Natural enzyme found to improve bread quality and shelf life
enzyme preparation for baking, which increases loaf volume and
crumb softness while also extending shelf life by three days.
The enzymes, called hemicellulases, work on compounds found in wheat that inhibit the optimal development of dough, say researchers at Teagasc and scientists at the National University of Ireland, Galway.
"Our primary goal was to find a way to improve the quality of bread without resorting to e-numbers or artificial additives that scare off consumers. The enzyme preparations we are testing have been derived from microbes grown on rye and white and wholemeal flours, which allow them to be optimally developed in order to break down these raw materials," said Gerard Downey of Teagasc's Ashtown Food Research Centre.
Hemicellulases act on arabinoxylans, found naturally in layers of bran. These are large molecules that interfere physically with dough formation when water is added to four. This occurs for two reasons: the molecules are mainly insoluble and are also capable of binding many times their weight in water. In this way, they disrupt the optimal formation of the protein mesh, or elasticity, of dough.
"If you can break up arabinoxylans into smaller molecules then you can reduce their interference. The challenge is to break them down into ideal lengths to aid gluten development," Downey told BakeryAndSnacks.com.
Although hemicellulases already exist on the market, Downey claims the preparations they have tested have had far superior results in breadmaking.
Tests were conducted on white bread loaves and rolls, wholemeal bread and rye bread, with results showing a bread volume increase by up to 21 per cent and a crumb softness increase by up to 128 per cent.
"In some cases, bread made with the enzymes was softer after three days than untreated bread was on the day of baking," said Downey.
The treated bread did not appear to have any mould growth after its three extra days of shelf life, even without the use of an anti-mould agent. However, no formal tests were conducted for mould formation.
"What is absolutely crucial for the commercial exploitation of this enzyme development is for it to work with a variety of wheat from different sources, as the amount of natural inhibitors varies in different wheat types," said Stanley Cauvain of BakeTran, a UK bakery consultancy firm.
"Provided that is achieved, then this really is a breakthrough for a naturally occurring enzyme," he added.
Many enzymes for bakery applications are derived from genetically modified (GM) microorganisms. Although this does mean that there is any genetically modified material in the finished enzyme preparation, an effective naturally occurring enzyme would generally have more appeal than a GM-derived one.
The research, which is funded by the Irish government's Department of Agriculture and Food, is due to be completed by the end of the year.
"The enzyme preparations are still experimental so are not as yet available commercially. But it is very possible that they could be taken up by an ingredients company and marketed in the near future," said Downey.
According to the scientists, the next step in their research will be to find a way to increase the amount of dietary fibre in bread while retaining crumb softness. Further assessment will also be carried out on evidence that indicates that the hemicellulases may release substances with antioxidant or probiotic activity.
