In recent years, with the reform of the traditional vinegar production process and the development and application of various new enzyme preparations, the traditional vinegar process has been injected with new vitality. Practice has proved that the use of new technology to make vinegar can not only reduce labor intensity, shorten production cycle, but also reduce production costs, reduce environmental pollution, improve product quality, and is worthy of promotion and application.

Enzyme preparation commonly used in vinegar production

China's vinegar industry is mostly developed on the basis of ancient backward production technology. With the continuous development of production, on the basis of maintaining the original characteristics, the vinegar factory began to use pure yeast and solid saccharification enzymes to ferment the wine cellar with low-temperature and saccharification of large cans, and then use acetic acid bacteria to make pool cylinders. , solid layered acetic acid fermentation, the new process of vinegar greatly improved labor productivity. In the 1990s, domestic large-scale vinegar enterprises began to transform the original wine cellar process drop-type and open-type production forms, using high-temperature amylase after raw material pulverization, continuous cooking, and saccharification enzyme saccharification and alcohol fermentation. ,got a good result. At present, the enzyme preparations commonly used in the production of vinegar have the following types:

1. High temperature resistant alpha-amylase (HTAA)

It is a liquid enzyme with a specification of 20000 U/ml and is added to the slurry adjustment process before cooking. The high temperature amylase can hydrolyze the starch in the raw material to soluble dextrin and a small amount of oligosaccharides at high temperature to reduce the viscosity of the mash, so as to facilitate the flow and transport of the mash. The optimum temperature is from 90 ° C to 110 ° C and the pH is from 6 to 6.5. At present, an acid-resistant high-efficiency and high-temperature resistant amylase new product is being introduced to the market. Due to its good acid resistance, it is more suitable for the acidity of raw materials in the production process. It is more conducive to the case where the saccharification does not adjust the pH value. The saccharification enzyme works and the operation is simpler.

2. Medium temperature alpha-amylase (LTAA)

The medium-temperature α-amylase is a liquid enzyme with a specification of 2000 U/ml and 3000 U/ml, and the action mode is the same as that of the high-temperature amylase, and the optimum temperature is 7° C.-90° C., and the pH is 6-7. For production, one of the medium or high temperature amylases may be selected for different process conditions.

3. High conversion saccharification enzyme (GA)

Glycosylase is an exo-enzyme, also known as glucoamylase. The enzyme is divided into solid and liquid dosage forms with specifications of 50000 U/g and 100000 U/g. It hydrolyzes alpha-1,4-glucosidic linkages from the non-primary ends of liquefied starch to produce glucose and small amounts of oligosaccharides. The saccharification enzyme has a working temperature of 60 ° C and a pH of 4-5.

Application of enzyme preparation in vinegar production

Drawing on the "double enzymatic process" of modern alcohol production, it is a major breakthrough in the traditional vinegar process. Practice has proved that small and medium-sized vinegar plants can improve the utilization rate of raw materials, reduce production costs and improve product quality by replacing koji with enzyme preparations such as saccharification enzymes.

1. Application of amylase

In the production of vinegar, the raw materials must be cooked after being crushed and pulverized. The purpose is as follows: (1) The starch material is completely broken under a certain temperature and pressure, and the starch granules contained in the raw material absorb and swell, and the starch granules change from crystal to dissolved state; (2) The raw materials are thoroughly sterilized under high temperature conditions to prevent acid production during fermentation.

In order to make the concentrated thinner when heated, it is convenient for pipeline transportation, and it is also convenient to flow in the cooking pot, and the medium temperature amylase is added during the slurry adjustment. When the temperature rises to 70 °C, its action temperature is reached. As the temperature increases, the medium temperature amylase acts and the viscosity of the mash decreases gradually. When it reaches 90 °C, the enzyme loses its vitality, thus completing its role in the early stage of high temperature cooking. . The medium-temperature amylase generally does not need to adjust the pH value when it is added, and the added amount is generally 1 U/g of raw material, and the volume fraction is 0.05% in terms of 2000 U/ml. High-temperature cooking is a traditional process in China, and its technology is relatively perfect. However, due to its high energy consumption and high equipment requirements, high temperature will cause excessive decomposition of starch to form non-fermentable sugar and other substances, so it is increasingly challenged by new processes.

2. Application of saccharification enzyme

After the cooked gelatinized mash, a certain amount of saccharifying agent (curved or enzyme) is added to further convert it into fermentable sugar, a process called saccharification. The saccharification process is divided into intermittent saccharification and continuous saccharification. The intermittent saccharification adopts a single saccharification pot. After the sputum is cooled to the saccharification temperature, the saccharification enzyme is added. At this time, the pH value is generally not required; after that, the mixture is kept warm and maintained for 30-60 minutes. Fermentation process. The amount of enzyme added is generally 80-120 U / g of raw materials, based on 100000 U / ml specifications, the volume fraction is 0.1%; continuous saccharification is generally made up of several saccharification pots in series, the sputum stay in the pot for not less than 30 Minutes, when the saccharification enzyme is added, the flow acceleration must be controlled to be consistent with the sputum flow.

In the selection of saccharification enzyme varieties, the traditional solid-state fermentation process can be selected by enzymes, and solid saccharification enzymes can be selected. In the case of intermittent saccharification, solid or liquid saccharification enzymes can be directly added to the saccharification pot without dilution; in continuous saccharification, The saccharification enzyme is diluted with warm water and then added; the liquid saccharification enzyme is superior to the solid saccharification enzyme because of high concentration ratio, high activity, pure enzymes and less impurities; the complex saccharification enzyme further improves the yield of the final finished vinegar. Therefore, it has a better effect than ordinary saccharification enzymes.

3. Application of other enzyme preparations

In recent years, with the emergence of more new enzyme preparations, various new processes are being continuously applied. In addition to starch in the production of raw materials, it also contains other components such as cellulose and protein. The use of different kinds of enzyme preparations to convert them into useful materials that can be produced and utilized will greatly improve the utilization rate of raw materials and help reduce costs. Reduce waste emissions.

(1) Cellulase is added to the starchy raw material. If cellulase is added to the starchy raw material, the cellulose can be degraded into sugar which can be used by the yeast, thereby increasing the alcohol yield. The reaction temperature is 50° C.-70° C., the pH value is 4-6.5, and the addition amount is 0.04%-0.05% in the saccharification step, and the alcohol yield can be increased by 1% or more during fermentation.

(2) Adding an acid protease to the saccharification step. Although the raw material contains a lot of protein, yeast cannot be directly used. Adding acid protease in the saccharification process can convert the protein into polypeptide and amino acid, increase the yeast absorbable nitrogen in the mash, promote the growth and reproduction of the yeast, and increase the alcohol production rate. Due to the increase of α-amino acid, the amino acid anabolic load of yeast cells is alleviated, and glucose is more turned to fermentation to produce ethanol, thereby increasing the raw material yield. The optimum pH value of the general acid protease is 3-5, the reaction temperature is 40 ° C - 50 ° C, and the addition amount is 0.01%.

As a representative of China's traditional brewing industry, vinegar must change the existing production appearance, continuously improve the production level and production scale, and must reform and innovate the old and backward production process. In recent years, with the application of various new enzyme preparations, the traditional industry of vinegar industry has been injected with new vitality, which will play an important role in promoting its continuous development and progress.