It’s an irritating issue with a very natural cause: cellulose.
In wheat, cellulose is mainly located in the bran. In rye, however, it is distributed throughout the kernel and in much greater quantities. So, when producing a wheat-mix bread with 40% rye flour, for example, dough processing can be severely compromised.
The issue lies in the large crystalline cellulose molecule, which, instead of absorbing the water in the dough, adsorbs it – leaving the water on the cellulose surface. Apart from the stickiness this creates, the final baked bread is characterised by a firm crumb, lacking the softness widely perceived as a sign of freshness.
An obvious approach to solving the problem is through the use of cellulases, the group of enzymes with the ability to break down cellulose into glucose. This action takes place in three steps, depending on the cellulase used:
- The amorphous structure is broken down, opening the crystalline structure of the cellulose molecule. Water can then be absorbed, reducing dough stickiness and easing processing.
- Two glucose molecules are split off from the non-reducing end of the glucan chain, leading to improved crumb softness and the perception of freshness.
- Tetra- and disaccharides are hydrolysed into glucose. By providing more substrate for the yeast, this results in better proofing stability and higher bread volume.
The right balance
Getting the right balance is of utmost importance when using cellulases. No one is interested in breaking down cellulose completely into glucose, as this means all the water bound in the dough by the cellulose will be lost. Consequently, cellulases are typically used to resolve stickiness and crumb firmness issues – much less for their ability to enhance volume.
At DuPont, we’ve conducted experiments to identify combinations of cellulase activity that make dough easy to handle and, at the same time, enhance crumb softness in the baked bread. You can see the result of our softness tests in the graph below – a clear demonstration that the addition of 50ppm and 100ppm cellulase has a beneficial effect.
So, if stickiness is a regular plague on your production line, you know where to find the problem – in the cellulose. Drop me a line if you need advice on the right cellulase for your product.
For our trials, we used our non-GM cellulase POWERBake® CU.