Science - March 14, 2011

Gluten-free and looking like bread

Gluten-free bread is hardly edible, according to bread lovers. But change is on its way. PhD student Lieke van Riemsdijk replaced gluten in bread with tiny particles of milk protein. The result was phenomenal.

Gluten-free bread
The new gluten-free bread is light and fluffy, has a crispy crust and looks a lot like 'real' bread. This is good news for people with gluten intolerance, since no good alternative to bread is available now. The current gluten-free bread is compact and has a cake-like structure, despite the addition of all kinds of bread improvers. Van Riemsdijk will defend her thesis on research into gluten alternatives on Wednesday 16 March.
Guinea pig
Gluten is a protein which occurs naturally in certain cereals. It is a component of many food substances, and one which is almost indispensible for bread: gluten makes bread dough elastic and helps the rising process by retaining gas bubbles. However, more and more people are getting gluten intolerance. Allergic reactions can be so serious that intestinal walls can get damaged. That's why van Riemsdijk was in search of good alternatives to gluten. Since it is very difficult to make good bread without gluten, this PhD student decided to use this staple food as the guinea pig. If her gluten alternative works with bread, then it should work with other food substances as well, was the thinking behind this.
The PhD student replaced gluten in bread with milk protein, an alternative which was already tried and tested earlier without much result. However, Van Riemsdijk did something new with the protein: she made tiny particles the thickness of a hair. She calls this 'structuring'. The result was spectacular: bread that looked surprisingly very much like 'real' bread. Usually, gluten-free bread dough is a thin watery batter. But with only 2.4 percent of milk protein particles, the batter turned out to have an elastic dough-like structure. 'That's something you don't expect, certainly not with the small amount of protein added', says the PhD student. According to her, the protein particles form a network, just like gluten does, since they stick to one another. That makes the dough elastic.
After baking, the bread also turned out to have a nice structure and looked very much like normal bread. One setback was that the bread was a little brittle. But the PhD student knows how to tackle this. 'Since milk protein particles cling extra hard to one another by so-called desulfide bonds, the bread becomes too tough', van Riemsdijk explains. 'By blocking some of the disulfide bonds chemically, the bread will acquire a better structure, but becomes unsuitable for consumption.' Therefore, future research work should be directed at finding a protein or protein mix which produces exactly the right amount of disulphide bonds. Something has also to be done about the taste before the bread is ready for the shop shelves. But the biggest obstacle has been overcome.