Propolis Assessment Kits

Propolis quality assessment kits are tools and test sets used to measure the cleanliness, wax content, alcohol-soluble fraction (balsam), total phenolic and flavonoid content and safety of raw propolis and propolis extracts. A beekeeper can make a rough assessment from appearance, smell, texture and a simple alcohol solubility test; reliable results on quality, origin and residues require laboratory analysis. Because the composition of propolis varies greatly with the source plant, no single number fully describes its quality.

Why is propolis quality assessed?

Propolis is not a standard product. Temperate-zone propolis based mainly on poplar buds is chemically very different from propolis collected from other resinous trees. Even within one apiary, collection method (trap or scraping), season and storage conditions change the quality. The assessment seeks to answer these questions:

• Is the product clean, and how much foreign matter and wax does it contain?
• What is the level of the phenolic compounds regarded as valuable?
• Which plant type does the propolis come from?
• Is the product safe: are there treatment residues, heavy metals or adulterants?

Which properties of propolis are measured?

In Türkiye, the Turkish Food Codex Communiqué on Bee Products sets criteria for raw propolis and propolis in its annexes. If you are going to sell, check the current limit values in the legislation in force.

How can beekeepers assess propolis themselves?

Visual and sensory checks

• Cleanliness: Look for bee parts, wood, paint flakes and dust on a light-coloured tray. Trap propolis is clearly superior to scraped propolis in this respect.
• Smell: Good propolis has a sharp, resinous, aromatic smell. A product that is odourless, stale or smells mouldy has been stored badly.
• Texture: Propolis is hard and brittle when cold and sticky when warm. A sample that is pale, feels greasy and stays soft and waxy even when only lukewarm has a high wax content.
• Colour: Ranges from pale yellow to reddish and dark brown; colour gives a clue to the source but does not indicate quality on its own.

A simple alcohol solubility test

How much of the propolis dissolves in alcohol gives a rough idea of its quality. The test below is no substitute for laboratory analysis, but it is useful for comparing batches with each other.

1. Take a weighed sample of frozen propolis broken into small pieces.
2. Cover the sample with food-grade ethyl alcohol in a lidded dark glass jar; leave it at room temperature away from light for a few days, shaking often.
3. Filter the mixture through a weighed filter paper; dry the insoluble residue completely together with the paper and weigh it.
4. Subtract the insoluble fraction from the starting weight to calculate the soluble share. Tests carried out by the same method can be compared between batches.

How is propolis analysed in the laboratory?

Laboratory analysis is essential for commercial trade and label information. Total phenolics and flavonoids are determined by measuring the propolis extract with spectrophotometric methods. Some "propolis test kits" on the market are based on the same chemical reactions and need a spectrophotometer and correctly prepared standards; used without training, they can give misleading results.

Chromatographic methods measure individual marker compounds that show the plant type and authenticity of the propolis. In poplar-type propolis, certain flavonoids and phenolic acid esters are typical markers. These methods are also used to expose adulteration, such as wax or plant extracts added to propolis.

How do you take a sample for the laboratory?

• A representative sample is made by mixing pieces taken from different parts of the batch.
• The sample goes into a clean, odourless, light-protected container marked with batch number, collection date, method (trap or scraping) and apiary.
• Keep the sample cool; if the laboratory requests it, send it frozen.
• If you want residue analysis, say so clearly; propolis collected during a treatment period is marked separately.

Common mistakes and misconceptions

• Judging quality by pH: pH is not a basic measure of propolis quality.
• Taking colour for quality: Dark colour means neither good nor bad propolis; colour depends on the source.
• Turning antimicrobial activity in the laboratory into a health claim: A test-tube result does not mean it prevents or treats a disease in people.
• Mixing scraped and trap propolis and having a single analysis done: The result reflects neither batch correctly.
• Using a rapid test in place of an official report: Sales and labelling require a report from a competent laboratory.