Method for controlling diacetyl generation amount through ultraviolet directional mutagenesis of beer yeast
Through ultraviolet rays, the diacetyl generation amount is controlled, which solves the problem of difficult to control the diacetyl generation amount in beer brewing, and achieves the effect of rapid maturation of beer and shortening the fermentation cycle.
Patent Information
- Application Number
- CN202510335025.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-20
- Publication Date
- 2025-06-20
AI Technical Summary
During beer brewing, the amount of diacetyl is difficult to effectively control, resulting in an extended beer maturity time and affecting product quality and production efficiency.
The amount of diacetyl generation is controlled by directed mutagenesis of Brewer yeast through ultraviolet light. The specific steps include irradiating liquid bacterial species with ultraviolet lamps after culturing brewer's yeast in a sterile room, with a distance of 30-50cm and a time of 40-60min.
This method can quickly reduce the content of diacetyl in beer, shorten the fermentation cycle, promote beer maturity, improve equipment utilization and reduce costs.
Smart Images
Figure BDA0005321472990000031
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of beer brewing, and particularly to a method for controlling the diacetyl production amount by ultraviolet ray directed mutagenesis of beer yeast. Background Art
[0002] Diacetyl is very important in beer brewing. Diacetyl is a representative, volatile and pungent by-product produced during the beer fermentation process. The content and reduction degree of diacetyl in beer are the main signs of beer maturity. The taste threshold of diacetyl in beer is 0.15 mg / L. If its content exceeds this limit value, there will be a smell of stale rice, cream or yogurt taste. For high-quality light and refreshing beer, the diacetyl content is required to be controlled below 0.1 mg / L.
[0003] Influencing factors for the formation and reduction of diacetyl:
[0004] 1. If the malt is not well dissolved or the proportion of adjuncts is too high, the wort prepared lacks valine and has a low α-amino nitrogen content, a high α-acetyl lactate content, and more diacetyl is produced.
[0005] 2. Yeast strain characteristics. The content of diacetyl produced in the early stage of beer fermentation is very high. In the later stage of fermentation, after the yeast reabsorbs it, it is reduced to butanediol. The flavor threshold of butanediol in beer is much greater than that of diacetyl, which can promote the beer taste to reach maturity. Therefore, studying the formation pathway of diacetyl during the beer brewing process and finding various methods to quickly reduce the diacetyl content in beer, so as to promote the maturity of beer, shorten the fermentation cycle, improve the utilization rate of equipment and reduce costs, has become the focus of attention of beer brewers and needs to be solved. Summary of the Invention
[0006] The main object of the present invention is to reduce the diacetyl production amount during the main fermentation period of beer, shorten the beer fermentation cycle, promote the rapid maturity of beer, and improve the equipment utilization rate.
[0007] To achieve the above object, the present invention adopts the following technical solution: A method for controlling the diacetyl production amount by ultraviolet ray directed mutagenesis of beer yeast, which comprises the following steps:
[0008] Step 1: Cultivate the beer yeast strain in a sterile room;
[0009] Step 2: When the beer yeast strain reaches the test tube activation stage, the liquid strain is irradiated with an ultraviolet lamp before inoculation, at a distance of 30 - 50 cm for 40 min - 60 min.
[0010] Preferably, the ultraviolet lamp is 20 - 40 W.
[0011] Advantages of the present invention: Rapidly reduce the content of diacetyl in beer, thereby promoting the maturation of beer, shortening the fermentation cycle, improving the utilization rate of equipment and reducing costs. Specific embodiments
[0012] The following will combine the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present invention.
[0013] A method for controlling the production amount of diacetyl by ultraviolet directed mutagenesis of beer yeast, which comprises the following steps:
[0014] Step 1: Cultivate the beer yeast strain in a sterile room;
[0015] Step 2: When the beer yeast strain reaches the test tube activation stage, the liquid strain is irradiated with an ultraviolet lamp before inoculation, the distance is 30-50 cm, and the time is 40 min-60 min.
[0016] Preferably, the ultraviolet lamp is 20-40W.
[0017] Test data of brewing industrial beer yeast is shown in Table 1
[0018] Table 1
[0019]
[0020] It can be seen that the mutagenized beer yeast can control the production amount of diacetyl, shorten the fermentation cycle, is beneficial to reducing the brewing time, and improving the production efficiency.
[0021] Using the mutagenized beer yeast to brew craft beer, brewing 12P whole wheat beer, controlling the main fermentation at 22°C for fermentation, taking 4-5 days, the main fermentation sugar reduction ends, the fermentation broth reaches the final fermentation degree of about 70%, the beer is mature, the taste of diacetyl cannot be tasted, the fermentation broth has no off-flavors, mellow flavor, and the lipid aroma metabolized during the fermentation of beer yeast is strong. The beer yeast is examined under a microscope, the budding rate > 30%, and the survival rate > 98%. At the same time as the main fermentation sugar reduction ends, the diacetyl meets the standard, the beer brewing is mature, and the temperature is lowered to the beer post-fermentation stage. The fermentation broth is sampled and sent to a third-party inspection, and the test result shows that the diacetyl content ≤ 0.07PPm.
[0022] After ultraviolet directed mutagenesis of beer yeast, brewing craft beer, the main fermentation ends, the diacetyl meets the standard, the beer has a pure taste, shortens the beer brewing time, and improves the equipment utilization rate.
[0023] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A method for controlling the amount of diacetyl produced by ultraviolet directed mutagenesis of brewer's yeast, characterized in that: It includes the following steps: Step 1, culturing brewer's yeast in a sterile room; Step 2: When the brewer's yeast strain reaches the test tube activation stage, the liquid strain is irradiated with ultraviolet light before inoculation, at a distance of 30-50 cm and for 40 min-60 min.
2. The method for controlling diacetyl production by ultraviolet directed mutagenesis of brewer's yeast according to claim 1, characterized in that: The ultraviolet lamp is 20-40W.