Method of Hydrothermally Treating Grain, Pulse and Cereal Crop Grains Before Processing

Abstract

This invention relates to agriculture, more specifically, to processing of grain, pulse and cereal crop grains, in particular, to a composition for the treatment of grain, pulse and cereal crop grains before processing wherein the composition includes a combination of enzyme preparations containing cellulases, cellobiohydrolases, xylanases, catalases, phytases, peroxidases, oxidoreductases, laccases, esterases and antioxidants. An object of the present technical solution is to increase the output of flour or grit mills with a concurrent gain in the quality and dietary value of the milled products.

Claims

1. A method of hydrothermally treating grain, pulse or cereal crop grains before processing into grits, semolina, flakes, or flour, the method comprising: contacting the grain, pulse or cereal crop grains with a composition comprising a combination of enzyme preparations comprising: a. cellulases comprising cellobiohydrolases; b. xylanases; c. oxidoreductases comprising catalases, laccases, peroxidases, or a combination thereof; d. esterases comprising phytases; and e. antioxidants selected from the group consisting of ascorbates, tocopherols, polyphenols, natural vegetable extracts, citric acid, ascorbic acid, and a combination thereof; and processing the grain, pulse or cereal crop grains into grits, semolina, flakes, or flour.

2. The method of claim 1 wherein the combination of enzyme preparations is provided in dry or solute form.

Description

DETAILED DESCRIPTION

[0022] Combinations of such enzymes as peroxidases and/or oxidoreductases and/or laccases and/or esterases favor the oxidation and decolorization of grain hull pigments thus providing for a greater whiteness of the milled products and a lighter color of the crump in the baked products made from flour produced using this method. Such enzymes as catalase and/or phytase acting synergistically with the abovementioned enzymes increase the proper antioxidant activity of the crushed and milled products thus preventing the oxidative deterioration and rancidity of semolina and flour made from grain, pulse and cereal crop grains during storage.

[0023] As a result of the partial biochemical destruction of the grain hulls the grain body becomes more permeable for humidity during conditioning, the bonds between the separated hulls and the endosperm are weakened, the endosperm structure loosens faster and the grain acquires elastic-plastic or plastic properties which is generally favorable for grain processing and increases the efficiency of hullers and finishers. The milling of grains treated as above yields naturally whiter flour, i.e. increases the top grade flour output and the overall graded flour output, and improves its dietary value, the gluten content increases due to the entering of starch-containing endosperm peripheral parts into the milled product and the gluten quality is improved. Furthermore, enzymatic hydrolysis of grain hulls reduces the content of heavy metals in the milled products due to the desorption of metal ions linked with non-starch-containing polysaccharides during the solubilization of the hull structure.

[0024] The treatment of grain, pulse and cereal crop grains with the present composition before processing to semolina or flour can be combined with conditioning or hydrothermal treatment thus being incorporated into the process routes of factories that process any grains, grit or beans equipped with standard vessels and batchers used in the flour milling industry without additional capital costs or water consumption.

[0025] The limit consumption rates of the present composition depend on the type of raw material, its quality and the activity of the constituent enzymes.

[0026] Exceeding the top consumption limits leads to excessive hydrolysis of the grain hulls which may cause grain aggregation. Reducing the consumption to below the lower limits does affects said technical result but slightly but increases the time required for hydrothermal treatment which hinders the target increase in the quality of the final product.

[0027] The present composition can be use at mills equipped with expansion vessels which can be used for the preliminary dissolution of the present composition at the conditioning stage.

[0028] The present composition is dissolved in the preliminary expansion vessel equipped with a stirrer. After cleaning the product is delivered to a screw feeder for conveying to hydrothermal treatment or conditioning together with the prepared composition solution at 10-50 C. The screw feeds the uniformly treated raw material with the composition solution to a hopper for tempering.

[0029] Furthermore, the present composition can be used at factories not equipped with expansion vessels which can be used for the preliminary dissolution of the present composition.

[0030] After cleaning the treated raw material is delivered to a screw feeder for conveying to hydrothermal treatment or conditioning together with water at 10-50 C. and the dry resent composition which is uniformly introduced by a batcher. The screw feeds the treated raw material, water and the present composition to a hopper for tempering, uniformly stirring the materials.

[0031] The present composition can be used at any stage of hydrothermal treatment or conditioning if the existing process route of the factory contemplates this treatment in multiple stages, in dry or solvent forms, as described above.

[0032] In every embodiment of the present composition the cleaned and pretreated product is then fed to the milling stage.

[0033] Examples of grain, pulse and cereal crop grain treatment composition embodiments for use before processing are presented in Table 1:

TABLE-US-00001 Composition Examples, % Name of Ingredients 1 2 3 4 5 6 7 8 9 Cellulose 30 50 10 40 30 60 50 10 20 Cellobiohydrolases 10 20 10 40 10 10 10 Xylanases 5 20 10 20 5 5 10 Catalases 10 10 20 30 5 Phytases 10 10 5 Peroxidases 5 10 20 10 20 10 5 Oxidoreductases 10 10 10 5 10 5 Laccases 10 10 10 20 5 Esterases 5 10 20 5 Antioxidants 35 10 15 30

[0034] Application examples for Compositions 1, 2 and 4: wheat milling experiments were conducted using a Nagema laboratory mill. The laboratory wheat samples were moistened to 16.5%. The enzyme combinations were dissolved in water and introduced at the hydrothermal treatment stage. The time of moistening was 12 and 18 hours. Milling of three wheat samples treated as described above provided the following final product yield: 73.5%, 79% and 82% depending on enzyme content. The total yield of the reference wheat sample (without enzyme treatment) milled with Nagema was 60.3%.

[0035] Application examples for Compositions 1, 2 and 4: industrial milling was on a 50 tpd mill. The grain tempering time was 10 hours for each of the batches. Visual inspection of each batch suggested that grains moistened with the enzymes had one grade lighter colors than those without the enzymes. Moreover, the hulls of the experimental batch grains were more loose and shriveled. After 30 minutes of mill work the whiteness and quality of flour were examined by streams. Based on the examination results it was considered appropriate to change the grade of 2 more flour streams to the top one. As a result, of the 11 flour streams qualified as top grade flour, 8 were permanent throughout milling, compared to 6 for conventional grain without the enzymes. The bran of the test grain batch was cleaner, lighter and coarser compared to that of the reference sample. The overall flour yield of the reference sample was 75.5% and that of the experimental enzyme treated wheat batch was 77.24%. The presence of antioxidant in the composition for popcorn grain treatment prevents the oxidative deterioration of the milled product.

[0036] Application examples for Compositions 5 and 7: industrial milling was on a 500 tpd factory. The interest to experimenting with milling at that factory was that the deficiency of good grain the milling batch mainly comprised medium and low grade red-grained wheat of Kazakhstan origin with a large fraction of small, shrunk grain and low grain unit. The main problem with milling this crop was the low yield (45-50%) of top grade flour.

[0037] The introduction of the enzyme combination at the conditioning stage during 6-8 h increased the top grade flour yield to 62% while retaining all the flour quality parameters.

[0038] Application examples for Compositions 6 and 9: industrial milling was on a 150 tpd mill. As a result the huller efficiency increased thus reducing the overall weight percentage of hulls fed to milling. Inspection revealed a drastic (natural) increase in flour whiteness for each mill and each stream (by 3 to 18 units) for wheat treated with the enzymes at the moistening stage followed by grain tempering which increased the percentage of top grade flour without compromise in the quality (including whiteness) of 1.sup.st grade flour. An antioxidant activity examination of the bread baked from the flour processed as described above proved that the test sample has this figure 5.6 times the one for bread baked from standard flour.

[0039] Application examples for Composition 3: experimental milling and rolling or whole oat grain yielded the following results: cleaned oat grit was steamed and moistened to 2.0-2.5% followed by tempering. Then the grit was rolled in smooth roll machines. As a result of grain treatment with the enzyme composition the grit acquired elastic-plastic or plastic properties which generally improved its rolling, reduced the percentage of losses (broken or crumbs) and retained the wholeness of the flakes. The presence of ascorbates as an antioxidant in the grit treatment composition increases its antioxidant activity.

[0040] Application examples for Composition 8: the use of the enzymes at the popcorn grain conditioning or hydrothermal treatment stages if favorable not only for the subsequent crushing and polishing operations but also for germ separation and preservation. The germ is bound to the endosperm by the cementing layer having no cell structure and consisting of protein and pentosans. As a result of moistening and the action of the enzyme composition said cementing layer softens and its bond to the endosperm weakens. This treatment may be important if the germs are used for the production of oil. The germs should be separated from the grains as completely as possible, and the endosperm content in the separated product should be as low as possible. After the treatment the germs separate in the form of coarser pieces and contain less endosperm. This technology is of special importance for the production of grit for flakes and sticks because it makes the hulls separate easier during crushing and the endosperm, crush into coarser pieces which are required for flakes. The presence of tocopherol as an antioxidant in the oat grain treatment composition prevents the oxidative deterioration of the final products.

[0041] The use of the present composition increases the output of flour or grit mills with a concurrent gain in the quality and dietary value of the milled products.