Fibre crusts give leather the boot

Add a few percent fibre to the recipe, and your healthy par-baked bread will end up as tough as old boots. Enzymes offer a solution.

Many have learned to accept a leather-like crust when targeting par-baked fibre bread at the health-conscious consumer. The problem begins with a fibre content of just a few percent – in other words, below the 6% required in the EU for a high-fibre claim.

Here’s what goes wrong.

Due to its high-water absorbing capacity, the fibre absorbs much of the water in the dough system. However, during the second baking, part of this water is released from the fibre and migrates towards the outer part of the bread. It is this water movement that hinders formation of a proper crust, leaving it tough and leathery.

Influencing the Maillard reaction
Among the commercial enzymes today available to the bakery industry, there are some solutions. We have tested two of them in combination – amyloglucosidase and glucose oxidase.

These enzymes catalyse a chain of events, influencing the Maillard reaction that takes place between reducing sugars and amino acids during baking and which is responsible for building the crust. Let’s take a look at that, step by step.

  • Much of the glucose in the dough is produced when the yeast is stressed by high temperature. The amyloglucosidase increases glucose availability for the Maillard reaction.
  • At the dough surface, some of the glucose reacts with the glucose oxidase, leading to the production of water peroxide.
  • The water peroxide oxidises the gluten and other proteins, altering the structure of the dough.
  • These oxidised proteins have an impact on the Maillard reaction, leading to a crisper crust.

A single word of warning: take care not to add too much glucose oxidase, as this will result in a thick crust susceptible to flake-off.

Once the quality of your crust is secure, you’ll find that par-baked fibre bread actually stays crisp for as long as white bread - enabling a longer display time with reduced waste in bake-off outlets. Most importantly, it brings an end to leathery eating experiences for consumers. That’s got to be good for sales.

We used the DuPont™ Danisco® enzymes GRINDAMYL™ AG 1500 for our trials.

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