Purpose and requirements of saccharification The purpos […]
Purpose and requirements of saccharification
The purpose of saccharification is to soak out as many soluble substances as possible in the raw materials, and create conditions that are conducive to the action of various enzymes, so that many insoluble substances become soluble substances under the action of enzymes and dissolve out, so as to obtain as much dissolution as possible. The proportion of the components contained in it is appropriate.
For example, the ratio of sugar to non-sugar: light beer is controlled at 1:0.4～0.5; dark beer is controlled at 1:0.5～0.7. The ratio of high, medium and low molecular nitrogen: high molecular nitrogen 15-20%; medium molecular nitrogen 20-25%; low molecular nitrogen 55-60%.
The starch in malt and auxiliary materials is generally surrounded by cell walls and exists in granular form. This granule is insoluble in water and is not affected by amylase. However, starch granules will quickly absorb water and expand when heated. When the temperature rises to a certain temperature, the cell wall ruptures and the starch molecules dissolve to form a viscous paste. This process is called gelatinization.
In short, gelatinization is the process of expansion and rupture of starch granules in hot solution.
Amylase quickly decomposes the long starch chains (amylose and amylopectin) composed of glucose residues into short chains to form low-molecular dextrins, thereby rapidly reducing the viscosity of the gelatinized mash and forming a thin mash. This process is called "liquefaction", and the liquefaction process is a biochemical reaction process.
The meaning of liquefaction is to reduce the viscosity of the gelatinized starch liquid through the action of α-amylase. Of course, β-amylase will also work during the liquefaction process, decomposing long chains from the non-reducing end, but its effect is slow and the decomposition time is long.
Saccharification refers to the process by which amylase converts starch into maltose, maltotriose, glucose and other sugars and dextrins. It is a biochemical reaction process.
Amylase can decompose the long chain of amylose or amylopectin into short chain dextrin consisting of 7-12 glucose units, and then β-amylase cuts two glucose from the end of the short chain at a time to form Maltose etc.
The action time of amylase is longer than that of α-amylase.
Decomposition of starch by amylase
(1)-Amylase decomposes long-chain starch into low-molecular-weight dextrin, the optimal temperature is 72～75℃, the deactivation temperature is 80℃, and the optimum pH value is 5.6～5.8;
(2)-Amylase decomposes from the end of the starch chain to form maltose, maltotriose and glucose. The best action temperature is 60-65°C, the inactivation temperature is 70°C, and the best pH is 5.4-5.5.
Factors affecting starch decomposition
Variety and quality of malt
The pH value of the mash: When the pH value of the mash is between 5.5 and 5.6, it can be regarded as the optimal pH range of the two amylases
Mash concentration: the material-water ratio of light beer is controlled at around 1:4