Enzymes as processing aids
By Gary Tucker - 2 February 2015
The baking industry faces a number of challenges in providing products that meet the needs of modern consumers. This is not easy - many of its products are seen as indulgent because of their high levels of fat and sugar.
Fat has many properties that make it an essential ingredient for baked goods. One of its functions is as a lubricant that helps bread and biscuit dough to soften and flow without sticking to surfaces. Reducing fat levels in a recipe can lead to dough sticking to moulders and transfer surfaces, which can cause expensive cleaning and product losses. Emulsifiers can replace some of the fat functionality but they appear on the ingredients label with an E–number. While the industry knows this means they are a safe ingredient, consumers are less tolerant.
One solution is the use of lipase enzymes. These have been used for several years to generate emulsification materials in situ. They are used in bread and cake manufacture and can reduce the fat required in a recipe. Like all enzymes they require suitable substrates, operating temperatures and pH. This is where an understanding of the lipase is necessary so that processing conditions can be adjusted. Enzymes can be expensive ingredients so it makes sense to use the minimum quantity and make sure that they work effectively.
Sugar also plays an important role in baked goods, conferring flavour, acting as a bulking agent and humectant, stabilising batter viscosity, influencing starch and protein setting temperatures, providing colour, and softening texture. However, it has received bad press recently. Sugar created enzymically in situ has significant advantages over added sugar, and not just to the clean label it allows. For example, amylase use in bread dough results in a gradual formation of fermentable sugars, which helps the yeast work in a more controlled way. Too much sugar could result in excess carbon dioxide and over–inflation of gas cells, which could rupture. Amylases work slowly to maintain the balance of sugars for fermentation until the yeast is killed around 55°C. Sugar generation continues for a few minutes after this until the amylases themselves are inactivated by the oven heat. Small quantities of sugar left in the dough contribute to crust browning and provide some flavour.
Also on the diet and health agenda is fibre. Fibre materials are beneficial to our health and efforts are made to include them in bakery products. However, fibres such as wheat bran absorb a lot of water and more slowly than other components in dough. This causes processing issues, with tight dough that does not mould well but also resists expansion by yeast action, resulting in poor quality bread. Xylanases are now used in most industrial bread manufacture to cut some of the linkages of large fibre molecules, releasing low molecular weight sugars and water. This helps soften dough slowly so that it can be processed with fewer issues. The fibre materials are still available as a dietary benefit.
There are significant legislative changes ahead with enzymes. For the first time, there may be specific EU legislation on the use of enzymes in food. The EU is in the process of compiling a long list of permitted enzymes that can be placed on the market and used in food. While it remains to be seen what the outcome will be, it is safe to say that it will have far–reaching implications for the baking industry.
We have been active in the application of enzymes to baking for many years. We can help manufacturers get the most out of enzyme systems by understanding the needs of the enzymes so that processing conditions can be optimised.
About Gary Tucker
Gary Tucker is Head of the Baking and Cereal Processing Department at Campden BRI and has worked for the company since 1989. He studied Chemical Engineering at Loughborough University and is a chartered chemical engineer. Read more...