Newly identified gum may have food potential
The study, published in the journal Food Hydrocolloids, isolated the gum from the roots of Acanthophyllum bracteatum – otherwise known as ‘chubak’ – and investigated its chemical makeup and potential uses for the food industry.
“[Acanthophyllum bracteatum gum (ABG)] had low surface and emulsification properties but moderate foaming capacity and relatively high foaming stability, which suggests that ABG could potentially be used in food systems to improve foaming properties,” report researchersled by Kambiz Jahanbin from Shahrood University of Technology, Iran.
The research team explained that hydrocolloids, such as water soluble gums, have many functional properties that make them useful in food applications – noting their widespread use in processed food products “in order to impart the required quality in terms of stability, texture and appearance.”
They noted that plant hydrocolloids are long chain, high molecular weight, polymers that dissolve or disperse in water to give a thickening, stabilising or gelling effect – examples of such hydrocolloids are gaur gum, gum arabic, and xanthan gum.
Jahanbin said that whilst many studies have been conducted to understand the chemical composition and functionality of these hydrocolloids, “there is still demand in the food industry for new sources of plant hydrocolloids.”
The new research aimed to isolate and characterize a new type of gum from the roots of Acanthophyllum bracteatum: “We hope that our study will shed some light on understanding its structural-function relationship and its potential application in the food industry,” explained the research team.
Crude gum was obtained as a water-soluble, light-yellow powder from the defatted roots using warm water (50 ºC) and precipitated with 95% ethanol, explained Jahanbin and his co-workers.
The yield of pure gum was found to be higher with air drying (12.4%) compared to freeze drying (5.8%).
“Generally, the total yield of air-dried gum from A. bracteatum root was high compared to other species such as A. pungens root (10%) and A. knorringianum root (5.7%),” said the researchers.
They reported that the protein content observed for ABG (0.9%) was lower than gum arabic (1.8%) and those reported for guar gum (8.2%) and xanthan gum (5.4%), whilst the the total sugar content of ABG was greater than guar gum, but slightly lower than arabic and xanthan gums.
Additional chemical analysis of thegum revealed it was an acidic glucoarabinogalactan, “mainly composed of galactose, glucose, uronic acids and arabinose”, they added.
“ABG solutions exhibited shear-thinning non-newtonian flow behavior for concentrations above 5%,” reported Jahanbin and his team.
The viscosity of 1% ABG solution was found to be around 26 times higher than 1% gum Arabic, and similar to other hydrocolloids, was observed to decrease as temperature increased.
The authors noted that ABG showed low surface and emulsification properties, which “may be due to low protein content and/or poor quality of the proteins in the gum structure,” – however they added that the gum had moderate foaming capacity and a good foaming stability, suggesting that it may have potential as an ingredient to improve foaming properties.
Source: Food Hydrocolloids
Published online ahead of print, doi: 10.1016/j.foodhyd.2011.09.007
“Isolation, purification and characterization of a new gum fromAcanthophyllum bracteatumroots”
Authors: K. Jahanbin, S. Moini, A.R. Gohari, Z. Emam-Djomeh, P. Masi