Cereal flour, its processing method and raw material for preparing baked foods

Abstract

The present invention relates to the field of cereal flours, and discloses a cereal flour, a processing method thereof, and a raw material for preparing baked foods. The processing method includes: (1) subjecting cereal raw materials to a germination treatment to obtain a germinated product; (2) subjecting the germinated product to a stabilization treatment to obtain a stabilized treatment product; (3) fermenting the stabilized treatment product and then optionally performing a post-treatment to obtain a cereal flour. The baked food prepared from the cereal flour prepared by this processing method not only has a unique fermentation flavor and good improvement in sensory quality characteristics, but also maximally enriches γ-aminobutyric acid in the food.

Description

Technical Field

[0001] The present invention relates to the field of cereal flours, and particularly to a cereal flour, a processing method thereof, and a raw material for preparing baked foods. Background Art

[0002] Cereals are rich in carbohydrates, proteins, vitamins, minerals, and dietary fiber, and can provide about two-thirds of the energy intake. It has been found that biotechnological means such as germination and fermentation can greatly increase the nutritional value of cereals, and the processing process is clean, green, and does not introduce excessive chemical components. The cereal raw materials prepared by this method are rich in nutrition and have a unique flavor.

[0003] Germinated cereals usually have high nutritional value and low antinutrient content. Some research reports have shown that the contents of folic acid, soluble dietary fiber, total protein, and free lipids in germinated wheat are significantly increased, and the contents of functional essential amino acids including phenylalanine, valine, leucine, isoleucine, γ-aminobutyric acid, etc. also increase by different multiples. Among them, the high content of γ-aminobutyric acid in germinated cereals has received extensive attention. γ-aminobutyric acid is an important neurotransmitter, and its main functions include lowering blood pressure, brain health, anti-anxiety, etc., and it has a regulatory effect on various functions of the body. It has been found that the content of γ-aminobutyric acid in germinated cereals is more than 10 times that of ungerminated cereals. The application of cereal fermentation technology in the field of cereals is also very mature. The cereal raw materials obtained by fermentation have a unique flavor and a high content of soluble dietary fiber such as β-glucan. At the same time, microbial fermentation also promotes the release of components such as γ-aminobutyric acid and polyphenols in cereals. Common strains used in cereal fermentation include Lactobacillus plantarum, Rhizopus, fungi, etc.

[0004] Products such as beverages made from fermented cereals in CN113825405A have a sweet taste and a low glycemic index. In CN113180190A and others, bread is made from germinated wheat flour. Since the raw materials are not subjected to enzyme inactivation treatment, the problem of reduced bread expansibility occurs when the addition amount of germinated wheat flour is low (10-20% by weight).

[0005] However, currently, cereals treated by germination or fermentation processes on the market usually have a high degree of germination or fermentation. The activities of various enzymes and the contents of small molecules and high-viscosity components in the prepared cereal raw materials are relatively high. Therefore, they are mainly applied to cereal beverages (including solid beverages). When applied to baked products, problems such as poor operability and expansibility will occur, so the addition amount is usually not high (10-20% by weight). Globally, the products made from germinated or fermented cereals are rich and diverse, but they are very rare in the Chinese market. In particular, the technical field of preparing special cereal flours for baking by using both germination and fermentation processes is still blank. Summary of the Invention

[0006] The object of the present invention is to overcome the problems in the prior art that cereal flours have poor flavor, low γ-aminobutyric acid content, and the prepared foods have poor sensory qualities, and to provide a cereal flour, its processing method, and a raw material for preparing baked foods. The baked foods prepared from this cereal flour have a unique fermentation flavor while ensuring good improvement in sensory quality characteristics, and at the same time, γ-aminobutyric acid in the foods is enriched to the greatest extent.

[0007] To achieve the above object, in a first aspect of the present invention, a processing method of a cereal flour is provided, and the processing method includes:

[0008] (1) Germinating cereal raw materials to obtain a germinated product;

[0009] (2) Stabilizing the germinated product to obtain a stabilized product;

[0010] (3) Fermenting the stabilized product and then optionally performing post-treatment to obtain a cereal flour.

[0011] In a second aspect of the present invention, a cereal flour prepared by the above processing method is provided;

[0012] In a third aspect of the present invention, a raw material for preparing baked foods is provided, and the raw material includes the above cereal flour and high-gluten wheat flour.

[0013] Through the above technical solution, the baked foods prepared from the obtained cereal flour have a unique fermentation flavor while ensuring good improvement in sensory quality characteristics, and at the same time, γ-aminobutyric acid in the cereal raw materials is enriched to the greatest extent. In addition, the nutrients in germinated cereals are more abundant and the flavor is more unique. However, in the prior art, when using germinated cereals to make baked foods, especially bread, adding too much will cause problems such as poor operability and expansibility. The present invention can also overcome this technical problem. Based on the total weight of the cereal flour and high-gluten flour in the raw material, the cereal flour can be added not less than 50% by weight. Description of the Drawings

[0014] Figure 1 is a picture of bread made from the cereal flour obtained according to Examples 3 and 4 of the present invention, raw oat flour, and commercially available fermented oat flour;

[0015] Figure 2 is the sensory evaluation result of the bread made from the cereal flour obtained according to Examples 3 and 4 of the present invention, raw oat flour, and commercially available fermented oat flour. Detailed Embodiments

[0016] The endpoints and any values within the ranges disclosed in this document are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered specifically disclosed in this document.

[0017] In a first aspect of the present invention, there is provided a method for processing cereal flour, and the processing method includes:

[0018] (1) Germinating cereal raw materials to obtain a germinated product;

[0019] (2) Stabilizing the germinated product to obtain a stabilized product;

[0020] (3) Fermenting the stabilized product and then optionally performing post-treatment to obtain cereal flour.

[0021] In the present invention, when the tip of the bud emerges, the germination of the cereal raw materials stops when the buds just germinate (the tip of the bud is seen). The germination situation can be checked regularly (such as checking every 4 hours) to ensure that the germination treatment causes the tip of the bud to emerge. The germination treatment stops when the tips of the buds of more than 90% (counting by the number of grains), preferably more than 95%, more preferably 98%, and most preferably 100% of the cereal raw materials emerge. Preferably, the tip length of the germinated product is less than 1 mm. Since it is difficult to ensure the uniform progress of germination of each cereal raw material during the germination treatment, the product after the germination treatment can be screened to make the material for step (2) meet the requirements of the emergence of the tip of the bud.

[0022] In the present invention, there is no limitation on the cereal raw materials, and any cereal that can be used as a raw material for baked goods is acceptable. Preferably, the cereal raw materials can include at least one of wheat, oats, brown rice, buckwheat, highland barley, quinoa, millet, and barley.

[0023] In the present invention, the cereal raw materials can be whole grains or moderately ground refined or semi-refined cereals, as long as the germination of the cereal raw materials is not affected.

[0024] In the present invention, in order to enable the cereal raw materials to germinate smoothly and obtain cereal flour with better quality, when selecting cereal raw materials, cereal raw materials with plump grains and good maturity can be selected, and sieving and impurity removal can be carried out.

[0025] In the present invention, before subjecting the cereal raw material to germination treatment, it can be soaked and disinfected. Preferably, the disinfection method includes soaking the cereal raw material in a disinfectant solution. More preferably, the weight ratio of the cereal raw material to the disinfectant solution is 1:0.8 - 2, which can be 1:0.8, 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, or 1:2, etc., but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable. More preferably, the soaking time in the disinfectant solution is 0 - 30 min, which can be 0 min, 5 min, 10 min, 15 min, 20 min, 25 min, or 30 min, etc., but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable. 0 min means that disinfection can be omitted according to the situation.

[0026] In the present invention, there is no restriction on the type and dosage of the disinfectant solution, as long as it can disinfect without affecting the germination of the cereal raw material and human health. Preferably, the disinfectant solution is one of hypochlorous acid solution and H2O2 solution. More preferably, the disinfectant solution is prepared from hypochlorous acid solution and H2O2 solution. More preferably, the concentration of the hypochlorous acid solution is 0.8 - 1.2 wt%. Further preferably, the concentration of the H2O2 solution is 0.08 - 0.12 wt%. More preferably, the weight ratio of hypochlorous acid to H2O2 is 1:0.1 - 10.

[0027] In the present invention, in order to eliminate the influence of the disinfectant solution on the cereal raw material, the disinfected cereal raw material can be washed with water.

[0028] In the present invention, in order to enable the cereal raw material to germinate smoothly and quickly, preferably, the washed cereal raw material is soaked in water for 10 - 14 h to reserve sufficient water in the cereal raw material.

[0029] In the present invention, there is no restriction on the conditions of the germination treatment, as long as the cereal raw material can germinate. Preferably, the conditions of the germination treatment include: avoiding light; the temperature is 14 - 22 °C, which can be 14 °C, 15 °C, 16 °C, 17 °C, 18 °C, 19 °C, 20 °C, 21 °C, or 22 °C, etc., but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable. More preferably, it is 16 - 20 °C, and further preferably 17 - 19 °C; the environmental humidity is above 95%.

[0030] In the present invention, there is no special requirement for the time of germination treatment, as long as the bud tip can emerge. Preferably, the time of germination treatment is 3 - 36 h, which can be 3 h, 4 h, 6 h, 8 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, 24 h, 26 h, 28 h, 30 h, 32 h, 34 h or 36 h, etc., but is not limited to the listed values. Other unlisted values within this numerical range are equally applicable. Preferably, it is 6 - 30 h, and more preferably 12 - 24 h.

[0031] The inventors of the present invention have found that within the range of germination treatment conditions and time of the present invention, not only can the cereal raw materials germinate successfully, but also the baked foods prepared from the obtained cereal flour can further ensure a unique fermentation flavor and improve sensory quality characteristics, and enrich γ-aminobutyric acid in the food to the greatest extent.

[0032] In the present invention, in order to prevent the enzyme activity in the product after germination treatment from being overly activated, which affects the quality of baked products, especially the fermentation flavor and sensory quality characteristics of products that require gluten network support (such as bread, etc.), the present invention performs the stabilization treatment in step (2) immediately after step (1).

[0033] Preferably, the enzyme inactivation degree of the stabilization treatment product is ≥80%, and the enzyme inactivation degree is: In actual operation, heat-resistant amylase can be used as a key detection index. The amylase detection method is "GB / T 5521 - 2008 Cereals and Oils Inspection - Determination of α-Amylase Activity in Cereals and Their Products - Colorimetric Method". The enzyme activity of amylase is defined as the number of grams of soluble starch liquefied by 1 g of amylase within 1 hour under the conditions of 60 °C and pH = 6. More preferably, the conditions of the stabilization treatment include: the temperature is 100 - 130 °C, which can be 100 °C, 105 °C, 110 °C, 115 °C, 120 °C, 125 °C or 130 °C, etc., but is not limited to the listed values. Other unlisted values within this numerical range are equally applicable. Preferably, it is 100 - 120 °C, and more preferably 100 - 110 °C; the time is 3 - 20 min, which can be 3 min, 5 min, 7 min, 10 min, 12 min, 14 min, 16 min, 18 min or 20 min, etc., but is not limited to the listed values. Other unlisted values within this numerical range are equally applicable. Preferably, it is 5 - 15 min, and more preferably 5 - 10 min. The inventors of the present invention have found that within the range of stabilization treatment conditions of the present invention, not only can the enzyme be effectively inactivated, but also the baked foods prepared from the obtained cereal flour can further ensure a unique fermentation flavor and improve sensory quality characteristics, and enrich γ-aminobutyric acid in the food to the greatest extent.

[0034] In the present invention, in order not to affect the fermentation in step (3), after the stabilization treatment, the product can be cooled, preferably to 25 - 35°C, which can be 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C or 35°C, etc., but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0035] Preferably, in step (3), the conditions of the fermentation are such that the content of γ-aminobutyric acid in the obtained fermentation product is not less than 8 mg / g, based on the dry basis of the fermentation product. More preferably, in step (3), the conditions of the fermentation include: the temperature is 32 - 38°C, which can be 32°C, 33°C, 34°C, 35°C, 36°C, 37°C or 38°C, etc., but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable; the time is 12 - 24 h, which can be 12 h, 14 h, 16 h, 18 h, 20 h, 22 h or 24 h, etc., but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0036] In the present invention, the manner of the fermentation is not limited, as long as it can enable the normal fermentation of the product of the stabilization treatment. Preferably, in step (3), the manner of the fermentation includes: inoculating the fermentation strain into the product of the stabilization treatment.

[0037] In the present invention, there is no limit to the number of colonies inoculated into the product of the stabilization treatment, as long as it can ferment normally. Preferably, relative to 1 g of the product of the stabilization treatment, the CFU of the inoculated fermentation strain is 10 2 -10 7 , more preferably 10 3 -10 6 , and further preferably 10 4 -10 6 .

[0038] In the present invention, there is no limit to the fermentation strain, as long as it can enable the normal fermentation of the product of the stabilization treatment to convert L-glutamic acid and its salts into γ-aminobutyric acid. It can be a strain commonly used in the field for fermenting cereal raw materials, such as yeast, lactic acid bacteria, molds, etc. Preferably, the fermentation strain is Lactobacillus fermentum; more preferably, it is the strain with the preservation number CGMCC No. 21156 (this strain has been disclosed in CN 114437960A).

[0039] The inventors of the present invention have found that within the range of the fermentation conditions, fermentation methods, number of inoculated colonies, and fermentation strains in the stabilization treatment product of the present invention, not only can efficient fermentation be achieved, but also the baked foods prepared from the obtained cereal flour can further ensure a unique fermentation flavor and improve sensory quality characteristics, and can enrich γ-aminobutyric acid in the food to the greatest extent.

[0040] In the present invention, in order to prevent over-fermentation and further facilitate subsequent processing, transportation, and use, the method may further include a post-treatment step, and the post-treatment may include: drying the fermentation product obtained by fermentation; preferably, the water content of the dried product obtained by drying is not higher than 12% by weight.

[0041] In the present invention, the conditions for drying are not limited as long as the water content of the dried product can meet the requirements. Preferably, the conditions for drying include: the temperature is 90 - 120 °C, more preferably 95 - 110 °C, and further preferably 95 - 105 °C; the time is 1 - 12 h, more preferably 5 - 10 h, and further preferably 7 - 9 h.

[0042] In the present invention, the method of drying is not limited as long as it has a drying function. Preferably, it can meet the temperature and time within the scope of the present invention. More preferably, the method of drying includes at least one of hot air drying, drum drying, and fluidized bed drying.

[0043] In the present invention, in order to facilitate the processing of baked foods, the post-treatment may further include: pulverizing the dried product to obtain a pulverized product.

[0044] In the present invention, according to the specific needs of the product, the dried product can be pulverized into cereal flour products with different particle sizes. Preferably, 95% or more of the pulverized product has a sieve aperture of 20 - 300 mesh, more preferably 60 - 180 mesh, and further preferably 80 - 120 mesh. The "sieve aperture" refers to the number of holes per square inch of the sieve mesh.

[0045] The second aspect of the present invention provides a cereal flour prepared by the above processing method.

[0046] Preferably, the content of γ-aminobutyric acid in the cereal flour is ≥ 8 mg / g.

[0047] Preferably, the content of phenylethyl alcohol in the cereal flour is 160 - 300 μg / kg, and it can be 160 μg / kg, 180 μg / kg, 200 μg / kg, 220 μg / kg, 240 μg / kg, 260 μg / kg, 280 μg / kg, or 300 μg / kg, etc., but is not limited to the listed values. Other unlisted values within this numerical range are equally applicable. More preferably, it is 200 - 300 μg / kg.

[0048] Preferably, the content of nonanal in the cereal powder is 200-400 μg / kg, and it can be 200 μg / kg, 220 μg / kg, 240 μg / kg, 260 μg / kg, 280 μg / kg, 300 μg / kg, 320 μg / kg, 340 μg / kg, 360 μg / kg, 380 μg / kg or 400 μg / kg, etc., but it is not limited to the listed values. Other unlisted values within this range are equally applicable, and more preferably it is 220-350 μg / kg.

[0049] Preferably, the content of 3-hydroxy-2-butanone in the cereal powder is 80-200 μg / kg, and it can be 80 μg / kg, 90 μg / kg, 100 μg / kg, 110 μg / kg, 120 μg / kg, 130 μg / kg, 140 μg / kg, 150 μg / kg, 160 μg / kg, 170 μg / kg, 180 μg / kg, 190 μg / kg or 200 μg / kg, etc., but it is not limited to the listed values. Other unlisted values within this range are equally applicable, and more preferably it is 100-190 μg / kg.

[0050] Preferably, the content of acetic acid in the cereal powder is 150-900 μg / kg, and it can be 150 μg / kg, 200 μg / kg, 250 μg / kg, 300 μg / kg, 350 μg / kg, 400 μg / kg, 450 μg / kg, 500 μg / kg, 550 μg / kg, 600 μg / kg, 650 μg / kg, 700 μg / kg, 750 μg / kg, 800 μg / kg, 850 μg / kg or 900 μg / kg, etc., but it is not limited to the listed values. Other unlisted values within this range are equally applicable, and more preferably it is 150-700 μg / kg.

[0051] Preferably, the content of ethyl lactate in the cereal flour is 180 - 660 μg / kg, and it can be 180 μg / kg, 200 μg / kg, 220 μg / kg, 240 μg / kg, 260 μg / kg, 280 μg / kg, 300 μg / kg, 320 μg / kg, 340 μg / kg, 360 μg / kg, 380 μg / kg, 400 μg / kg, 420 μg / kg, 440 μg / kg, 460 μg / kg, 480 μg / kg, 50 μg / kg, 520 μg / kg, 540 μg / kg, 560 μg / kg, 580 μg / kg, 600 μg / kg, 620 μg / kg, 640 μg / kg or 660 μg / kg, etc., but not limited to the listed values. Other unlisted values within this numerical range are equally applicable. More preferably, it is 200 - 600 μg / kg.

[0052] Preferably, the content of diacetyl in the cereal flour is 60 - 300 μg / kg, and it can be 60 μg / kg, 80 μg / kg, 100 μg / kg, 120 μg / kg, 140 μg / kg, 160 μg / kg, 180 μg / kg, 200 μg / kg, 220 μg / kg, 240 μg / kg, 260 μg / kg, 280 μg / kg or 300 μg / kg, etc., but not limited to the listed values. Other unlisted values within this numerical range are equally applicable. More preferably, it is 100 - 260 μg / kg.

[0053] Preferably, the content of 2 - pentanone in the cereal flour is 30 - 100 μg / kg, and it can be 30 μg / kg, 40 μg / kg, 50 μg / kg, 60 μg / kg, 70 μg / kg, 80 μg / kg, 90 μg / kg or 100 μg / kg, etc., but not limited to the listed values. Other unlisted values within this numerical range are equally applicable. More preferably, it is 40 - 90 μg / kg.

[0054] The third aspect of the present invention provides a raw material for preparing baked foods, and the raw material includes the above - mentioned cereal flour and high - gluten wheat flour.

[0055] In the present invention, there is no limitation on the baked foods, as long as they are foods produced by baking. Preferably, the baked foods include at least one of bread, cakes and biscuits.

[0056] In the present invention, based on the total weight of the cereal flour and high-gluten wheat flour in the raw materials, the content of the cereal flour is not limited. The inventors of the present invention have found that the content of the cereal flour can be not less than 50% by weight (such as 50-80% by weight), and the obtained baked food can still ensure having a unique fermentation flavor and also having a good improvement effect on sensory quality characteristics while enriching γ-aminobutyric acid in the food to the greatest extent.

[0057] The present invention will be described in detail below through examples. In the following examples and comparative examples, the cereal raw materials are all commercially available raw materials that have been cleaned, with an impurity rate ≤ 0.5%. The brown rice is from Heilongjiang; the oats are from Australia; the wheat is from Canada; the barley is from France; the highland barley is from Tibet; the hypochlorous acid is from Sinopharm Chemical Reagent Co., Ltd.; H2O2 is from Sinopharm Chemical Reagent Co., Ltd.; the high-gluten wheat flour is from COFCO Hailjia (Xiamen) Flour Industry Co., Ltd.; the vital gluten is from Zhongyu Food Co., Ltd., with a protein content ≥ 80%; the milk powder is from Fonterra Co-operative Group Limited, whole milk powder; the granulated sugar is from COFCO Sugar Co., Ltd., first-grade white sugar; the yeast is from Angel Yeast Co., Ltd., a high-sugar tolerant active dry yeast; the butter is from Fonterra Co-operative Group Limited, unsalted butter.

[0058] Determination method of γ-aminobutyric acid: Refer to the standard "NY / T 2890-2016 Determination of γ-aminobutyric acid in rice - High performance liquid chromatography method".

[0059] Determination method of α-amylase activity: Refer to the standard "GB / T 5521-2008 Cereals and oils inspection - Determination of α-amylase activity in cereals and their products - Colorimetric method".

[0060] Example 1

[0061] (1) Raw material screening: Select plump and well-matured brown rice, and conduct sieving and impurity removal.

[0062] (2) Soaking and disinfection: First, soak the cereals in a mixed solution of 1% by weight of hypochlorous acid and 0.1% by weight of H2O2 (weight ratio of 1:1) for 10 min (weight ratio of cereals to the mixed solution is 1:1), and then rinse repeatedly with clean water.

[0063] (3) Germination: Soak the cereal raw materials in water for 12 h, then place them in a constant temperature incubator at 16 °C in the dark for continuous germination for 12 h, turning them over every 8 h, and keeping the environmental humidity above 95%. Stop germination when the cereals just germinate (seeing the bud tip length < 1 mm).

[0064] (4) Stabilization treatment: Place the germinated brown rice obtained in step (3) in a steamer at 105 °C and steam for 10 min; the inactivation degree of α-amylase is 90%.

[0065] (5) Cooling: Cool the steamed cereal raw material to 30 °C;

[0066] (6) Fermentation: Inoculate the bacterial agent of Lactobacillus plantarum (purchased from Hebei Yiran Biotechnology Co., Ltd., Lactobacillus plantarum LP45) (CFU = 10 7 cfu / mL) into the cereal raw material described in step (5) at an addition amount of 1% by volume, and perform fermentation at 36 ± 1 °C for 12 h. The content of γ-aminobutyric acid in the fermented raw material is 9.3 mg / g, and the fermented product is calculated on a dry basis.

[0067] (7) Drying: After fermentation, the sample is dried using a drum dryer at a drying temperature of 100 °C and a drying time of 5 h. The water content of the dried sample is 7% by weight.

[0068] (8) Crushing: Crush the dried brown rice material to a 97% passing rate through a 200-mesh sieve.

[0069] The content of γ-aminobutyric acid in the obtained brown rice flour is 8.7 mg / g.

[0070] Example 2

[0071] (1) Raw material screening: Select plump and well-matured highland barley and barley (weight ratio 1:1), and perform sieving and impurity removal;

[0072] (2) Soaking and disinfection: First soak the grains in a mixed solution of 1% by weight hypochlorous acid and 0.1% by weight H2O2 (weight ratio 1:0) for 15 min (weight ratio of grains to mixed solution 1:1.5), and then rinse repeatedly with clean water.

[0073] (3) Germination: Soak the grains in clean water for 12 h, then place the grains in a 20 °C constant temperature incubator and continuously germinate them in the dark for 12 h, turning them over every 8 h to keep the environmental humidity above 95%. Stop germinating when the grains just germinate (the length of the bud tip < 1 mm).

[0074] (4) Stabilization treatment: Place the germinated highland barley and barley obtained in step (3) in a 120 °C steamer and steam for 7 min; the inactivation degree of α-amylase is 80%;

[0075] (5) Cooling: Cool the steamed cereal raw material to 25 °C;

[0076] (6) Fermentation: Inoculate the fermented Lactobacillus plantarum (purchased from Hebei Yiran Biotechnology Co., Ltd., Lactobacillus plantarum LP 45) bacterial agent (CFU = 10 8 cfu / mL) into the cereal raw material described in step (5) at an addition amount of 0.5% by volume, and perform fermentation at 36 ± 1 °C for 18 h. The content of γ-aminobutyric acid in the fermented raw material is 8.9 mg / g, and the fermented product is calculated on a dry basis.

[0077] (7) Drying: After fermentation, the sample is dried using a drum dryer at a drying temperature of 90 °C for 12 h, and the water content of the dried sample is 10% by weight.

[0078] (8) Grinding: The dried brown rice is ground to a 97% passing rate through a 100-mesh sieve.

[0079] The content of γ-aminobutyric acid in the obtained oat flour is 8.5 mg / g.

[0080] Example 3

[0081] (1) Raw material screening: Select oats with plump grains and good maturity, and perform screening and impurity removal.

[0082] (2) Soaking and disinfection: First, soak the grains in a mixed solution of 1% by weight hypochlorous acid and 0.1% by weight H2O2 (weight ratio 1:10) for 5 min (weight ratio of grains to mixed solution 1:0.8), and then rinse repeatedly with clean water.

[0083] (3) Germination: Soak the grains in clean water for 12 h, then place the grains in a constant temperature incubator at 14 °C and germinate continuously in the dark for 36 h, turning once every 8 h, and maintaining the environmental humidity above 95%. Stop germination when the grains just germinate (tip length of the bud < 1 mm).

[0084] (4) Stabilization treatment: Place the germinated oats obtained in step (3) in a steamer at 100 °C and steam for 20 min; the inactivation degree of α-amylase is 85%.

[0085] (5) Cooling: Cool the steamed grain raw material to 35 °C.

[0086] (6) Fermentation: Inoculate the grain raw material described in step (5) with a bacterial agent of Lactobacillus fermentum (strain with deposit number CGMCC No. 21156) (CFU = 10 8 cfu / mL) at an addition amount of 0.3% by volume and ferment at 36 ± 1 °C for 20 h. The content of γ-aminobutyric acid in the fermented raw material is 10.5 mg / g, based on the dry basis of the fermentation product.

[0087] (7) Drying: After fermentation, the sample is dried using a drum dryer at a drying temperature of 120 °C for 1 h, and the water content of the dried sample is 5% by weight.

[0088] (8) Grinding: Grind the dried oats to a 98% passing rate through a 60-mesh sieve.

[0089] The content of γ-aminobutyric acid in the obtained oat flour is 9.7 mg / g.

[0090] Example 4

[0091] (1) Raw material screening: Select oats with plump grains and good maturity, and conduct screening and impurity removal;

[0092] (2) Soaking and disinfection: First soak the grains in a mixed solution of 1 wt% hypochlorous acid and 0.1 wt% H2O2 (weight ratio of 1:0.5) for 30 min (weight ratio of grains to the mixed solution is 1:1), and then rinse repeatedly with clean water.

[0093] (3) Germination: Soak the grains in clean water for 12 h, then place the grains in a constant temperature incubator at 22 °C and germinate continuously in the dark for 3 h, keeping the environmental humidity above 95%. Stop germination when the grains just germinate (the length of the bud tip < 1 mm).

[0094] (4) Stabilization treatment: Place the germinated oats obtained in step (3) in a steaming box at 130 °C and steam for 3 min; the inactivation degree of α-amylase is 80%;

[0095] (5) Cooling: Cool the steamed grain raw materials to 30 °C;

[0096] (6) Fermentation: Inoculate the strain of Lactobacillus fermentum (the strain with the preservation number of CGMCC No. 21156) bacteria agent (CFU = 10 9 cfu / mL) into the grain raw materials described in step (5) at an addition amount of 0.05 vol%, and ferment at 36 ± 1 °C for 12 h. The content of γ-aminobutyric acid in the fermented raw materials is 10.1 mg / g, calculated on a dry basis of the fermentation product.

[0097] (7) Drying: After fermentation, dry the samples using drum drying. The drying temperature is 110 °C and the drying time is 2 h. The water content of the dried samples is 12 wt%.

[0098] (8) Crushing: Crush the dried oats to a passing rate of 98% through a 60-mesh sieve.

[0099] The content of γ-aminobutyric acid in the obtained oat flour is 9.3 mg / g.

[0100] Example 5

[0101] (1) Raw material screening: Select wheat with plump grains and good maturity, and conduct screening and impurity removal;

[0102] (2) Soaking and disinfection: First soak the grains in a mixed solution of 1 wt% hypochlorous acid and 0.1 wt% H2O2 (weight ratio of 1:5) for 20 min (weight ratio of grains to the mixed solution is 1:0.8), and then rinse repeatedly with clean water.

[0103] (3) Germination: Soak the grains in clean water for 12 h, then place the grains in a constant temperature incubator at 18 °C and germinate continuously in the dark for 24 h, turning them over every 8 h to keep the environmental humidity above 95%. Stop germinating when the grains have just germinated (the length of the bud tip < 1 mm).

[0104] (4) Stabilization treatment: Steam the germinated wheat obtained in step (3) in a steamer at 110 °C for 8 min; the degree of enzyme inactivation of α - amylase is 90%;

[0105] (5) Cooling: Cool the steamed grain raw materials to 30 °C;

[0106] (6) Fermentation: Inoculate the fermentation starter of Lactobacillus fermentum (the strain with the preservation number of CGMCC No. 21156) (CFU = 10 8 cfu / mL) into the grain raw materials described in step (5) at an addition amount of 0.5% by volume, and ferment at 36 ± 1 °C for 24 h. The content of γ - aminobutyric acid in the fermented raw materials is 9.6 mg / g, based on the dry basis of the fermentation product.

[0107] (7) Drying: After fermentation, the samples are dried using a drum dryer at a drying temperature of 100 °C for 6 h. The water content of the dried samples is 5% by weight.

[0108] (8) Crushing: Crush the dried wheat to a 96% passing rate through a 40 - mesh sieve.

[0109] The content of γ - aminobutyric acid in the obtained wheat flour is 8.4 mg / g.

[0110] Example 6

[0111] Prepare the cereal flour according to the method of Example 4, except that in step (3), the germination time is changed to 40 h, and stop germinating when the grains have just germinated (the length of the bud tip is 8 mm).

[0112] The content of γ - aminobutyric acid in the obtained oat flour is 6.8 mg / g.

[0113] Example 7

[0114] Prepare the cereal flour according to the method of Example 4, except that in step (4), for the stabilization treatment, place the germinated oats obtained in step (3) in a steamer at 90 °C. The degree of enzyme inactivation of α - amylase is 40%.

[0115] The content of γ - aminobutyric acid in the obtained oat flour is 7.5 mg / g.

[0116] Example 8

[0117] The cereal powder was prepared according to the method of Example 4, except that in step (5), the fermentation time was changed to 30 h, and the content of γ-aminobutyric acid in the fermented raw material was 5.6 mg / g.

[0118] The content of γ-aminobutyric acid in the obtained oat powder was 5.3 mg / g.

[0119] Comparative Example 1

[0120] The cereal powder was prepared according to the method of Example 4, except that step (3) was not carried out.

[0121] The content of γ-aminobutyric acid in the obtained oat powder was 3.4 mg / g.

[0122] Comparative Example 2

[0123] The cereal powder was prepared according to the method of Example 4, except that step (4) was not carried out.

[0124] The content of γ-aminobutyric acid in the obtained oat powder was 6.7 mg / g.

[0125] Comparative Example 3

[0126] The cereal powder was prepared according to the method of Example 4, except that step (6) was not carried out.

[0127] The content of γ-aminobutyric acid in the obtained oat powder was 1.7 mg / g.

[0128] Test Example

[0129] (1) Test method

[0130] 1) Determination method of flavor substances in cereal powder:

[0131] Take 2 g of cereal powder and put it into a 40 mL headspace vial, add 1 μL of internal standard 2-methyl-3-heptanone with a concentration of 0.816 μg / μL, then seal it, and place it in a constant temperature water bath at 60 °C for 20 min for equilibration. After equilibration, insert the SPME injection needle into the sample vial, carefully push out the fiber extraction head, adsorb for 40 min, then retract the fiber head, carefully pull out the needle. After the gas chromatograph shows "ready", carefully and quickly insert the SPME injection needle into the injection port, push out the extraction head again, perform desorption for 5 min, then retract the fiber head and pull out the needle.

[0132] Chromatographic conditions: polar capillary column DB-WAX; the stationary phase is polyethylene glycol; the carrier gas is high-purity helium, with a flow rate of 1.0 mL / min; the injection port temperature is 230 °C; in splitless mode; the initial temperature is 40 °C, held for 2 min, heated to 50 °C at a rate of 2 °C / min, then heated to 110 °C at a rate of 5 °C / min, and then heated to 230 °C at a rate of 3 °C / min, held for 4 min.

[0133] Mass spectrometry conditions: Electron ionization (EI) source, electron energy 70 eV; ion source temperature 200 °C; interface temperature 280 °C, mass scanning range 29 - 800 u; standard tuning, data acquisition in full scan mode; no solvent delay.

[0134] 2) Method for preparing bread:

[0135] ① Experimental formula

[0136] High-gluten wheat flour: 250 g, cereal flour: 250 g, vital wheat gluten: 15 g, milk powder: 15 g, eggs: 50 g, water: 160 g, granulated sugar: 100 g, salt: 5 g, yeast: 5 g, butter: 70 g.

[0137] ② Preparation method

[0138] Put the high-gluten wheat flour, cereal flour, vital wheat gluten, granulated sugar, yeast, milk powder and salt into the dough mixer according to the above amounts and stir evenly; add the above amounts of eggs and water and beat until the gluten reaches 60%; then add the above amount of butter and stir until the dough is fully developed; let it stand for 10 min, divide it into 6 doughs, roll them into balls, let them stand for 20 min, form them once with a toast forming machine, let them stand for another 20 min, and then shape them twice and put them into a mold (450 g mold) and put them into a proofing box, proof at 210 °C for 30 min until the mold is full.

[0139] 3) Method for sensory evaluation of bread:

[0140] Mainly focus on the sensory evaluation tests of the bread's expansibility, tissue fineness, taste, aroma and flavor indicators. This test is a blind test after product coding. The number of testers is 17, and a total of 16 questionnaires are received. Among them, 15 questionnaires are valid for the preference test and 1 questionnaire is invalid; the average age is 30 years old, the maximum age is 36 years old, and the minimum age is 25 years old. Each evaluator has received training and mastered the unified scoring criteria and scoring methods before the evaluation. The scoring criteria are shown in Table 1.

[0141] Table 1

[0142]

[0143]

[0144] (2) Test results

[0145] 1) Test results of flavor substances in cereal flour

[0146] Determine the flavor of the cereal flour prepared in the examples and comparative examples according to the method in 1) of the test method. The test results are shown in Table 2.

[0147] Table 2

[0148]

[0149] Among them, phenethyl alcohol has the fragrance of fresh bread and sweet rose-like floral fragrance; nonanal has the fragrance of wax, citrus, fatty and floral fragrance; 3-hydroxy-2-butanone and diacetyl have obvious milk / yogurt fragrance; ethyl lactate and 2-pentanone show different types of fruit fragrance, and acetic acid has a sour taste characteristic. Among them, the thresholds of phenethyl alcohol, acetic acid and ethyl lactate are relatively high, and their contribution to flavor is relatively low. The thresholds of diacetyl, 3-hydroxy-2-butanone, 2-pentanone, nonanal, etc. are relatively low, and their contribution to flavor is relatively high. When the concentration of nonanal is too high, there will be bad flavors such as soap and grass. As can be seen from Table 2, the contents of diacetyl, 3-hydroxy-2-butanone and 2-pentanone are relatively high in Examples 3, 4 and 8, and the prepared cereal flour has obvious milk fragrance and fruit fragrance. These substances are easily enriched during the sufficient fermentation of lactic acid bacteria. If germination and fermentation are not sufficient (Comparative Examples 1 and 3), the contents of the above substances are relatively low. The concentration of nonanal should not be too high. If the fermentation is excessive (Example 8) or the enzyme activity is too high (Comparative Example 2), the concentration of nonanal is likely to increase, resulting in poor flavor of the cereal flour raw material.

[0150] 2) Bread sensory evaluation results

[0151] The oat flour prepared in the examples and comparative examples was used to prepare bread with raw oat flour and commercially available fermented oat flour respectively according to the method in Test Method 2), and the bread sensory evaluation was measured according to the method in Test Method 3). The test results are shown in Table 3, Figure 1 and Figure 2 , among which, Table 3 is the bread sensory evaluation results obtained from the cereal flour made from different examples and comparative examples, raw oat flour and commercially available fermented oat flour of the present invention; Figure 1 are the bread pictures made from the cereal flour obtained from Examples 3 and 4, raw oat flour and commercially available fermented oat flour of the present invention; Figure 2 are the bread sensory evaluation results obtained from the cereal flour made from Examples 3 and 4, raw oat flour and commercially available fermented oat flour of the present invention. Among them, A is the bread made from raw oat flour; B is the bread made from the oat flour of Example 3; C is the bread made from the oat flour of Example 4; D is the bread made from commercially available fermented oat flour.

[0152] Table 3

[0153]

[0154]

[0155] It can be seen from the test results that the cereal flour prepared by the technical scheme of the present invention has a more unique flavor, enriches a higher content of γ-aminobutyric acid, and has a higher sensory evaluation score after being made into bread.

[0156] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. Use of a cereal flour in improving the sensory quality of bread, characterized in that, The processing method of the cereal flour comprises: (1) Germinating cereal raw materials to obtain a germinated product; (2) Performing stabilization treatment on the germinated product to obtain a stabilized treatment product; (3) Fermenting the stabilized treatment product and then optionally performing post-treatment to obtain cereal flour; wherein, the tip length of the germinated product is less than 1 mm; wherein, in step (3), the conditions of the fermentation are such that the content of γ-aminobutyric acid in the obtained fermentation product is not less than 8 mg / g based on the dry basis of the fermentation product; wherein, the conditions of the stabilization treatment include: temperature of 100 - 130 °C; time of 3 - 20 min; wherein, the inactivation degree of α-amylase in the stabilized treatment product is ≥ 80%; 2. The application according to claim 1, wherein, The cereal raw materials include at least one of wheat, oats, brown rice, buckwheat, highland barley, quinoa, millet and barley.

3. The application according to claim 1 or 2, wherein The conditions of the germination treatment include: light avoidance; temperature of 14 - 22 °C; environmental humidity above 95%; and / or, the time of the germination treatment is 3 - 36 h.

4. The application according to claim 3, wherein, The conditions of the germination treatment include: temperature of 16 - 20 °C; and / or, the time of the germination treatment is 6 - 30 h; and / or, the conditions of the stabilization treatment include: temperature of 100 - 120 °C; time of 5 - 15 min.

5. The application according to claim 4, wherein, The conditions of the germination treatment include: temperature of 17 - 19 °C; and / or, the time of the germination treatment is 12 - 24 h; and / or, the conditions of the stabilization treatment include: temperature of 100 - 110 °C; time of 5 - 10 min.

6. The application according to claim 1 or 2, wherein In step (3), the conditions of the fermentation include: temperature of 32 - 38 °C, time of 12 - 24 h; and / or, in step (3), the fermentation method includes: inoculating a fermentation strain into the stabilized treatment product.

7. The application according to claim 6, wherein, The inoculation amount of the fermentation strain is 10 2 -10 7 CFU relative to 1 g of the stabilized product.

8. The application according to claim 7, wherein, The inoculation amount of the fermentation strain is 10 3 -10 6 CFU relative to 1 g of the stabilized product.

9. The application according to claim 8, wherein, With respect to 1 g of the stabilized product, the inoculation amount of the fermentation strain is 10 4 -10 6 CFU.

10. The application according to claim 6, wherein, The fermentation strain is Lactobacillus.

11. The application according to claim 10, wherein, The Lactobacillus is the strain with the preservation number of Lactobacillus fermentum CGMCC No. 21156.

12. The application according to claim 1 or 2, wherein, The post-treatment includes: drying the fermentation product obtained by the fermentation.

13. The application according to claim 12, wherein, The water content of the dried product obtained by the drying is not higher than 12% by weight.

14. The application according to claim 12, wherein, The conditions of the drying include: temperature of 90 - 120 °C; time of 1 - 12 h.

15. The application according to claim 14, wherein The conditions of the drying include: temperature of 95 - 110 °C; time of 5 - 10 h.

16. The application according to claim 15, wherein The conditions of the drying include: temperature of 95 - 105 °C; time of 7 - 9 h.

17. The application according to claim 12, wherein, The drying method includes at least one of hot air drying, drum drying and fluidized bed drying.

18. The application according to claim 12, wherein, The post-treatment further includes: pulverizing the dried product obtained by the drying to obtain a pulverized product.

19. The application according to claim 18, wherein, The sieve aperture of 95% or more of the pulverized product is 20 - 300 mesh.

20. The application according to claim 19, wherein, The sieve aperture of 95% or more of the pulverized product is 60 - 180 mesh.

21. The application according to claim 20, wherein The sieve aperture of 95% or more of the pulverized product is 80 - 120 mesh.

22. The application according to claim 1, wherein, The sensory quality includes expansibility, tissue fineness, taste, aroma and flavor.

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