Method for adjusting germination process in malting process

Abstract

The invention provides a method for adjusting a germination process in a malting process, and belongs to the technical field of malting. According to the method, based on the germination uniformity after wheat steeping and the NAD < + > / NADH level indicating the germination activity of barley after wheat steeping, by adjusting the germination temperature and the germination time and combining the synergistic effect of adjustment of fresh air, return air, spraying water amount and spraying time, low malting loss of the germination process and preparation of high-leaching-rate malt can be achieved, and the method is suitable for large-scale popularization and application. The method is key to both a malting maker and a brewer.

Description

Technical Field

[0001] The invention belongs to the technical field of malting, and in particular relates to a method for adjusting a germination process in a malting process. Background Art

[0002] Beer malt refers to malt for brewing beer made from two-row or multi-row beer barley, which is soaked, germinated, dried and roasted. The whole process requires a large amount of water, electricity and steam consumption. The prepared malt undergoes a saccharification process, and the enzyme system regained after malting degrades starch, protein, pentosan, etc. into sugars and amino acids that can be used by brewer's yeast through the catalytic action of the saccharification process. Drinkable beer beverages are obtained through low-temperature fermentation.

[0003] In recent years, the concept of low-carbon factories and energy conservation and consumption reduction has gradually deepened, and the beer industry, including the malting industry, has also become more and more concerned. Similarly, the ultimate pursuit of the malting industry is to obtain more fermentable extracts by consuming water, electricity and steam. On the premise that the quality meets the brewing performance, it is crucial to reduce malting losses and increase the extraction rate. Summary of the invention

[0004] The present invention provides a method for adjusting the germination process in the malting process, the method is based on germination uniformity and NAD + By adjusting the germination temperature and germination time, combined with the synergistic effect of new return air, spraying water volume and spraying time adjustment, low malting loss and high leaching rate of the germination process can be achieved, which is the key for malt makers and brewers.

[0005] NAD + The full name is nicotinamide adenine dinucleotide, which is a coenzyme widely present in organisms. It plays an important role in key cell processes, including energy generation, DNA repair and enzyme activity. + The reduced form of NADH is also called reduced nicotinamide adenine dinucleotide. NADH is produced in the citric acid cycle in glycolysis and cellular respiration. The NADH molecule is a control marker in the energy production chain in mitochondria, and the rise and fall of its level indicates the cellular metabolic state of germinating barley.

[0006] In order to achieve the above-mentioned object, the present invention provides a method for adjusting the germination process in the malting process, based on the germination uniformity after the malting is completed and the NAD indicating the germination activity of the barley after the malting is completed. + / NADH level, the germination process is adjusted to achieve low malting losses and produce high extraction rate malt.

[0007] Preferably, the barley germination uniformity is the time required for the germination rate to reach 20%-90% during the barley germination process.

[0008] Preferably, the adjustment of the germination process includes adjustment of the germination time, the fresh air / return air ratio, the spraying time and the spraying water volume.

[0009] Preferably, the return air volume ratio = 1 - the fresh air volume ratio.

[0010] As a preferred embodiment, the adjustment method is specifically as follows:

[0011] When germination uniformity is less than 8h, NAD + / NADH ratio>0.25, set the germination time to 72h, the germination temperature to 22℃, the fresh air / return air ratio from 0-24h to 24-48h to 48-72h is 9:1-8:2-4:6, the spraying time is 6h, and the spraying water volume is 0.04t / t malt;

[0012] When the germination uniformity is ≥8h and ≤12h, NAD + / NADH ratio is 0.15-0.25, germination time is set to 84h, germination temperature is 20℃, 0-24h~24-48h~48-72h~72-84h fresh air / return air ratio is 9:1-8:2-4:6-4:6, spraying time is 12h, spraying water volume is 0.03t / t malt;

[0013] When germination uniformity is greater than 12h, NAD + / NADH ratio is <0.15, the germination time is set to 90h, the germination temperature is 18℃, the fresh air / return air ratio of 0-24h~24-48h~48-72h~72-90h is 8:2-6:4-4:6-4:6 respectively, the spraying time is 18h, and the spraying water volume is 0.02t / t malt.

[0014] Preferably, NAD + =3.75×ΔA 测定 / W×ΔA 标(NAD+) , in nmol / g, where ΔA 测定 =A 测定 -A 对照 , ΔA 标(NAD + ) =A standard (NAD + ) -A 空白 , W is the sample mass.

[0015] Preferably, NADH = 3.75 × Δ A测定 / W×ΔA 标(NADH) , in nmol / g, where ΔA 测定 =A 测定-A 对照 , ΔA 标(NADH) =A standard (NADH) -A 空白 , W is the sample mass.

[0016] As a preferred embodiment, the malting loss can be reduced by 0.7-1.02% and the leaching rate can be increased by 0.9-1.3%.

[0017] Compared with the prior art, the advantages and positive effects of the present invention are:

[0018] The present invention provides a method for adjusting the germination process in the malting process, the method is based on the germination uniformity after the malting is completed and the NAD indicating the germination activity of the barley after the malting is completed. + / NADH level, by adjusting the germination temperature and germination time, combined with the synergistic effect of new return air, spraying water volume and spraying time adjustment, low malting loss in the germination process and preparation of high leaching rate malt can be achieved.

[0019] In order to meet the standards of malt's physical and chemical indicators, traditional malting technology adopts a long soaking and germination process to promote the dissolution of barley macromolecules. The traditional malting process will cause large malting losses, and the prepared malt has a low leaching rate. The present invention can achieve low malting losses in the germination process and prepare malt with a high leaching rate, which is the key for malt makers and brewers. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] According to the differences in germination conditions of barley after soaking, the present invention introduces new control indicators including germination uniformity and NAD after soaking. + / NADH, by detecting the values ​​of the two indicators, different germination processes are set, including the fresh air / return air ratio, spraying water volume, spraying time, and germination time, ultimately achieving low malting loss and preparing malt with a higher extraction rate.

[0022] It can be understood that in this scheme, the concept of malting germination uniformity is introduced, that is, the time required for barley germination to reach a germination rate of 20%-90% is defined as the uniformity of malting germination. + The germination process for setting the ratio of / NADH is as follows.

[0023]

[0024]

[0025] Example 1

[0026] The finished malt was prepared by continuously tracking 7 batches of barley of different qualities for soaking, germination and drying tests. The germination uniformity index and the finished malt index were tracked and obtained, as shown in Table 1.

[0027] Table 1

[0028]

[0029] By testing the physical and chemical indicators and the uniformity of soaked malt germination in the above table, it is found that the higher the uniformity of soaked malt germination (the shorter the time required for barley germination to reach a germination rate of 20%-90%), the higher the leaching rate, the improvement in storage value and β-glucan, etc., and the less the malting loss. This is mainly because the better the germination uniformity, the better the germination consistency of the population after the malting process is completed, and it promotes germination energy metabolism. Germination energy metabolism includes sucrose and raffinose family oligosaccharides (RFOs) metabolism and triacylglycerol (TAG) metabolism. This is because seed germination in the malting stage requires energy on the one hand and substances on the other. There is no decomposition of protein and starch in the malting stage, and barley cannot use these carbon and nitrogen sources to synthesize root buds and germinate. Therefore, the malting stage is mainly sucrose and raffinose family oligosaccharides (RFOs) metabolism and triacylglycerol (TAG) metabolism to provide energy and material basis for barley germination. After the malting is completed, amylase, protease and glucanase are synthesized under the catalysis of GA (gibberellic acid). The uniformity of malting germination reflects the effect of malting as a whole. The metabolic capacity of various enzyme systems, mainly amylase system, is improved, which increases starch solubility, thereby greatly increasing the leaching rate. Because of the increase in germination uniformity, the dissolution of individual barley in the population is more uniform, and the gap between fast-dissolving and slow-dissolving individuals is shortened, thus reducing the malting losses of fast-dissolving individuals, thereby reducing the malting losses overall.

[0030] On the other hand, energy supply is very critical in this stage. During the soaking stage, the seeds have just germinated, and the energy metabolism of the seeds is in a complex supply stage. Before germination, the seeds rely on a combination of anaerobic respiration and aerobic metabolism for energy supply, and there is a big difference between anaerobic respiration and aerobic respiration energy metabolism. After the seeds germinate, the root buds synthesize vigorously and break through the seed coat and pericarp, which act as semi-permeable membranes, through germination. The breakthrough of the seed coat and pericarp disrupts the energy supply, rapidly increases aerobic respiration, and changes the energy metabolism. Changes in energy metabolism can show the germination state of the seeds after the soaking is completed, and monitor NAD +The redox state of NADH level is the best parameter to characterize the mitochondrial function in vivo, so the intracellular metabolic state of germinated barley after the soaking can also characterize the entire germination vitality of barley after the soaking, which can provide data support for the formulation of subsequent germination process.

[0031] Among them, NAD + / NADH detection method is as follows:

[0032] 1. NAD + and NADH extraction (the sample volume and proportion can be adjusted appropriately according to the preliminary experimental results)

[0033] ① NAD in tissues + Extraction of NADH

[0034] NAD + Extraction: treat the sample in the ratio of sample mass (g): extracting solution A volume (mL) of 1: (5-10) (it is recommended to weigh 0.1g barley sample and add 1mL extracting solution A), homogenize in an ice bath, treat at 95℃ for 5min (seal to prevent water loss), cool to room temperature in an ice bath, centrifuge at 15000g at 4℃ for 10min, draw 500μL supernatant, add 500μL reagent 1 and 500μL extracting solution B in sequence, mix thoroughly, centrifuge at 15000g at 4℃ for 10min, take the supernatant as the sample to be tested, and place it on ice for testing.

[0035] Extraction of NADH: treat the sample in the ratio of sample mass (g): extracting solution B volume (mL) of 1: (5-10) (it is recommended to weigh 0.1g sample and add 1mL extracting solution B), homogenize in an ice bath, treat at 95℃ for 5min (seal to prevent water loss), cool to room temperature in an ice bath, centrifuge at 15000g at 4℃ for 10min, aspirate 500μL supernatant, add 500μL reagent 1 and 500μL extracting solution A in sequence, mix thoroughly, centrifuge at 15000g at 4℃ for 10min, take the supernatant as the sample to be tested, and place it on ice for testing.

[0036] 2. Determination steps

[0037] ① Preheat the spectrophotometer for more than 30 minutes, adjust the wavelength to 570nm, and zero it with distilled water.

[0038] ② Preparation of standard dilution (prepared immediately before use): 2 μmol / mL NAD + The standard solution and 2 μmol / mL NADH standard solution were diluted to 1.25 nmol / mL NAD using distilled water. + Standard dilution and 1.25nmol / mL NADH standard dilution.

[0039]

[0040] ③ Preparation of co-solvent: Prepare according to the volume ratio of anhydrous ethanol: distilled water = 24:1, and mix thoroughly to obtain the co-solvent.

[0041] ④ Preparation of reagent five application solution (prepared before use): Prepare according to the volume ratio of reagent five: reagent six = 1:4 according to the usage amount.

[0042] ⑤ Add the following reagents in sequence to a brown centrifuge tube (under light-proof conditions), mix thoroughly, let stand at room temperature for 5 minutes, centrifuge at 15000g for 15 minutes, discard the supernatant, and keep the precipitate.

[0043]

[0044]

[0045] Absorbance determination: Shake thoroughly to dissolve the precipitate completely, place the reaction solution in a 1mL glass cuvette, and measure the absorbance at 570nm. Note: The blank tube only needs to be measured 1-2 times, and a control tube is required for each sample.

[0046] NAD + , NADH content is calculated as follows (calculated according to the mass of tissue samples)

[0047] NAD + =C 标(NAD + ) ×ΔA / 测定 ×V 提 ×3ΔA 标(NAD + ) ×W=3.75×ΔA 测定 / W×ΔA 标(NAD + ) , in nmol / g, where ΔA 测定 =A 测定 -A 对照 , ΔA 标(NAD + ) =A standard (NAD + ) -A 空白 , W is the sample mass, V 提 is the amount of extract added;

[0048] NADH (nmol / g) = C standard (NADH) × ΔA measurement × V 提 ×3 / ΔA standard (NADH) × W = 3.75 × ΔA 测定 / W×ΔA 标(NADH), in nmol / g, where ΔA 测定 =A 测定 -A 对照 , ΔA 标(NADH) =A standard (NADH) -A 空白 , W is the sample mass, V 提 is the amount of extract added.

[0049] After calculation, the uniformity of germination and NAD of the above 7 batches of barley with different qualities were obtained. + / NADH levels, as shown in Table 2.

[0050] Table 2

[0051]

[0052] By detecting NAD + / NADH level, it was found that it was positively correlated with the uniformity of germination of soaked wheat in the above table, that is, the higher the uniformity of germination of soaked wheat, the higher the NAD + The higher the / NADH ratio level, the higher the metabolic stability in the barley seeds after the soaking and the stronger the mitochondrial function in the cells.

[0053] Example 2

[0054] Tracking 3 batches of barley samples with different germination uniformity, and detecting NAD + / NADH and germination uniformity, and different germination processes were formulated for three batches of barley, as shown in Table 3, 1-1, 2-1, and 3-1 are ordinary germination processes, 1-2, 2-2, and 3-2 are the germination processes of this application based on germination uniformity and NAD + / The adjusted germination process set under the conditions of NADH level detection.

[0055] Table 3

[0056]

[0057] The malt obtained by the above process was used to prepare finished malt, and the germination uniformity index and finished malt index were tracked and obtained, as shown in Table 4.

[0058] Table 4

[0059]

[0060]

[0061] Combined with the data analysis in the above table, it can be seen that the higher the germination uniformity, the better the consistency of the soaked wheat germination. The germination temperature can be appropriately increased to accelerate germination. +The ratio of NADH to NADH can represent the activity of barley germination after the soaking. The higher the ratio, the stronger the activity, and the germination time can be appropriately reduced. Therefore, when adjusting the germination temperature and germination time, combined with the synergistic effect of the new return air, spraying water volume, and spraying time adjustment, it is indeed possible to achieve low malting loss and prepare high leaching rate malt. Compared with the ordinary germination process, the malting loss can be reduced by 0.7-1.02% and the leaching rate can be increased by 0.9-1.3%.

[0062] Further research combined with the germination process provided by the present invention found that hydration in advance during germination promoted the large-scale synthesis of the amylase enzyme system by regulating the metabolic pathways of active oxygen supply ROS (active oxygen) and RNS (active nitrogen), while hydration in the late germination did not produce this effect. These adjustments are beneficial to the synthesis of amylase systems including α-amylase and limit dextrinase, thereby improving the dissolution of starch, increasing the soluble sugar component, and thus increasing the leaching rate. However, hydration in advance during germination will cause a layer of water film to form on the surface of the germinating barley, and the presence of the water film inhibits respiration to a certain extent. The water film inhibits respiration, and other negative effects are the accumulation of arabinoxylan, pentosan, dextrin, etc., so it is necessary to coordinately adjust the germination ventilation at this time, and increase the amount of fresh air on the first and second days of germination, so as to ensure that the maximum moisture in the germination stage is advanced, increase the fresh air to ensure accelerated metabolism, and then combine the temperature setting, The diffusion of moisture is also accelerated, and the maximum moisture in the germination process is increased by changing the amount of spray water, which promotes dissolution. This also shows that the method provided by the present invention is indeed effective.

Claims

1. A method for adjusting the germination process in a malting process, characterized in that: Based on the uniformity of germination after the end of steeping and NAD indicating the germination activity of barley after the end of steeping + / NADH level, the germination process is adjusted to achieve low malting losses and high leaching rates in the process.

2. The adjustment method according to claim 1, characterized in that: The barley germination uniformity refers to the time required for the germination rate to reach 20%-90% during the barley germination process.

3. The adjustment method according to claim 1, characterized in that: Adjustments to the germination process include adjustments to the germination time, germination temperature, fresh air / return air ratio, spraying time, and spraying water volume.

4. The adjustment method according to claim 1, characterized in that: Return air volume ratio = 1-fresh air volume ratio.

5. The adjustment method according to claim 1 or 2, characterized in that: The specific adjustment method is: When germination uniformity is less than 8h, NAD + / NADH ratio>0.25, set the germination time to 72h, the germination temperature to 22℃, the fresh air / return air ratio from 0-24h to 24-48h to 48-72h is 9:1-8:2-4:6, the spraying time is 6h, and the spraying water volume is 0.04t / t malt; When the germination uniformity is ≥8h and ≤12h, NAD + / NADH ratio is 0.15-0.25, germination time is set to 84h, germination temperature is 20℃, 0-24h~24-48h~48-72h~72-84h fresh air / return air ratio is 9:1-8:2-4:6-4:6, spraying time is 12h, spraying water volume is 0.03t / t malt; When germination uniformity is greater than 12h, NAD + / NADH ratio is <0.15, the germination time is set to 90h, the germination temperature is 18℃, the fresh air / return air ratio of 0-24h~24-48h~48-72h~72-90h is 8:2-6:4-4:6-4:6 respectively, the spraying time is 18h, and the spraying water volume is 0.02t / t malt.

6. The adjustment method according to claim 5, characterized in that: NAD + =3.75×ΔA 测定 / W×ΔA 标(NAD + ), the unit is nmol / g, where ΔA 测定 =A 测定 -A 对照 , ΔA 标(NAD + )=A standard (NAD + )-A 空白 , W is the sample mass.

7. The adjustment method according to claim 5, characterized in that: NADH=3.75×Δ A测定 / W×ΔA 标(NADH) , in nmol / g, where ΔA 测定 =A 测定 -A 对照 , ΔA 标(NADH) =A standard (NADH) -A 空白 , W is the sample mass.

8. The adjustment method according to any one of claims 1 to 7, characterized in that: Malting losses can be reduced by 0.7-1.02% and leaching rates can be increased by 0.9-1.3%.

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