Illustration Enzymes

Enzymes act as catalysts in biological processes – and for innovative products.

Illustration 1

Enzymatic activity depends on a number of factors.

Illustration 2

Reduction of activation energy by enzymatic catalysis.

Illustration 3

The xylanase family.

Illustration 4

Effects of lipases on fat molecules.

Illustration 5

Proteolytic enzymes.

Illustration 6

Effects of various amylases.

Enzymatic processes are gaining more and more ground – not only in food production. Enzymes have shown themselves to be true all-rounders. They are able to simplify chemical reactions, reduce energy requirements and achieve the desired results with incredible precision.

In food production, for example, they improve the properties of dough and prolong the shelf-life of bread; they ensure that pasta stays firm when boiled and that confectionery stores well, and they simplify the production of beer and spirits. Each enzyme is highly specific to a particular substrate or reaction. New enzymes and enzyme compounds can therefore be designed expressly to optimize the properties of foods or create innovative products.

Organic catalysts with incredible potential.

Scientists estimate that over 10,000 enzymes occur naturally, and that only about half of these have so far been discovered and analyzed. Enzymes are proteins that act as catalysts. They lower the resistance encountered by a specific chemical reaction and speed up this reaction several times. In some cases they ensure that the reaction can take place at all.

In the past the raw materials used in the production of alcohol, for example, first had to be hydrolyzed (broken down) by heat. But with the aid of enzymes they can be hydrolyzed without boiling, which greatly reduces the energy requirement and cuts the production costs.

Like a key in a lock.

Enzymes act very precisely and only catalyze the reactions of particular substrates, which they change in a specific manner. In enzymatic processes the risk of unintentional side reactions can be excluded almost entirely, since each enzyme fits only one substrate like a key in a lock: it only boosts the reaction to which it belongs. Amylase, for example, can break a tetrasaccharide down into a disaccharide, but a different enzyme is needed to break a disaccharide down into a monosaccharide (simple sugar).

This is how the important constituents of the enzyme compounds work:

Amylases (α-amylases, β-amylases, glucoamylases)
Amylases have the effect of converting starch into a source of energy for yeast. In this process α-amylases form dextrins, which are further converted into maltose or glucose by β-amylases and glucoamylases. The hydrolysis of the starch gel releases water and lowers the viscosity. The short-chain, reducing sugars are also involved in the formation of flavouring substances and promote browning. Since glucoamylase releases dextrose from the starch it is possible to reduce the amount of sugar added.

The stability of the wheat protein (gluten) is largely responsible for the use of energy, more of which is needed as the resistance of the dough to mixing and kneading increases. In liquid doughs, such as wafer batters, the protein forms agglomerates, which may make processing difficult and result in an inhomogeneous end product. Proteases play an important role in controlling these properties. Endoproteases split the polypeptide chains within the molecule and thus weaken the protein. Exo-proteases, by contrast, have only a limited effect on the structure. However, they form short-chain peptides and amino acids which serve as precursors of flavour molecules and pigments.

Hemicellulases (xylanase, pentosanase)
Even in its native condition, i.e. in cold dough, hemicellulose binds large volumes of water. Hemicellulase breaks the hemicellulose polymer down into tiny fragements, thereby destroying the gel. This releases water and lowers viscosity. Hemicellulose also forms complexes with the proteins in the flour. So hemicellulases also influence the mechanical properties of the gluten network and reduce both the firmness and the elasticity of the dough while increasing its extensibility.

Carboxylesterase (lipases, phospholipases and glycolipases)
Our applications research into carboxylesterases concentrates on their effects on the structure of bakery products. Carboxylesterases convert both the lipoids contained within the flour and the added fats and oils into substances that emulsify better (e.g. mono and diglycerides). This can benefit the structure and reduce the amount of emulsifier needed or make its addition unnecessary. However, these enzymes, particularly lipases, also release copious amounts of fatty acids, which may have a desirable effect on the end product, as in the maturing of cheese, or an undesirable effect (rancidity).

Invertase has the ability to convert sucrose into glucose (dextrose or grape sugar) and fructose. A little water is consumed in this process: exactly one molecule per molecule of sucrose. The mixture of sucrose, glucose and fructose has a lower viscosity and shows less tendency to crystallize than sucrose alone. So the product stays softer. Moreover, fructose is hygroscopic: it attracts and binds water. This reduces the tendency of the water to evaporate. Invertase can therefore be used to prolong the shelf-life of cream fillings and marzipan etc.

Lactoperoxidase is an enzyme that occurs naturally in milk and protects new-born calves against infection. In the oral cavity of human beings the peroxidase of the saliva has an important protective function. It oxidizes thiocyanate to form hypothiocyanate, consuming hydrogen peroxide in the process. Thiocyanate is present in saliva, in foods and also in tobacco smoke. Hypothiocyanate and its derivatives constitute an effective system of defence against cariogenic bacteria. In other words: the addition of lactoperoxidase can help the body to resist tooth decay.