Malt produced from dehusked barley grains

Abstract

The invention relates to a malted dehusked barley that contains one or more microbial cell wall degrading enzymes selected from cellulase, arabinoxylanase, beta-glucanase and pectinase. Another aspect of the invention relates to a process of producing malted dehusked cereal grain, said process comprising: a) mechanically removing husk from cereal grains, thereby producing dehusked grains and husk material; b) steeping the dehusked grains with steeping water to produce steeped grains having a water content of at least 30 wt.%; c) germinating the steeped grains at a temperature in the range of 15-25 °C during 12 to 72 hours to produce green malt; and d) drying the green malt to produce malt having a water content of less than 15 wt.%; wherein, during step b) the grains are contacted with steeping water containing one or more cell wall degrading enzymes selected from cellulase, arabinoxylase, beta-glucanase and pectinase.

Description

[0001] MALT PRODUCED FROM DEHUSKED BARLEY GRAINS

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The present invention relates to a malt that has been produced from dehusked barley grain. More particularly, the invention relates to a malted dehusked barley having the following combination of features:

[0004] • a moisture content of less than 15 wt.%;

[0005] • a Klason lignin content (CL) of less than 1.8% by weight of dry matter;

[0006] • an ash content (CA) of less than 2.2 % by weight of dry matter; wherein CL*CA 3.6; and wherein the malted dehusked barley contains one or more microbial enzymes selected from cellulase, arabinoxylanase, beta-glucanase and pectinase.

[0007] The invention also provides a process of producing malted dehusked cereal grain, said process comprising: a) mechanically removing husk from cereal grains, thereby producing dehusked grains and husk material; b) steeping the dehusked grains with steeping water to produce steeped grains having a water content of at least 30 wt.%; c) germinating the steeped grains at a temperature in the range of 15-25 °C during 12 to 72 hours to produce green malt; and d) drying the green malt to produce malt having a water content of less than 15 wt.%; wherein, during step b) the grains are contacted with steeping water containing one or more cell wall degrading enzymes selected from cellulase, arabinoxylase, beta-glucanase and pectinase.

[0008] BACKGROUND OF THE INVENTION

[0009] Malt is germinated cereal grain that has been produced in a process known as "malting".

[0010] Malting is a process of steeping, germinating, drying and deculming grain to convert it into malt. The main purpose of the malting process is to develop the endogenous enzymes a- amylase and p-amylase. These enzymes catalyse the conversion of starch into fermentable sugars when malt is used to produce a wort, i.e. the liquid extracted from the mashing process during the brewing of beer or whisky. Various grains are used for malting; the most common are barley, sorghum, wheat and rye. The malted grains obtained by malting barley or rye still contain the outer husk.

[0011] Steeping is the start of the malting process and comprises the addition of steep water to cover the grain to increase the moisture content of the grain to between 40 and 45%. In a modern pneumatic malt house, the grain is alternatively submerged (wet stand) and then drained (an air rest) for one, two or three cycles to achieve the target grain moisture content and the desired chit count. The chit is the first sign of the emerging rootlets. At the end of steeping the grain is cast-out to germination.

[0012] The aim of germination is to sprout the grains. During sprouting, malt enzymes are activated and these enzymes start modifying the structure of the barley endosperm by breaking down the cell walls and the protein matrix. Germination produces a large amount of heat. The grain bed is maintained at a constant temperature of between 10 and 16 °C by the constant supply of fresh humidified air and turners move through the grain bed to keep it loose to allow for sufficient air-flow. Germination typically takes 4-6 days and results in what is called “green malt”.

[0013] Kilning reduces the grain moisture content of the green malt and stops the germination process. In the first stage, the free drying stage, the air temperature is kept cool to dry the grain without causing the enzymes to denature. As the grain dries it is possible to raise the air temperature (the second stage or the forced drying stage) to further dry the grain without inactivating the amylase enzymes. The target malt moisture after kilning is around 5% by weight. During the last few hours of kilning the air temperature is raised to above 80 °C (the curing stage) to break S-methyl methionine down to dimethyl sulphide to reduce the dimethyl sulphide potential of the malt. Dimethyl sulphide is an off flavour that tastes like cooked vegetable and / or cabbage in the final beer.

[0014] Deculming is the term used for the removal of rootlets of the malt. Deculming is normally carried out shortly after transfer from the kiln.

[0015] “Chit malt” is a special type of malt that differs from ordinary malt in that it is obtained by a process that employs a shortened germination period of typically 1-2 days. In comparison to ordinary malt, the alpha-amylase activity of chit malt is considerably lower.

[0016] In brewing and distilling, mashing is the start of the brewing process, where crushed grains, including malt, are mixed with water to form a porridge-like mixture called the “mash”, followed by heating of the mash. Mashing allows the enzymes in the malt (primarily, a- amylase and p-amylase) to break down the starch in the grain into fermentable sugars, creating the sweet liquid called “wort”.

[0017] US 3,896,001 describes a process for the production of malt comprising removing at least a part of the husk of the barley in such manner as to perforate the pericarp and testa to render the aleurone layer of the barley accessible to externally applied gibberellic acid, steeping the barley in an aqueous medium, resting the steeped barley in air, resteeping the barley in an aqueous medium, treating the barley with an aqueous mineral acid during or at the end of the resteeping step, applying at least 0.1 p.p.m. gibberellic acid, based on the barley weight to said barley at or before completion of the resteeping operation, allowing the resteeped barley to germinate for a period of 35-45 hours and then terminating germination before visible growth of micro-organisms has taken place.

[0018] DE-A 2 146 102 describes a malting process in which active agents in the form of gibberellic acid and / or enzymes are added during steeping and / or germination. Example 1 describes a malting process in which barley grains are steeped to a moisture content of 26%, perforated in a crusher mill, and further steeped to a moisture content of 44% using soaking water that contains active agents. The steeped grains are germinated during 48 hours, at which stage enzymes are sprayed onto the grains, followed by an additional 24 hours of germination. The green malt so obtained is crushed in a crush mill before being kilned.

[0019] US 4,004,034 describes a process for the manufacture of a wort which comprises subjecting barley to at least one treatment cycle comprising a steeping in water followed by exposure to air, the conditions of temperature and the duration of the stages of this cycle being chosen to cause chitting of the barley to form chit malt and to promote the development of a maximum enzymatic potential, rolling the chit malt, drying the rolled chit malt to stop the development of the biological processes occurring in it while retaining its enzymatic potential, grinding the dried and rolled chit malt and extracting it with a mixture of hot water and malt, the quantity of malt being 10 to 40% by weight on a solids basis of the dry weight of the mixture of ground chit and malt, and separating the wort so produced.

[0020] GB 1 403 391 A describes a process for the manufacture of a wort which comprises subjecting barley to at least one treatment cycle comprising a thorough wetting in water followed by exposure to air to form chit malt and to promote the development of a maximum enzymatic potential, rolling the chit malt, grinding the rolled chit malt, extracting it with a mixture of hot water and malt, the proportion of malt being 10 to 40% by weight on a solids basis of the dry weight of the mixture of ground chit malt and malt, and separating the wort so produced.

[0021] Jamar et al. (Cell wall polysaccharides hydrolysis of malting barley (Hordeum vulgare L): a review, Biotechnol. Agron. Soc. Environ. 2011 15(2), 301-313) mentions that malting uses internal changes of the seed occurring during germination, such as enzymes synthesis, to obtain a good hydrolysis process and the components required. The authors observe that among the three main hydrolytic events observed, that are namely starch degradation, cell wall breakdown and protein hydrolysis, an efficient cell wall polysaccharides hydrolysis is an essential condition for a final product of quality.

[0022] Van Donkelaar et al. (Brewing with fractionated barley, thesis - Wageningen University, the Netherlands - 2016) describes the removal of husk from barley by pearling and the use of pearled unmalted barley in brewing.

[0023] To reduce the total carbon footprint of malt production it is desirable to increase the productivity of malt houses and to improve the efficiency of transport and storage. It is further desirable to improve efficiency of mashing operations by providing a malt that generates a high extract yield after short mashing.

[0024] SUMMARY OF THE INVENTION

[0025] The inventors have developed a novel type of malt that delivers the aforementioned benefits.

[0026] The malt of the present invention can be produced by a malting process that comprises the following steps:

[0027] (i) at least partial dehusking barley grains prior to malting,

[0028] (ii) contacting the dehusked barley grains with cell wall degrading enzymes during steeping, and

[0029] (iii) germinating the steeped barley grains during a period of not more than 72 hours.

[0030] Due to the removal of husk prior to malting, steeping time can be shortened and / or the total amount of water that is absorbed by the grains can be reduced. The amount of energy needed to remove water during kilning can also be reduced considerably by husk removal. Furthermore, thanks to the removal of husk, the extract content of the malted dehusked barley is increased. The removal of husk prior to steeping also renders the endosperm of the barley more accessible to the cell wall degrading enzymes that are added during steeping. Although the inventors do not wish to be bound by theory, it is believed that during steeping cell wall degrading enzymes break down the cell walls of the endosperm tissue, thereby facilitating the conversion of insoluble protein into soluble protein, and the enzymatic hydrolysis of starch, beta-glucans and arabinoxylans during malting and subsequent mashing.

[0031] The special properties of the malted dehusked barley of the present invention enable significant efficiency and quality gains to be realized in mashing and / or brewing operations.

[0032] The malted dehusked barley of the present invention is characterized by a low husk content and the presence of added (microbial) cell wall degrading enzymes. The low husk content of the malted dehusked barley is evident from the low lignin content and the low ash content of the dehusked malt.

[0033] Accordingly, a first aspect of the invention relates to a malted dehusked barley having the following combination of features:

[0034] • a moisture content of less than 15 wt.%, as determined by EBC method 4.2 (Moisture Content of Malt);

[0035] • a Klason lignin content (CL) of less than 1.8% by weight of dry matter, as determined by the standard method TAPPI T 222 om-02;

[0036] • an ash content (CA) of less than 2.2 % by weight of dry matter; wherein CL*CA 3.6; and wherein the malted dehusked barley contains one or more microbial cell wall degrading enzymes selected from cellulase, arabinoxylanase, beta-glucanase and pectinase.

[0037] Another aspect of the invention relates to a process of producing malted dehusked cereal grain, said process comprising: a) mechanically removing husk from cereal grains, thereby producing dehusked grains and husk material; b) steeping the dehusked grains with steeping water to produce steeped grains having a water content of at least 30 wt.%; c) germinating the steeped grains at a temperature in the range of 15-25 °C during 12 to 72 hours to produce green malt; and d) drying the green malt to produce malt having a water content of less than 15 wt.% ; wherein, during step b) the grains are contacted with steeping water containing one or more cell wall degrading enzymes selected from cellulase, arabinoxylase, beta-glucanase and pectinase.

[0038] The process or producing the malted dehusked cereal grain of the present invention requires considerably less time and energy than the production of ordinary malt as the germination period is reduced from a period ranging from 5 to 6 days to a period of only 12 hours to 3 days. Furthermore, since a substantial part of the husk has been removed from the malt of the present invention, substantially less transportation volume and storage volume is needed. Finally, the present process yields a malt that enables the production of wort that, in comparison to a wort made from ordinary malt, has an increased fermentable sugar content, an increased soluble protein content and a reduced beta-glucan content.

[0039] According to a particularly preferred embodiment, the malted dehusked barley of the present invention has not been mechanically perforated during steeping.

[0040] DETAILED DESCRIPTION OF THE INVENTION

[0041] The present invention provides a malted dehusked barley having the following combination of features:

[0042] • a moisture content of less than 15 wt.%, as determined by EBC method 4.2 (Moisture Content of Malt);

[0043] • a Klason lignin content (CL) of less than 1.8% by weight of dry matter, as determined by the standard method TAPPI T 222 om-02;

[0044] • an ash content (CA) of less than 2.2 % by weight of dry matter; wherein CL*CA 3.6; and wherein the malted dehusked barley contains one or more microbial cell wall degrading enzymes selected from cellulase, arabinoxylanase, beta-glucanase and pectinase.

[0045] The term “barley” as used herein refers to husk-carrying grains from the species Hordeum vulgare. Husk-free or "naked" barley (Hordeum vulgare L. var. nudum) is not encompassed by the term “barley” as used herein.

[0046] The term “malt” as used herein refers to a germinated barley grains that have been dried. The term “husk” as used herein refers to the outer layer of barley grains that surrounds the pericarp layer.

[0047] The term “dehusking” as used herein refers to the application of abrasion and / or friction to remove husk from barley grains. Dehusking can be done, for instance, by using a dehusker / dehuller in which the grains are passed between rotating rollers, or by using pearling equipment which typically employs grinding stones to peel the husk from the grain.

[0048] The term “dehusked barley” as used herein refers to barley grains from which at least a part of the original husk was mechanically removed.

[0049] The term “malted dehusked barley” refers to dehusked barley that has been malted to produce a malt.

[0050] The term “microbial enzyme” as used herein refers to an enzyme that has been produced by a micro-organism (e.g. bacteria, fungi or yeast). The enzymes naturally present in barley are not microbial enzymes.

[0051] The “aleurone layer” as referred to herein refers to layer of living endosperm cells that encloses the outer surface of the starchy endosperms of grain.

[0052] The term “steeping” as used herein refers to a procedure in which grains are covered with steep water to increase the moisture content of the grain (‘wet stand’). The wet stands may be interrupted by so called ‘dry stands’, during which the water is drained out and fresh air may be supplied to remove excess carbon dioxide.

[0053] The term “germinating” as used herein refers to the procedure in which a bed of steeped grains is allowed to germinate under humid conditions.

[0054] The term “beer” as used herein refers to a yeast fermented malt beverage that has optionally been hopped. Beer is commonly produced by a process that comprises the following basic steps:

[0055] • mashing a mixture comprising malted grains, preferably malted barley, optionally supplementary grains and water to produce a mash;

[0056] • separating the mash in wort and spent grains;

[0057] • boiling the wort to produce a boiled wort;

[0058] • fermenting the boiled wort with live yeast to produce a fermented wort; • subjecting the fermented wort to one or more further process steps (e.g. maturation and filtration) to produce beer; and

[0059] • packaging the beer in a sealed container, e.g. a bottle, can or keg.

[0060] Hop or hop extract is usually added during wort boiling to produce hopped beer. Depending on the beer style and brewing facility, the employed hopping method and timing may vary.

[0061] Ordinary malt comprises a core that is composed of starchy endosperm (distal end) and germinated embryo (proximal end). The outside of the starchy endosperm that is not adjacent the scutellum that separates the starch endosperm from the germinated embryo is covered (going from the inside to the outside) by an aleurone layer, testa, pericarp and husk.

[0062] According to a particularly preferred embodiment, the malted dehusked barley of the present invention has not been mechanically perforated during steeping. Even more preferably, the malted dehusked barley has not been mechanically perforated. Most preferably the malted dehusked barley has not been perforated.

[0063] Perforation of cereal grains during steeping inherently causes fracturing of the grains (see DE-A 2 146 102, page 5, last paragraph). The malted dehusked barley of the present invention preferably contains less than 2 wt.%, more preferably less than 1.8 wt.%, even more preferably less than 1.5 wt.% and most preferably less than 1.0 wt.% of broken barley kernels.

[0064] The malted dehusked barley according to the present invention preferably has been dried to a moisture content of less than 12 wt.%, more preferably to a moisture content of 1 to 11 wt.%, even more preferably to a moisture content of 2 to 10 wt.%, most preferably to a moisture content of 3 to 9 wt.%, as determined by EBC 4.2.

[0065] According to a particularly preferred embodiment, the Klason lignin content (CL) of the malted dehusked barley is less than 1.5% by weight of dry matter, more preferably less 1.2% by weight of dry matter, even more preferably less than 1.1% by weight of dry matter and most preferably less than 1.0% by weight of dry matter.

[0066] The ash content (CA) of the malted dehusked barley preferably is less than 2.1% by weight of dry matter, more preferably less 2.0% by weight of dry matter, even more preferably less than 1.9% by weight of dry matter and most preferably less than 1.8% by weight of dry matter. Preferably, the lignin and ash content of the malted dehusked barley are such that CL*CA 3.0, more preferably such that CL*CA 2.4, even more preferably such that CL*CA 2.0 and most preferably such that CL*CA 1.8.

[0067] Complete removal of the husk is economically unattractive as it is inevitably accompanied by loss of starch. Consequently, the malted dehusked barley advantageously contains some husk. Accordingly, in a preferred embodiment CL*CA S 0.2, more preferably CL*CA S 0.4, even more preferably CL*CA S 0.6 and most preferably CL*CA S 0.8.

[0068] Since husk contains virtually no starch, removal of husk from the barley grains inherently results in an increase of extract content. Consequently, in a preferred embodiment, the malted dehusked barley of the present invention has an extract content (CE) of at least 79% by weight of dry matter, as determined by EBC method 6.3 (Extract Content of Solid Adjuncts; ASBC Method). More preferably, the extract content of the malted dehusked barley is at least 80% by weight of dry matter, even more preferably 81-88% by weight of dry matter and most preferably 82-86% by weight of dry matter.

[0069] According to a preferred embodiment, the ratio CE / (CL*CA) is in the range of 25 to 160. In accordance with a particularly preferred embodiment, the ratio CE / (CL*CA) is in the range of 28 to 150, even more preferably in the range of 32 to 120 and most preferably in the range of 35 to 100.

[0070] The malted dehusked barley preferably has an alpha-amylase activity of 1-100 Dextrinizing Units (DU) per gram of dry matter, as determined by EBC method 4.13. More preferably, the alpha-amylase activity is in the range of 1-50, more preferably in the range of 2-35, even more preferably in the range of 3-32, and most preferably in the range of 4-30 Dextrinizing Units (DU) per gram of dry matter as determined by EBC method 4.13.

[0071] The malted dehusked barley preferably has a Free Amino Nitrogen (FAN) content of at least 100 mg / L, more preferably of 110 to 200 mg / L, most preferably of 120 to 170 mg / L, as determined by EBC method 4.10.

[0072] The malted dehusked barley preferably has a beta-amylase activity of at least 1 unit per gram of dry matter, more preferably of 2-20 units per gram of dry matter, most preferably 3- 10 units per gram of dry matter, as determined using Megazyme B-amylase assay kit (Betamyl-3). The one or more microbial cell wall degrading enzymes that are contained in the malted dehusked barley of the present invention may have been inactivated during the kilning step. The presence of such inactive enzymes can be determined by LC-MS / MS or Maldi-TOF-MS.

[0073] According to a particularly preferred embodiment, the malted dehusked barley contains one or more cell wall degrading enzymes selected from arabinoxylanase and beta-glucanase. Most preferably, the one or more microbial enzymes comprise beta-glucanase.

[0074] The malted dehusked barley of the present invention preferably has a reduced beta-glucan content, resulting from hydrolysis of this polysaccharide. Reduction of beta-glucan content is advantageous as it results in a less viscous and therefore more filterable mash. Preferably, the malted dehusked barley has a beta-glucan content of less than 800 mg per liter congress mash, more preferably of 100 to 550 mg per liter congress mash, and most preferably of 150 to 500 mg per liter congress mash. The beta-glucan content of the malted dehusked barley can be determined according to EBC 8.13.2.

[0075] The colour of malt can be determined spectrophotometrically according to EBC 4.7.2 (Colour of Malt: Visual Method. Preferably the colour of the malted dehusked barley is 1-10 EBC, more preferably 1.5-8 EBC, most preferably 2-4 EBC.

[0076] Preferably, the malted dehusked barley has a S-methyl methionine content, expressed as dimethyl sulphide equivalent of less than 100 pg per g of dry matter, more preferably 0.01-10 pg per gram of dry matter, most preferably 0.05-1 pg per gram of dry matter. The S-methyl methionine content can suitably be determined by LC-MS / MS.

[0077] Preferably, the malted dehusked barley has a dimethyl sulphide content of less than 10 pg per gram of dry matter, more preferably less than 6 pg per gram of dry matter, most preferably less than 0.2 pg per gram of dry matter, as determined by GC-MS / MS.

[0078] According to a particularly preferred embodiment, the malted dehusked barley of the present invention has been ground. Grinding of the malt offers the advantage that in the brewing house the malt can be introduced directly into the mash. Furthermore, grinding of the malted dehusked barley can be used to increase the bulk density of the malt, thereby reducing the volume needed for transportation and storage. Unlike ordinary malt, the malted dehusked barley of the present invention can be ground without generating a lot of dust. Preferably the bulk load density (freely settled) of the ground malt according to the invention is of at least 54-kg / hl , more preferably at least 58 kg / hl, most preferably 60-67 kg / hl. The bulk load density of the ground malt can suitably be determined by means of a chondrometer.

[0079] Preferably the particle size distribution of the ground malt, as determined using a set of sieves, is as follows:

[0080] • less than 20 wt.% > 1.0 mm

[0081] • not more than 15 wt.% < 0.15 mm

[0082] More preferably the particle size distribution of the ground malt is as follows:

[0083] • less than 15 wt.% > 1.0 mm

[0084] • not more than 10 wt.% < 0.15 mm

[0085] Most preferably the particle size distribution of the ground malt is as follows:

[0086] • less than 10 wt.% > 1.0 mm

[0087] • not more than 5 wt.% < 0.15 mm

[0088] Milling of the malted dehusked barley also offers the advantages that the variation in particle size may be minimized, especially if fines are removed after milling. Accordingly, in a preferred embodiment, the ground malt contains less than 2 wt.%, more preferably less than 1 wt.% of fines having a particle size of not more than 0.15 mm.

[0089] According to a particularly preferred embodiment, the ground malted dehusked barley is packaged for transportation in a bag or a container. Typically, the bag or container holds at least 50 kg of the ground malted dehusked barley.

[0090] Another aspect of the invention relates a process of producing malted dehusked cereal grain, said process comprising: a) mechanically removing husk from cereal grains, thereby producing dehusked grains and husk material; b) steeping the dehusked grains with steeping water to produce steeped grains having a water content of at least 30 wt.%; c) germinating the steeped grains at a temperature in the range of 15-25 °C during 12 to 72 hours to produce green malt; and d) drying the green malt to produce malt having a water content of less than 15 wt.%; wherein, during step b) the grains are contacted with steeping water containing one or more cell wall degrading enzymes selected from cellulase, arabinoxylase, beta-glucanase and pectinase.

[0091] The cereal grains employed in the present process are preferably selected from barley, rye and combinations thereof. Most preferably, the cereal grain employed is barley.

[0092] Preferably, the present process is an industrial process wherein at least 10 tons, more preferably at least 30 tons, even more preferably at least 50 tons, most preferably at least 70 tons of malted dehusked cereal grain are prepared within 1 week.

[0093] According to a particularly preferred embodiment of the present process, the cereal grains are not completely dehusked prior to malting. Complete dehusking may damage the aleurone layer of the cereal grains, causing the cereal grains to lose the ability to germinate.

[0094] During the dehusking step, the cereal grain preferably undergoes a weight reduction of 2- 18%, more preferably of 3-14%, most preferably of 4-10%.

[0095] The cereal grain that is dehusked in the present process preferably has a moisture content of not more than 15 wt.%, more preferably of not more than 12 wt.% and most preferably of 2- 10 wt.%, as determined by EBC method 4.2.

[0096] The cereal grain that is dehusked in the present process preferably has an extract content of not more than 81% by weight of dry matter, more preferably of not more than 80% by weight of dry matter and most preferably of 72-79% by weight of dry matter, as determined by EBC method 6.3.

[0097] The dehusking step preferably increases the extract content of the cereal grain by at least 1%, more preferably by at least 1.5% and most preferably by 2 to 10% (extract content being determined by EBC method 6.3). Here the percentage increase is calculated as: 100% X ([ECafter] ' [ECbefore]) I [ECbefore] wherein

[0098] [ECbefore] represents the extract content after dehusking;

[0099] [ECafter] represents the extract content before dehusking.

[0100] The lignin content of the cereal grain that is provided in the present process preferably is in the range of 1.5-4.0% by weight of dry matter, more preferably in the range of 1.6-3.5% by weight of dry matter and most preferably in the range of 1.7-3.0% by weight of dry matter, as determined by the standard method TAPPI T 222 om-02.

[0101] In the dehusking step, preferably at least 25 wt.%, more preferably at least 35 wt.% and most preferably at least 40 wt.% of the lignin is removed (lignin content being determined by the standard method TAPPI T 222 om-02).

[0102] As it is practically impossible to remove all lignin without also removing starch and thereby reducing extract content of the cereal grain grains, it is preferred not to remove all lignin present in the cereal grain. Preferably, not more than 90 wt.%, even more preferably not more than 80 wt.% of the lignin is removed by dehusking in the present process.

[0103] The ash content of the cereal grain that is dehusked in the present process preferably is more than 1.6% by weight of dry matter, more preferably more than 1.8% by weight of dry matter and most preferably in the range of 1.9-3.0% by weight of dry matter.

[0104] Dehusking of the cereal grain is preferably achieved by passing the cereal grain through a dehusking machine comprising one or more rotatable abrasive rollers. Preferably, the dehusking machine comprises two or more rotatable abrasive rollers that apply friction to grains that pass through the gap between these rollers by rotating at different speeds.

[0105] Typically, the present process employs a steeping period of 3 to 30 hours, more preferably 4 to 26 hours, most preferably 5 to 25 hours.

[0106] The temperature of the steeping water employed in the present process preferably is in the range of 10 to 35°C, more preferably in the range of 15 to 30 °C and most preferably in the range of 18 to 25 °C.

[0107] The steeped grains obtained at the end of step b) preferably have a water content of 31 wt.% to 46 wt.%, more preferably of 32 wt.% to 44 wt.%, most preferably of 33 wt.% to 42 wt.%. According to a particularly preferred embodiment, during step b) the grains are contacted with the steeping water containing one or more cell wall degrading enzymes for at least 30 minutes, more preferably for 1 to 24 hours, even more preferably for 2 to 18 hours and most preferably for 4 to 15 hours. The one or more cell wall degrading enzymes that are employed in the present process are preferably selected from arabinoxylanase, beta-glucanase and combinations thereof. Most preferably, the one or more cell wall degrading enzymes comprise beta-glucanase.

[0108] The one or more cell wall degrading enzymes that are employed in the present process preferably are microbial enzymes.

[0109] According to a particularly preferred embodiment of the present process, the steeping of the dehusked grains with steeping water comprises contacting dehusked grains having a water content of less than 25 wt.%, more preferably of less than 20 wt.% and most preferably of less than 18 wt.% with steeping water containing the one or more cell wall degrading enzymes. Although the inventors do not wish to be bound by theory, it is believed that the steeping water containing the one or more enzymes is absorbed into the dehusked grains, allowing the absorbed enzymes to exert their activity inside the endosperm.

[0110] The inventors have found that the present method is particularly effective in yielding a malt having an increased soluble protein and an increased fermentable sugar content if during step b) the grains are contacted with steeping water that contains gibberellic acid. This may be achieved by successively contacting the grains with steeping water containing one or more cell degrading enzymes and steeping water containing gibberellic acid (in any order). Alternatively, the grains may be contacted with steeping water containing one or more cell wall degrading enzymes as well as gibberellic acid. In a preferred embodiment, the steeping water containing one or more cell wall degrading enzymes also contains gibberellic acid.

[0111] Gibberellic acid is dosed to the steeping water, the dosage expressed in ppm, i.e. grammes per ton of dry barley steeped) preferably 0.01 to 3 ppm, more preferably 0.01 to 1.5 ppm and most preferably 0.01 to 0.3 ppm of gibberellic acid.

[0112] The germination period employed in the present process preferably is in the range of 15 hours to 60 hours, more preferably of 18 hours to 48 hours, most preferably of 20 to 40 hours.

[0113] Typically, during germination at least 85%, more preferably at least 90% and most preferably at least 93% of the cereal grains develop a visible chit.

[0114] During germination of the dehusked cereal grains, the temperature is preferably maintained at 15 to 25°C, more preferably at 16 to 22°C. The moisture content of the dehusked cereal grains is preferably maintained at 30-40 wt.%, more preferably at 31-38 wt.% and most preferably 32-36 wt.% during the germination.

[0115] According to a preferred embodiment, the present process does not comprise perforation of the cereal grains during steeping by means of roller milling. More preferably, the process does not comprise mechanical perforation of the cereal grains during steeping. Even more preferably, the process does not comprise machinal perforation of the cereal grains prior to steeping, during steeping, between steeping and germination or during germination.

[0116] Most preferably, the process does not comprise mechanical perforation of the cereal grains.

[0117] In the present process less than 2 wt.%, more preferably less than 1.5 wt.% and most preferably less than 1 wt.% of the cereal grains are broken during steps a) to c).

[0118] The present process can be carried out as a continuous process or a batch process. Advantageously, at least the germination step is carried out in a continuous manner. Accordingly, in a preferred embodiment, the germination of the steeped grains comprises transporting a stream of the steeped grains through a germination stage to produce a continuous stream of green malt, said germination stage comprising (i) maintaining the grains at a temperature in the range of 10 to 30°C for 12 to 72 hours and (ii) maintaining the water content of the grains at a minimum of 20 wt.%.

[0119] According to a particularly preferred embodiment, each of steps b), c) and d) is carried out in a continuous fashion.

[0120] According to a particularly preferred embodiment, the grains are agitated during at least a part of the germination step c). Agitation may be achieved by, for instance, raking, stirring, vibration, dropping (e.g. dropping onto a moving belt) and / or gas flow.

[0121] In the present process the green malt is preferably dried by contacting the green malt with a stream of hot air having a temperature. According to a particularly preferred embodiment, the stream of hot air that is used to dry the green malt reaches a maximum temperature of at least 55°C, more preferably a maximum temperature in the range of 60-90 °C during the drying. Here the temperature of the hot air refers to the temperature of the hot air immediately before it comes into contact with the green malt. The drying time preferably is in the range of 2-12 hours, more preferably in the range of 2.3- 10 hours and most preferably in the range of 2.5-6 hours.

[0122] A further aspect of the invention relates to a method of producing a malt beverage, said method comprising:

[0123] • providing a mixture comprising malt and water, wherein at least 1 wt.% of the malt is a malted dehusked barley according to the present invention;

[0124] • mashing the mixture to convert starch into fermentable sugars and to produce a mash containing fermentable sugars; and

[0125] • subjecting the mash containing fermentable sugars to a solid-liquid separation to separate wort from insoluble matter.

[0126] Preferably at least 50 wt.%, more preferably at least 75 wt.%, most preferably 100 wt.% of the malt in the mixture comprising malt and water is barley malt.

[0127] Preferably at least 5 wt.%, more preferably at least 10 wt.%, even more preferably at least 20 wt.% and most preferably at least 30 wt.% of the malt in the mixture comprising malt and water is the malted dehusked barley according to the present invention.

[0128] Typically, not more than 80 wt%, more preferably not more than 70 wt.% and most preferably not more than 60 wt.% of the malt in the mixture comprising malt and water is the malted dehusked barley of the present invention.

[0129] According to a preferred embodiment the mashing is an infusion mashing. Infusion mashing is more energy- and time-efficient in comparison to other mashing methods such as decoction mashing.

[0130] The mixture comprising malt and water preferably does not comprise adjuncts.

[0131] In a particularly preferred embodiment, the solid-liquid separation of the mash comprises filtering of the mash through a filter bed that comprises at least 80 wt.%, more preferably at least 90 wt.% and most preferably 100 wt.% of insoluble material originating from the malt.

[0132] Examples of devices that may be used for such filtration include a lautertun, a mash filter and a mash / lauter vessel. In a preferred embodiment, the present method yields a wort that is 100% malt based.

[0133] According to a particularly preferred embodiment, the wort is further processed to produce a malt beverage in the form of beer or whiskey, said further processing comprising the step of subjecting the wort to a yeast fermentation. Preferably the fermentation is a bottom fermentation.

[0134] The invention is further illustrated by the following non-limiting examples.

[0135] EXAMPLES

[0136] Example 1

[0137] Different malts were prepared as described below.

[0138] Barley (2 rowed spring barley, origin France) was dehusked in batches of 100g in a Satake Test Mill (TM05C(2)-T) for 12 seconds (dehusked barley A) or 25 seconds (dehusked barley B). The total amount of material removed during dehusking was 2 wt.% and 5 wt.%, respectively.

[0139] The original barley and the dehusked barleys A and B (1200 grams each) were steeped with water and water containing 0.5 g / L added cell wall degrading enzyme (Laminex® MaxFIow 4G, ex IFF) in accordance with the following procedure:

[0140] • The different types of barley were put in separate containers and put in a steeping tank. Next, 25 g of the enzyme preparation was introduced into the steeping tank, after which the tank was filled with 50 L of water.

[0141] • The barleys were left to steep for 10 hours at 18 °C

[0142] • Then the water was drained and the barleys were left under air for 2 hours.

[0143] Laminex® MaxFIow 4G contains beta-glucanase and arabinoxylanase.

[0144] The moisture content of the steeped grains was determined. The results of the analyses are shown in Table 1.

[0145] Table 1

[0146] The steeped barleys were germinated for 24 hours at 16 °C and the green malt so obtained was dried in accordance with the following procedure:

[0147] 30°C, 5 minutes

[0148] Heating to 55°C in 30 minutes

[0149] 55°C, 5.5 hours

[0150] Heating to 60°C in 30 minutes

[0151] 60°C, 8.5 hours

[0152] Heating to 76°C in 1 hour

[0153] 76°C, 1 hour

[0154] Heating to 80°C in 30 minutes

[0155] 80°C, 2,5 hours

[0156] Cooling to 30°C in 1 hour

[0157] 30°C, 1 hour

[0158] Moisture content after steeping, percentage of chitted barley and moisture content after germination were determined. The results are shown in Table 2.

[0159] Table 2

[0160] The dried malts were also analysed. The results of the analyses are shown in Tables 3a, 3b and 3c.

[0161] Some of the analyses were performed on a wort that had been prepared from the relevant malt:

[0162] • The analyses of Table 3a were performed on wort that had been produced in accordance with method EBC 6.3. • For the analyses of Table 3c a wort was prepared as follows: o 100 g malt was milled using a Buhler Disc Mill set to a gap of 0.2 mm o The malt was put in mash beakers o The malt was mashed in with 300 mL of water at 60 °C o The mashing was performed in a regular lab mashing bath o The mash was continually stirred with 100 rpm o The mash was kept at 60 °C for 10 minutes o The mash was heated to 65°C in 5 minutes o The mash was kept at 65°C for 30 minutes o The mash was heated to 78°C in 13 minutes o The mash was kept at 78 °C for 10 minutes. o The mash was filtered over a pleated paper filter in a funnel o The spent grains retained on the filter were extracted with an additional 50 mL of water.

[0163] Table 3a

[0164] Table 3b

[0165] Table 3c

[0166] The FAN concentrations mentioned in Tab e 3c are higher than the FAN concentrations that would have been determined by EBC 4.10 due to the fact that the wort used for the FAN analysis was more concentrated than the wort of EBC 4.10.

[0167] Example 2

[0168] In the experiment that is described in Example 1, also malt samples were prepared by steeping the original barley and the dehusked barleys A and B with water containing added cell wall degrading enzyme (Laminex ® MaxFIow 4G, ex IFF) as well as gibberellic acid (0.125 mg / L). Table 1 shows the different samples that were prepared.

[0169] Table 4

[0170] The dried malts were analysed. The results of the analyses are shown in Tables 5a and 5b.

[0171] The analyses shown in Table 5b were performed on a wort that had been prepared as follows:

[0172] • For the analyses in Table 5b a separate wort was prepared: o 100 g malt was milled using a Buhler Disc Mill set to a gap of 0.2 mm o The malt was put in mash beakers o The malt was mashed in with 300 mL of water at 60 °C o The mashing was performed in a regular lab mashing bath o The mash was continually stirred with 100 rpm o The mash was kept at 60 °C for 10 minutes o The mash was heated to 65°C in 5 minutes o The mash was kept at 65°C for 30 minutes o The mash was heated to 78°C in 13 minutes o The mash was kept at 78 °C for 10 minutes. o The mash was filtered over a pleated paper filter in a funnel. o The spent grains retained on the filter were extracted with an additional 50 mL of water. Table 5a

[0173] Table 5b

Claims

CLAIMS1. Malted dehusked barley that has not been mechanically perforated during steeping, said malted dehusked barley having the following combination of features:• a moisture content of less than 15 wt.%, as determined by EBC method 4.2 (Moisture Content of Malt);• a Klason lignin content (CL) of less than 1.8% by weight of dry matter, as determined by the standard method TAPPI T 222 om-02;• an ash content (CA) of less than 2.2 % by weight of dry matter; wherein CL*CA 3.6; and wherein the malted dehusked barley contains one or more microbial cell wall degrading enzymes selected from cellulase, arabinoxylanase, beta-glucanase and pectinase.

2. Malted dehusked barley according to claim 1, wherein the malt has an extract content (CE) of at least 79% by weight of dry matter, as determined by EBC method 6.3 (Extract Content of Solid Adjuncts; De Clerck Method).

3. Malted dehusked barley according to claim 2, wherein the ratio CE / (CL*CA) is in the range of 25 to 1604. Malted dehusked barley according to any one of the preceding claims, wherein the malted dehusked barley has an alpha-amylase activity of 1-100 Dextrinizing Units (DU) per gram of dry matter, as determined by EBC method 4.13.

5. Malted dehusked barley according to any one of the preceding claims, wherein the malted dehusked barley has a Free Amino Nitrogen (FAN) content of at least 100 mg / L as determined by EBC method 4.10.

6. Malted dehusked barley according to any one of the preceding claims, wherein the malted dehusked barley has a beta-amylase activity of at least 1 unit per gram of dry matter, as determined using Megazyme B-amylase assay kit (Betamyl-3).

7. Malted dehusked barley according to any one of the preceding claims, wherein the malted dehusked barley has a beta-glucan content of less than 800 mg per liter congress mash.

8. Malted dehusked barley according to any one of the preceding claims, wherein the malted dehusked barley contains one or more microbial enzymes selected from arabinoxylanase and beta-glucanase.

9. A process of producing malted dehusked cereal grain, said process comprising: a) mechanically removing husk from cereal grains, thereby producing dehusked grains and husk material; b) steeping the dehusked grains with steeping water to produce steeped grains having a water content of at least 30 wt.%; c) germinating the steeped grains at a temperature in the range of 15-25 °C during 12 to 72 hours to produce green malt; and d) drying the green malt to produce malt having a water content of less than 15 wt.% ; wherein the process does not comprise mechanical perforation of the cereal grains during steeping, and wherein, during step b) the grains are contacted with steeping water containing one or more cell wall degrading enzymes selected from cellulase, arabinoxylase, beta-glucanase and pectinase.

10. Process according to claim 9, wherein the cereal grain is selected from barley, rye and combinations thereof.

11. Process according to claim 9 or 10, wherein the mechanical removal of husk reduces the weight of the cereal grains by 2-18%.

12. Process according to any one of claims 9-11, wherein during step b) the grains are contacted with the one or more cell wall degrading enzymes for at least 30 minutes.

13. Process according to any one of claims 9-12, wherein the one or more cell wall degrading enzymes are selected from arabinoxylanase, beta-glucanase and combinations thereof.

14. Process according to any one of claims 9-13, wherein during step b) the grains are contacted with steeping water containing gibberellic acid.

15. A method of producing a malt beverage, said method comprising:• providing a mixture comprising malt and water, wherein at least 1 wt.% of the malt is a malted dehusked barley according to any one of claims 1-8;• mashing the mixture to convert starch into fermentable sugars and to produce a mash containing fermentable sugars; andsubjecting the mash containing fermentable sugars to a solid-liquid separation to separate wort from insoluble matter.5

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