Transformation of major substances during saccharification

Saccharification refers to the use of various hydrolytic enzymes contained in malt itself to convert soluble polymers (starch, protein, hemicellulose and their intermediate decomposition products, etc.) , Gradually decompose into soluble low molecular substances, this decomposition process is called saccharification.

Breakdown of starch

The quality of starch decomposition directly affects the cost of beer and the quality of beer. Amylolytic enzymes in malt include α-amylase, β-amylase, isoamylase, limit dextrinase, sucrase, etc., through these enzymes Starch is continuously degraded into maltose, maltotriose, glucose and other fermentable sugars and oligomeric dextrins.

Breakdown of β-glucan

At 35-50°C, the macromolecule dextran in the malt dissolves and increases the viscosity of the mash. Especially for poorly dissolved malt, the residual β-glucan is high, it is difficult to filter the malt mash, and the viscosity of the wort is high.

Breakdown of protein

Under the action of protease, protein is decomposed into high-molecular nitrogen, medium-molecular nitrogen and low-molecular nitrogen in turn, and finally decomposed into amino acids. The decomposition products are not only nutrients for yeast, but also affect the flavor, foam and abiotic stability of beer.

Titration of acidity and pH changes

The acidity of the mash mainly comes from acid phosphate, oxalic acid, etc. in the malt, and the dissolution of soluble acids and their salts in the malt is the original acidity of the mash. Amino acids, succinic acid, oxalic acid, etc. produced by protein decomposition will increase the titration acidity, decrease the pH, and enhance the buffering capacity.

Changes in polyphenols

Polyphenols exist in barley husk, endosperm, aleurone layer and storage protein layer, and polyphenols are easy to combine with high molecular weight proteins and precipitate when the temperature is above 50°C. Appropriately lowering the pH is conducive to the precipitation of polyphenols and proteins, reducing the color of wort.

Lipolysis

The change of lipids is divided into two stages: the first stage is the decomposition of lipids, that is, the formation of glycerides and fatty acids through the action of lipase at the optimum temperature; the second stage is the oxidation of fatty acids under the action of lipoxygenase .

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