Preparation method of low-beta-glucan malt

Abstract

The invention discloses a preparation method of low-beta-glucan malt, and belongs to the technical field of malting. According to the technical scheme, the method comprises the following steps: adjusting a drying step according to relative beta-glucanase activity (RAG) of malt and an optimal time interval (KPG) of the beta-glucanase activity; rAG is the ratio of the activity peak value of beta-glucanase in malt in the drying process to the activity peak value of beta-glucanase in the germination process; the KPG is obtained by the following method: determining a moisture change interval of the malt beta-glucanase activity in a high activity state in the drying process by detecting a change curve of the malt beta-glucanase activity along with malt moisture in the drying process; and determining the time corresponding to the change of the malt moisture in the interval according to a curve of the change of the malt moisture along with the drying time in the drying process, namely the KPG. The method is applied to malting, the problem that dissolution of beta-glucan is difficult to adjust and improve in an existing malting method is solved, and the glucanase activity can be rapidly and efficiently adjusted, so that the content of beta-glucan in final malt is reduced, and high-quality finished malt is prepared.

Description

Technical Field

[0001] This invention belongs to the field of malt processing technology, and particularly relates to a method for preparing low β-glucan malt. Background Technology

[0002] β-glucan is an important component of soluble non-starch polysaccharides (SNSP) in barley. It is one of the main reasons for beer turbidity, poor foam persistence, and weak clinging. However, the β-glucan content in malt needs to be controlled within a reasonable range. During the malting process, its content in the wort should be reduced as much as possible, and ultimately controlled below 100mg / 100g.

[0003] Barley undergoes soaking, germination, drying, and root removal to ultimately produce finished malt. The degradation of β-glucan during malting is crucial for malt quality. Incomplete degradation leads to excessively high β-glucan content in the finished malt and wort, negatively impacting beer production during the mashing and filtration stages. The mashing stage requires increased β-glucanase to improve efficiency, while the filtration stage is affected by β-glucan, leading to prolonged filtration time, reduced filter membrane life, and increased brewing costs. The dissolution of β-glucan during malting depends on the activation of β-glucanase after soaking. β-glucanase catalyzes the dissolution of macromolecular glucan under specific conditions (temperature, humidity, etc.). Soaking and germination processes are typically carried out at 14-20℃ for a total of 4-5 days, a low-temperature, slow catalytic process. Malters spend most of their effort on dissolving glucan during germination, mainly because the germination process is long and β-glucanase is continuously produced during germination. Therefore, malters typically control the temperature, moisture, and time during the germination stage to reduce the effect of β-glucan. However, there is a drawback to adjusting the process parameters during germination: adjusting temperature, moisture, and time has little impact on β-glucanase activity. Adjustments during soaking and germination have a poor effect on β-glucan dissolution and mostly involve extending the time and increasing energy consumption. As is well known, the optimal temperature for β-glucanase is 40-60℃, while the temperature range for soaking and germinating barley is 14-20℃. It is easy to understand that glucan dissolves more slowly under low-temperature germination conditions. From the perspective of the optimal operating temperature, the drying process should be a rapid and efficient stage for β-glucanase action. However, due to the differences in moisture, humidity, pH and other factors inside barley grains, the specific drying temperature still needs to be explored and optimized in conjunction with the drying process.

[0004] Therefore, a crucial aspect of malting is improving β-glucan solubility and reducing its content in malt through process adjustments. This includes modifying soaking and germination processes, such as adjusting soaking temperature, maximum germination moisture content, later germination temperature, and germination time. However, these adjustments have a slow and time-consuming effect on β-glucan degradation because low-temperature and prolonged soaking and germination processes promote uniform malt dissolution. Furthermore, some varieties, such as Australian, French, and domestic wheat, are difficult to adjust to achieve the desired β-glucan levels through soaking and germination alone due to their varietal characteristics. Therefore, this technology focuses on the drying stage of malting, aiming to increase glucan degradation through rapid and efficient drying processes, thereby reducing β-glucan content in malt and lowering energy consumption. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is that it is difficult to adjust and improve the solubility of β-glucan in the existing malting methods. The present invention proposes a method for preparing high-quality low-β-glucan finished malt that can quickly and efficiently adjust the activity of glucanase.

[0006] To solve the aforementioned technical problem, the technical solution adopted by the present invention is as follows: This invention provides a method for processing low-β-glucan malt, adjusting the drying steps based on the relative β-glucanase activity (RAG) and the optimal time interval (KPG) for β-glucanase activity. RAG is the ratio of the peak β-glucanase activity during the malt drying process to the peak β-glucanase activity during the germination process. KPG is obtained by: determining the moisture variation range where β-glucanase activity is at a high activity level during the drying process by detecting the curve of malt β-glucanase activity versus moisture; and then determining the time required for barley moisture to change within the above range based on the curve of malt moisture versus drying time, which is the KPG.

[0007] Preferably, RAG is the ratio of β-glucanase activity when malt is dried for 4 h to β-glucanase activity when malt is germinated for 82 h.

[0008] Preferably, KPG is the time required for the malt moisture content to decrease from 35±2.0% to 20±2.0% during the drying process.

[0009] Preferably, the β-glucanase includes endo-β-1,4-glucanase and exo-β-1,3-glucanase.

[0010] Preferably, the value range of RAG includes: RAG < 1.0; 1.0 ≤ RAG ≤ 1.4; RAG > 1.4; and the value range of KPG includes: KPG < 3h; 3.0h ≤ KPG ≤ 4.5h; KPG > 4.5h.

[0011] Preferably, the values ​​of RAG and KPG in barley during the barley production process are within the following ranges: RAG < 1.0, KPG < 3.0h; 1.0 ≤ RAG ≤ 1.4, 3.0h ≤ KPG ≤ 4.5h; RAG > 1.4; KPG > 4.5h.

[0012] Preferably, when the values ​​of RAG and KPG in the barley during the barley processing are: RAG < 1.0, KPG < 3.0h, the drying process is adjusted relative to the standard drying process as follows: the initial drying temperature is reduced to 41℃; before the initial temperature rises to 65℃, the fresh air volume is increased to 80-100%; and the temperature is set between 45℃ and 55℃ as follows: 47℃ 4 h - 51℃ 2 h - 54℃ 1 h.

[0013] Preferably, when the values ​​of RAG and KPG in the malt during the malting process are: 1.0≤RAG≤1.4, 3.0h≤KPG≤4.5h, the drying process is adjusted relative to the standard drying process as follows: the initial drying temperature is reduced to 42℃; before the initial temperature rises to 60℃, the fresh air volume is increased to 70-80%; and the temperature between 50-60℃ is set to: 54℃ 2 h-58℃ 2 h.

[0014] Preferably, when the values ​​of RAG and KPG in the malt during the malting process are: RAG > 1.4; KPG > 4.5h, the drying process is adjusted relative to the standard drying process as follows: the initial drying temperature is reduced to 43℃; the fresh air consumption is increased to 60%.

[0015] Preferred standard drying process is: 45℃ 2 h - 50℃ 2 h - 55℃ 4 h - 65℃ 4 h - 70℃ 2 h - 75℃ 2 h - 84℃ 3 h, with fresh air consumption of 50%.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a method for preparing low-β-glucan malt. Based on the relative β-glucanase activity (RAG) and the optimal time range (KPG) for β-glucanase activity, the method can quickly and efficiently adjust the glucanase activity by adjusting the drying process after germination, thereby reducing the β-glucan content of the final malt and preparing high-quality finished malt. Attached Figure Description

[0017] Figure 1The curves showing the relative enzyme activity and moisture content changes of β-glucan during the wheat drying process provided in this embodiment of the invention. Detailed Implementation

[0018] The technical solutions in specific embodiments of the present invention will be described in detail and completely below. Obviously, the described embodiments are only some specific implementations of the overall technical solution of the present invention, and not all implementations. Based on the overall concept of the present invention, all other embodiments obtained by those skilled in the art fall within the protection scope of the present invention.

[0019] This invention provides a method for preparing low-β-glucan malt, adjusting the malt drying steps based on the relative β-glucanase activity (RAG) of the malt and the optimal time range (KPG) for β-glucanase activity. RAG is the ratio of the peak β-glucanase activity during drying to the peak β-glucanase activity during germination. KPG is obtained by: determining the moisture variation range where β-glucanase activity is high during drying by detecting the malt β-glucanase activity versus moisture change curve; and then determining the time required for malt moisture to change within this range based on the malt moisture versus drying time curve, which is the KPG. The β-glucanase includes endo-β-1,4-glucanase and exo-β-1,3-glucanase.

[0020] Regarding RAG, the above technical solution tracks the activity of glucanase in barley germination from 0 to 96 hours, including endo-β-1,4-glucanase and exo-β-1,3-glucanase, to determine the enzyme activity value at which the glucanase activity is 100%. By detecting the enzyme activity at each time point during the malt drying process, the relative activity of glucanase during the drying process is calculated, and the β-glucanase activity RAG is defined (taking the average of the two relative enzyme activities): RAG% = peak enzyme activity during drying process / peak enzyme activity during germination process * 100%.

[0021] The above technical solution, based on relative β-glucanase activity (RAG) and the optimal time range (KPG) for β-glucanase activity, can quickly and efficiently adjust glucanase activity by adjusting the drying process after germination, thus producing high-quality low-β-glucan malt.

[0022] In a preferred embodiment, RAG is the ratio of β-glucanase activity at 4 h of malt drying to β-glucanase activity at 82 h of germination. Throughout the malting process, from 0 h of germination to 96 h of germination, the activity of endoβ-1,4-glucanase and exoβ-1,3-glucanase initially increases, then decreases, and eventually stabilizes in the later stages of germination. By tracking the activity curves of endoβ-1,4-glucanase and exoβ-1,3-glucanase during the germination process of multiple batches of barley, it was found that the enzyme activity reaches its peak around 80-88 h during germination and then gradually decreases after a period of time. By tracking the activities of endoβ-1,4-glucanase and exoβ-1,3-glucanase during malt drying, it was found that the activities initially increased slightly or remained stable for a period of time before rapidly decreasing. The main reason is that the moisture content inside the barley grains is high at the beginning of drying. As the drying temperature gradually increases, the air temperature rises rapidly. However, the temperature inside the barley grains rises gradually over time. After 3-7 hours of drying, the temperature inside the grains gradually rises to the optimal temperature and humidity for glucanase and remains at this level for a period of time. This period is the optimal stage for amylase to function.

[0023] In a preferred embodiment, KPG is the time required for the moisture content of malt to decrease from 35±2.0% to 20±2.0% during the malt drying process.

[0024] Firstly, by tracking the changes in β-glucanase activity during malt drying, including the changes in endo-β-1,4-glucanase and exo-β-1,3-glucanase throughout the drying process, it was determined that β-glucanase activity was highest when the moisture content of malt decreased from 35% to 20%, thus identifying this period as the critical time point for glucanase activity. Throughout the drying process, the moisture content of green malt rapidly decreased from approximately 42-46% to approximately 3%-5%. Tracking the moisture change curves and glucanase activity curves of multiple batches of malt during drying revealed that both endo-β-1,4-glucanase and exo-β-1,3-glucanase activity was relatively high during the stage when the moisture content of green malt decreased from 35.0±2.0% to 20.0±2.0%. The enzyme activity decreased rapidly with increasing temperature as the moisture content decreased. Therefore, the time when the malt moisture content is 35-20% during the drying process is defined as the critical time point for the regulation of glucanase activity, and the time required for the moisture content to decrease from 35% to 20% is taken as the KPG.

[0025] In a preferred embodiment, the value range of RAG includes: RAG < 1.0; 1.0 ≤ RAG ≤ 1.4; RAG > 1.4; and the value range of KPG includes: KPG < 3h; 3.0h ≤ KPG ≤ 4.5h; KPG > 4.5h.

[0026] In a preferred embodiment, the values ​​of RAG and KPG in barley during the barley production process include: RAG < 1.0, KPG < 3.0h; 1.0 ≤ RAG ≤ 1.4, 3.0h ≤ KPG ≤ 4.5h; RAG > 1.4; KPG > 4.5h.

[0027] In a preferred embodiment, when the values ​​of RAG and KPG in the barley during the barley processing are: RAG < 1.0, KPG < 3.0h, the drying process is adjusted as follows: the initial drying temperature is reduced to 41℃; before the initial temperature rises to 65℃, the fresh air volume is increased to 80-100%; and the temperature is set between 45℃ and 55℃ as follows: 47℃ 4 h - 51℃ 2 h - 54℃ 1 h.

[0028] In a preferred embodiment, the standard drying process is: 45℃ 2 h - 50℃ 2 h - 55℃ 4 h - 65℃ 4 h - 70℃ 2 h - 75℃ 2 h - 84℃ 3 h, with a fresh air consumption of 50%. When the RAG and KPG values ​​in the malt during the malting process are: RAG < 1.0, KPG < 3.0h, the drying process is adjusted to: 41℃ 2 h (100%) - 47℃ 4 h (90%) - 51℃ 2 h (80%) - 54℃ 1 h (70%) - 65℃ 3 h (60%) - 70℃ 2 h (60%) - 75℃ 2 h (50%) - 84℃ In a preferred embodiment, when the values ​​of RAG and KPG in the green malt during the malting process are: 1.0≤RAG≤1.4, 3.0h≤KPG≤4.5h, the drying process is adjusted relative to the standard drying process as follows: the initial drying temperature is reduced to 42℃; before the initial temperature rises to 60℃, the fresh air volume is increased to 70-80%; and the temperature between 50-60℃ is set to: 54℃ 2 h-58℃ 2 h.

[0029] In a preferred embodiment, the standard drying process is: 45℃ 2 h - 50℃ 2 h - 55℃ 4 h - 65℃ 4 h - 70℃ 2 h - 75℃ 2 h - 84℃ 3 h, with a fresh air consumption of 50%. When the values ​​of RAG and KPG in the barley during the malting process are: 1.0 ≤ RAG ≤ 1.4, 3.0h ≤ KPG ≤ 4.5h, the drying process is adjusted as follows: 42℃ 2 h (80%) -48℃ 2 h (70%) -54℃ 2 h (70%) -58℃ 2 h (80%) -65℃ 4 h (60%) -70℃ 2 h (60%) -75℃ 2 h (50%) -84℃ 3 h (50%) In a preferred embodiment, when the values ​​of RAG and KPG in the green malt during the malting process are: RAG > 1.4; KPG > 4.5h, the drying process is adjusted relative to the standard drying process as follows: the initial drying temperature is reduced to 43°C; the fresh air consumption is increased to 60%.

[0030] In a preferred embodiment, the standard drying process is: 45℃ 2 h - 50℃ 2 h - 55℃ 4 h - 65℃ 4 h - 70℃ 2 h - 75℃ 2 h - 84℃ 3 h, with a fresh air consumption of 50%. When the values ​​of RAG and KPG in the barley during the malting process are: RAG > 1.4; KPG > 4.5h, the drying process is adjusted to: 43℃ 2 h - 46℃ 2 h - 48℃ 2 h - 52℃ 2 h - 65℃ 4 h - 70℃ 2 h - 75℃ 2 h - 84℃ 3 h, with a fresh air consumption of 60%.

[0031] In a preferred embodiment, the standard drying process is as follows: 45℃ 2 h - 50℃ 2 h - 55℃ 4 h - 65℃ 4 h - 70℃ 2 h - 75℃ 2 h - 84℃ 3 h, with a fresh air consumption of 50%.

[0032] To provide a clearer and more detailed description of the preparation method of low β-glucan malt provided in the embodiments of the present invention, specific embodiments will be described below.

[0033] Example 1 Using the same variety and batch of Copeland malt, after soaking and germination, three samples of green malt that had finished germination were selected, with 1 kg of each sample weighed. The relative enzyme activity (RAG) and the optimal time interval (KPG) of β-glucanase activity were measured 4 hours after the start of drying using three different drying processes. The β-glucan content and wort viscosity of the finished malt were also measured, as shown in Table 1. The results indicate that higher RAG and KPG values ​​correlated with lower β-glucan content and viscosity in the final malt, suggesting that under different drying processes, RAG and KPG are correlated with both β-glucan content and viscosity.

[0034] Table 1. RAG, KPG, dextran, and viscosity under different drying processes

[0035] In Table 1, drying process 1 is: 50℃ 5 h - 55℃ 4 h - 65℃ 4 h - 70℃ 2 h - 84℃ 3 h; drying process 2 is: 50℃ 3 h - 53℃ 2 h - 55℃ 3 h - 60℃ 3 h - 65℃ 2 h - 70℃ 2 h - 84℃ 3 h; drying process 3 is: 48℃ 3 h - 52℃ 3 h - 55℃ 2 h - 60℃ 2 h - 65℃ 3 h - 70℃ 2 h - 84℃ 3 h.

[0036] The results showed that during the initial drying stage, the temperature gradually increased, but the internal temperature of the green malt rose slowly. The glucanases (including endo-β-1,4-glucanase and exo-β-1,3-glucanase) inside the green malt were not rapidly inactivated. Under the corresponding temperature, humidity, and moisture conditions, the two enzymes began to play a catalytic role. Because the drying process was adjusted between 40-85℃, compared with the low temperature conditions of 14-20℃ for soaking and germination, the enzyme effect was more significant, as the optimal temperature for glucanase activity was within this range. Under the specific temperature, humidity, and moisture conditions in the early stage of drying, endo-β-1,4-glucanase and exo-β-1,3-glucanase rapidly catalyzed the decomposition of glucan, playing a short-term and highly efficient role. Therefore, the higher the RAG (glucanase) activity, the longer the KPG action time, and the lower the β-glucan content and wort viscosity of the final malt.

[0037] Example 2 The same control drying process was used to dry Synergy barley, Planet barley, and Maximum barley from Australia. The relative enzyme activity (RAG) and the optimal time range (KPG) of β-glucanase activity were measured 4 hours after the start of drying. The β-glucan content of the finished malt and the agreed wort viscosity were also measured. Based on the test results, the drying process was optimized. The optimized drying process was then used to dry Synergy barley, Planet barley, and Maximum barley from Australia. The relative enzyme activity and the optimal time range of β-glucanase activity were measured 4 hours after the start of drying. The β-glucan content of the finished malt and the agreed wort viscosity were also measured. The results are shown in Table 2. All three barley varieties used for the control and optimization experiments were from the same source. Green malt from the same soaking and germination processes were used for comparison. To ensure the comparison effect, the performance of the same variety of barley from two consecutive batches was kept as consistent as possible.

[0038] Table 2. RAG, KPG, glucan, and viscosity of different barley varieties

[0039] The control drying process is as follows: 45℃ 2 h - 50℃ 2 h - 55℃ 4 h - 65℃ 4 h - 70℃ 2 h - 75℃ 2 h - 84℃ 3 h, with a fresh air consumption of 50%.

[0040] The optimized drying process is as follows: 43℃ 2 h (60%) - 46℃ 2 h (90%) - 48℃ 2 h (90%) - 52℃ 2 h (70%) - 65℃ 4 h (60%) - 70℃ 2 h (60%) - 75℃ 2 h (50%) - 84℃ 3 h (50%), where the amount of fresh air is in parentheses.

[0041] The results showed that by adjusting the drying temperature setting and the amount of fresh air, adjusting the drying temperature extended the critical time point for glucanase. After temperature adjustment, the internal temperature of green malt was more suitable for glucanase activity. Adjusting the amount of fresh air within the critical time point increased the oxygen content in the drying oven, which in turn increased glucanase activity. Under these conditions of temperature and fresh air adjustment, the increased enzyme activity and extended time effectively catalyzed the dissolution of glucan, ultimately leading to a decrease in β-glucan and a reduction in wort viscosity. Furthermore, this method was effective for different varieties, including Synergy (Canadian wheat), Planet (French wheat), and Maximum (Australian wheat), indicating that the drying process's impact on RAG and KPG indicators is universally applicable across different varieties.

[0042] Example 3 The drying process of different varieties and batches of wheat was tracked in Table 3, and different samples were obtained. The results are shown in Table 4.

[0043] Table 3. RAG, KPG and corresponding drying processes of different varieties and batches of barley

[0044] Among them, Sample 1 was Australian wheat (FAQ); Sample 2 was Australian wheat (Spartacus); and Sample 3 was Canadian wheat (Copeland).

[0045] The control drying processes 1, 2, and 3 in Table 3 are as follows: 45℃ for 2 h, 50℃ for 2 h, 55℃ for 4 h, 65℃ for 4 h, 70℃ for 2 h, 75℃ for 2 h, and 84℃ for 3 h, with a fresh air consumption of 50%.

[0046] Optimized drying process 1 is as follows: 43℃ 2 h - 46℃ 2 h - 48℃ 2 h - 52℃ 2 h - 65℃ 4 h - 70℃ 2 h - 75℃ 2 h - 84℃ 3 h, with a fresh air consumption of 60%. Its main improvements over the control drying process are: lowering the initial drying temperature to 43℃; and increasing the fresh air consumption to 60%.

[0047] Optimized drying process 2 is as follows: 42℃ 2 h (80%) - 48℃ 2 h (70%) - 54℃ 2 h (70%) - 58℃ 2 h (80%) - 65℃ 4 h (60%) - 70℃ 2 h (60%) - 75℃ 2 h (50%) - 84℃ 3 h (50%). The main improvements over the control drying process are: lowering the initial drying temperature to 42℃; increasing the fresh air volume to 70-80% before the initial temperature rises to 60℃; and setting the temperature range between 50-60℃ as: 54℃ 2 h - 58℃ 2 h.

[0048] Optimized drying process 3 is as follows: 41℃ 2 h (100%) - 47℃ 4 h (90%) - 51℃ 2 h (80%) - 54℃ 1 h (70%) - 65℃ 3 h (60%) - 70℃ 2 h (60%) - 75℃ 2 h (50%) - 84℃ 3 h (50%). The main improvements over the control drying process are: lowering the initial drying temperature to 41℃; increasing the fresh air volume to 80-100% before the initial temperature rises to 65℃; and setting the temperature range between 45℃ and 55℃ as follows: 47℃ 4 h - 51℃ 2 h - 54℃ 1 h.

[0049] Table 4. RAG, KPG, dextran, and viscosity of barley from different varieties and batches during the drying process.

[0050] Table 4 shows the changes in RAG, KPG, dextran, and viscosity of barley before and after adjusting the drying process. It can be seen that by adjusting the drying process according to the RAG and KPG of barley before the process adjustment and following the adjustment method provided by this invention, the activity of dextranase can be adjusted quickly and efficiently, thereby reducing the β-glucan content of the final malt and wort, and preparing high-quality finished malt.

[0051] Example 3 shows that the different sample characteristics may be due to the sample quality itself, the quality of the barley, and the effects of the soaking process (the soaking process may affect the internal state of the barley grains during the malting process, such as factors affecting the production of glucan, thus affecting the state and activity of malt glucanase), which in turn affects RAG and KPG. Therefore, a specific drying process should be set according to the actual condition of the sample, and different drying processes will have different effects on different samples.

[0052] Comparative Example 1 Similar to Sample 1 in Example 3, except that the barley was dried using an optimized drying process 4. The RAG, KPG, dextran, and viscosity of the barley are shown in Table 5.

[0053] The control process is as follows: 45℃ for 2 h - 50℃ for 2 h - 55℃ for 4 h - 65℃ for 4 h - 70℃ for 2 h - 75℃ for 2 h - 84℃ for 3 h, with a fresh air consumption of 50%.

[0054] Among them, the optimized drying process 4 is as follows: 48℃ 4h-56℃ 4h-64℃ 4h-68℃ 2h-75℃ 2h-84℃ 3h, with a fresh air consumption of 80%.

[0055] Table 5. RAG, KPG, and dextran and viscosity of barley in Comparative Example 1

[0056] The results in Table 5 show that when the initial temperature was increased to 48℃ and the set temperature was increased by 4℃ every 2 hours, the fresh air consumption was directly increased to 80%, but RAG showed a downward trend, while KPG increased slightly. Ultimately, β-glucan and viscosity decreased slightly, but this was not the optimal process.

[0057] Comparative Example 2 Similar to Sample 2 in Example 3, except that the barley was dried using an optimized drying process 5. The RAG, KPG, dextran, and viscosity of the barley are shown in Table 6.

[0058] The optimized drying process 5 is as follows: 46℃ for 4 h (60%) - 54℃ for 2 h (70%) - 58℃ for 2 h (80%) - 62℃ for 2 h (80%) - 66℃ for 2 h (80%) - 70℃ for 2 h (80%) - 75℃ for 2 h (80%) - 84℃ for 3 h (80%) Table 6. RAG, KPG, and dextran and viscosity of barley in Comparative Example 1

[0059] The results in Table 6 show that the initial temperature was 46℃, the set temperature was increased by 4℃ every 2 hours, the fresh air consumption was gradually increased from 60% to 80%, RAG increased slightly, KPG increased significantly, and finally β-glucan and viscosity decreased slightly, but this was not the optimal process.

Claims

1. A process for the preparation of low beta-glucan malt, characterized in that, The drying step is adjusted according to relative β-glucanase activity (RAG) and β-glucanase activity optimal time interval (KPG); RAG is the ratio of the peak value of β-glucanase activity in the drying process to the peak value of β-glucanase activity in the malting process; KPG is obtained by detecting the curve of the change of malt β-glucanase activity with the change of malt moisture in the drying process to determine the moisture change interval in which the malt β-glucanase activity is in a high activity state, and then according to the curve of the change of malt moisture with the change of drying time to determine the time corresponding to the change of malt moisture in the above interval, which is KPG.

2. The malting method of low beta-glucan malt according to claim 1, characterized by, RAG is the ratio of the β-glucanase activity of green malt dried for 4 h to the β-glucanase activity of barley malted for 82 h.

3. The method of producing low beta-glucan malt according to claim 1, characterized in that, KPG is the time required for the malt moisture to decrease from 35±2.0% to 20±2.0% in the drying process.

4. The malting process for low beta-glucan malt according to claim 1, characterized by, The β-glucanase includes endo-β-1,4-glucanase and exo-β-1,3-glucanase.

5. The method of producing low beta-glucan malt according to claim 1, characterized in that, The value range of RAG includes: RAG<1.0; 1.0≤RAG≤1.4; RAG>1.4; and the value range of KPG includes: KPG<3h; 3.0h≤KPG≤4.5h; KPG>4.5h.

6. The method of producing low beta-glucan malt according to claim 5, characterized in that, The value range of RAG and KPG in the malting process includes: RAG<1.0, KPG<3.0h; 1.0≤RAG≤1.4, 3.0h≤KPG≤4.5h; RAG>1.4; KPG>4.5h. When the values of RAG and KPG in the malting process are RAG<1.0 and KPG<3.0h, the relative standard drying process is adjusted as follows: the initial drying temperature is lowered to 41℃; the fresh air usage is increased to 80-100% before the temperature is raised to 65℃; and the temperature between 45-55℃ is set as: 47℃ for 4 h, 51℃ for 2 h, and 54℃ for 1 h. When the values of RAG and KPG in the malting process are 1.0≤RAG≤1.4 and 3.0h≤KPG≤4.5h, the relative standard drying process is adjusted as follows: the initial drying temperature is lowered to 42℃; the fresh air usage is increased to 70-80% before the temperature is raised to 60℃; and the temperature between 50-60℃ is set as: 54℃ for 2 h and 58℃ for 2 h.

7. The method of claim 5, wherein the low beta-glucan malt is prepared by the steps of: When the values of RAG and KPG in the malting process are RAG>1.4 and KPG>4.5h, the relative standard drying process is adjusted as follows: the initial drying temperature is lowered to 43℃; and the fresh air usage is increased to 60%.

8. The method of claim 5, wherein the low beta-glucan malt is prepared by the steps of: The standard drying process is: 45℃ for 2 h, 50℃ for 2 h, 55℃ for 4 h, 65℃ for 4 h, 70℃ for 2 h, 75℃ for 2 h, and 84℃ for 3 h, and the fresh air usage is 50%.

9. The malting process for low beta-glucan malt according to claim 5, characterized by, ​ 10. The low beta-glucan malting process according to claim 7 or 8 or 9, characterized in that, ​

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