USDA scientists are continuing to expand the potential of corn fibre gum as an emulsifier in beverages, with a new study pinpointing the emulsifying properties of the gum.
A model emulsion system showed that corn fibre gum is a better emulsifier than the more well-known and used gum arabic, according to results published online in the journal Food Hydrocolloids.
Furthermore, the results showed that the purified corn fibre gum contained minor but “perhaps functionally important” lipids and proteins, which may be vital for the emulsifying properties, added the researchers..
“Understanding the critical structural elements required for optimal emulsification properties will allow future commercial producers of CFG to provide consistent quality and functionality in their products,” wrote lead author Dr Madhav Yadav from the USDAs Agricultural Research Service.
The research builds on previous studies by the same researchers. FoodNavigator.com reported on these earlier findings in October 2006. At the time, Dr. Yadav told this website that the applications for corn fibre gum beyond beverages could possibly include encapsulation of essential oils and fatty acids, glossy coatings and biodegradable edible films, and even as a prebiotics.
The need for an alternative to gum arabic
The supply of gum arabic (E414 in the EU), also known as acacia gum because it comes from Acacia trees in the gum belt of Africa, is variable due to political and climatic factors in the primary producing countries like Sudan and Nigeria and this has led to spikes in the price of the ingredient.
Attempts to find an alternative have lead researchers, particularly in the US, to look into the use of corn fibre, a readily available and low valued by-product of corn milling, to produce a gum that could be used as a thickener, adhesive, and stabiliser for food and beverage applications.
For the new study, Dr. Yadav and co-workers compared the emulsifying properties of various corn fibre gum preparations with both native gum arabic and modified gum arabic (both from TIC gums). The industrial grade corn fibre was provided by National Starch.
Model emulsion systems were prepared using each of the gums, and after two days the researchers found that the emulsion stabilities of all corn fibre gum samples were similar, but superior to both gum arabic samples.
After 10 days, the emulsion stabilities of the corn fibre gum emulsions were still higher than those prepared using both native and modified gum arabic, with the modified gum arabic better than the native for the preparation of the emulsion.
Out of all the types of corn fibre gum tested, Dr Yadav and co-workers report that the gum extracted from wet milled pericarp fibre was the “superior emulsifier”, and this was related to the higher protein content.
Looking to the near future
Dr Yadav and co-workers highlighted the next stage in the research and development of the corn fibre gum. The next series of studies should identify the effects of the protein and lipid parts of corn fibre gum, and this will be achieved by totally removing these parts from the gum.
“The important factor is that the interaction between corn fibre gum and protein should be strong and the complex should remain soluble in order to retain its good emulsifying properties,” wrote the researchers.
“The protein [part] of the conjugate will anchor the molecules on the oil interface and the covalently linked high-molecular-weight hydrophilic corn fibre chain will extend into the aqueous phase and stabilise the layer around the oil droplets by steric and electrostatic repulsion.
“This mechanism will protect the dispersed tiny oil droplets in the emulsion against flocculation and coalescence,” they concluded.
Source: Food Hydrocolloids
Published online ahead of print, doi: 10.1016/j.foodhyd.2008.08.012
“Corn fiber gum: new structure/function relationships for this potential beverage flavor stabilizer”
Authors: M.P. Yadav, D.B. Johnston, K.B. Hicks