Amylase

Function

The term "amylases" refers to a group of enzymes that break down starches and that are very widespread in Nature: they are found in animals and plants and are produced by many microorganisms.

In order to make use of the plant-based starches present in food, large starch molecules first must be split into smaller units. This breakdown of starches is performed by amylases and other enzymes. These enzymes are produced by microorganisms that live in the digestive system.

• A variety of types of amylase exist. These "cut" the branches of starch molecules, each at a particular point. Depending on the type of amylase, the resulting compounds may be simple sugars such as glucose or fructose, compound sugars such as maltose, malt sugar, or special forms of starch such as dextrine.
• For example, differences are drawn between alpha-amylase, beta-amylase, glucoamylase (also known as: gamma-amylase, amyloglucosidase), maltogene amylases and pullulanase.

Application

The most important areas of application of amylases in food production are the starch industry and the production of sugars from starch:

• amylases transform maize or potato starch in several steps to syrups containing sugar (glucose syrup, fructose syrup). These are subject to a wide variety of uses, for example in sweets, baked goods, ice cream or tomato ketchup. Furthermore, glucose syrup is a basic ingredient of many other food ingredients and additives.

• baked goods: large quantities of amylases are present in cake mixes. They "pre-digest" the starch. In baked goods produced using yeast, this leads to an enhanced yeast performance and increases the volume of the product. Particularly in the case of white bread, both the stability of the crust and the storage life of the bread itself are improved. The addition of amylases to deep-frozen baked goods and dough is gaining significance.

• alcoholic beverages: many spirits are produced from starches (e.g. in cereals or potatoes). These starches first must be split by amylases into sugar units, which then may be fermented into alcohol.

• fruit juice: amylases eliminate lees that contain starch.

• beer (not in Germany): in traditional malting, the amylases naturally present in the wheat eliminate starch. In order to optimize this procedure, amylases and other isolated enzymes are added. This practice is widespread outside of Germany but is not allowed in Germany since it violates the legally-binding purity laws.

• feed additives: amylases increase the breakdown of starches and thereby contribute to the better use of plant-based feed.

• in washing and cleaning agents, starch-based soil is removed by amylases.

• the production of textiles

Gene technology

It has been possible for a long time to produce amylases with a variety of fungal and bacterial cultures. As a rule, bacterial amylases are more stable in regard to temperature than are amylases derived from fungal cultures.

• Bacterial amylases now are produced predominantly with genetically modified microorganisms (various types of Bacillus).

• In the production of amylases using fungi, cultures are most often used that are not regarded as genetically modified. In one preparation genetically modified microorganisms (Trichoderma) are used.

Labelling: labelling of enzymes in regard to their production using GM microorganisms is generally not foreseen in the European Union.