New USP standards will help stevia formulators cut costs, improve accuracy

Among food ingredients, USP has announced new testing protocols to be added to the Food Chemicals Codex for stevia, caffeine and silver and gold (trace amounts get included in foods wrapped in foils of these metals).  In addition, the organization announced a new testing standard for krill oil.

One of the issues in the testing of stevia is the size and complexity of the molecules, said Markus Lipp, PhD, director of food standards for USP.

“I think the profile of the stevia plant is fairly well established.  There are these nine steviol glycosides that all have certain taste profiles and a certain sweetness profiles attached to them.  Most well known of course is Reb A,”​ Lipp told FoodNavigator-USA.

“The whole family, if you ever look at the chemical structure, are a fairly large, complex molecules.  These are fairly unwieldy molecules to deal with in analytical chemical procedures.”​

Tests degrade equipment​

The various glycosides have the effect of fairly quickly degrading the columns used in the liquid chromatography testing protocols, Lipp said. This can both cloud results as the columns degrade, and raise costs as labs testing for these molecules need to purchase more consumables.

“You don’t want your equipment to be damaged because it affects your bottom line but it may also affect your analytical results because the error margin becomes bigger,”​ Lipp said.

“These are the things that keep analytical chemists awake at night.”​

Sorting out the glycosides​

The new testing procedure offers a simplified approach to separating out the glycosides, one that is not as hard on the equipment.  Identifying these ingredients becomes ever more important as formulators increasingly look to various combinations of glycosides to get the best taste profile, Lipp said.  New testing standards are also helpful as more growers supplying raw stevia enter the market every year.

“We have to be sure what we have, and we have to sure how pure it is,”​ Lipp said.

New caffeine standard​

The new caffeine testing standard augments existing wet chemistry methods used for the ingredient, Lipp said. The revision to this standard is part of USP’s ongoing program to keep up with technological developments in the food ingredients testing sphere.

“(The existing) methods are good, but they have not been as specific to caffeine as we would like them to be,”​ he said.

The new standards can help formulators get accurate caffeine numbers in different matricies, Lipp said.  But it will be up individual companies to verify the method for their individual formulations.  Energy beverages, as an example of a product category that frequently includes caffeine as an ingredient, can be a challenge form a testing perspective because the formulations can be quite complex, Lipp said.

The proposed standards are available for public review for a 90-day comment period, which closes March 31, 2013. To make comments, click here​.