A new test for flavored fish oils that solves the problem of false rancidity readings could be a big win for industry, sources say.
The test, developed by fish oil finished products manufacturer Nordic Naturals and Nutrasource Diagnostics, a research firm, eliminates the problem of false positives that plagued earlier testing for flavored fish oils, especially those with citrus flavors. The test, based on a HPLC analysis, is called the True Anisidine Value (TAV).
Though fish oils are subject to oxidation like any other oil, rancid products on the market has not been thought to be a problem in recent years, said Harry Rice, vice president of regulatory and scientific affairs for the Global Organization of EPA and DHA Omega 3s (GOED).
“The reality is that people don’t want to take rancid oil,” Rice told NutraIngredients-USA. “Even if they did, there is no evidence that it poses a risk.”
Nevertheless, it has been a complication for the purveyors of flavored oils to not be able to demonstrate freshness with an undisputed test, Rice said. And the new test could help manufacturers better verify shelf life claims for flavored oil products, he said.
“What some manufacturers were doing was providing test results before the flavors were added,” Rice said.
The new method properly distinguishes lipid oxidation from other factors such as flavors, antioxidants or vitamins that may interfere with the rancidity measurement in finished omega-3 formulas, according to the developers.
“The True Anisidine Value test will revolutionize the way in which flavored oils are tested and substantiated for stability. It provides a direct measurement of stability, free of the interferences traditionally found in the method used by the American Oil Chemists’ Society (AOCS)," said NDI president and CEO William Rowe.
Cleaning up problems with existing test
That existing AOCS test relies on the reaction of aldehydes, formed when oil goes rancid, with p-Anisidine. But flavorings can interfere with this reaction and skew the results, said James Neal-Kababick, director of Flora Research Laboratories.
“While this [existing AOCS] method is suitable for straight oil samples, it is not suited for use when the oils have flavoring such as lemon oil added. Lemon oil has aldehydes in the essential oil profile that can react with the reagent and give a falsely elevated p-Anisidine value. In addition, other oil additives such as antioxidants, preservatives and such are suspected of having similar effects,” Neal Kababick said.
“Thus, there is a great need for a more selective method that will measure aldehydes formed from rancidity while not incorporating other compounds that falsely elevate the measured value. If the Nordic Naturals HPLC method is valid and fit for purpose, it would be a significant benefit to the industry,” he said.
Interesting assertion, but how is it arrived at?
But, Neal Kababick said a more thorough evaluation of the test’s validity and fitness for purpose awaits some more detailed information from the test’s developers. The information made public so far states that the test can distinguish between the p-Anisidine that is reacting with aldehydes that arise from rancidity and the p-Anisidine that reacts with the flavoring agents, but doesn’t specify how that the method arrives at that distinction.
“It is not clear from this very limited information how the test is able to account for the amount of p-Anisidine reacting with aldehydes in flavoring agents since they would be ‘consumed’ during the reaction too unless their method has some step to block that reaction (such as a special cleanup process or inhibitor reagent),” Neal Kababick said.
“From our understanding this has been verified and validated and this would be a big win for the industry,” Rice said.