A week, a month, two months – expectations for the fresh-keeping shelf life of cakes continue to push the limits. Whether they have just left the production line or reached their last sell-by date, cakes have to deliver maximum indulgent quality. Anything less, and they are destined to disappoint.
One means of maintaining freshness over an extended shelf life is through the use of enzymes. Acting on flour starch during the baking process, their anti-staling impact remains long after their deactivation in the oven.
Enzymes represent an important area of research for us at DuPont. Our interest in meeting cake shelf-life expectations is behind one of our latest enzyme projects.
Inspiration from bread
The inspiration for our study came from our G4-amylases, which we have used successfully to optimise and maintain the fresh-keeping quality of bread. Here, the use of G4-amylases in yeast-raised bakes with a high fat and sugar content – sweet rolls and brioche for example – has proven particularly advantageous.
This sets the scene for testing G4-amylases in cakes.
The inhibition issue
High sugar content is typically a problem for traditional anti-staling enzymes in cake recipes. The starch-hydrolysing activity of a standard maltogenic α-amylase results in the production of maltose, a disaccharide comprising two glucose molecules. At the same time, the sucrose in cake recipes is a disaccharide of glucose and fructose. As sucrose resembles maltose, it may block the active site of the enzyme and diminish further enzyme activity.
Previous lab studies have shown that this inhibition of maltogenic α-amylase means up to 80% of enzyme activity is lost in the presence of just 5% sucrose.
Improved sugar toleranceBy contrast, G4-amylases hydrolyse starch into maltotetraose, comprising four glucose molecules. This secures a far higher sucrose tolerance, with a loss of around 10% enzyme activity in a 5% sucrose assay.
What we wanted to find out was whether the high efficiency of G4-amylases at a low dose in high-sugar bread products would also apply to cake products with a sugar content of some 20%.
Our application trials have so far included sponge cake, pound cake and high-ratio muffin recipes from markets around the world. In all cases, G4-amylases had a positive effect, not only displaying a good fresh-keeping effect, but also enhancing and maintaining the cakes’ initial softness and moistness throughout a two-month shelf life.
Sponge cakes: TPA firmness and resilience
Opportunities moving on
Depending on the water activity and pH of the formulation and cake storage conditions, microbiological problems may set in before staling becomes significant. With the addition of a suitable anti-mould solution, an opportunity exists for pushing the limits on cake shelf life even further.