A PROCESS FOR MICROBIAL STABILIZATION AND PROCESSING OF BREWERS SPENT GRAIN, MICROBIOLOGICALLY STABILIZED BREWERS SPENT GRAIN POWDER AND USE THEREOF

Abstract

A process processing fresh brewer's spent grains (BSG), the process comprising the steps of: Producing a mash comprising barley malt; Separating the mash from BSG; Collecting the BSG; Microbiologically stabilizing the collected BSG; drying said BSG; and powdering said dried BSG.

Claims

1-15. (canceled)

16. A process processing fresh brewer's spent grains (BSG), the process comprising the steps of: producing a mash comprising barley malt; separating the mash from BSG; collecting the BSG; microbiologically stabilizing the collected BSG to obtain a MS-BSG slurry; wherein said MS-BSG slurry is separated into a water soluble and water insoluble fraction by filtration or decanting to obtain a liquid phase (permeate) comprising salts, oligosaccharides, water soluble proteinaceous material and water soluble arabinoxylans; and a wet solid phase comprising precipitated proteins and water-insoluble arabinoxylans; drying said fractions; and powdering said fractions to a powder, wherein said powder has an average mean particle size of below 1.4 mm.

17. The process according to claim 16, wherein said powder has an average mean particle size of between 10 micron and 700 micron.

18. The process according to claim 16, wherein said drying and powdering occurs by spray-drying.

19. The process according to claim 16, comprising mixing or blending the dried water soluble and dried water insoluble fraction.

20. The process according to claim 16, the step of microbiologically stabilizing the collected BSG, comprising acidifying the BSG to a pH of 4 or lower, such that the BSG: is acidified prior to reaching mycotoxin levels higher than 3 μg/kg Ochratoxin A (OTA), higher than 750 μg/kg deoxynivalenol (DON), higher than 20 μg/kg nivalenol (NIV), and higher than 75 μg/kg zearalenone (ZEA) and/or having a colony count of not higher not higher than 103 CFU/g MS-BSG total aerobic bacteria and; not higher than 103 CFU/g MS-BSG fungi and; not higher than 103 CFU/g MS-BSG yeast and; not higher than 103 CFU/g MS-BSG mesophilic aerobic bacteria and; not higher than 103 CFU/g MS-BSG total anaerobic bacteria, after one week of storage at 25° C.

21. The process according to claim 20, wherein within a time frame of 8 hours after the separation of the mash from the BSG, acidifying the BSG to a pH of between 3.85-3.95.

22. The process according to claim 20, wherein acidification is achieved by the addition of one or more of the acids of the group comprising: lactic acid, acetic acid, benzoic acid, malic acid, formic acid and ascorbic acid.

23. The process according to claim 22, wherein acidification is achieved by the addition of 0.4% food-grade acetic acid and 0.4% food-grade lactic acid.

24. The process according to claim 16, wherein the BSG are collected by transferring the BSG from a mash separation unit to a collection tank by or through a BSG transfer line, and wherein the acidification of the BSG is done during transfer of the BSG to the collection tank.

25. Microbiologically stable brewers' spent grains (MS-BSG) powder enriched for water-soluble arabinoxylans derived from said BSG, said powder having a colony count of not higher than 103 CFU/g MS-BSG counts of aerobic bacteria, fungi, yeast, mesophilic aerobic and anaerobic bacteria, after one week of storage at 25° C., characterized in that the mean average particle size of said powder is below 1.4 mm.

26. Microbiologically stable brewers' spent grains (MS-BSG) powder enriched for water-insoluble arabinoxylans derived from said BSG, said powder having a colony count of not higher than 103 CFU/g MS-BSG counts of aerobic bacteria, fungi, yeast, mesophilic aerobic and anaerobic bacteria, after one week of storage at 25° C., characterized in that the mean average particle size of said powder is below 1.4 mm.

27. Microbiologically stable brewers' spent grains powder according to claim 25, characterized in that the mean average particle size of said powder is between 10 micron and 700 micron.

28. Microbiologically stable brewers' spent grains powder according to claim 25, having mycotoxin levels not higher than 3 μg/kg Ochratoxin A (OTA), not higher than 750 μg/kg deoxynivalenol (DON), not higher than 20 μg/kg nivalenol (NIV), and not higher than 75 μg/kg zearalenone (ZEA).

29. Microbiologically stable brewers' spent grains powder according to claim 25, obtained by a process comprising the steps of: producing a mash comprising barley malt; separating the mash from BSG; collecting the BSG; microbiologically stabilizing the collected BSG to obtain a MS-BSG slurry; wherein said MS-BSG slurry is separated into a water soluble and water insoluble fraction by filtration or decanting to obtain a liquid phase (permeate) comprising salts, oligosaccharides, water soluble proteinaceous material and water soluble arabinoxylans; and a wet solid phase comprising precipitated proteins and water-insoluble arabinoxylans; drying said fractions; and powdering said fractions to a powder, wherein said powder has an average mean particle size of below 1.4 mm.

30. A bakery product, candy bar or beverage comprising the microbiologically stable brewers' spent grains (MS-BSG) according to claim 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0041] Fresh brewers' spent grain (BSG) with a moisture content of 70% is retrieved from the wort filter or lauter tun. Fresh BSG is preferably processed no later than 8 hrs from release from the filter/lauter tun and are preferably collected by transferring the BSG from a mash separation unit to a collection tank by or through a BSG transfer line, wherein the acidification of the BSG is done during transfer of the BSG to the collection tank. Preferably, BSG is processed ‘in-line’ as it is conveyed from the filter/lauter tun to storage or transport vessels.

[0042] The present invention, amongst others, concerns the process of chemical acidification of BSG by addition of one or a combination of acid compounds to reduce the pH of BSG to a level not higher than 4.1 pH units, more specifically 3.85-3.95 pH units. Specifically, the process makes use of one or a combination of organic acids such as, but not limited to lactic acid, acetic acid, citric acid, benzoic acid, malic acid, formic acid or ascorbic acid to reduce the pH of BSG to a level not higher than 4.1 pH units, more specifically 3.85-3.95 pH units. Even more specifically, the process makes use of 0.4% food-grade acetic and 0.4% food-grade lactic acid to reduce the pH of BSG to a level not higher than 4.1 pH units, more specifically 3.85-3.95 pH units and to obtain a sensorially agreeable product.

[0043] It is the object of this invention to provide microbiologically stable BSG (MS-BSG) powder which is characterized by: [0044] a pH level not higher than 4.1 pH units, more specifically 3.85-3.95 pH units [0045] the same nutritional value as fresh BSG [0046] after one week storage at 25° C., a colony count not higher than 10.sup.3 CFU/g MS-BSG total aerobic bacteria and; not higher than 10.sup.3 CFU/g MS-BSG fungi and; not higher than 10.sup.3 CFU/g MS-BSG yeast and; not higher than 10.sup.3 CFU/g MS-BSG mesophilic aerobic bacteria and; not higher than 10.sup.3 CFU/g MS-BSG total anaerobic bacteria [0047] after one week storage at 25° C., mycotoxin levels not higher than 3 μg/kg Ochratoxin A (OTA), preferably not higher than 1 μg/kg OTA, even more preferably undetectable levels of OTA and; not higher than 750 μg/kg deoxynivalenol (DON), preferably not higher than 20 μg/kg DON, even more preferably undetectable levels of DON and; 20 μg/kg nivalenol (NIV), more preferably undetectable levels of nivalenol and; not higher than 75 μg/kg zearalenone (ZEA), preferably not higher than 30 μg/kg ZEA, and more preferably undetectable levels of ZEA

[0048] In one embodiment of this invention, fresh BSG is mixed with stock solutions of acetic acid and lactic acid, to a final concentration of 0.4% each, in storage vessels no later than 8 hrs after release from filters/lauter tun.

[0049] In the preferred embodiment of this invention, fresh BSG is mixed with stock solutions of acetic and lactic acid, to a final concentration of 0.4% each, ‘in-line’ as it is conveyed from filter/lauter tun to storage. This embodiment represents the most efficient application of the method here described.

[0050] In accordance with the present invention, the stabilized BSG (MS-BSG) is dried and further processed into a powder.

[0051] Different options are available for drying and powdering the MS-BSG. A first option comprises drying the MS-BSG, which is typically a slurry, by conventional drying methods such as freeze drying, lyophilization, heating, press-drying, vacuum evaporation, air drying or combinations of one or more of such techniques.

[0052] After drying, the MS-BSG can be processed into a powder by milling or cutting the dried matter into fine particles, preferably with a average mean particle size of below 1.4 mm, preferably ranging between 10 micron and 700 micron, more preferably between 250 and 650 micron.

[0053] Alternatively, the MS-BSG slurry is first separated into fractions by filtration or decanting to obtain a liquid phase (permeate) comprising salts, oligosaccharides, water soluble proteinaceous material and water soluble arabinoxylans; and a wet solid phase comprising amongst others precipitated proteins and water-insoluble arabinoxylans.

[0054] Both fractions can subsequently be dried independently from one another by conventional drying methods such as freeze drying, lyophilization, heating, press-drying, vacuum evaporation, air drying or combinations of one or more of such techniques. Also spray-drying can be used to dry and powderize the liquid phase in a single processing step. In this last case, further powdering or reduction of the powder particle size can be achieved by milling or mixing.

[0055] The two powderized streams can either be kept separate, ie. one powder originating from the permeate and one powder originating from the retentate or both powders can be blended/mixed together in a preferred ratio.

[0056] As prior to the drying and the powderization, the BSG material was microbiologically stabilized, the powder itself, if handled with due care according to HCCP standards, is microbiologically stable.

[0057] The above described microbiologically stable brewers' spent grain (MS-BSG) powder can be used in the following applications: [0058] Animal feed. MS-BSG powder can be used as feed or feed complement for animals. More specifically, it can be used as feed or feed complement for ruminant cattle, such as dairy cows. [0059] As human food or food ingredient. MS-BSG powder can be used as an ingredient in the manufacture of foods such as breads, cookies, cereal products, baked snacks, extrusion cooked snacks, candy bars or pasta products; and/or in the manufacture of food ingredients such as flours; and/or in the manufacture of dietary supplements such as fiber supplements.

[0060] The brewer's spent grain is preferably obtained from a regular beer production process, wherein malt and potentially some adjuncts such as corn, rice, sorghum, wheat, barley, rye, oat or combinations thereof are mixed with water to form a mash wherein enzymes—either originating from the barley malt or added separately to the mash—are allowed to break down starch into fermentable sugars, typically a mixture of glucose, maltose and maltotriose. At the end of the mashing, the mash is filtered to obtain a fermentable wort that is further processed in to beer. The retentate of the mash filtering is the brewer's spent grain (BSG) that is subsequently stabilized by a method described supra.

REFERENCES

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