Analysis of high-intensity sweeteners

Although sugars are found in juices, the high-intensity sweeteners are not. However, they are often used in juice-based drinks or nectars, and here it is important to ensure that there is resolution of the sweeteners of interest from the compounds naturally present in fruit juices. This can be a particular problem in drinks with a high juice content as naturally occurring polyphenolic materials in the juice can disturb the analysis. 

There are a large number of other published procedures for the separation of a number of sweeteners and preservatives at one time these are all based on reverse-phase HPLC. Perhaps one of the most startling is the method published by Williams (1986). This uses a small particle size (3 xm) C8 column and allows the separation of a range of colours, sweeteners and preservatives in less than 5 min. The materials separated were amaranth, quinoline yellow, quinine sulphate, sunset yellow, caffeine, aspartame, saccharin, vanillin, sorbic acid, benzoic acid and green S. 

HPLC conditions column 3 fim Spherisorb RP8100 X 4.6 mm, solvent = 17.5% acetonitrile, 12.5% methanol, 70% buffer (0.85% sulphuric acid in HPLC-grade water containing 17.5 mM KH2P04 at pH 1.8) flow rate 1.35 ml/min UV detection at 220 nm. 

HPLC conditions column C18 250 X 4.6 mm solvent = 0.02 M phosphate buffer/acetonitrile from 97 3 at pH 5.0 to 80 20 at pH 3.5 using a linear gradient. 

Acesulfame K was intr oduced as a high-intensity sweetener at around the same time as aspartame. It too is much sweeter than sucrose but is also stable under the low pH conditions of soft drinks. Its analysis in a soft drink is relatively straightforward and an HPLC procedure is given by Grosspietsch and Hachenburg (1980). 

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Since the publication of the first edition of this book, a few more validated methods for the analysis of soft drinks ingredients have been documented. When the first edition was published in 1998, only a handful of methods for the analysis of soft drinks ingredients had been collaboratively tested in the Association of Official Analytical Chemists (AOAC) official methods manual, and only two of these were modern HPLC approaches. At that time, no methods could be found in the British Standards catalogue. Inspection of the British Standards website (http //www.bsi-global.com) now shows that there are two standardised approaches for the analysis of high-intensity sweeteners in soft drinks, both of which use HPLC. This overall lack of standardisation of methods is probably because a soft drink s matrix is relatively straightforward, without many of the problems associated with other areas of food analysis, and so the industry has not felt the need to standardise the test methods. 

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