut oats that have been kilned may still retain a low level of their original enzyme activity. The remaining enzymes have been found to be inactivated by steaming before the groat is rolled into flakes. Oat flakes or kilned groats may be used to produce commercial oat bran.
• Oats have a strong reputation as a nutritious cereal providing more protein than any other cereal as well as insoluble fiber, soluble fiber ⁇ - glucan. minerals, vitamins, other phytochemicals and the unsaturated fatty acids, oleic and linoleic. Interest in soluble fibers within oats has been spurred by the approval of approved health claims.
• the present inventors have determined that a bran product, which is enriched with at least two components, selected from ⁇ -glucan. fats and fibre derived from the original cereal may be provided through an improved method of processing bran from cereals.
• the present invention relates to a method of manufacturing a bran product derived from a grain, the method including the steps of:
• the present invention relates to a method of manufacturing a bran product derived from a grain, the method comprising the steps of:
• the bran product is enriched with all three components ⁇ -glucan. fats and fibre.
• the ⁇ -glucan is present in an amount of greater than 10% (w/w) : fats in an amount of greater than 10% (w/w); and fibre in an amount of greater than 20% (w/w). Proteinaceous material may also be present in an amount of greater than 15% (w/w).
• a variety of grains may be used in the methods according to the present method, such as oats, barley, wheat, rice, corn, rye, maize, or millet. While the majority of grains have a hull, there are some varieties of grains that do not have hulls in their natural state. It is also envisaged that the above methods will be applicable to legumes, pulses and oilseeds. The bran from these grains may include germ.
• the dehulling step may be carried out before or after the grain has been stabilised.
• Dehulling may be by carried out according to any known prior art method.
• cleaned grains are dehulled prior to stabilisation by impact/abrasion hullers. It will be appreciated that the dehulling step is not required for grains that do not have hulls in their natural state.
• the grain is not defatted.
• a grain bran with an increased concentration of fats derived from the grain may. therefore, be obtained according to the methods of the present invention, such that the grain bran is shelf stable and not susceptible to rancidity.
• Such a grain bran has the nutritional advantages of the fats originally contained in the grain.
• the present inventors have manipulated the method of producing bran so that the intermediates and products are stable during the stages of the method.
• the present inventors have recognised that the method requires minimal disruption of the cell walls of the bran (aleurone and endosperm cell layers) as it is separated from the endosperm, that is. minimal disruption to the outer bran layer. This has been achieved with controlled rolling and milling steps, which are discussed below.
• the grains are stabilised to inactivate the majority of the enzymes in the grain, such as lipases. ⁇ -glucanases and amylases and other unwanted enzymes, which may result in the destruction of nutrients in the grain.
• the stabilisation process also appears to have a beneficial effect on the development of flavour and on resistance to oxidative rancidity.
• Stabilisation may be carried out by treatment with acids or, preferably, by the known method of kilning.
• the kilning method preferably involves heating the grain with wet steam for a period to inactivate the enzymes, followed by a holding step for flavour enhancement, followed by a cooling step.
• grain that needs to be dehulled is dehulled prior to stabilisation.
• a dehulled grain is wet steamed at a temperature of 75 to 150°C. preferably 95 to 100°C. for a period of 15 to 50 minutes, preferably. 20 to 35 minutes.
• the holding step may be carried out at 130 to 70°C. preferably. 95 to 80°C for a period of 30 minutes to 3 hours, preferably, 1 to 2 hours.
• the cooling step may be carried out from 130 to 20°C preferably. 80 to 30°C. for a period of 15 minutes to 2 hours, preferably 30 to 60 minutes.
• Heat treatment is preferably carried out for a time sufficient to deactivate the majority of the enzymes.
• the heat treatment step may also be carried out for a time sufficient to control the moisture content of the grain.
• a relatively high moisture content is desirable.
• a moisture content of 6 % to 16%. more preferably, 9% to 12% is achieved.
• a high moisture content is preferable in order to compensate the moisture lost during the process and to help make the cell wall of the outer bran more pliable and less likely to be disrupted during the process of removing the endosperm from the outer bran layer.
• a second heat treatment step may be carried out after step (b) and before step (c) in the first aspect of the invention and after step (a) and before step (d) in the second aspect of the invention.
• the second heat treatment step is carried out for a time sufficient to inactivate any residual enzymes that were not destroyed during stabilisation. It is believed that the second heat treatment step helps release the endosperm from the cell wall of the bran with minimal disruption.
• the dehulled grain is then subject to milling.
• the present inventors have recognised that minimal disruption of the outer bran layer of the grain is required to maximise the yield of the ⁇ -glucan. fibre and fat components of the bran.
• the present inventors have achieved this by minimal or no bumping of the grain, that is. the grain is rolled so that there is minimal or no flattening of the grain.
• the grain is rolled to a thickness of not less than about 900 to 1500 ⁇ m.
• the grain is rolled to about 1000 to 1100 ⁇ m. This is in contrast to most prior art processes in which the grain is typically rolled to 750 to 550 ⁇ m.
• Milling and sieving of the dehulled grain is carried out to separate grain bran from the first pass of grain flour containing starch. Again, these steps are carried out preferably with minimal disruption to the outer bran layer. Milling may be carried out using a gristing mill or break rolls although it will be appreciated that other similar techniques may be used. Preferably, the gristing mill or break rolls have a flute specification of 10 - 36 flutes/inch D/D. more preferably 28 flutes/inch D/D. Sieving is preferably carried out using a method that allows a dehulled stabilised grain with a relatively high fat and moisture content to be separated from a first pass of grain flour without substantial hindrance, such as clogging of the sieve.
• Sieving preferably takes place in a vibrosifter.
• the grain is sieved through a screen having pores greater than 350 ⁇ m, preferably about 350 to 600 ⁇ m and more preferably, about 400 to 500 ⁇ m.
• This step produces coarse bran, preferably as flakes and more preferably, with a diameter of approximately about 2 to 5 mm diameter.
• oat bran >90% of the bran stayed on a 500 ⁇ m screen (see Table 3). These flakes have some adherence of endosperm.
• the coarse grain bran may undergo a succession of grinding and sieving steps to separate flour from the grain bran to produce a grain bran product of varying density and particle size.
• these steps are preferably carried out in a manner such that there is minimal disruption to the outer bran layer until the endosperm is mostly removed.
• All grinding steps are preferably carried out at low speeds and sieving is preferably carried out utilising density rather than particle size to minimise disruption to the outer bran and to facilitate removal of the endosperm.
• the grinding step is followed by an air density separation step.
• Sieving may be achieved by known processes such as air classification or vibratory sifters or the like. More preferably, the air classification system is used. This system preferably consists of an attrition type ring grinder, the output particle size of which is controlled by balancing the centrifugal force applied by the fixed speed rotor, with the air flow through the grinder as regulated by the variable speed classifier within. After grinding, two components may then be separated using a main classifier, which separates on the basis of density in a moving variable air stream.
• the coarse grain bran may undergo a grinding step followed by a sieving step to separate fine grain bran from a second pass flour.
• the air speed setting for air travelling through the grinder is about 125 to 1000 rpm, more preferably, about 250 to 650 rpm.
• the coarse bran is passed through an air classifier to remove a second pass of grain flour, the air classifier, preferably has a setting of about 75 to 475 rpm. more preferably, about 150 to 350 rpm.
• the resulting fine grain bran preferably has an average diameter of approximately about 100 to 1000 ⁇ m. For example, in the production of fine oat bran. > 70% of the bran passed through 500 ⁇ m screen and remained on a 250 ⁇ m screen (see Table 3).
• the fine grain bran may undergo a further grinding step and sieving step to separate a grain bran product that will hereinafter be referred to as the coarse grain bran concentrate, from a third pass of grain flour.
• the air speed setting for air travelling through the grinder is about 200 to 1200 rpm. more preferably, about 400 to 800 rpm.
• Sieving may be achieved by known processes such as air classification, rotary sifters or the like.
• the coarse bran is passed through an air classifier to remove a third pass of grain flour, the air classifier, preferably has a setting of about 75 to 600 rpm. more preferably, about 150 to 400 rpm.
• the resulting coarse grain bran concentrate preferably has an average diameter of about 50 to 300 ⁇ m. For example, in the production of coarse oat bran concentrate. > 70% of the bran passed through 425 ⁇ m screen and remained on 150 ⁇ m screen (see table 3).
• the coarse grain bran concentrate may undergo a further grinding step to produce a superfine grain bran concentrate.
• a further sieving step may be carried out to separate a fine grain bran concentrate from a fourth pass of grain flour.
• the air speed setting for air travelling through the grinder is about 400 to 2000 rpm. more preferably, about 600 to 1000 rpm.
• Sieving may be achieved by known processes such as air classification.
• the ground coarse bran concentrate is passed through an air classifier to remove a fourth pass of grain flour, the air classifier, preferably has a setting of about 100 to 500 rpm. more preferably, about 150 to 300 rpm.
• the resulting fine grain bran concentrate has an average diameter of about 20 to 150 ⁇ m.
• > 70% of the bran passed through 250 ⁇ m screen (see Table 3).
• the present invention is directed to a method of manufacturing an improved bran product derived from a grain, the method comprising the steps of:
• the bran product is enriched with all three components ⁇ -glucan. fats and fibre.
• the ⁇ -glucan is present in an amount of greater than 10% (w/w) : fats in an amount of greater than 10% (w/w) : and fibre in an amount of greater than 20% (w/w). Proteinaceous material may also be present in an amount of greater than 15% (w/w).
• the invention according to the first or second aspect is carried out using oats.
• the present invention relates to a method of manufacturing an improved oat bran product derived from oat, the method comprising the steps of:
• the improved oat bran product in the form of the oat bran concentrate product is enriched with at least two of the following: (a) greater than 10% (w/w) ⁇ -glucan;
• the oat bran product is enriched with all three components ⁇ -glucan. fats and fibre.
• Proteinaceous material may also be present in an amount of greater than 15% (w/w).
• the improved oat bran product may be used to produce oat bran enhanced food products such as bread, biscuits, cereal flakes, muesli bars, extruded snacks and as a supplement for drinks.
• the present invention is directed to grain brans and bran concentrates produced according to the first or second aspects of the present invention.
• the present invention is directed to the use of grain brans and grain bran concentrates obtained by the process according to the first or second aspect of the invention in the manufacture of food and/or drink products.
• the resulting grain brans and grain bran concentrates may be used in the preparation of food and drink products. For instance, they may be used in the preparation of bakery products such as bread, biscuits and pastry; cereal products such as cereal flakes, muesli bars: as a powder supplement in drinks: meat and meat analog products: soups, sauces, pastes: confectionary products: butters: spreads: non-frozen and frozen desserts: dairy and dairy analogs: dietary supplements: cosmetics: stockfeed animal and veterinary care products.
• the resulting food and drink products are nutritionally enriched with the grain bran and/or grain bran concentrate produced according to the first or second aspects of the invention.
• the present invention is directed to a grain flour prepared according to the method according to the first or second aspect of the invention.
• the grain flour may contain proteins, ⁇ -glucan and fats which may be fractionated by known methods and further processed for use in food and drink products.
• the present invention is directed to a method of producing a bran gel or paste hereinafter referred to as a bran gel.
• the method comprising subjecting the grain bran or grain bran concentrate made according to the first or second aspect of the present invention to enzymatic starch hydrolysis.
• the coarse or fine grain bran or the grain bran concentrate in either, coarse, fine or superfine forms may undergo further processing steps to produce a bran gel. More preferably, the grain bran concentrate is subject to enzymic starch hydrolysis to produce a bran gel, being an enzymically modified grain bran concentrate.
• the present invention is directed to a method of producing bran gel.
• the method comprising treating an aqueous solution of the grain bran concentrate product with an ⁇ -amylase under conditions which will hydrolyse the grain bran concentrate product to produce an bran gel.
• an aqueous suspension of the grain bran concentrate, ⁇ - amylase and optionally ⁇ -amylase is heated to a temperature within the operable range 50 to 95 °C. preferably 70 to 90°C. More preferably, the grain bran concentrate contains 16 to 70%. more preferably 35 to 45% solids.
• the pH is maintained between 5.0 to 8.0. more preferably. 6.0 to 7.0. The mixture may be cooled to less than approximately 70°C. preferably less than 50°C. after approximately. 10 to 120 minutes and the pH is preferably adjusted to 4.5 for approximately 10 to 30 minutes after which the pH is preferably adjusted to approximately 6.5.
• This step functions to deactivate the enzyme and it will be appreciated that other methods known in the art may be used eg addition of chelating agents such as poly phosphate or heat treatment such as UHT for approximately 4 sees at approximately 121°C.
• the final product may be pasteurised or sterilised and packed. Alternatively, the final product may be dehydrated by known means to produce a bran gel powder.
• the powder is suitable for reconstitution or rehydration into a liquid preparation.
• the powder may also be placed in a water limited environment, for example in a lipid based or cheese spread.
• the bran gel powder may be used in the production of drinks, ice cream, dairy and dairy analogs, frozen and non-frozen desserts, meat and meat analogs, soup, sauces, pastes, dressings, spreads or as a fat replacer.
• the bran gel powder may also be used in stabilising syrup systems such as in food coating and binding such as syrup for muesli bars.
• the grain brans, grain bran concentrate products and grain bran gels may be added to any number of food products and combined with any number of dietary supplements such as vitamins and minerals.
• oat bran or an oat bran concentrate in either, coarse, fine or superfine forms undergoes further processing to produce an oat gel in the above described manner.
• Oat gel has a nutritional profile equal to or better than traditional wet oat products such as. porridge but in a form that has broader organoleptic appeal and more readily consumable form.
• the oat gel is capable of being added to other products to enable delivery of the goodness of oats in a broader product format.
• the oat bran concentrate it is converted into a form that can be readily consumed as nutritious gel, delivering the enriched goodness of oats.
• the gel may be also added to other foods to fortify them with the nutritional benefits of oats.
• the oat gel powder can be used in the production of the food and drinks listed above and in stabilising syrup systems.
• the oat bran and oat bran concentrate products according to the invention generally contain residual starch.
• the difference between the oat bran/oat bran concentrate and the oat gel powder is that the residual starch present in the oat bran/oat bran concentrate is converted into a form that does not interfere with liquid processes.
• the formation of the oat gel powder employs the use of an enzyme that breaks down the starch and therefore reduces the viscosity of the oat gel powder.
• the present invention consists in an improved grain bran product derived from grains, the grain bran product comprising at least two of the following components: (a) greater than 10% (w/w) ⁇ -glucan; (b) greater than 10% (w/w) lipid; and (c) greater than 20% (w/w) total dietary fibre (TDF); wherein the ⁇ -glucan, lipid and TDF are derived from the grains used to make the grain bran product.
• Proteinaceous material may also be present in an amount of greater than 15% (w/w).
• the grain bran product is not supplemented with additional quantities of components (a) to (c). all components are derived from the grains used to produce the grain bran.
• the grain bran product is shelf stable and despite the high lipid concentration does not go rancid under normal handling conditions.
• ⁇ -glucan is present in an amount of 10 to 20% (w/w), lipid in an amount of 10 to 20% (w/w) and TDF in an amount of 23 to 50% (w/w).
• the TDF is defined as containing non-starch polysaccharides (NSP). resistant starch (RS) and lignin and may be classified into soluble and non-soluble fibre.
• the soluble fibre is in an amount of 6 to 30% (w/w) and the insoluble fibre in 15 to 50% (w/w).
• the grain bran product may also include proteinaceous material in an amount of 15-50% (w/w), ash in an amount of 3 to 10% (w/w), carbohydrate in an amount of 30 to 70% and starch in an amount of 25 to 55% (w/w).
• the grain bran product may further include vitamins such as thiamine, riboflavin, niacin. alpha-tocopherol. pyridoxine and folate and minerals such as calcium, iron, potassium, magnesium, sodium, phosphorous and zinc.
• the present invention provides an improved oat bran product derived from oats.
• the oat bran product comprises:
• Figure 1 shows a flow diagram for the steps used to produce the oat bran and oat Bran concentrate products according to a preferred embodiment of the invention.
• Figure 2 shows the viscosity of a number of oat bran products including an oat bran product according to the present invention.
• the stabilised groat was steamed for 10-25 mins, which brings the temperature to 95-90°C.
• the groat was then fed into the flaking mill to produce a rolled oat.
• the preferred thickness, targeted is 1050 ⁇ m.
• the rolled oat was then fed into a gristing mill (28 flutes/inch D/D). Alternately a breaker mill could be used.
• bran to flour was then passed through a rotary sifter with a 450 ⁇ m nylon screen, with the overtails material being described as a coarse oat bran. Approximately —50/50 yield of bran to flour was obtained.
• Fine oat bran was repassed through fine grinder/ classifier 1 speed setting 590 rpm.
• the low-density fraction was coarse Oat Bran concentrate. Yield —60/40 bran: flour.
• the low-density fraction was fine Oat Bran concentrate. Yield — 45/55 bran: flour Preparation of oat gel
• Example 1- Extruded (Processed) Bran Formulation Including Oat Bran concentrate
• Example 2 Flake Formulation Including Oat Bran concentrate
• TDF 28.4 30.6 insoluble fibre 17.5 18.9 soluble fibre 10.9 11.7 ash 4.3 4.6 beta-glucan 12.4 13.4 total starch 0.0
• bran products Over 100 tonne of bran products have been produced in accordance with the present invention.
• the bran products according to the present invention have been used in a variety of food products and that use has not compromised the taste, texture or shelf life of any of the products. This is in contrast to many of the prior art bran products which can become rancid due to the fat component.
• the present invention provide an important dietary component or additive for food products, it does not adversely effect the character or quality of the food products.
• Samples 1-4 and 7 were stored at room temperature. Samples 5 and 6 were stored at -70°C. After initial inactivation of endogenous enzymes, samples were stored in a desiccator at room temperature. Sample preparation
• Samples 1 and 3 were used without any grinding. Samples 2, 4 and 7 were ground in a coffee mill. Sample 5 was frozen in liquid nitrogen and then ground with a mortar and pestle. Sample 6 was thawed, broken into small pieces, re-frozen with liquid nitrogen and then ground with a mortar and pestle
• Duplicate preparation of each sample was carried out. Two grams of each sample were weighed into 50 ml Falcon tubes and suspended in 50 ml of 50 mM sodium phosphate buffer pH 6.5 containing 80 ppm calcium chloride. The tubes were then placed into a water bath preheated to 90°C. Tubes were initially shaken every ⁇ 5 min. After 20 min, 500 ⁇ l of Thermamyl 120L type LS (Novo Nordisk, Denmark) was added. Two controls which did not receive any thermamyl were also extracted. Extraction and digestion continued for a further 2 hours with shaking of the tubes every 15- 20 min. The tubes were then centrifuged in a table top centrifuge at ⁇ 2.400g for 10 min.
• the residue was re-extracted with 10 ml cold buffer, re- centrifuged and the s ⁇ pernatants combined.
• the extracts were checked for the presence of starch by iodine/iodide analysis. Samples were then centrifuged at ⁇ 35.000g for 1 hour. The resulting supernatants were decanted through mira-cloth. and ⁇ -glucans were then precipitated with 2 vol ethanol.
• the precipitated samples were allowed to stand for at least 2 hours at room temperature before gentle centrifugation at ⁇ 500g for 10 minutes to pellet precipitated ⁇ -glucan (coherent "mats" or "globs" of precipitate were removed before centrifugation and combined with the pelleted material after centrifugation).
• the precipitate was washed first with 50 ml 66% ethanol and then with 15 ml pure ethanol. After initial air-drying, the samples were frozen and freeze-dried. The weight of each sample was recorded after freeze-drying.
• ⁇ -glucan preparations might contain small amounts of protein and other non-starch polysaccharides such as xyloglucans (Miller and Fulcher 1995 Cereal Chem 72; 428-432).
• a complete purification and quantification was not performed as the main purpose of the analysis was to detect changes in molecular weight of the ⁇ -glucans as a function of processing conditions of the food samples.
• freeze-dried samples labelled 1-7 and A-F were measured for shear viscosity, intrinsic viscosity and particle sizing.
• freeze-dried samples were dispersed in distilled water and left to hydrate at room temperature for 2 hours.
• the dispersion was then heated to 70°C in a waterbath and then mixed with a Ystral high speed mixer for 30 seconds, it is then left to hydrate further for an hour at room temperature.
• a 1.0 % dispersion was used for shear viscosity measurement.
• Shear viscosity was measured on a 4 cm cone-plate system (59 ⁇ m gap. 1.59° angle) with the Carri-Med Controlled Stress Rheometer (CSL 100) at 25°C. Viscosity was plotted against shear rate.
• freeze-dried samples were dispersed in distilled water and left to hydrate at room temperature for 2 hours.
• the dispersion was then heated to 70°C in a waterbath and then mixed with a Ystral high speed mixer for 30 seconds, it was then left to hydrate further for an hour at room temperature.
• the dispersion was filtered with a 2 ⁇ m filter before measurement.
• the intrinsic viscosity is measured with the Ubbelohde viscometer attached to a Schott AVS 350 and TA20 set-up for automatic dilution.
• the ⁇ - glucan concentration was kept to 0.1%.
• Particle sizes indicate that the molecules are aggregated to a significant degree.
• the primary particle sizes. Dl and D2 vary significantly in their relative percentage by volume. This indicated that significant amounts of aggregated material is present after rehydration using the above procedure.
• the stated molecular weights (from the smaller diameter) are calculated using dextran as a standard and assuming both polysaccharides are in the random coil state.
• the molecular weights interpreted from PCS measurement are significantly larger than those measured using GPC-MALLS by other (Cui and Wood 2000 Hydrocolloids - Part 1. Ed. Nishinari, Elsevier, 159- 169).
• the molecular weights determined using GPC-MALLS indicated lower values of order 0.4 through to 3.1M.
• the shear imposed on the system by the GPC column may be responsible for the reduction in the apparent molecular weights measured.
• the data obtained in this study indicates that the ⁇ -glucan is in aggregated form in aqueous solution.
• the aggregates will therefore be the species which show physiological activity unless the polymer aggregates disperse in the acid conditions of the stomach.
• Intrinsic viscosity was used as a measure of duplication of the extraction process and Tables 7 and 8 clearly indicates that there was reproducibility to +/- 10 n L/g.
• Shear viscosity and intrinsic viscosity show similar trends.
• the shear viscosity can potentially be used as a quick measurement to determine degradation of samples.
• Shear viscosity is usually less time consuming to perform and in factory environment is often the only available method for measurement of viscosity.
• Figure 2 shows the viscosity curves of the samples 1-6.
• the ⁇ -glucan extracted from the different oat sources all show significant aggregation and are not low molecular weight material. There appeared to be two major species present at approximately 70 nm and 300 - 600 nm diameters as aggregates in solution.
• the study began with a two-week control phase during which subjects became accustomed to a diet avoiding barley and oat products, specialty margarines and psyllium. Subjects then proceeded to a 3-phase test period comprising low glucan. high glucan and low glucan supplemented foods. Each phase lasted 3 weeks. The design therefore provided two control periods flanking the test period.
• the habitual diets were determined by a modified food frequency questionnaire, which served to establish for each person a constant background pattern for eating.
• the ⁇ -glucan was incorporated into three foods - cereal, muffins and bread in approximately equal amounts within 40 g breakfast cereal. 70 g sliced bread and a 50 g muffin.
• the low glucan periods comprised the same study foods but without ⁇ -glucan supplementation.
• the foods were eaten through the day. All foods were colour-coded but only the subjects were blinded to the identity of the foods. The laboratories carrying out the various assays, however, were unaware of the nature of the study.
• the ⁇ -glucan was produced according to the present invention. For this study, approximately 60 g of oat bran concentrate contained 8 g ⁇ - glucan. Subjects
• Inclusion criterion was a total cholesterol >5.5 mmol/L. Exclusion criteria included smoking, alcohol exceeding 2 standard drinks per day, dietary supplements, medication likely to affect plasma lipids, bowel, liver and kidney disorders, thyroid dysfunction and diabetes mellitus.
• the experimental design allowed pairwise comparisons between low and high glucan periods, so that analyses were based on paired t-test.
• the average age of the 7 men and 7 women was 52 ⁇ 10 yr (range 34-69) and their BMI was 25 ⁇ 3.4 kg/nr (range 19.3-29.8) as shown in Table 9.
• Plasma lipid values on screening showed that two subjects were inadvertently entered with a cholesterol value below 5.5 mmol/L (the inclusion criteria): 5.2 mmol/L. 5.4 mmol/L. They were therefore primarily hypercholesterolemic. All subjects were overweight with BMI greater than 25 cnr/kg. none were obese. All men and women had abdominal obesity defined as _> 0.9 for men and > 0.8 for women. Glucose readings were within the normal range. Dietary record
• the 3-day food frequency questionnaire showed that the percent energy from fat (35 ⁇ 5 versus 34 ⁇ 6) and from saturated fat (13 ⁇ 4 versus 13 ⁇ 4) was not significantly different during the low and high glucan periods.
• Total fiber from the background diet (18 ⁇ 5 g) remained constant.
• the average daily ⁇ -glucan consumption was 7.4 ⁇ 1.28 g during the supplemented phase, 92% of the 8 g target. Compliance, as judged from the daily records of test foods consumed and the 3-day food frequency questionnaire, was very satisfactory. The lower than targeted consumption of ⁇ -glucan was due to some people, especially women, unable to eat the full ration of muffins.
• Increased viscosity of gastrointestinal content induced by appropriate forms of ⁇ -glucan may be a key factor in cholesterol-lowering. Viscosity depends on the solubility of the ⁇ -glucan and its molecular weight, which in turn is influenced by technological treatment, the cultivar and growing conditions. The hypothesis is that increased viscosity in the gut leads to an unstirred layer adjacent to the mucosa. This layer may serve as a physical barrier to bile acid reabsorption. which leads to increased uptake of LDL cholesterol into the liver to replenish hepatic cholesterol.

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• 1999
  • 1999-09-17 AU AUPQ2933A patent/AUPQ293399A0/en not_active Abandoned
• 2000
  • 2000-09-15 WO PCT/AU2000/001113 patent/WO2001021012A1/en active IP Right Grant

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