Unilever R&D searches out new ways to quantify thickeners in foods
Writing in Food Chemistry, the experts present a new strategy for the ‘unambiguous identification and selective quantification’ of xanthan gum and locust bean gum (LBG) in gelled food concentrates.
Led by Christian Grün, the team from Unilever, Eurofins and Wageningen University, noted that while polysaccharides are regularly used for structuring food products – such as thickeners in soups and sauces, or stabilisers in ice cream and oil–water emulsions and gelling agents in jams and jellies - the identification and quantification such polysaccharides within a food “is not necessarily straightforward.”
“To enable the unambiguous identification and quantification of polysaccharide gums in complex food matrices, we here present a multi-angle strategy for the isolation, identification and selective quantification,” wrote the team. “The methods used within this approach include DNA detection by PCR, an isolation procedure for the polysaccharide gums from the food matrix, NMR spectroscopy, (quantitative) enzymatic fingerprinting, and quantitative monosaccharide analysis.”
“This approach is tested on gelled food concentrates containing the commonly used polysaccharide gums xanthan gum and LBG.”
New approach
Grün and his colleagues revealed that DNA detection by polymerase chain reaction (PCR) was showed to be a fast, sensitive, and selective method that can be used as a first screening tool in intact gelled food concentrates.
NMR spectroscopy then enabled the direct identification of xanthan gum and the discrimination between different galactomannans in the isolated polysaccharide fraction, said the team – adding that an enzymatic fingerprinting method using endo-β-mannanase - in addition to being used to differentiate between galactomannans - was developed into “a selective, quantitative method for LBG,” while monosaccharide analysis was used to quantify xanthan gum.
DNA analysis by means of PCR enables very fast and selective screening of polysaccharides present and can be used to further define and specify the analysis strategy. After this, they used a combination of techniques to isolate and recover the polysaccharides.
NMR spectroscopy in combination with enzymatic fingerprinting gives direct and unambiguous identities of the polysaccharides present in the isolate, they revealed.
“Selective and accurate quantification of LBG was obtained by quantitative enzymatic fingerprinting, whereas xanthan gum can be selectively and accurately quantified by monosaccharide analysis,” they added.
The Dutch researchers concluded that although the new method should be tested before application to other gelling systems, they believe the strategy ‘in principle’ is suitable for the unambiguous identification and quantification of a broader range of polysaccharide gums in various food products.
Source: Food Chemistry
Volume 166, Pages 42–49, doi: 10.1016/j.foodchem.2014.05.129
“Strategy to identify and quantify polysaccharide gums in gelled food concentrates”
Authors: Christian H. Grün, et al
