β-glucans from cereal: healthy, green and functional food ingredients

Cereal β-glucans are present in e.g. oat and barley. These soluble fibers form highly viscous solutions in water. Because of this, they reduce the uptake of glucose and cholesterol in the intestine, and thus have a positive effect on health. This makes them a desirable food ingredient. β-glucans can also improve the texture of foods, for example in low-fat dairy products.

Even better than using the highly purified fibers would be the use of mildly purified oat fractions. These are much more sustainable, because less water and energy are used for their production. For example, oat bran concentrate is produced from oat flour by only dry fractionation, and contains already 12% β-glucan compared to 4% in oat flour.

Molecular structure of cereal β-glucan
Molecular structure of cereal β-glucan

Like with any polymer, adding β-glucan to a food product will have physical effects, such as an increase in viscosity and depletion interaction. This can change the structure or stability of the product. These effects need to be characterized before we can use β-glucan as a food ingredient.

Using pure β-glucan, we have shown that adding β-glucan to emulsions can induce instability by depletion flocculation. But it can also slow down destabilization. We try to explain these differences in macroscopic behaviour by studying the phase separation kinetics and rheological properties.

Similar studies will be performed with mildly purified oat fractions instead of pure β-glucan. A challenge here is to take into account the effects of other (fiber) components of the material. We study the chemical properties and contents of the oat fractions in order to explain the observed physical effects.