According to findings published in Food Hydrocolloids, the novel hydrogel, which is non-toxic and transparent, also possessed antimicrobial and texture properties that make it “very promising” for food applications.
“The texture studies show that it can also be used as an excellent food ingredient,” wrote Chandroth Kalyad Simi and Tholath Emilia Abraham from India’s Council of Scientific and Industrial Research (CSIR).
“The gel which is transparent, colourless, thermostable, and biocompatible with ordered structure and from renewable resources and made cost effective, is in great demand globally,” they added.
The growing field of hydrogels
The research taps in to growing interest in hydrogels, and the potential for food formulation, with previous reports coming from around the world.
Hydrogels are liquid or semisolid materials composed of long-chain molecules cross-linked to one another to create many small empty spaces that can absorb water or other liquids like a sponge.
If the spaces are filled with a bioactive compound, for example, the hydrogel can release it gradually as the structure biodegrades.
Earlier this year, Nestle scientists reported preliminary results with carrageenan-based gels for the delivery of flavour, texture and nutrient components.
According to the Indian researchers, the oxidized xyloglucan and chitosan formed a strong transparent gel without the need of a cross-linking agent.
The right mix
Simi and Abraham oxidized the xyloglucan, which they extracted from tamarind seed. This particular xyloglucan is already used as a thickener in the Japanese food industries, they said. While pure xyloglucan does not form a gel, when mixed with 1 per cent chitosan in 1 per cent acetic acid in water a self-assembled gel is produced.
Results of texture analyses showed that the gel had “good springiness, hardness, and gumminess nature”, said the researchers. No significant effects were observed when they added flavours like vanillin, sweeteners like sucrose, or salt.
Furthermore, the gel displayed good thermal stability, said Simi and Abraham.
“We have accomplished the synthesis and characterization of a transparent, colourless, nontoxic, biodegradable and biocompatible gel from oxidized xyloglucan and chitosan,” they stated.
As reported earlier this year by FoodNavigator, scientists from the Nestle Research Center (NRC) collaborated with scientists at the University of Graz in Austria to produce so-called internally self-assembled emulsion droplets (ISAsomes) that could subsequently be trapped in carrageenan-based gels.
In an email to this website in February, Hilary Green, PhD, Nestle’s head of R&D communications said: “In this new research, the Nestlé Research Centre and the University of Graz have developed a simplified biological membrane that can potentially be applied in foods for the delivery of flavour, texture and nutrient components.”
“However, any commercial food application is still a long way off,” she added.
Source: Food Hydrocolloids
Published online ahead of print, doi: 10.1016/j.foodhyd.2009.08.007
“Transparent xyloglucan-chitosan complex hydrogels for different applications”
Authors: C.K. Simi, T.E. Abraham