Using laccase and protease enzymes led to improved breadmaking performances and enhanced textural quality of finished bread, write researchers from University College Cork and the Catholic University of Leuven in the journal Food Chemistry.
“The improved breadmaking performances could be related to the increased softness, deformability and elasticity of oat batters with laccase and protease supplementation,” wrote the researchers, led by Professor Elke Arendt from the Department of Food and Nutritional Science at University College Cork.
On the other hand, glucose oxidase, another enzyme interesting conventional bread makers, was detrimental to the quality of the oat-based gluten-free bread, said the researchers.
The gluten-free market is growing rapidly. According to a recent report from Packaged Facts, the market has grown at an average annual rate of 28 per cent since 2004, when it was valued at $580m, to reach $1.56bn last year. Packaged Facts estimates that sales will be worth $2.6bn by 2012.
The market researcher said it expected to see a much wider range of gluten-free products on shelves by 2012, and said that this will be driven by companies reformulating existing products for gluten-free acceptability, as well as by releasing new ones.
Care with oats
It should be noted that, although oats do not actually contain gluten there is some concern over their presence in foods since they are commonly contaminated during processing with gluten from wheat, rye or barley, according to Coeliac UK.
Prof Arendt and her co-workers prepared breads using oat flour (Flavahans, Ireland) and instant dried yeast (Pante, Puratos) supplemented with one of three types of enzymes - glucose oxidase, laccase, and protease (all from Novozymes) – to produce oat-based bread.
Both laccase and protease preparations “significantly improved the breadmaking performances of oat flour and the textural quality of oat bread, by increasing specific volume and lowering crumb hardness and chewiness”, said the researchers.
“The improved breadmaking performances of oat breads with laccase and protease addition was explained by the increase in batter softness, deformability and elasticity which were achieved upon addition of these enzyme preparations, both containing discernible levels of endo-beta-glucanase side activity,” they explained.
“With laccase, the effect is due to prevalence of beta-glucan depolymerisation over protein polymerisation while, with protease, it is due to the combined effect of protein and beta-glucan degradation,” they added.
On the other hand, glucose oxidase did not favourable improve the textural quality of oat bread, with increases in crumb hardness recorded.
This was proposed to be due to extensive protein polymerization, said the researchers.
The study was funded by the European Commission in the Communities 6th Framework Programme, Project HEALTHGRAIN.
Source: Food Chemistry
Published online ahead of print, doi: 10.1016/j.foodchem.2009.09.028
"Oxidative and proteolytic enzyme preparations as promising improvers for oat bread formulations: rheological, biochemical and microstructural background”
Authors: S. Renzetti, C.M. Courtin, J.A. Delcour, E.K. Arendt