CN101892134A - A kind of microbial malting method and its application - Google Patents

Abstract

The invention discloses a microbial malting method and its application. By adding microorganisms in the traditional malting process, the quality of malt produced from domestic low-quality barley is improved; malt products obtained during the malting process are used in the beer brewing process In the saccharification process, 20% of imported malt can be replaced. When the present invention is used in the production of beer, under the premise of not changing the existing malting process in the malt factory and adding other malting equipment, the microbial malt produced can partially replace imported malt, reducing the cost of domestic beer production enterprises. The cost of production raw materials has good economic benefits.

Description

A kind of microbial malting method and its application

technical field

The invention belongs to the technical field of beer brewing, and relates to a microbial malting method and its application.

Background technique

my country is a big beer country in the world, and its output has ranked first in the world for many years. In 2009, my country's beer output has exceeded 40 million kiloliters, and the output is still increasing. As the main raw material for beer brewing, barley is in increasing demand. At present, beer brewing technology has been relatively perfect, and the market competition is becoming increasingly fierce. To win the competition, the most important thing for enterprises is to reduce the production cost of beer as much as possible under the premise of ensuring the quality of beer. In the current high proportion of high-priced imported barley raw materials, improving the malting performance of domestic malting barley and increasing the use of domestic barley is one of the effective methods to reduce production costs. However, the germination rate of some domestic malting barley is relatively low, the germination is uneven, the dissolution is difficult, the activity of hydrolytic enzymes in the malt is relatively low, and the produced wort has disadvantages such as high viscosity and slow filtration speed. If the quality of malt made from domestic malting barley with low filtration performance can be improved and used in beer production, on the one hand, the proportion of imported malting barley can be reduced, the cost of beer production can be reduced, and obvious economic benefits can be achieved. The development of malting barley planting and processing industry chain will produce far-reaching social significance and economic benefits.

The malting process is actually the gradual dissolution of barley. It is an emerging malting technology to improve the quality of malt by introducing beneficial microorganisms in the malting process. These added beneficial microorganisms can produce a variety of hydrolytic enzymes during the growth process. These hydrolytic enzymes can assist the dissolution of the malt endosperm cell wall and facilitate the action of other various hydrolytic enzymes, thereby improving the dissolution of the finished malt endosperm cells and improving Filterability of malt. Geotrichum candidum CGMCC-2245 (JN4) developed by our laboratory in the early stage is applied to domestic barley with low germination rate and difficult dissolution. The finished malt produced by it has greatly improved in terms of filtration performance and dissolution performance. Based on previous studies, the present invention aims to develop a technology that can be applied industrially to improve the malting performance of domestic low-quality barley, and apply the obtained product malt to the saccharification process of beer.

Contents of the invention

The technical problem to be solved by the present invention is to provide a malting method for improving the quality of malt produced from domestic low-quality barley.

In order to solve the above technical problems, the invention provides a microbial malting method, the specific technical scheme is as follows:

(1) Take Geotrichum candidum CGMCC-2245 as the starting strain, add it to an appropriate amount of 5 ^o P wort medium, and culture it on a shaker at 30°C with a rotation speed of 180-200r/min for 24 hours as a seed culture solution for inoculation; The initial pH value of the 5 ^o P wort medium was adjusted to 5.5, the inoculum concentration of Geotrichum candidum spores was 3%, 50mL medium was filled in a 250mL Erlenmeyer bottle, the speed of the shaker was 180-200r/min, and cultured for 48h to make the concentration of Geotrichum candidum spores Reach 1.0×10 ⁸ cfu/mL;

(2) After germination treatment, the liquid culture is directly added to the barley soaking water when the barley is soaked for the first time, and the inoculation concentration is 10 ⁸ -10 ⁹ spores/kg barley;

(3) Wheat immersion process: soak in water for 6 hours, cut off water for 6 hours, soak in water for 2 hours, cut off water for 6 hours, soak in water for 2 hours, and the wheat soaking degree is 42.5%;

(4) Germination process: Germinate for 5 days, 15°C on the first day, 15°C on the second day, 19°C on the third day, 19°C on the fourth day, 15°C on the fifth day, add water to 45.5% for 20 hours after germination;

(5) Drying process: the air inlet temperature is 45°C, the temperature is raised to 50°C within 1 hour, the temperature is raised to 2°C per hour, the temperature is raised to 60°C and kept for 3 hours, the temperature is raised to 85°C within 6 hours, and kept for 3 hours.

The present invention also provides an application of the above-mentioned microbial malting method to produce malt.

The application method is as follows: in the maltosaccharification process of the beer brewing process, 20% of the imported malt is replaced by the malt produced by the above-mentioned microbial malting method.

The saccharification process is as follows: feed at 48°C, hold for 30 minutes, heat up to 65°C, hold for 30 minutes, heat up to 72°C, hold for 10 minutes, heat up to 78°C, and hold for 10 minutes. The ratio of saccharification material to water is 1:4.5, 15 grams of gypsum is added to the saccharification water, and the pH of the saccharification mash is adjusted to 5.4.

The present invention adds beneficial microorganisms in the wheat soaking section of the malting process, utilizes the hydrolytic enzyme system produced by the microorganisms during the growth process, assists the dissolution of barley endosperm cells with low germination rate, and effectively solves the problem of insufficient dissolution of domestically produced low-quality barley endosperm cells. The original poor quality barley malt has been significantly improved in quality. Without changing the existing malting process of the factory and without adding other malting equipment, the microbial malt produced can partially replace imported malt, reducing the The production raw material cost of domestic beer production enterprises has greatly alleviated the current situation of insufficient supply of high-quality raw materials in my country's beer production.

Detailed ways

Malt-making microorganisms: Geotrichum candidum JN4 screened from malt epidermis in our laboratory was preserved in China General Microorganism Culture Collection and Management Center in November 2007 with the preservation number CGMCC-2245.

Example 1:

A microbial malting experiment was carried out in a malting factory in Sheyang, Jiangsu, with a malting scale of 150 tons/batch. The barley variety used is Su Beer, and some of its physical and chemical indicators are: moisture 13.5%, germination rate 82% in 5 days, protein 14.0%, and thousand-grain weight 41.6g.

Malting process:

Wheat immersion process: soak in water for 6 hours, cut off water for 6 hours, soak in water for 2 hours, cut off water for 6 hours, soak in water for 2 hours, and the soaking degree is 42.5%;

Germination process: Germination for 5 days, 15°C on the first day, 15°C on the second day, 19°C on the third day, 19°C on the fourth day, 15°C on the fifth day, germinate for 20 hours to replenish water to 45.5%;

Baking and drying process: the air inlet temperature is 45°C, the temperature is raised to 50°C within 1 hour, the temperature is raised to 2°C per hour, the temperature is raised to 60°C and kept for 3 hours; the temperature is raised to 85°C within 6 hours, and kept for 3 hours;

Control group malt: Su beer malt obtained without adding Geotrichum candidum strain CGMCC-2245 during ordinary malting;

Experimental group malt: obtained by adding Geotrichum candidum strain CGMCC-2245 to germinate spores in the first soaking water of the malting process

Geotrichum candidum malt, the addition amount is 10 ⁸ -10 ⁹ spores/kg barley. See Table 1 for the physical and chemical indicators of the saccharification wort of the two finished malt agreements.

Table 1 Index of saccharified wort for two kinds of malt agreements

It can be seen from Table 1 that in the large-scale production of 150 tons, among the saccharification wort indicators of the malt agreement in the experimental group, the filtration speed of 100mL wort was significantly faster than that of the control group, and the other indicators were in line with the QB1686-2008 beer malt standard. The improvement of wort filtration performance can shorten the production cycle of beer and save production cost, which will bring good economic benefits to beer enterprises.

Example 2:

A 1000-liter saccharification and fermentation test was carried out by using the obtained finished Geotrichum candidum malt instead of 20% of the imported malt, wherein: the imported malt was the Australian wheat Gairdner malt, and its relevant physical and chemical indicators are shown in Table 2.

Table 2 Physical and chemical indicators of Gairdner malt

(1) The maltosaccharification formula is:

The control group is: 60% imported malt + 40% control malt;

The experimental group was: 40% imported malt + 40% control malt + 20% microbial malt.

(2) The saccharification program is: feed at 48°C, hold for 30 minutes, heat up to 65°C, hold for 30 minutes, heat up to 72°C, hold for 10 minutes, heat up to 78°C, hold for 10 minutes. The ratio of saccharification material to water is 1:4.5, 15 grams of gypsum is added to the saccharification water, and the pH of the saccharification mash is adjusted to 5.4.

(3) Parameter control during boiling: the wort is boiled for 90 minutes, the amount of hops added is 0.04%, added in two times, 0.025% is added when boiled for 10 minutes, and 0.015% is added when 10 minutes before the end of boiling; )5.45-5.5, add 4.5 grams of K ₂ S ₂ O ₄ when boiling for 40 minutes; add 25 grams of gypsum, and add 0.32 grams of ZnCl ₂ 10 minutes before the end of boiling.

(4) Fermentation: Yeast inoculation concentration: 10 ⁷ cfu/mL wort, main fermentation at 12°C, measure the appearance concentration and diacetyl content every day, when the appearance drops to 3.6-3.8 ^o P, seal the tank and prepare for pressure, when diacetyl When the content drops to 0.1mg/L, it starts to cool down and enters the post-fermentation of beer. After the end of the post-fermentation, the conventional physical and chemical indicators of the beer brewed from the two kinds of wort were measured.

See Table 3 for indicators of microbial malt replacing 20% of imported malt saccharified wort, and see Table 4 for the corresponding wort fermentation results.

Table 3 Indicators of saccharified wort obtained from two different malt ratios

It can be seen from Table 3 that compared with the control group, the total filtration time of the wort in the experimental group was prolonged by 8.5%, but the increase was not obvious. Some indicators related to nitrogen content, such as α-amino nitrogen and total soluble nitrogen, increased slightly, which was related to the high total protein content of domestic barley. Generally speaking, the physical and chemical indexes of the two kinds of wort showed no obvious difference.

Next, the two kinds of worts were fermented, and the differences in the conventional physical and chemical indicators of the products obtained after the two kinds of worts were fermented for beer were investigated.

Table 4 Conventional physical and chemical indicators of beer made from two different malt ratios

It can be seen from Table 4 that the conventional physical and chemical indicators of beer brewed from two batches of wort are not much different. Compared with the control group, the degree of fermentation of the beer brewed from wort in the experimental group was only relatively reduced by 1.7%, and the difference was not significant. TBZ is a very important indicator. A high value means that there are more carbonyl compounds in the beer, which will lead to the taste of the finished beer is not pure and clean, and the flavor stability is poor. Therefore, it is necessary to reduce the beer in the brewing process. TBZ. The TBZ value of the beer brewed from the wort of the experimental group was lower than that of the control group, which indicated that the taste and flavor of the beer were improved after the addition of microbial malt, which enhanced the flavor stability of the beer and was beneficial to prolong the shelf life of the beer.

The technical scheme provided by the invention can well improve the quality of malt produced from domestic low-quality barley, and the obtained malt can replace 20% of imported malt for beer fermentation.

Claims (3)

1. A microbial malting method is characterized in that the specific malting method is as follows: (1) Take Geotrichum candidum CGMCC-2245 as the starting strain, add it to an appropriate amount of 5 ^o P wort medium, and culture it on a shaker at 30°C with a rotation speed of 180-200r/min for 24 hours as a seed culture solution for inoculation; The initial pH value of the 5 ^o P wort medium was adjusted to 5.5, the inoculum concentration of Geotrichum candidum spores was 3%, 50mL medium was filled in a 250mL Erlenmeyer bottle, the speed of the shaker was 180-200r/min, and cultured for 48h to make the concentration of Geotrichum candidum spores Reach 1.0×10 ⁸ cfu/mL; (2) After the liquid culture is germinated, it is directly added to the barley soaking water when the barley is soaked for the first time, and the inoculation concentration is 10 ⁸ -10 ⁹ spores/kg barley; (3) Wheat immersion process: soak in water for 6 hours, cut off water for 6 hours, soak in water for 2 hours, cut off water for 6 hours, soak in water for 2 hours, and the wheat soaking degree is 42.5%; (4) Germination process: Germinate for 5 days, 15°C on the first day, 15°C on the second day, 19°C on the third day, 19°C on the fourth day, 15°C on the fifth day, add water to 45.5% for 20 hours after germination; (5) Drying process: the air inlet temperature is 45°C, the temperature is raised to 50°C within one hour, the temperature is raised to 2°C per hour, the temperature is raised to 60°C and kept for 3 hours, the temperature is raised to 85°C within 6 hours, and kept for 3 hours. 2. according to the described microbial malting method of claim 1, it is characterized in that described barley is the barley of domestic low germination rate, dissolving difficulty. 3. The application of the malting method according to claim 1, characterized in that in the maltosaccharification process, 20% of the imported malt is replaced by the malt produced by the above-mentioned microbial malting method.