Pro Tip: Lipase enzymes can unlock the potential of lipids that are naturally present in wheat flour to emulsify the dough, leading to better loaf volume and improved handling of proofed dough.

Many conventional dough stabilizers, such as sodium stearoyl-2-lactylate (SSL) and diacetyl tartaric acid of mono- and diglycerides (DATEM), are falling out of favor due to consumer concerns surrounding complicated sounding ingredient labels. This has led to the baking industry’s search for clean label alternatives to replace these powerful emulsifiers, and many bakers have turned to enzyme-based technologies.

A number of these solutions are commercially available, but let’s consider why they work, and what you should consider in replacing these ingredients for typical baked good formulations.

Here we will examine how bread proofs into a foam, explore the importance of wheat’s natural lipid composition and show why lipase enzymes work when they are used at the correct levels.

Figure 1: Structure of a lipase enzyme isolated from Rhizomucor miehei, a common fungus used to produce lipase enzymes. Green is the structure of the protein, light grey is the surface of the protein and yellow indicates where a lipid interacts with this enzyme to be broken down. When lipids interact with these proteins, they are broken down into smaller components that can act as emulsifiers in dough. Structure prepared from PDB ID: 4WY5, rendered in UCSF Chimera.

 

When dough is mixed, long gluten strands provide strength and structure, but there is also a significant amount of water and air that is mixed into the dough. During proofing, and the first several minutes of baking, yeast releases carbon dioxide, which causes the air bubbles to expand and the dough to rise.

At this time, the dough is a fairly weak foam, and if emulsifiers are not present, it is prone to collapse, much like whipped cream that is left to sit for too long.

Emulsifiers such as SSL and DATEM help form a flexible layer around the air bubbles that can prevent them from collapsing, which is why bread often has a dense crumb structure and low loaf volume if emulsifiers are removed.

Recent work, however, has shown that natural wheat lipids that comprise 2% to 3% of wheat flour are also good emulsifiers, although they are typically stuck to starch granules or proteins in the dough. This is where lipase enzymes come in.

Lipase enzymes are esterases that break chemical bonds in lipids, making them smaller and freeing them from interactions with other components in the dough.

Lipases are typically produced by fungi where they break down lipids for the growing mycelium to consume. When the right lipases are added to dough, such enzymes produced by Fusarium oxysporum, degrade phospholipids and galactolipids that form flexible layers around air cells in the proofing dough. This leads to stability and loaf volume like conventional enzymes. Since these lipids are already present in wheat flour, however, they are a good clean label alternative.

Lipases do not only act on the lipids that are good emulsifiers. They also act on non-polar lipids that can decrease loaf volume, so if too much is added, they can make dough collapse. In recent work, levels between 100 and 1,000 parts per million of lipase enzymes have been shown to lead to similar loaf volume and crumb structure as DATEM and SSL.

A great deal of current research in lipase technology is aimed at creating lipases that target specific lipids. For now, however, make sure you test dosing conditions, and consider incorporating these ingredients into blends of other ingredients so you don’t accidentally use too much in your production.

Harrison Helmick is a PhD candidate at Purdue University. Connect on LinkedIn and see his other baking tips at BakeSci.com.

His research is conducted with the support of Jozef Kokini, Andrea Liceaga, and Arun Bhunia.