MXPA00006581A - Method and apparatus for treating cereal kernels, treated cereal kernels and their use - Google Patents

Abstract

The invention relates to a heat treatment method of cereal kernels which enables the decrease in the mould content of the cerealkernels without disturbing their germinability. The method is especially applicable to the treatment of kernels to be germinated e.g. before malting. The invention also relates to the treated cereal kernels, cereal kernel products made of them and their use in malting and brewing. Further, apparatuses are described which are applicable to the heat treatment of cereal kernels.

Description

METHOD AND APPARATUS FOR TREATING GRAINS OF CEREALS, GRAINS OF TREATED CEREALS, AND THEIR USE FIELD OF THE INVENTION The invention relates to a method for treating grains (seeds) of cereals to reduce their mold content. The invention also relates to the treated cereal grains, cereal grain products obtained therefrom, and to its use in the malting, brewing and food and fodder industries. The invention also relates to apparatus for treating cereal grains to reduce their mold content. More specifically, the method of the invention allows the mold content of the cereal grains to be decreased without interfering with the germination capacity of the grains. This is particularly important in the malting process of the grains.

BACKGROUND OF THE INVENTION Molds can be found anywhere in nature, for example, in the soil and in the air, from where they disperse to the growing grain. Although molds thus belong to the natural flora of the grain, their broad occurrence is harmful because they reduce the quality of the grain and the malt obtained from it. For example, molds can produce several mycotoxins harmful to health. In addition, for example, they can decrease the germination capacity of a grain, and the growth of the germs, which is not only harmful for the grain, but also for the malting of the same. It has also been shown that fermented beer obtained from heavily contaminated grain and malt tends to spill, which is a major problem in the fermentation industry. The spill is apparently due to metabolites produced by Fusarium and other molds, whose metabolites survive the fermentation process. The beans are exposed to molds as soon as they are planted in the soil. Mold growth is influenced by many factors, particularly humidity, temperature and time. Other significant factors are the supply of nutrients and oxygen and the competition between microorganisms. The growing grain is dominated by the so-called wild mushrooms, the most common of which are Alternaria, Aureobasidium, Cladosporium, Epicoccum, Fusarium, Cochliobolus, Drechslera and Pyrenophora. Some of the wild mushrooms are phytopathogens, the most noxious being Fusarium graminearum and F. culmorum. Also Cochliobolus sativus and Fusarium ssp. They cause diseases in plants, and can be very harmful to the malting process. In particular, the wet weather during the maturation of the spike and the harvest presents favorable conditions for the growth of Fusarium. After harvest, the grain must be dried quickly to prevent molds from continuing to reproduce. Wild mushrooms can not reproduce themselves in properly dried grain (approximately 12 to 13% moisture content), but remain alive and reproduce on their own again, if exposed to wet conditions. The grain stored for a short time is dominated by the so-called storage fungi, that is, Aspergillus and Penicillium, which survive in low moisture contents. Also, storage fungi reduce the quality of the grain and constitute health risks for those who treat the contaminated grain and those who consume it. When the grain is malted, the humidity of the grain is again increased up to 45 to 50% and the supply of oxygen is ensured, with which the grain begins to germinate. However, the prevailing conditions during the malting process are not only suitable for germination, but also for the growth of molds. A large amount of molds is detrimental to the procedure. The malting process helps to make physical, chemical and biochemical changes in the grain. The malting process comprises three main stages: soaking, germination and baking. First of all, the cleaned and screened grain is soaked in water to achieve the right moisture content. When the grains have a sufficient moisture content, they are germinated from 13 to 16 ° C generally for at least 5 days. In this way, the "green malt" is produced. Real malt is produced by drying the green malt under controlled conditions in which the temperature is slowly raised from about 45 ° C to about 85 ° C, whereby the moisture content decreases by up to 4%. After drying, the rootlets are removed, and can be used as animal fodder. The malt can also be processed, for example, in a malt extract for the food industry. Already in the soaking stage during the malting, the mold content of the grain may increase, and it increases even more in the germination stage. The normal baking of the malt does not substantially decrease the mold content of the grains. Malt is used mainly for brewing beer, but also for the production of distilled spirits. Brewing includes the production of beer must, primary and secondary fermentations, and post-treatment. First, the malt is ground, stirred in water and heated. During this "pasting", activated enzymes in malting degrade grain starch into fermentable sugars. The beer must produced is clarified, yeast is added, the mixture is fermented, and post-treatment is carried out. Many molds are known to produce toxic compounds, that is, mycotoxins, which can harm the health of humans and animals. They can also harm malting and fermentation. In this way, if there are many molds in the grain, the probability that mycotoxins exist is also greater. The most examined mycotoxins that grow in the grain originate from Fusarium, Cochliobolus sativus, Aspergillus and Penicillium.

Several species of Fusarium not only pathogenic of cereals, but also potential sources of several mycotoxins. Particularly important mycotoxins trichothecenes, zearalenone (ZEN) and its derivatives, fumonisins, moniiiformin, fusarocromanones and fusaric acid. More than 100 different trichothecenes have been identified and characterized. Most attention has been focused on type A trichothecenes, including T-2 toxin, neosolaniol (NEO) and diacetoxyscirpenol (DAS) and trichothecenes type B, comprising deoxynivalenol (DON, ie vomitoxin) and its derivatives. acetyl (3-ADON and 15-ADON), nivalenol (NIV) and fusone X. Fusarium mycotoxins and the factors that affect them presented in JPF D'Mello and AMC Macdonald: Some Factors Affecting the Product of Fusarium Mycotoxins, p. 35-44, in: J. P. F. D'Mello: Mycotoxins in Cereals: An Emerging Problem ?, Manual for the Fourth SAC Conference, October 1996, Edinburgh. In the chapter "Mycotoxins in Malting and Brewing" of the work mentioned above, B. Flanigan (p.45-55) discusses the effects of mycotoxins on the brewing and malting industry. It is pointed out, for example, that the harmful effect of Cochliobolus sativus and Fusarium ssp. on the capacity of gemination is attributed at least in part to the production of mycotoxins or other phytotoxic metabolites. The trichothecenes produced by Fusarium ssp. inhibit the synthesis of proteins, and thus reduce the production of alpha-amylase important for malting. Also, the concentrations of alpha-amino nitrogen in the beer must decrease.

Fusarium can produce DON and zearalenone during malting. Grain and malt can also be contaminated with toxins produced by Penicillium verrucosum or Aspergillus clavatus, which cause allergic lung disease. T-2 toxin and other potent trichothecenes may slow fermentation, but although DON may be present in the beer must, it has little effect on fermentation. Mycotoxins not found in distilled spirits, but DON, nivalenol, fumonisins, aflatoxins, ochratoxin A and some other mycotoxins have been found in beer, but at low concentrations. The spill of the beer seems to correlate with zearalenone or DON. The risk to the health of humans who consume beer contaminated by mycotoxins is still uncertain, but the toxic effect of mycotoxins from stored forages on contaminated malting and fermentation byproducts is not at issue. For example, DON has been found at high concentrations in rootlets used as animal fodder, and aflatoxins, zearalenones and ochratoxin A have been found in the waste of the wort. Several solutions have been suggested to the problems related to the molds in the grain and the malt. It is naturally useful to dry the grain immediately after harvest, and store it dry. The growth of molds can be delayed already in the field, sprinkling pesticides. Several cereals have also been developed with a genotype resistant to, for example, Fusarium diseases. Attempts have been made to reduce the deleterious effects of molds in malting and fermentation, for example by supplying microbicidal substances such as formaldehyde in the soaking water. However, the use of formaldehyde on a large scale is prohibited for health reasons. A safe and generally acceptable chemical compound has not been found. Rather, the addition of lactic acid bacteria or preparations produced by them (WO94 / 16053) during the germination process has yielded good results. The effect of lactic acid bacteria in preventing the growth of molds is apptly due at least in part to the microbicidal substances produced by them. Surprisingly, a method for decreasing the mold content of cereal grains by physical means has now been invented. The invention thus allows the reduction or prevention of the previous harmful effects of molds in a natural form, without the need to use chemical pesticides or other additives. The present invention provides means to decrease the content of molds of cereal grains without disturbing the parameters of germination capacity of the grain. In this way, the invention allows the improvement of the quality of the grain, particularly of the grain that will be malted and of the grain for seed. Along with the decrease in mold content, the invention provides means to diminish the harmful effects thereof. The deleterious effects that can be avoided by the invention include the formation of mycotoxins, reduced germination capacity, reduced enzyme production, delayed growth of rootlets, delayed fermentation, beer spillage and health risks to humans and animals.

BRIEF DESCRIPTION OF THE INVENTION The method of the invention for treating grains (seeds) of cereals is characterized by exposing the grains to heat at such a temperature and during such a period that the mold content of the grains decreases, but its gemination capacity persists, with which the temperature of the grains that will be treated rises from 60 to 100 ° C for 0.5 to 30 seconds. The cereal grain of the invention is characterized in that it is treated with the method of the invention, and the cereal grain product is characterized in that it is obtained from the cereal grain of the invention. The invention also relates to the use of said cereal grains in malting, and to the use of said cereal grain products in malting, and to the use of said cereal grain products in fermentation. The apparatus of the invention for treating cereal grains is characterized in that it comprises transport means (1) for transporting cereal grains, steam feeding means (2) for treating grain grains with steam, and air cooling means ( 3) to cool the cereal grains with air, whereby the steam feeding means are adapted upstream of the air cooling means in the transport direction of the transport means. Another apparatus of the invention is characterized in that it comprises a compartment for nutrition (14) for nourishing grains, a vertical tube (13) containing a control cone (16) for dispersing grains, and steam feeding means (19) to treat the grains with steam. Preferred embodiments of the invention are described in the dependent claims. Cereal grains are living material, which normally has to be treated with care to avoid effecting its viability. It is well known that molds survive well enough to the controlled heat treatment used in the baking of green malt. Therefore, it is surprising that cereal grains can be heat treated in such a way that their mold content decreases, but their germination capacity is not weakened. In fact, the heat treatment described below was put to the test first in the green malt, to which it is not adapted, because the enzymatic activity of the malt fell completely, and the grain "died". In this way, it was not expected that the mold content of an unmalted cereal grain could be reduced to a minimum with an adequate heat treatment without impairing the viability of the grain, as in the case of germination and enzyme capacity parameters. vital, for example, activity of α-amylase and β-glucanase, which are important during germination.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows an apparatus for treating cereal grains to decrease their mold content; Figure 2 illustrates the effect of heat treatment on the amount of grains contaminated with molds in the 50 kg malting; Figure 3 illustrates the effect of the heat treatment and the addition of a lactic acid bacteria initiator on the amount of Fusarium-contaminated grains in the 1 kg malting; Figure 4 shows another apparatus for treating cereal grains to decrease their mold content.

DETAILED DESCRIPTION OF THE INVENTION In accordance with the invention, the mold content of the cereal grains is decreased by treatment of the grains. The heat treatment of the invention also reduces the content of mycotoxins in the grains, and the tendency of the beer to the spill prepared from the treated grains or from the malt prepared therefrom. The method of the invention is particularly applicable to the reduction in the amount of Fusarium. The cereal grains to be treated according to the invention are generally dried seed in the storage of threshed grain. They are preferably sowing material that will be germinated, and especially cereal grains that will be malted. The best results are achieved if a so-called initiator is added, in this case a preparation of lactic acid bacteria or a product produced by them in the germination stage, to the sowing material that will be germinated, and which is treated in accordance with the invention The initiator has a preventive effect on the growth of microbes during the germination process. Suitable grains to be treated according to the invention are, for example, barley, rye, wheat, corn and oats, with barley being particularly suitable. The cereal grains are exposed to the heat according to the invention at said temperature and during said period and which are sufficient to substantially reduce the amount of molds without impairing the parameters of germination capacity, such as germination capacity and energy for germination. . It is obvious that the higher the temperature used, the shorter the treatment time that is required. In general, it can be started so that the required heat treatment is brief and vigorous. The treatment of cereal grains with heat can be implemented in various ways, and the appropriate temperature and time can vary depending on the media used with the heat treatment. What is essential is that the parameters of temperature and time of the method are optimized to reduce the mold content considerably without impairing the essential vital functions of the grain, for example, its germination capacity. A suitable treatment temperature may be 60 to 100 ° C and a time of 0.5 to 30 seconds, preferably 70 to 90 ° C for 1 to 15 seconds. What is apparently crucial is the temperature reached in the grain itself and its duration.

The heat treatment can be carried out, for example, in an oven. The grains can also be heated with high frequency waves, for example, radio waves or microwaves, whereby the treatment time depends of course on the energy of the apparatus used and the amount of grains that will be treated. However, the most promising results have been obtained by treating the grains with moist heat, for example, by immersing the grains in hot water, or by treating them with steam, which is the most preferable form. Grains can also be treated naturally with air that contains steam or water. When the grains are treated with steam, it is preferred to use overpressured heated steam, and preferably in such a way that the steam is sprayed from several directions onto a fairly thin layer, for example, about 0.5 to 2 cm of the grains. In practice, the temperature of the steam used is generally from 100 to 140 ° C (overpressure from 0.4 to 2.5 bar), preferably from about 110 to 130 ° C (overpressure from about 0.4 to 1.7 bar), more preferably from 115 to 125 ° C (overpressure of 0.7 to 1.3 bar), and particularly of 120 to 125 ° C (overpressure of 1.0 to 1.3 bar). Preferably, the temperature of the grain material is elevated in this treatment to about 70 to 85 ° C, more preferably to 75 to 79 ° C, and particularly to 78 to 79 ° C, whereby the recommended treatment time is in corresponding form from about 1 to 15 seconds, preferably from 5 to 10 seconds, and particularly from 4 to 6 seconds. In practice, it is preferred to cool the grains after the heat treatment to avoid overheating, which would impair the germination capacity. The grains can be cooled, for example, with air or water. The cereal grain of the invention can be any cereal grain treated in accordance with the present invention. It can be, for example, a seed, that is, planting grain, but preferably it is a grain of barley, rye, wheat, corn or oats that will be germinated, and particularly barley that will be malted. The cereal grain product of the invention is obtained from said cereal grain. Some examples are products from the food industries, for example, milling and fodder industries, but particularly products from the brewing and malting industries such as malt, malt extract, green malt, foods that originate from the malting process, and beer. The cereal grains of the invention can be applied for use in the food and feed industry, for example, in grinding and baking. Preferably, they are used in malting and fermentation, and in particular in the production of malt, to which lactic acid bacteria are added during the malting process, for example, in the soaking or germination stage. The cereal grain products that are produced according to the invention are especially applicable to the manufacture of beer. Beer is mainly produced from malt, but a variable amount of non-malted grain can also be used here. An apparatus applicable to the treatment of cereal grains to reduce the mold content is shown in Figure 1. The apparatus comprises conveying means 1, steam feeding means 2 and air cooling means 3. The conveying means are preferably an endless conveyor, more preferably a conveyor belt with holes to let steam and air pass, so the holes have to be too small so that the grains do not fall through them. A suitable hole size for barley is, for example, 0.5 to 1 mm x 5 to 10 mm. The speed of the transport means 1 is preferably adjustable, for which purpose the transport means comprise operating means 6 for regulating the speed. In this regard, the means of operation 6 are not described in greater detail, since it is obvious to the person skilled in the art that it is easy to plan them in various ways. The steam feeding means 2 at the front end of the conveying means directing the steam towards the grains to be treated, preferably comprise at least one steam nozzle 4, and more preferably several steam nozzles arranged in series for direct the steam towards the grains that will be treated. More preferably, the steam nozzles are arranged in such a way that the steam can be sprayed to the grains which will be treated from several directions, for example, from the top and the bottom, so that the treatment of the grains with heat would be as uniform as possible. It can also be considered that the steam feed nozzles are arranged only above the conveyor 7. The steam feed means 2 are preferably adapted for overpressurized steam, the overpressure of 0.1 to 2.5 bar is advisable. It is further preferred that the steam feeding means comprise means (8) for adjusting the vapor pressure. The air cooling means 3 at the outlet end of the conveying means which cools the steam-treated grains comprise an air-blowing apparatus, which preferably comprises at least one nozzle 5, and more preferably several nozzles arranged in series to direct the air towards the grains that will be treated. The air cooling means are particularly adapted for compressed air, and comprise a source of compressed air 9. The apparatus further preferably comprises a feeding funnel 11 for moving the grains towards the conveyor belt 7, and removal means 10 for removing the treated grains. Preferably, the feeding funnel further comprises regulating means 12, which can be, for example, a disc for regulating the thickness of the grain layer to be fed on the conveyor belt. The removal means 10 comprises the point of rotation of the conveyor belt, in which the grains fall due to gravity in a collection container. The apparatus of Figure 1 can be used for heat treatment of grains by the use of steam. The beans are fed from the feed funnel 11 in the apparatus to form a layer approximately 1 cm thick, after which they move on the conveyor belt towards a vaporization area. The steam is directed on the conveyor belt 7 from the nozzle lines above and below it (lines of 2 x 6 nozzles). The speed of the conveyor belt can be regulated, and the number of used nozzle lines can be modified. The treatment temperature of the steam and the grain that moves on the conveyor belt, can be regulated by means of steam pressure. The preferred temperature scale of the vapor is 100 to 140 ° C, and preferably 110 to 130 ° C. The conveyor belt moves the steamed grains from the steaming area, where it is recommended that the grains remain 0.5 to 30 seconds, and preferably 2 to 15 seconds, to the cooling area, where the grains are cooled by the compressed air blown on the conveyor belt, after which the grains are picked up at the other end of it. In the apparatus of Figure 1, the seeds move substantially in the horizontal direction du the heat treatment. However, they can also be moved in a vertical direction due to gravity. An apparatus for treating seeds that move vertically du heat treatment is shown in Figure 4. Said apparatus comprises a compartment for nutrition 14 for nourishing the grains, a vertical tube 13 containing a control cone 16 for distributing them, and steam feeding means 19 for treating the grains with steam. The compartment for nutrition is adapted in the upper part of the vertical tube, where the steam treatment will be carried out. Preferably, the nutrition compartment is connected to feeding adjustment means 15 for controlling the speed of the seeds fed. The control cone 16 preferably comprises cone movement means 17, for example, a control screw, for rotating the cone and moving it in the vertical direction. It is further preferred that the tube includes flow controlling means 18 to retard the speed of the seeds. The flow control means preferably have the shape of rings. The steam feed means 19 are adapted below the control cone, and may comprise inputs connected to the steam diffusion means 20, for example, steam rings within the pipe 13 near its inner surface. The steam rings are tubes with holes of approximately 1.5 mm to direct and diffuse the steam. The direction of the holes is indicated by tabs in figure 4. Other types of steam diffusion nozzles can also be applied. The apparatus described above preferably comprises at least two control cones 16 arranged one above the other, and several steam feeding means 19 below them, containing various vapor diffusion means 20 in the form of vapor rings surrounding the surface inside the tube to diffuse the vapor in the tube 13. The vaporization tube can be connected to cooling means, for example, a tube for cooling the seeds with air, or to a container of water for dropping the seeds therein.

The apparatus of Figure 4 is suitable for the treatment of cereal grains with heat to reduce the amount of grains contaminated with molds. The apparatus comprises a vertical vaporization tube 13 in a vertical position on a shelf. The barley is fed to the apparatus through the nutrition compartment 14, and the feeding amount is controlled with feeding adjustment means 15. The barley flows through the tube due to gravity and the vapor stream. The speed of the barley in motion is delayed with two control cones 16 and three flow control means 18. The upper control cone is connected to the tube with cone movement means 17 in the form of a screw. The upper control cone can be rotated and moved in the vertical direction. The thickness of the layer of the cereal seeds can be controlled with the space (0-2 cm) between the upper cone and the upper flow controlling means. The steam is fed into the vaporization tube (in the same way as in the apparatus of Figure 1) through steam feeding means 19 comprising steam diffusion means 20. The surplus of steam flows with the cereal seeds treated. The processing time in a steaming tube 80 cm high is about one second. The processing time can be extended by lengthening the vaporization tube with additional modules. The results of the heat treatment obtained with the apparatus of Figure 4 were similar to those obtained with the apparatus of Figure 1. The invention is illustrated by the following examples.

EXAMPLE 1 Effect of heat treatment on mold content and germination capacity of barley Heat barley was treated using the apparatus of Figure 1. Table 1 describes the effect of steam temperature, vapor pressure, and treatment temperature and treatment time on the conveyor belt, on the percentage of the grains of barley contaminated with Fusarium and on the germination capacity of barley. The heat treatment decreased the percentage of barley grains contaminated with Fusarium without weakening its germination capacity. The treatment seemed to improve even some germination parameters.

TABLE 1 Effect of steam temperature (pressure) and treatment temperature and treatment time on the conveyor belt, on the mold content and the germination capacity of the barley EXAMPLE 2 Malting of the barley treated with heat, on the scale of 1 kg Kustaa barley that has a protein content of 10.6%, was malted in batches of 1 kilogram in a test malting device Seeger. The barley that had to be malted was treated for five seconds with the apparatus of figure 1. The steam temperatures used were 115 ° C, 120 ° C and 125 ° C. The untreated barley was used as a comparison. Half of the barleys (containers 1 to 4) was malted immediately after treatment, and the other half (containers 5 to 8) after 24 hours of storage. Storage was carried out at 15 ° C. The barleys were soaked in the following manner: 8 hours in water at 13 ° C, 16 hours in dry at 15 ° C, and 8 hours in water at 13 ° C. The barleys were germinated one day at 16 ° C, after which the humidity was regulated up to 49%. Then, the barleys were germinated for 4 days at 14 ° C. After germination, the baking of the barleys was started with air at 50 ° C, and concluded with air at 82 ° C. Table 2 illustrates the effect of heat treatment on barley and malts obtained from it. Malt analysis are described, for example, in the Analytica-EBC / European Brewery Convention publication, published by EBC Analysis Committee, Verlag Hans Cari, Getránke-Fachverlag, Nürnberg, 1998. Heat treatment decreased the percentage of barley grains contaminated with Fusarium and the total amount of molds. In the field of normal variation, the malt analyzes showed no differences.

TABLE 2 Test Malteo Barley Malting procedure Analysis of malt * Amount of mold colonies on Sabouraud dextrose agar (Oxold) cfu / g dm; the method reveals all molds (also Fusarium) and yeasts. * cfu / g dm = units of formation of colonies / one gram of dry matter.

EXAMPLE 3 Malting of barley treated with heat on the 50 kg scale Kustaa barley that has a protein content of 10.6%, was malted in batches of 50 kg by a malting apparatus. The barley that would be malted was treated with the apparatus of figure 1 for 5 seconds. The temperature of the steam used was 125 ° C. The untreated barley was used as a comparison. The barley was malted immediately after treatment. The barleys were soaked in the following manner: 8 hours in water at 13 ° C, 12 hours in dry at 16 ° C, and 4 hours in water at 13 ° C, 12 hours in dry at 16 ° C, and 1 hour in water at 13 ° C. The barleys were germinated one day at 16 ° C, after which the humidity was regulated up to 49%. Then, the barleys were still germinated 4 days at 14 ° C. After germination, the baking of the barleys was started with air at 50 ° C, and concluded with air at 82 ° C. Table 3 describes the effect of heat treatment on barleys and malts obtained from it. Figure 2 illustrates the effect of heat treatment on the percentage of grains contaminated with Fusarium at different stages of malting. The heat treatment decreased the percentage of barley and malt grains contaminated with Fusarium. The heat treatment also decreased the percentage of grains contaminated with Fusarium in the samples taken after soaking and germination. In the field of normal variation, the malt analyzes showed no differences.

TABLE 3 Effect of heat treatment on barley and malt obtained from it Barley Malting procedure Malt analysis EXAMPLE 4 Malting on the 1 kg scale after heat treatment and initiator of lactic acid bacteria Kustaa barley, which has a protein content of 10.6%, was malted in batches of 1 kg in a Seeger test malting device. The barley that would be malted was treated with the apparatus of figure 1 for 5 seconds. The temperature of the steam used was 125 ° C. The untreated barley was used as a comparison. In addition, the effect of the addition of the lactic acid bacteria initiator was tested on malting. The initiator, VTT-E-78076 from Lactobacillus plantarum, was developed in MRS broth (Oxoid) at 30 ° C (the development was carried out in accordance with patent application WO96 / 02141). The growth medium of the initiator including the cells was added to the first and second soaking waters with 120 ml / kg of barley. The disposition of the test is shown in table 4. The barleys were soaked at 15 ° C as follows: 8 hours in water, 13 hours in dry, 3 hours in water, 11 hours in dry and 1 hour in water. The barleys were germinated one day at 16 ° C, after which the humidity was adjusted to 49%. Then, the barleys were germinated for 4 days at 14 ° C. After germination, the baking of the barleys was started with air at 50 ° C, and concluded with air at 82 ° C. Table 4 describes the effect of heat treatment on barley and malts obtained from it. Figure 3 illustrates the effect of heat treatment on the percentage of grains contaminated with Fusarium in different stages of malting. The heat treatment decreased the percentage of barley and malt grains contaminated with Fusarium. The heat treatment also decreased the percentage of grains contaminated with Fusarium in the samples taken after soaking and germination. The treatment with an initiator combined with heat treatment also decreased the percentage of grains contaminated with Fusarium. In the field of normal variation, the malt analyzes showed no differences.

TABLE 4 Test Malteo Barley Malting procedure Analysis of malt EXAMPLE 5 Effect of various heat treatment methods on the mold content and germination capacity of barley The same Kustaa barley used previously was used in the tests. 50 grams of barley were soaked in 5 liters of hot water, after which the barley was cooled in water at 10 ° C (8 I) for 20 seconds. 25 grams of barley was heated in a microwave oven and allowed to cool to room temperature. The test provisions are shown in table 5. The immersion of the barley in hot water decreased the percentage of grains contaminated with Fusarium, while the germination capacity continued to be good. The treatment in a microwave oven also decreased the Fusarium contamination. A longer treatment time in the microwave oven also decreased the germination capacity.

TABLE 5 Effect of various heat treatment methods on the percentage of grains contaminated with Fusarium EXAMPLE 6 Barley at rest, heavily contaminated with Fusarium, received the treatment described in example 1. The effects of steam temperature (pressure) and the treatment temperature and the treatment time on the conveyor belt, on the mold content and the germination capacity of barley. The results are given in table 6. In the treatment, Fusarium could be eliminated without interfering with the parameters of germination capacity.

TABLE 6 Treatment of resting barley heavily contaminated with Fusarium It is obvious to the person skilled in the art that the basic idea of the invention can be implemented in several ways. The invention and the embodiments thereof are not restricted to the foregoing examples, but may vary within the scope of the claims.

EXAMPLE 7 Barley Kymppi, which was heavily contaminated with Fusarium, was malted in batches of 1 kg. The barley was treated with the apparatus shown in Figure 1 in the same manner as in Example 4. The effects of the heat treatment on the mold content and tendency to spill were determined.

The proportion of grains contaminated with Fusarium on Czapek Iprodion Dicloral agar (CZID agar, Difco) specific for Fusarium was tested in accordance with the method described by Abidgren et al. (Lett. Appl. Microbiol. 5 (1987) 83-86). The proportion of contaminated grains was tested Aspergillus and Penicillium (storage fungi) on Malt Salt agar (MSA, Difco) specific for Aspergillus and Penicillium, according to a method described in EBC, Analytica Microbiologica, part 2, 1991. The proportion of contaminated grains was tested wild mushrooms (eg Alternaria, Cephalosporium, Cladosporium, Epicoccum, Stemphylium) on wet filter paper, in accordance with a method described in EBC, Analytica Microbiologica, part 2, 1991. The tendency to spill was tested in accordance with a method described by Vaag et al. (Eur. Brew, Conv. Proc. Twenty-fourth congress, Oslo 1993, 155-162). The results are shown in table 7. The effects of heat treatment on the Fusarium molds of barley, barley after soaking, barley after germination and baked malt, were similar to the results shown initially. In addition, the proportion of barley grains contaminated with Aspergillus and Penicillium (storage fungi) and wild mushrooms, decreased without loss of germination capacity. The tendency to spill decreased to zero in malt prepared from treated barley. The tendency to spill in the malt obtained from untreated barley was high (128 g).

TABLE 7 Malting barley Kvmppi heavily contaminated with Fusarium ANALYSIS OF THE BARLEY MALTING PROCEDURE ANALYSIS OF MALTA EXAMPLE 8 Barley Robust, which was heavily contaminated with the DON toxin, was malted in batches of 1 kg. The barley was treated with the apparatus shown in Figure 1 in the same manner as in Example 4. Fusarium trichothecenes, such as deoxynivalenol (DON) and 3-acetyldeoxynivalenol (3-ADON), were determined as trimethylsilyl ether derivatives by means of a gas chromatograph equipped with a selective mass detector (GC-MSD). Zearalenone and ochratoxin A were separated and quantitated by reverse phase HPLC with a fluorescence detector. The molds were determined as in Example 7. The results are shown in Figure 8. The effect of the heat treatment on the Fusarium molds of the barley, barley after soaking and baked malt, was similar to the results shown above. The gemination capacity was good in all cases. In addition, the proportion of grains contaminated with Aspergillus decreased in malt prepared from barley number 1 treated with heat. The tendency to spill decreased to 1 g in malt prepared from barley number 2 treated with heat. The tendency to spill untreated malt was 26 g. Surprisingly, a significant reduction of mycotoxins (7-50%) was achieved in barley and malt by heat treatment.

EXAMPLE 9 The storage of dried and heat treated Kustaa barley was investigated. The barley was treated with the apparatus shown in Figure 1 in the same manner as in Example 4. After the heat treatment, the moisture content of the barley was 14.3%. The barley was dried for 3 hours at 45 ° C in a test malting device (Seeger). After drying, the moisture content of the barley was 7.9%. The barley was stored in closed containers at 5 ° C and 23 ° C. The energy for germination (4 and 8 ml), the germination capacity and the contamination caused by storage fungi and Fusarium, were determined as described above during a period of 4 months. The results are shown in Table 9. No growth of Fusarium or storage fungi could be detected. Likewise, the germination of the barley remained unchanged at both temperatures for a period of 4 months.

TABLE 8 Robust barley malting strongly contaminated with DON toxin Compartment number 1 2 3 4 Number of barley 1 1 2 2 Vapor temperature ° C No treatment 125 No treatment 125 Steam pressure, barias No treatment 1.3 No treatment 1.3 Conveyor belt temperature, No treatment 79 No treatment 79 ° C Treatment time, seconds No treatment 5 No treatment 5 BARLEY ANALYSIS Humidity,% 11.2 13.9 11.5 14.4 Germination capacity in water,% 99 99 99 99 Energy for germination, 4 mi% 93 89 87 89 Sensitivity to water, 8 mi% 59 78 67 72 Classification, mm > 2.2mm > 2.2mm > 2.2mm > 2.2mm Fusarium,% (contaminated grains) 82 12 83 5 DON toxin, mg / kg before malting 4223 3475 13540 12209 MALTING PROCEDURE Moisture after the first soaking,% 31.3 31.6 31.2 31.7 Moisture after soaking,% 44.4 43.8 44.1 43.9 Fusarium after soaking,% (grains 95 10 94 12 contaminated) Germination for 2 days,% 98 97 97 97 Moisture of green malt,% 44.5 45.1 45.1 45.2 MALT ANALYSIS Humidity,% 3.6 3.7 3.6 3.5 Flour extract,% / dm 78.8 79.3 79.6 79.4 Color of the beer must, ° EBC 4.4 4.1 4.7 4.4 pH of the beer must 5.97 5.99 5.96 5.95 Saccharification, 15 minutes 15 15 15 a-amylase, DU / g dm 52 50 47 49 Diastatic energy, WK IOOg dm 560 540 500 500 Spill, g 0 0 26 1 Fusarium,% (contaminated grains) 100 52 100 60 Aspergillus,% (contaminated grains) 51 8 0 0 DON toxin, mg / kg 811 410 2344 2178 Toxin 3-A DON, mg / kg 77 < 50 128 < fifty Zearalenone, mg / kg 118 11.1 156.1 50.3 TABLE 9 Storage of dried and heat treated Kustaa barley Storage of barley at 23 ° C

Claims (22)

NOVELTY OF THE INVENTION CLAIMS

1. - A method for treating cereal grains to reduce their mold content, characterized by exposing the grains to heat at said temperature and during said period, that the mold content of the grains decreases, but the germination capacity persists, with which The temperature of the grains to be treated rises from 60 to 100 ° C for 0.5 to 30 seconds.

2. The method according to claim 1, further characterized by exposing the grains to heat at said temperature and during said period, that the Fusarium content of the grains decreases, but the germination capacity of the grains persists.

3. The method according to claim 1, further characterized by exposing the grains to heat at said temperature and during said period, the mycotoxin content of the grains decreases, but the germination capacity thereof persists.

4. The method according to any of claims 1 to 3, further characterized in that the grains to be treated are grains to be germinated.

5. The method according to claim 3, further characterized by treating the barley that will be malted.

6. - The method according to claims 1 or 5, further characterized by exposing the grains to heat at said temperature and during said period, that the tendency to spill the beer prepared from said grains, decreases.

7. The method according to claim 4 or 5, further characterized in that after the treatment, lactic acid bacteria are added in the germination stage to the grains to be germinated.

8. The method according to any of the preceding claims, further characterized by carrying out the treatment with heat, with moist heat.

9. The method according to claim 8, further characterized by carrying out the treatment with heat, with steam.

10. The method according to claim 9, further characterized by raising the temperature of the grains that will be treated from 70 to 90 ° C for 1 to 15 seconds.

11. A grain of cereal, characterized in that it is treated with the method according to any of claims 1 to 10.

12. The grain according to claim 11, further characterized because it is primed to be malted.

13. A cereal grain product, characterized in that it is obtained from the cereal grain according to claim 11.

14. A grain product according to claim 13, characterized in that it is malt.

15. - The use of the grains as claimed in claim 1, in the malting, brewing, food or fodder industries.

16. The use as claimed in claim 15, wherein the cereal grains are used in the malting, and where lactic acid bacteria are added during the malting process.

17. The use of the product of cereal grains as claimed in claims 13 or 14, in the brewing, food or fodder industries.

18. An apparatus for treating grain grains to reduce their mold content, characterized in that it comprises means of transport (1) to transport cereal grains, steam feeding means (2) to treat the cereal grains with steam, and air cooling means (3) to cool the grains of cereals with air, whereby the steam feeding means are adapted upstream of the air cooling means in the transport direction of the means of transport.

19. The apparatus according to claim 18, further characterized in that the transport means (1) comprise an endless conveyor belt (7) with holes and operating means (6) to regulate the speed of the conveyor belt.

20. The apparatus according to claim 18 or 19, further characterized in that the steam feed means (2) comprise means (8) for regulating the vapor pressure and several steam nozzles (4) arranged above and below the the conveyor belt, and in that the air cooling means (3) comprise a source of compressed air (9) arranged to feed several air nozzles (5).

21. An apparatus for treating cereal grains to reduce their mold content, characterized in that it comprises a compartment for nutrition (14) to nourish the grains, a vertical tube (13) containing a control cone (16) to disperse the grains. grains, and steam feeding means (19) to treat the grains with steam.

22. The apparatus according to claim 21, further characterized in that it comprises at least two control cones (16) whose upper cone comprises means of cone movement (17), and various steam diffusion means (19) in shape of rings with holes, said rings surrounding the inner surface of the tube (13).