Preparation method of glutinous barley sweet distiller's grains

Abstract

This invention discloses a method for preparing glutinous highland barley sweet mash, belonging to the field of agricultural and sideline product production and preparation technology. The method includes: raw material pretreatment, temperature-controlled germination treatment, normal pressure cooking, and saccharification and fermentation. This invention adopts a staged process of "high temperature short-time germination + low temperature long-time germination" and precisely controls the germination length, which synergistically improves the content of functional components such as γ-aminobutyric acid, polyphenols, and flavonoids, as well as the sugar content of the product. The resulting sweet mash is milky white to light yellow in color, has a rich aroma, and a soft, sweet and glutinous taste. It solves the problem of insufficient functionality of traditional sweet mash and is easy to industrialize.

Description

Technical Field

[0001] This invention belongs to the field of agricultural and sideline product production and preparation technology, specifically relating to a method for preparing glutinous highland barley sweet mash. Background Technology

[0002] Sweet fermented grains, a traditional fermented food characteristic of Northwest my country, are mainly made from grains such as oats and highland barley. They are steamed, mixed with koji, and fermented, resulting in a unique flavor that is widely loved. Although traditional oat sweet fermented grains have distinctive characteristics, the content of functional active ingredients (such as γ-aminobutyric acid, polyphenols, and flavonoids) is generally not high. The product's advantages are mainly limited to flavor and taste, and it is insufficient in terms of health and nutritional functions, resulting in limited market competitiveness.

[0003] In existing technologies, although there have been attempts to produce sweet mash using ordinary barley or through germination, the following problems still exist: 1) The background values ​​of functional components in the raw materials used are limited, resulting in insufficient potential for product upgrades; 2) Germination processes mostly use a single constant temperature, failing to finely control the metabolic flow during grain germination, and thus failing to simultaneously maximize the enrichment of functional components and optimize brewing performance (such as saccharification efficiency); 3) There is a lack of systematic process design for the specific end product "sweet mash," especially the lack of synergistic optimization of precise control of sprout length after germination, water volume for cooking, and saccharification and fermentation parameters, making it difficult to achieve a balanced improvement in flavor, taste, and nutritional function.

[0004] Therefore, developing a method for preparing glutinous highland barley sweet mash that can significantly increase the content of functional active ingredients and sugar content while maintaining excellent sensory quality has significant industrial value. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing traditional sweet barley mash, which has weak functionality and insufficient advantages, and to provide a method for preparing sweet barley mash with high functional active ingredient content and high sugar content by using glutinous highland barley as raw material and by precisely controlling key steps such as germination, cooking and saccharification and fermentation.

[0006] The main steps of this invention include:

[0007] (1) Raw material pretreatment: Select plump glutinous highland barley, wash and soak it, and drain it until there is no water on the surface;

[0008] (2) Temperature-controlled germination treatment: The drained glutinous barley was subjected to a first-stage germination treatment and a second-stage germination treatment in sequence; the first-stage germination treatment conditions were: temperature 25-28℃, time 6-8h, relative humidity ≥85%; the second-stage germination treatment conditions were: temperature 12-16℃, time 18-36h, relative humidity ≥80%; the first-stage germination treatment and the second-stage germination treatment controlled the glutinous barley sprout length to 0.1-0.3mm;

[0009] (3) Atmospheric pressure cooking: The glutinous barley after germination treatment is directly cooked under atmospheric pressure for 25-35 minutes until it is fully cooked and has no hard core, to obtain cooked barley;

[0010] (4) Saccharification and fermentation: The cooked barley is cooled to 28-32℃, mixed with sweet wine yeast, mixed evenly, and then placed in a clean container and sealed. It is saccharified and fermented at 25-30℃ for 36-48 hours to obtain the final product, glutinous barley sweet mash.

[0011] Furthermore, in step (2), the second stage of germination treatment adopts a variable temperature process: at Under these conditions, the temperature is switched between 12℃ and 16℃ every 5-7 hours, with a total processing time of 20-28 hours.

[0012] Furthermore, in step (2), before the germination treatment, the glutinous barley is soaked in warm water at 25-30℃ for 2-4 hours, and the amount of water used for soaking is 2-3 times the mass of the glutinous barley.

[0013] Furthermore, in step (3), the atmospheric pressure cooking time is 30 minutes, and the amount of water used for cooking is 1.2-1.5 times the mass of glutinous highland barley after germination treatment.

[0014] Furthermore, in step (4), the cooling process involves spreading the ripened barley into a thin layer no more than 5 cm thick and allowing it to cool naturally until... .

[0015] Furthermore, in step (4), the sweet wine starter is a Rhizopus type sweet wine starter, and the inoculation amount is 0.5-0.8% of the mass of the mature highland barley.

[0016] Furthermore, in step (4), the saccharification and fermentation conditions are: temperature 28-30℃, time 40-44h; after fermentation, the pH value of the final product, glutinous highland barley sweet mash, is 3.8-4.5, and the total acid content is ≤5.0g / kg.

[0017] Furthermore, the sensory evaluation criteria for the final product, glutinous highland barley sweet mash, are as follows: the color is milky white to light yellow, it has a rich sweet wine aroma and the unique aroma of highland barley, the taste is soft, glutinous and sweet, there is no off-flavor, and there are no impurities visible to the naked eye.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. This invention pioneers a staged, precise control process of "high-temperature short-term germination + low-temperature long-term germination," which conforms to the physiological and metabolic laws of seeds;

[0020] The first stage of germination treatment: rapidly activates key metabolic enzyme systems inside the seed (such as glutamate decarboxylase, amylase, etc.), initiates life activities, and makes full preparations for subsequent biosynthesis. The temperature is relatively high at this stage, which can quickly break seed dormancy, activate enzyme activity, and shorten the overall treatment time.

[0021] The second stage of germination treatment: The low temperature environment is conducive to the stable and efficient synthesis and accumulation of functional components such as γ-aminobutyric acid (GABA), polyphenols, and flavonoids. Low temperature can inhibit excessive respiratory consumption, avoid ineffective loss of substrates such as starch and protein, and retain more fermentable sugar sources for subsequent saccharification and fermentation, thereby achieving a dual improvement in "functional components" and "sugar content".

[0022] Precise control of sprout length: By controlling the sprout length within the range of 0.1-0.3mm, the seeds are ensured to be in the best physiological state. If the sprout length is too short, the metabolism will not be fully activated and the functional components will not be enriched enough. If the sprout length is too long, the nutrients will be excessively consumed, affecting the efficiency of subsequent fermentation and sugar production.

[0023] 2. In the second stage of germination treatment, the present invention employs a variable temperature process to simulate the diurnal temperature variation in nature, further stimulating the metabolic activity of seeds, promoting the synthesis and accumulation of functional components, and optimizing the material transformation state inside the grain, thus providing better substrate conditions for subsequent fermentation.

[0024] 3. This invention provides optimized ranges for parameters such as the amount of water used for cooking, the thickness of the cooling layer, the amount of yeast inoculated, the pH at the fermentation endpoint, and the total acid, ensuring process stability and product quality consistency, and facilitating industrialization and promotion. Detailed Implementation

[0025] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0026] Example 1: A method for preparing glutinous highland barley sweet mash

[0027] (1) Raw material pretreatment: Select 5kg of "Ganken Nuo No. 2" glutinous highland barley with plump grains, no mold, and no insect infestation. Wash it three times with clean water to remove impurities and dust. Then soak it in 28℃ warm water for 3 hours. The amount of water used for soaking is 2.5 times the weight of the glutinous highland barley. After soaking, drain it until there is no visible water on the surface.

[0028] (2) Temperature-controlled germination treatment: The drained glutinous barley was placed in a constant temperature incubator and germinated for 7 hours at 27℃ and 85% relative humidity. Then the temperature was adjusted to... Sprouting treatment was carried out under varying temperatures at 80% relative humidity: the temperature was switched between 12℃ and 16℃ every 6 hours, for a total treatment time of 24 hours. After treatment, the sprout length of the glutinous barley was controlled at 0.1-0.3 mm.

[0029] (3) Steaming under normal pressure: Drain the glutinous barley after germination treatment, put it into a steamer, add 1.3 times the weight of the glutinous barley in water, and steam under normal pressure for 30 minutes until fully cooked and without a hard core, to obtain cooked barley.

[0030] (4) Saccharification and fermentation: Spread the cooked barley into a thin layer of 4cm thickness and let it cool naturally to 30℃. Inoculate with Rhizopus type sweet wine yeast at 0.6% of the weight of the cooked barley. After mixing thoroughly, put it into a clean ceramic jar, press it down gently, leaving a depression in the middle. After sealing, place it in a constant temperature box at 28℃ for saccharification and fermentation for 42h. After fermentation, the product pH value is 4.2 and the total acid content is 4.5g / kg.

[0031] The resulting final product, glutinous highland barley sweet mash, is milky white in color, has a rich sweet wine aroma and the unique aroma of highland barley, and has a soft, sweet, and smooth taste with no off-flavors.

[0032] Example 2: A method for preparing glutinous highland barley sweet mash

[0033] (1) Raw material pretreatment: Select 5kg of plump "Ganken Nuo No. 2" glutinous highland barley, wash it clean with water, and then soak it in 25℃ warm water for 4 hours. The amount of water used for soaking is 3 times the weight of the glutinous highland barley. After soaking, drain until there is no water on the surface.

[0034] (2) Temperature-controlled germination treatment: After draining, the glutinous barley was placed in a constant temperature incubator and germinated for 8 hours at 25℃ and 90% relative humidity. Then, it was kept at 12℃ and 85% relative humidity for 36 hours. After the treatment, the glutinous barley sprout length was controlled at 0.2-0.3 mm.

[0035] (3) Steaming under normal pressure: Drain the glutinous barley after germination treatment, put it into a steamer, add 1.5 times the weight of the glutinous barley in water, and steam under normal pressure for 35 minutes until fully cooked and without a hard core, to obtain cooked barley.

[0036] (4) Saccharification and fermentation: Spread the cooked barley into a thin layer of 5cm thickness and let it cool naturally to 28℃. Inoculate with Rhizopus type sweet wine yeast at 0.8% of the weight of the cooked barley. After thorough mixing, put it into a clean container, seal it, and place it in a constant temperature box at 25℃ for saccharification and fermentation for 48h. After fermentation, the product pH value is 4.0 and the total acid content is 4.8g / kg.

[0037] The resulting final product, glutinous highland barley sweet mash, is pale yellow in color, has a rich sweet wine aroma, and a soft and glutinous texture.

[0038] Example 3: A method for preparing glutinous highland barley sweet mash

[0039] (1) Raw material pretreatment: Select 5kg of plump "Ganken Nuo No. 2" glutinous highland barley, wash it clean with water, and then soak it in 30℃ warm water for 2 hours. The amount of water used for soaking is twice the weight of the glutinous highland barley. After soaking, drain until there is no visible water on the surface.

[0040] (2) Temperature-controlled germination treatment: After draining, the glutinous barley was placed in a constant temperature incubator and germinated for 6 hours at 28℃ and 85% relative humidity. Then, the temperature was adjusted to 16℃ and 80% relative humidity for 18 hours. After the treatment, the glutinous barley sprout length was controlled at 0.1 mm.

[0041] (3) Steaming under normal pressure: Drain the glutinous barley after germination treatment, put it into a steamer, add 1.2 times the weight of the glutinous barley in water, and steam under normal pressure for 25 minutes until fully cooked and without a hard core, to obtain cooked barley.

[0042] (4) Saccharification and fermentation: Spread the cooked barley into a thin layer with a thickness of 3cm, cool it naturally to 32℃, inoculate it with Rhizopus type sweet wine yeast at 0.5% of the weight of the cooked barley, mix it thoroughly, put it into a clean container, seal it, and place it in a 30℃ constant temperature box for saccharification and fermentation for 36h. After fermentation, the product pH value is 4.3 and the total acid content is 4.2g / kg.

[0043] The resulting final product, glutinous highland barley sweet mash, is milky white in color, has a rich aroma, and a sweet and smooth taste.

[0044] Comparative Example 1 (Traditional Oat Fermented Rice)

[0045] Using 5 kg of oats as raw material, without any germination or sprouting treatment, the oats were directly rinsed with clean water, steamed at normal pressure for 30 minutes, cooled to 30℃, and inoculated with Rhizopus-type sweet wine koji at 0.6% of the oat weight. After mixing well, the mixture was placed in a clean container, sealed, and placed in a 28℃ constant temperature incubator for saccharification and fermentation for 42 hours.

[0046] Comparative Example 2 (Ordinary highland barley constant temperature germination sweet mash)

[0047] Using 5 kg of ordinary highland barley (non-glutinous) as raw material, after washing it clean with water, it was germinated at a constant temperature of 25℃ for 30 hours, then steamed at normal pressure for 30 minutes, cooled to 30℃, and inoculated with Rhizopus-type sweet wine yeast at 0.6% of the weight of the highland barley. After mixing well, it was put into a clean container, sealed, and placed in a constant temperature incubator at 28℃ for saccharification and fermentation for 42 hours.

[0048] Comparative Example 3 (Ungerminated glutinous barley sweet mash)

[0049] Using 5 kg of "Ganken Nuo No. 2" glutinous highland barley as raw material, without germination treatment, the barley was directly washed with clean water, steamed at normal pressure for 30 minutes, cooled to 30℃, and inoculated with Rhizopus-type sweet wine yeast at 0.6% of the weight of the glutinous highland barley. After mixing, the mixture was placed in a clean container, sealed, and placed in a 28℃ constant temperature incubator for saccharification and fermentation for 42 hours.

[0050] Comparative Example 4 (Treatment for excessively long buds)

[0051] Using 5 kg of "Ganken Nuo No. 2" glutinous highland barley as raw material, after washing it clean with water, it was first germinated at 27℃ for 7 hours, and then germinated at 14℃ for 48 hours until the sprout length reached 0.8-1.0 mm. The subsequent steaming, mixing with koji, and fermentation steps were the same as in Example 1.

[0052] The key indicators of the sweet fermented mash products obtained in Examples 1-3 and Comparative Examples 1-4 were tested, and the results are shown in the table below:

[0053]

[0054] A comparison with Examples 1, 2, and 3 shows that...

[0055] 1. Variable temperature germination (germination at 27℃ initially, followed by alternating periods of 12-16℃) is more effective than constant temperature germination in controlling bud length (0.1-0.3mm). Variable temperature germination simulates the natural diurnal temperature range, stimulating metabolic activity and more fully activating endogenous enzyme systems, promoting moderate starch degradation. The final product is free of hard cores and off-flavors, and is soft, sweet, and glutinous. Example 1 sugar content (35.4°Bx) > Example 2 (34.8°Bx) > Example 3 (33.6°Bx), proving that the variable temperature process is superior to the single constant temperature process.

[0056] 2. All three sets of examples obtained sugar content ≥33°Bx (significantly higher than the comparative example), GABA ≥54mg / 100g (significantly higher than the comparative example), and excellent sensory quality, proving that the preparation method has strong stability.

[0057] Based on the above results, it can be concluded that

[0058] 1. Compared with Comparative Example 1 (traditional oat sweet mash): the sugar content of Example 1 increased by 57.6%, the GABA content increased by 107.4%, the total phenol content increased by 208.4%, and the flavonoid content increased by 280.0%, which shows that the method of the present invention is significantly superior to the traditional sweet mash preparation process.

[0059] 2. Compared with Comparative Example 2 (ordinary barley constant temperature germination sweet mash): the sugar content of Example 1 increased by 23.8%, the GABA content increased by 38.9%, the total phenol content increased by 63.5%, and the flavonoid content increased by 66.7%. This indicates that the staged temperature-controlled germination treatment is better than the single constant temperature germination treatment.

[0060] 3. Compared with Comparative Example 3 (ungerminated glutinous barley sweet mash): the sugar content of Example 1 increased by 16.8%, the GABA content increased by 65.4%, the total phenol content increased by 103.1%, and the flavonoid content increased by 131.7%. This indicates that germination treatment plays a key role in improving the functional components and sugar content of the product.

[0061] 4. Compared with Comparative Example 4 (excessive bud length treatment): The sugar content of Example 1 increased by 20.0%. Although the GABA and total phenol content were slightly higher, the overall quality was significantly better than that of the excessive bud length treatment. This indicates that controlling the bud length within the range of 0.1-0.3 mm is the key to achieving a synergistic improvement in functional components and sugar content.

[0062] In summary, this invention, through staged temperature-controlled germination treatment, precisely controls the bud length to 0.1-0.3 mm, synergistically optimizing the enrichment of functional components and the retention of saccharification and fermentation substrates, achieving a dual improvement in the content of functional components and sugar content of glutinous highland barley sweet mash, and obtaining unexpected technical effects.

[0063] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. The present invention has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing glutinous highland barley sweet mash, characterized in that: The main steps include: (1) Raw material pretreatment: Select plump glutinous highland barley, wash and soak it, and drain it until there is no water on the surface; (2) Temperature-controlled germination treatment: The drained glutinous barley was subjected to a first-stage germination treatment and a second-stage germination treatment in sequence; the first-stage germination treatment conditions were: temperature 25-28℃, time 6-8h, relative humidity ≥85%; the second-stage germination treatment conditions were: temperature 12-16℃, time 18-36h, relative humidity ≥80%; the first-stage germination treatment and the second-stage germination treatment controlled the glutinous barley sprout length to 0.1-0.3mm; (3) Atmospheric pressure cooking: The glutinous barley after germination treatment is directly cooked under atmospheric pressure for 25-35 minutes until it is fully cooked and has no hard core, to obtain cooked barley; (4) Saccharification and fermentation: The cooked barley is cooled to 28-32℃, mixed with sweet wine yeast, mixed evenly, and then placed in a clean container and sealed. It is saccharified and fermented at 25-30℃ for 36-48 hours to obtain the final product, glutinous barley sweet mash.

2. The method for preparing glutinous highland barley sweet mash according to claim 1, characterized in that: In step (2), the second stage of germination treatment adopts a variable temperature process: at Under these conditions, the temperature is switched between 12℃ and 16℃ every 5-7 hours, with a total processing time of 20-28 hours.

3. The method for preparing glutinous highland barley sweet mash according to claim 1, characterized in that: In step (2), before the germination treatment, the glutinous barley is soaked in warm water at 25-30℃ for 2-4 hours, and the amount of water used for soaking is 2-3 times the mass of the glutinous barley.

4. The method for preparing glutinous highland barley sweet mash according to claim 1, characterized in that: In step (3), the atmospheric pressure cooking time is 30 minutes, and the amount of water used for cooking is 1.2-1.5 times the mass of glutinous highland barley after germination treatment.

5. The method for preparing glutinous highland barley sweet mash according to claim 1, characterized in that: In step (4), the cooling process involves spreading the cooked barley into a thin layer no more than 5 cm thick and allowing it to cool naturally until... .

6. The method for preparing glutinous highland barley sweet mash according to claim 1, characterized in that: In step (4), the sweet wine starter is a Rhizopus type sweet wine starter, and the inoculation amount is 0.5-0.8% of the mass of the ripened highland barley.

7. The method for preparing glutinous highland barley sweet mash according to claim 1, characterized in that: In step (4), the saccharification and fermentation conditions are: temperature 28-30℃, time 40-44h; after fermentation, the pH value of the final product, glutinous highland barley sweet mash, is 3.8-4.5, and the total acid content is ≤5.0g / kg.

8. The method for preparing glutinous highland barley sweet mash according to any one of claims 1-7, characterized in that: The sensory evaluation criteria for the final product, glutinous highland barley sweet mash, are as follows: it is milky white to light yellow in color, has a rich sweet wine aroma and the unique aroma of highland barley, has a soft, sweet and glutinous taste, no off-flavors, and no visible impurities.

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