Protease Enzymes in Flour

Protease enzymes, also known as proteolytic enzymes or “proteases”, naturally occur in flour and are also produced by yeast and bacteria during fermentation. They are active from the moment the dough is mixed until baking, and play a central and essential role in the fermentation process. They break down and weaken the gluten structure by breaking down the gluten-forming proteins, into:

• Amino acids (the building blocks of proteins)
• Peptides and polypeptides (chains of amino acids of different lengths)

The process of breaking down the proteins in the dough is called proteolysis. It softens the dough by weakening the gluten structure and makes it easier to work with. This also affects the dough’s elasticity and extensibility properties, as well as the final texture of the pizza crust (soft, chewy, leathery etc.).

In addition to breaking down the gluten structure and softening the dough, the breakdown of proteins into amino acids significantly affects the flavor; This is because it “produces” amino acids and peptides as a result of the gluten breakdown:

1. Amino acids are essential for the Maillard reaction (browning) during baking, which gives the pizza crust deep and complex flavors.
2. Amino acids interact with other components in the dough, primarily alcohol and organic acids, through a chemical reaction. This interaction leads to the formation of flavor and aroma compounds that directly impact the dough’s flavor and aroma.

In simpler terms, the flavor potential of the dough increases as more proteins are broken down into amino acids. Unfortunately, this natural process cannot be artificially sped up and requires time.

It is important to note that the activity of protease enzymes in the dough is desirable up to a certain point. If the protease enzymes work for too long, they will excessively break down the gluten in the dough, resulting in a weak gluten structure, excessive extensibility, a liquid consistency, and easy tearing – essentially, an over-fermented dough.

It is also crucial to understand that the activity of protease enzymes in the flour is irreversible. Once the dough has reached over-fermentation (due to excessive gluten/protein degradation), it cannot be “repaired”, because the gluten-forming proteins have lost their ability to create new gluten bonds.

In terms of dough maturation, a “ripe” dough is one in which the proteins (gluten) have been sufficiently broken down by protease enzymes. This allows for achieving a dough that is easy to shape and stretch before baking. The ideal dough has a balance between extensibility and elasticity, meaning it stretches easily without tearing, yet remains strong enough and has sufficient elasticity.

The type of flour used affects the degree of gluten breakdown required by the proteolytic enzymes. A dough made from flour with a higher protein (gluten) content will require longer protease activity compared to dough made from lower protein flour. You can find more information about this topic in the following article: The Ultimate Guide to Pizza Flour – How to Choose the Ideal Flour for Pizza.

There are dough conditioners/reducers available that “mimic” the action of protease enzymes in the dough. These additives essentially ‘artificially’ soften the dough and shorten its maturation time. Examples of such dough conditioners include L-cysteine and glutathione (‘dead yeast’). However, these dough conditioners only help in softening the dough, and they generally do not impact flavor (they break/weaken the gluten bonds but do not break down proteins into amino acids).