Natural Biopolymers

Impact of oat beta-glucan on plant protein-stabilized emulsions

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.

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.

Contact
Dana te Brinke – dana.tebrinke@wur.nl

Molecular structure of cereal β-glucan
Macroscopic phase stability of emultions containing 0-12 mg/mL β-glucan after 7 days
Dry fractionation of seeds for high protein drinks

Due to the shift of people’s dietary pattern, the plant protein have drew more attention these years. However, the plant protein ingredient has not been developed to fulfil consumer wishes. In order to control the viscosity, thickness etc. which are generally contributed by an increased protein concentration, a plant-based native protein ingredient would be favoured. The Mung bean protein ingredient project consists of three subunits. To initiate the project, a more sustainable dry fractionation technique is employed to extract protein bodies from Mung beans, then the aqueous phase separation method is applied to study the extract efficiency of proteins at their native states. Afterwards, mung bean protein colloids are formulated and investigated. Meanwhile, with assistance of microscopy techniques such as light microscopy, SEM and CLSM, it would be possible to track protein bodies during the whole process quantitatively. We expect that the present ingredient is stable and enriched in protein, have promise to be added in high-protein drinks.

Contact
Qiuhuizi Yang – qiuhuizi.yang@wur.nl

Scanning Electron Microscope image of the dry fractionated Mung bean cell. Protein bodies (PB), pieces of non-protein cell components (NP) and starch granules (SG) can be distinguished.
Light Microscope image of mung bean protein colloids
Encapsulation using plant proteins

In this research, we are aiming at using plant proteins as ingredients for replacing synthetic polymers and animal-based materials in encapsulation applications. We use a classical but efficient technique, coacervate encapsulation, to encapsulate functional payloads. For example, think of the fragrances in washing powders: these are enclosed in little plastic shells that break when you rub your towel and then release a “fresh” smell. Right now synthetic polymers made from fossil fuels are used for such shells, but together with an industry partner, Firmenich, we are looking for ways to use plant proteins to make such capsules.

Contact
Xiufeng Li – xiufeng.li@wur.nl

Oil droplets in water with protein coarcervates on the surface

Smart cellulose colloids using Natural Deep Eutectic Solvents

There is an increasing awareness that our future materials must be made sustainably using renewable resources. cellulose is an outstanding candidate starting material, being one of the most abundant natural biopolymers available on earth, and being both biodegradable and environmental-friendly. However, solution processing of cellulose is often unsustainable due to the lack of cheap and environmentally friendly solvents that can break the strong intramolecular and intermolecular hydrogen bonding networks of natural cellulose materials. In this project, we propose to explore and develop a novel alternative class of solvent for cellulose, so-called Natural Deep Eutectic Solvents (NADES). In the next coming stages, we propose to produce various types of “smart” colloids (e.g. nanoparticles, fibres, gels etc.) from biomass products by using an anti-solvent precipitation method.

Contact
Huy Nguyen – vu1.nguyen@wur.nl

Confocal microscopy image of regenerated cellulose precipitated by an anti-solvent