Steviol Glycoside Testing for Stevia Ingredients and Finished Products: Why Purity and Profile Both Matter

Overview

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For manufacturers formulating with stevia — across dietary supplements, food products, beverage mixes, functional foods, and stevia ingredient supply chains — steviol glycoside testing answers two distinct questions that are often collapsed into one: is the ingredient pure, and is it the specific sweetener the formulation calls for? Total steviol glycoside content, tested against the USP-FCC and JECFA specification of not less than 95% on a dry-weight basis, answers the purity question. The individual glycoside profile — resolving Rebaudioside A, B, C, D, E, F, M, N, and O, Stevioside, Dulcoside A, Rubusoside, and Steviolbioside — answers the identity and quality question, because two ingredients can both meet the purity threshold and taste, and perform, very differently. At Cambium Analytica, we resolve total content and the full individual profile using Ultra High Performance Liquid Chromatography with Diode-Array Detection (UPLC-DAD), with results in 2–5 business days.

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Total Steviol Glycosides: The Purity Benchmark

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Total steviol glycoside content is the figure most buyers, regulators, and formulators check first. The USP Food Chemicals Codex monograph and the JECFA specification both set the bar at not less than 95% total steviol glycosides on a dried basis for high-purity steviol glycoside products, a threshold reflected in FDA's response to the relevant GRAS notifications. This number drives ingredient qualification, supplier certificate-of-analysis verification, batch release, and the substantiation behind any purity claim on a label. It's a necessary check — but on its own, it doesn't tell you which glycosides make up that 95%, which is where the second layer of testing comes in.

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Individual Glycoside Profile: Why Composition Is Its Own Quality Attribute

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Two ingredients can both clear the 95% purity threshold and be functionally different products, because steviol glycosides don't taste the same. Stevioside and Rebaudioside A are associated with a more pronounced, lingering, licorice-like aftertaste, particularly noticeable at higher concentrations. Rebaudioside D and Rebaudioside M — often marketed as next-generation steviol glycosides — deliver a cleaner, faster-onset, more sugar-like sweetness with significantly less bitterness and a shorter aftertaste. That difference matters commercially: formulations built around Reb M or Reb D command a taste-quality position that a Stevioside- or Reb A-heavy extract can't replicate, even at identical total purity. Resolving the full glycoside profile is also the most direct way to catch substitution — an ingredient sold and priced as Reb M-rich but actually composed mostly of cheaper Stevioside would still pass a total-purity check while failing to deliver the taste and identity the formulation was built around.

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Why Dry-Weight Basis and Moisture Correction Matter

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Ingredient-level testing (STEVG) reports results on a dry-weight basis with a moisture correction applied, while finished-goods testing (STEVA) reports results as a straight percentage. This isn't an arbitrary distinction. Raw steviol glycoside ingredients can carry variable residual moisture, and moisture dilutes a straight percentage reading — an ingredient that is genuinely ≥95% pure on a dry basis could read below spec if moisture isn't corrected for. Comparing an ingredient against the FCC/JECFA 95% threshold without that correction risks both false failures and false passes. Finished goods don't need the same correction because the moisture content is simply part of the finished product being evaluated as-is.

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Instrumentation: UPLC-DAD

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Ultra High Performance Liquid Chromatography with Diode-Array Detection (UPLC-DAD) is well suited to steviol glycoside analysis because the glycosides are structurally similar compounds that need strong chromatographic resolution to separate and quantify individually — not just as a lumped total. Diode-array detection adds spectral confirmation of each peak's identity, which matters when thirteen related compounds are eluting in sequence. UPLC's higher resolution and shorter run times over conventional HPLC make full 13-glycoside-plus-total profiling practical at commercial testing turnaround.

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Method Summary

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Parameter // Details
Analyte // Steviol Glycosides (13 individual glycosides + Total)
Equipment // UPLC-DAD
Reportable Units // %, mg/g (dry-weight basis for ingredients)
Sample Requirement // 10g
Available For // Finished goods (STEVA); Ingredients (STEVG)
Turnaround // 2–5 business days

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Who Should Be Testing

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Steviol glycoside profiling is relevant across the stevia supply chain. Ingredient suppliers and importers confirming FCC/JECFA purity compliance before a lot is sold, brand and product teams verifying that a supplier's certificate of analysis matches the actual glycoside profile received, dietary supplement and functional food or beverage manufacturers confirming sweetener identity and consistency for label claims, and regulatory and QA teams building specification and GRAS/FCC compliance documentation all rely on this level of detail — total purity alone doesn't cover any of these use cases on its own.

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Get Started

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To submit samples or discuss your steviol glycoside testing needs, fill the form below or contact us at sales@cambiumanalytica.com. Our team is happy to help you determine whether STEVA or STEVG is the right test code for your sample type.