The research – published in Food Hydrocolloids – reports that gum extracted from flaxseed hulls could provide industry with a readily available soluble fibre that has potential to deliver acceptable mouthfeel and texture even when used in the high amounts needed to enhance the nutritional value of foods.
Led by Professor Douglas Goff from the University of Guelph, Canada, the research team extracted soluble flaxseed gum from hulls before separating the gum extracts into neutral and acidic fractions. The research team said the gum fractions have potential applications as a ‘fibre fortifier’ that delivered in terms of mouthfeel and texture.
“Soluble dietary fibre with low viscosity has the potential to deliver acceptable mouthfeel and texture when included in the diet in a significant amount to show health benefits. Soluble flaxseed gum (SFG) was reported to have low viscosity, thus has potential in applications as a fibre fortifier,” said Goff and his colleagues.
“In comparison to locust bean gum, guar gum and xanthan gum at a concentration of 0.3% (w/v), soluble flaxseed gum exhibited much lower viscosity,” they added.
Goff and his team said that low viscosity – such as that of flax gum – is favoured in the dietary fibre fortification of food, as it does not lead to the problem of ‘over-texturization’ when a significant concentration of fibre is required to show health benefits
Since late 2010 the food industry has faced a constant problem with supply, as guar gum is now being heavily used in the oil and gas industry, for the process of fracking, causing an increase in demand and prices to rise.
A recent IMR International report published by consultant, Dennis Seisun, noted that the guar gum situation remains critical for food buyers, with tight supplies and high prices set to continue until at least the end of 2012 – probably beyond.
Seisun said that as a result many food formulators are partially replacing guar with blends, completely replacing the thickener with another hydrocolloid, or eliminating the use of hydrocolloids entirely.
In the new study Goff and his team extracted the soluble gum from flaxseed hulls, before separating them into ‘neutral’ and ‘acidic’ fractions. The team the analysed the gums to test their viability for industrial use.
The team noted that the protein content in the soluble flax gums were completely removed by protease – “to obtain two more protein-free fractions.” They noted that only the complete soluble fibre and acidic fibre contained protein, with neutral fibre containing no protein from the beginning.
“Neutral flaxseed gums consisted of high molecular weight (MW) (1470 kDa) arabinoxylans and exhibited pseudoplastic flow behaviour; whereas acidic flaxseed gum was mainly composed of rhamnogalacturonans with a higher MW fraction (1510 kDa) and a lower MW fraction (341 kDa) and showed Newtonian flow behaviour,” reported the authors.
They said that in comparison with gums that had no, or removed protein, the full soluble flaxseed gum extract, and the initial acidif fractios showed better surface activities and emulsifying stabilities – "due to the presence of protein in both fractions.”
Source: Food Hydrocolloids
Volume 28, Issue 2, Pages 275–283, doi: 10.1016/j.foodhyd.2011.12.019
“Flaxseed gum from flaxseed hulls: Extraction, fractionation, and characterization”
Authors: K.Y. Qian, S.W. Cui, Y. Wu, H.D. Goff