Enzymes provide a powerful, varied set of specialised tools for food and beverage preparation. They are proteins that act as biocatalyst to bring about a specified biochemical reaction. So, they can function exceptionally well to control process time, enrich the flavour, improve texture, increase shelf life and decrease the use of chemical food additives.

Nowadays as the consumers’ preferences are inclined more towards healthy and artificial additive-free foods, enzymes have the potential to fulfil the same. Thus, today enzymes play a central role in food technology to produce diverse products and its applications in bakery products are growing at an increasingly rapid rate.

The enzymatic treatment of wheat flour is an interesting alternative to generate changes in the dough structure and, consequently, to improve the functional properties of the flour. In baking, enzymes come from three different sources viz. the endogenous enzymes in the flour, enzymes associated with the metabolic activity of the dominant microorganisms (e.g. enzymes present in yeast), and the exogenous enzymes added to the flour.

The endogenous enzymes in wheat, a-amylase, and ß-amylase readily degrade the damaged starch produced during milling to dextrins and maltose. This provides additional sugars to yeast for fermentation and affects the rheological properties of food. The flour quality is also influenced by the preharvest sprouting which leads to increased levels of enzymes like proteases, amylases, lipases and xylanases. 

The enzymes in the production of baked foods can be added discretely or in combination at a very low level that may act in a synergic way. 

Amylase is added to standardise the variable and generally low level of endogenous a-amylase of flour to provide sufficient maltodextrins, which optimise the dough handling properties and the loaf volume, crumb structure, flavour, and crust colour of the final bread.

On the other hand, exo-acting amylases, such as ß-amylase and amyloglucosidase, produce a large amount of mono- and disaccharides, which not only boost fermentation and but also give rise to a larger loaf volume. Moreover, they contribute to an enhanced caramelisation and Maillard reaction, resulting in a darker crust colour.

Hemicellulases are a diverse group of enzymes capable of hydrolysing hemicellulose, which in wheat flour primarily consists of arabinoxylans. Although arabinoxylans only constitute approximately 2% of the flour, of which two-thirds is water-unextractable, they can absorb large quantities of water, and thus affect dough rheology. The hemicellulase of primary importance to modify the rheological properties of dough is endoxylanase. The benefits of the use of xylanase in dough handling consequently give rise to improved oven spring, larger loaf volume, and improved structure and softness of the crumb. A disadvantage of xylanases is that they can cause dough stickiness, particularly when highly dosed or not sufficiently specific for the water-unextractable arabinoxylans.

Glucose oxidase is an enzyme that can strengthen and dry a slack and sticky dough caused by excessive xylanase action or just by improving the gluten network of a relatively weak flour having low gluten quality or quantity. Besides glucose oxidase, other redox enzymes, such as sulfhydryl oxidase, hexose oxidase, pyranose oxidase, laccase, and peroxidase, were explored for their effects in bread making, but have not been equally commercially successful as glucose oxidase yet.

Proteases hydrolyse peptide bonds in proteins and are classified according to their endo- or exo-type mode of action, catalytic mechanism, and structural homology. For optimisation of dough mixing and handling properties of particularly strong wheat flours endoproteases are applied.

Moreover, proteases have largely replaced bisulfite, which was previously used to control the consistency of the dough by reducing the disulfide bonds of proteins. Therefore, adding protease to the dough would lead to changes in the dough handling properties, gluten elasticity, and consistency leading to shorter kneading time and increased loaf volume.

Lipases are enzymes that act on the endogenous lipid fraction in the dough. Lipases enhance the interfacial properties of the gas cells, enabling them to retain the expanding gas longer without collapsing or coalescing with neighboring cells.

The enzymes not only optimise the dough handling properties but also are used as anti-staling enzymes. Any amylase able to act on amylopectin’s side branches can be beneficial to prevent bread staling to some extent. The best known and most effective type of anti-staling enzyme is maltogenic amylase. 

The combination of maltogenic amylases with lipases is often suggested to improve and prolong the freshness of the bread during storage. The maltogenic amylase is also used to keep the cake soft and moist over a longer storage period. 

In cookies, the low water activity and high sugar levels make cookie dough prone to excessive Maillard reaction during baking. This can lead to too high levels of acrylamide in some type of cookies. To overcome this, the recipe or processes can be adjusted, or asparaginase can be used. This enzyme converts asparagine, the main precursor for acrylamide, into aspartic acid, thus reducing the level of acrylamide in the final baked cookie. In wafers to reduce the water level in the recipe to reach the desired low viscous batter which reduces the energy required to bake the wafers, protease can be added as a processing aid. By cleaving the gluten proteins in the flour, the chances of gluten proteins forming an elastic network are reduced, and a lower viscosity is obtained. 

Thus, enzymes can be a promising alternative for innovating bakery products. However, the wheat species and variety used, the concentration of damaged starch and the levels of endogenous enzymes of the flour, and the process selected can vary tremendously. All these factors are important determinants for the choice and dosage of enzymes required to result in a baked product of the desired quality and acceptance.