SE521559C2 - Wet fractionation of cereal bran components for use as feed/food additives, by treating with starch- and phytate-hydrolyzing enzyme, wet milling and separating Germ-rich-, residual endosperm- and protein-fractions - Google Patents

Abstract

Cereal bran components are wet fractionated by treating bran with starch- and phytate-hydrolyzing enzymes, aqueous wet milling, and inactivating enzyme (option) by wet heat. Insoluble phase containing a cleaned bran of both pericarp and aleurone fractions are separated by centrifugation into germ rich fraction aqueous phase (AP) and residual endosperm (ES)-AP, and proteins in ES-rich fraction are concentrated. Independent claims are included for the following: (1) Germ derived protein fraction having (in %) protein (35), oil (10), fiber (5); (2) Insoluble fiber fraction which consists of cell wall components of bran (at least 85%), aleurone proteins (at least 10%), substantially free from gluten and starch, and with a high water holding capacity of at least 6 g water/g dry product; (3) Residual endosperm derived sugar fraction containing more than 65% sugar e.g. glucose, maltose and malto-triose; (4) Soluble hemicellulose fraction having medium molecular weight hemicellulose (MMWH) (20 kDa) which is at least 40% of arabinoxylans from wheat, rye, rice, and triticale, and beta-glucans from oat and barley, and proteins (less than 10%) and monosaccharides (less than 10%) and free of glucan and starch (less than 1%); (5) Soluble oligosaccharide fraction having MMWH subunits of below 20 kDa which is at least 40% of the groups arabinoxylans and beta-glucans, and proteins (less than 10%) and monosaccharides (less than 20%), lignans and related phenolics (less than 5%) and free of glucan and starch (less than 1% on DMB); (6) Germ oil containing sterols which reduce the uptake of cholesterol in humans and intact vitamin E complex, sterols, lecithins, phospholipids and glycolipids; (7) Defatted germ rich protein; (8) Aleurone-rich oil; (9) Defatted aleurone-rich protein; (10) Use of the protein fraction in feed and food application; (11) Set up, for the process, comprising a hydrolysis vessels (1,8,11), wet mill (2), heat exchange for enzymatic inactivation (3), decanters (4,7), a holding tank (6), an ultra-filter (10) and optionally evaporators (12,13) and dryers (5,9).

Description

Background of the Invention U.S. Patent 4,361,665l discloses a process for making fermentable sugars and high protein products from grains, mainly corn. In this method, the grains are soaked for -30 hours before grinding and separation of the seed component, saccharification of carbohydrates (mainly starch), and separation of fiber. The yield of starch is maximized for fermentation to alcohol. In the process described, there is no specific fractionation of the click component, separation of protein species, or consideration of the germ component.

U.S. Patent 5,3 12,636 provides knowledge of a process for fractionating a crop into industrial raw materials. This is focused on oat grain and the incorporation of cleavage fractionation processes which involve the extraction of fl your hydrophobic components such as lipids in polar organic solvents before an alkaline extraction of the remaining bran to produce beta-glucan, protein and gum-free fiber. Use of the organic solvent is a key step in the process and hydrolyzing enzymes were not used during the fractionation process.

U.S. Patent 4,746,073 discloses a method and apparatus for physically separating and recovering enriched fractions of aleurone wheat particles from wheat bran. This is achieved by grinding the bran with a hammer mill and then subjecting the resulting particles to a physical separation. No wet processing was used during the fractionation procedure described herein.

Two related U.S. patents (4, 171, 3,83 and 4, 171, 3,84) provide knowledge of dry and wet milling processes for refining whole wheat grains. 4, l7l, 3 83 focuses on wet grinding of the entire core. The produced bran is mixed with a separated (mainly) endosperm protein fraction to give animal feed. 4, 171.3 83 describes dry milling of the whole core to produce an endosperm fraction, a seed fraction and a climbing fraction.

The endospen fraction is then subjected to wet milling and separation of starch-rich and protein-rich fractions. The protein-rich fraction is added to the bran to give an animal feed. It ~, ».». there is no description of a specific wet fractionation of the bran itself in either of the patents.

U.S. Patent 3,879,373 discloses a process in which pentosanes are isolated from wheat bran after alkali ethanol extraction of oils, fats, pectin, and lignin or chlorine-mediated delignification.

This way creates problem your problems, most notably the extreme chemical situation used and subsequent treatment of outlet fates. Furthermore, the use of chlorine in the preparation of food and animal feed qualities is questioned.

U.S. Patent 5,308,618 discloses a process for preparing diets as an extract from wheat bran.

The bran is extracted at high temperature and pressure in water (180 - 200 ° C), to give a glucose-rich diet component in the aqueous phase. The process specifically refers to the production of dietary fiber and is not in reality / strictly a fractionation process in that other products are substantially ignored.

It is clear that none of the above inventions has arrived at a process for classical cereal fractionation which is both chemical-free and gives different food quality fractions.

The main object of the invention is to achieve an efficient and cost-effective wet process for separating valuable fractions with distinct chemical-physical properties from cereal clay. Combine the use of biological treatment with cell-free enzymes with wet grinding to minimize both hydrolysis time and degree of fi ber contamination in non-fi ber fi actions. 3. Ensure that in the fractionation process protein fractions with distinct physical properties and thus functionalities are obtained. 4. The process is carried out in such a way as to avoid the use of chemical extraction procedures and therefore food grade fractions can be produced.

. Minimize changes in the nutritional value, structure and functionalities originally observed in the main components, and in particular maintain the antioxidant capacity present in the oil so as to prolong the shelf life of the protein-rich fraction.

Description of Preferred Embodiments It is widely known and accepted that when cereals are ground for the purpose of producing flour, the most nutritious part of the grain is separated in the by-product, i.e. cerealiekliet. Despite the fact that cereal bran is rich in proteins, oils, vitamins, and minerals, its use in the food industry and the high-quality animal feed industry is quite limited. This is primarily because bran, such as wheat bran, contains insoluble fiber.

The inventors have developed an industrial process that makes it possible to separate fractions of different natures from different cereal branches, to produce high-quality protein and sugar fractions and to extract practically all insoluble fiber as a separate fraction. The resulting low fi ber protein and sugar fraction as well as fraction with insoluble fiber have much wider market applications and greater value than the original bran.

EXAMPLE 1 Wheat bran prepared from short milling (SMB) and conventional milling (CMB) methods was used in this experiment. 25 kg clip samples were transferred to a mixing tank and hydrolyzed sequentially at temperatures ranging from 70 ° C in the first step with otamylase to 60 ° C in the second step with amyloglucosidase for a total hydrolysis time of 4 hours.

During this period, the reaction mixture was wet ground intensely to increase the surface area and dispersion of soluble components. The pH of the reaction mixture was initially set at neutral and then reduced to 4.5 with acetic acid in the second step. In addition to maximizing enzyme activity, the acidic pH allowed partial dissolution of phytates present in the bran.

At the end of the enzyme hydrolysis - wet milling step, the enzymes in the reaction mixture were inactivated by wet heating by heat exchange and rapid cooling to room temperature. The hydrolysed bran solution was then introduced into a two-phase decanter to separate insoluble (fiber and aleurone fractions) from the soluble fraction.

The soluble fraction was introduced into a separator so that the heavy phase containing mainly germ components could be separated from the light phase containing mainly components from the remaining endosperm present in the bran. The light fraction, which was highly contaminated with sugar, was passed through an ultrafilter with a 50 kDa filter to separate low molecular weight sugar and protein fraction with less sugar contamination from each other.

All protein fractions, i.e. heavy and light phases, mixed together and finally processed by spray drying. The sugar fraction was concentrated by vacuum evaporation at low temperature (40 to 60 ° C) until a 75% sugar concentration was reached. The fiber fraldion was dried in a conventional laboratory oven, but in an industrial process this can be done with a number of different dryers, i.e. tumble dryer, ring dryer, grinder etc.

The average chemical composition of bran and their respective fractions is shown below: Sample Dry Substance Protein Oil Fiber Ash NNE *** ns CMB * 90.8 15.7 4.1 45.4 5.5 29.3 CMB fractions acc. process Protein phase 92.9 31.8 7.7 1.1 7.9 51.5 Fiber 92.8 13.6 3.0 76.9 4.1 2.4 SMB ”89.1 14.3 2.3 23.7 3.2 56.5 SMB fractions acc. Process Protein phase 93.9 27.8 1.5 0.9 3.4 66.4 Fiber 94.3 22.5 4.1 64.8 1.6 7.0 * Bran from conventional milling ** Bran from short milling *** Non-nitrogen extracts EXAMPLE 2 Wheat bran produced from conventional milling was subjected to enzymatic treatment and wet milling as described in Example 1. The hydrolyzed bran was fractionated using two-phase decants into an insoluble (combined fi ber and aleurone) and a soluble fraction.

The soluble fraction was fed to a separator for fractionation using centrifugal forces so as to produce two phases. The frog-rich fraction was washed with water and fed back to the separator to remove excess sugar and other light contaminants. The resulting protein fraction was kept as such or mixed with evaporated surface whey in a 1: 1 ratio (dry matter basis).

The endospermic fraction, which was highly contaminated with sugar, was fed to an ultrafilter to separate low molecular weight sugar and protein fraction with less sugar contamination.

All soluble protein fractions, i.e. germ and endosperm-rich phases, and mixtures with whey were spray-dried separately. The sugar fraction was concentrated by vacuum evaporation at low temperature (t = 60 ° C) until a 75% sugar concentration was reached. The fiber fraction was dried.

Additional washing performed by both the frog-rich protein fraction and the fiber fraction was very effective in reducing the amount of readily soluble contaminants from each fraction and therefore increasing the relative content of valuable components.

Composition data indicate that germ and endosperm-rich protein fractions have a different relative content of protein and oil. Protein and oil content from the former were 48.6% and 18.6% respectively and those from the latter were 28.7% and 1.5% respectively. The insoluble phase containing primarily kliperic carp (fi ber) and aleurone proteins had 86.4% fiber and 12.6% protein. The chemical composition of the frog-rich phase - the whey mixture was 31.5% protein, 9.8% oil and 37% lactose. "i" D ... . l); 2 = i7; _ 1'- 7 A further important observation was that spray dried seed-rich fraction containing 18.6% oil was significantly more resistant to oxidation (rancidity) compared to the original wheat bran. The original wheat bran tended to turn rancid after 3 weeks of storage. Despite the fact that no external antioxidants were added to the germ-rich fraction, it only started to get worse after 12 weeks of storage.

EXAMPLE 3 Previous examples illustrate the use of starch hydrolyzing enzymes and wet milling followed by various separation steps to obtain protein, sugar and fiber fractions, the latter still containing substantially high amounts of aleurone proteins. It may be of interest to some applications to separate, at least in part, the aleurone proteins from the bran shell (fiber) and recover such proteins in the same fraction as the endosperm-rich fraction, for example.

An experiment was set up in the same manner as described in Example 2 except that a cocktail of polysaccharidases containing both high cellulase and xylanase activities was added together with the amyloglucosidases and allowed to work for 3 hrs. Temperature and pH conditions were kept unchanged. The resulting reaction mixture was further treated exactly as described in Example 2.

The inclusion of polysaccharidase during the hydrolysis step had a positive effect on the aleurone protein extraction and protein recovery as measured by racial balance and protein content. The protein content of the endosperm-rich fraction increased from 28.7% (without polysaccharidase) to 34.7% (with polysaccharidase) and total protein recovery increased by% when polysaccharidase was added.

EXAMPLE 4 The color of the protein ingredients may be important, especially in certain food and animal feed applications. Dairy products such as caseinates, whey powder, and whey protein concentrate have a light color and soy protein concentrate has a light brown color.

These products are the main ingredients in high quality animal feed such as calf milk substitutes. However, in the same food applications, such as sausages and burgers, 521 5E9¶pzg 8 despite the fact that small amounts are included, color can still play an important role in product acceptance.

The technical suitability of bleaching the frog-rich fraction was carried out by two means. 1. Alkali and hydrogen peroxide bleach only and 2. Alkali fi in peroxidase and hydrogen peroxide bleach. Ten g samples of a sprout fraction were incubated in 1 L beaker containing 100 ml of water.

Samples were dispersed with stirring and about 0.25 ml of NaOH was added until pH 12 was reached.

Solutions were heated to 50 ° C and 3.5, 5 and 10 ml of 30% H 2 O 2 were added to various flasks to provide an uptake level of 10, 15 and 30% H 2 O 2 by weight of the frog-rich action.

Mixtures were stirred for 1 hr and neutralized with acetic acid.

Full bleaching was achieved with 15 and 30% H 2 O 2. Samples treated with 10% H 2 O 2 were only partially bleached. All alkali bleached samples became darker with drying. Ten g samples of a sprout fraction were incubated in 1 L beaker containing 100 ml of water.

Samples were dispersed with stirring and about 0.25 ml of NS 51004 Novozymes peroxidase was added. The solution was heated to 50 ° C and 3.5 ml of 30% H 2 O 2 was added to the flask, i.e. 10% H 2 O 2 on a weight-based seed fraction and the mixture was stirred for 2 hrs.

Peroxidase - hydrogen peroxide bleaching was effective, consumed less chemicals and no darkening of the sample was observed after drying.

EXAMPLE 5 Among the various end uses of the frog-rich fraction, meat products such as burgers, sausages and meatballs can be described. In such end uses, the frog-rich fraction can replace meat, soy aprotein concentrate and isolates, but also milk casein and caseinates, just to name a few. It is therefore important to test the whole effect of the frog-rich fraction with regard to emulsification and binding capacity, taste, etc. f) 1% (L r:.; Ti; -, JJ /; _, 9 An experiment was set up to test the suitability of incorporating various frog-rich fractions extracted from wheat bran to traditional meatball recipes consisting of meat, garlic, premix, and water.

The following spray-dried fractions were tested: - Seedling fraction extracted from short grinding of wheat bran - (I) - Seedling fraction extracted from conventional ground wheat bran- (II) - 1: 1 mixture of whey and II, on dry matter basis (HI) Meatball recipe tested without rich fraction (kåtroll recipe) or with 2.5% inclusion of samples I, II and III. Meatballs were analyzed for weight loss, taste, texture and color after frying.

The results are described in the table below.

Weight loss by Color Texture Tested recipe frying (%) Control (meat, garlic, premix and water) 23.4 Reference Reference Control + 2.5% of I 21.3 Slightly darker Slightly tougher Control1 + 2.5% of H 20.8 Similar Similar Control + 2.5% of III 18.0 Similar Slightly more tender The overall conclusion is that the samples worked well as additives in meatball recipes and were particularly interesting because they all reduced weight loss after frying.

END OF TURNINGS Frog-rich fractions The high protein content of frog-rich fractions makes them ideal substitutes for existing expensive animal and vegetable proteins. In addition, due to the nature of its protein, the presence of high-quality oil and phospholipids, the frog-rich fraction also exhibits interesting functionalities such as emulsification, texture and binding. 521 (_71 One can list, by way of example, the following existing products, which can be replaced by the frog-rich fraction in the food industry.

Animal protein: casein and caseinates, plasma protein and egg whites Vegetable proteins: Soy apricot concentrate and isolate, textured soy, hydrolyzed gluten and potato protein.

In general, the above products can be used as meat substitutes and texturizing ingredients in burgers, sausages, and meatball production to just feed some. Or as a casein substitute in the production of sausages, cold cuts, dressings, etc.

In the animal feed industry, the frog-rich fraction is an ideal ingredient for high-quality feeds such as calf milk substitutes, star feed for calves, piglets and chickens, fish feed and pet food. In such applications, it can essentially replace the use of soy proteins (textured soy, concentrate and isolate), potato protein, hydrolyzed gluten, high quality fishmeal, plasma protein, and dry milk products such as whey protein concentrate, whey and skim milk.

Endosperm-rich fraction The endosperm-rich fraction can be used in the food industry primarily as a gluten substitute but also partly to replace soy aproteins in the production of various meat and vegetable products. In feed applications, it can partially replace gluten, soy and milk proteins as an ingredient in calf milk replacements, piglet starter feeds, and skim feeds.

Fiber fraction The fiber fraction consisting of pericarp and aleurone can be used as an interesting gluten- and phytase-free source to replace conventional cereal bran. The main end uses as food can be in the bakery industry and as breakfast cereals.

A preferred embodiment of a plant for carrying out the invention is shown in the accompanying drawing, in which 1 indicates a suspension and hydrolysis vessel 1 and connected to a wet grinding unit 2 which in its grinding action increases the effective surface of the hydrolyzate. 521 ll The slurry is allowed to pass the wet comb 2, 1-3 times. The slurry is then transferred to a 2-phase decanter 6 via a heat exchanger 3, which decanters separate the bran and liquid (water and protein) phases.

The bran with a dry matter content of about 40% is then further washed once with water in a suspension vessel 4 and allowed to pass a second decanter 6, again. The pure bran obtained has a dry matter content of 95% after being dried in a ring dryer 10. The combined liquid phases, with a dry matter content of 5%, are transferred to a separator 7, via a mixing tank 5, in which separator 7 insoluble protein is separated by . The liquid phase from the separator 7 with a dry matter content of 2% and comprising water and soluble proteins is allowed to pass an ultra-filter 8 with a molecular separation at 50 kD. Depending on different requirements, this separation can vary between 20 and 100 kD. In the ultrafilter 8 a liquid phase is obtained which is evaporated in an evaporator 9 and concentrated to a syrup with a dry matter content of 75%.

The concentrate from the ultrafilter is either isolated as such or added to the fraction with insoluble protein which later has a dry matter content of 9.5%. The protein sugar fraction obtained is spray dried in a spray dryer II to give a concentrated, dried protein sugar fraction and the protein oil fraction is dried in a spray dryer II to give a concentrated dried protein oil fraction.

Claims (1)

A process for wet fractionation of cerealic clay components, characterized in that bran is first subjected to a combination of enzymatic treatment with enzymes of the group starch and phytate hydrolyzing enzymes and wet milling, followed by a possible step of enzyme inactivation by wet heat treatment, and the next step, wherein the insoluble phase containing both pericarp and aleurone fractions is separated by centrifugal forces from the aqueous phase containing germ and remaining endospen components, and that the aqueous phase is further separated by centrifugal force into a frog-rich fraction and an endospheric-rich fraction and that concentrated. A process according to claim 1, wherein cerealikli is the ñber residue resulting from a primary grain milling, i.e. After separation of the endosperm fraction, of wheat, rice, barley, oats, rye, and tritical, and with varying chemical compositions, the presence of anti-nutrient factors and the presence of different anatomical fractions, ie. pericarp, germ and remaining endosperm. A method according to claim 1, wherein the combination of wet milling with enzyranatic treatment is arranged to increase the availability of the substrate and thereby improve the overall hydrolysis effect and subsequent separation of both insoluble and soluble fractions with varying density / solubility. The method of claim 1, wherein the enzymatic treatment is performed using amylases and / or amyloglucosidases, polysaccharidases (cellulases, beta-glucans, xylanases, and pectinases, for example) or by a combination of such enzymes and phytases. Protein fraction obtained substantially from the germ and prepared according to claims 1-4, wherein said fraction contains at least 40% protein and 10% oil on a dry matter basis and shows an increased storage capacity with respect to resistance fi to 10 15 20 25 30 10. ll. 12, Éš i: ') 5 1: j 13 oxidation compared to the original bran and that said fraction contains less than 1% fi ber, and it retains the emulsifying ability of wheat germ. The protein fraction according to claim 5, wherein the surface whey is incorporated into said fraction at levels ranging from 20 to 80% by weight on a dry matter basis and that the final mixture is dried. Protein fraction obtained substantially from the remaining endosperm and prepared according to claims 1-4, wherein said fraction contains at least 35% protein and 10% sugar and less than 2% oil and 1% fi ber. The protein fraction according to claim 7, wherein the surface whey is incorporated into said fraction at levels ranging from 20 to 80% by weight on a dry matter basis and that the final mixture is dried. Fiber fraction prepared according to claims 1-4, wherein said fraction consists of cell wall components of bran (> 85%) and aleurone proteins (> 10%) and substantially free of gluten and starch. The sugar fraction prepared according to claims 1-4, wherein said fraction originates from the remaining endosperm and it contains more than 65% sugars (such as glucose, maltose and malto-trios) on a dry matter basis. Use of a protein fraction as described in claims 5-6, in feed and food applications to replace other protein products from vegetable and animal sources. Use of a protein fraction as described in claims 7-8, in feed and food applications to replace other protein products - from vegetable and animal sources. Use of a fi ber fraction as described in claim 9, in feed and food applications to replace other insoluble fi ber products or as raw material for further processing. Plant for carrying out the process according to claims 1-4, characterized in that it comprises a hydrolysis vessel (1), a wet mill (2), a heat exchanger (3) for enzymatic inactivation, washing tanks (4), a mixing vessel (5), a decanter (6), a separator (79, an ultra filter (S), an evaporator (9) and optionally a dryer (10).