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The enzymes in honey

Honey is the only common food that arrives carrying the enzymes of the animal that made it. Two of them made the honey, one defends it, and all of them are read in a laboratory as a record of how it has been treated.

Honey scienceReviewed 2026-09-29

Where they come from

The enzymes in honey are secreted by the bee, mostly from the hypopharyngeal glands in a worker's head, and added to nectar during the repeated regurgitation that concentrates it. A few come from the nectar itself and from pollen, but the significant ones are the bee's. This is why honey is not a plant product in the way that maple syrup is: maple syrup is sap boiled down, and nothing was added to it by an animal.

The three that matter

  1. Invertase — the one that makes honeySplits sucrose into fructose and glucose. Its activity continues slowly in the jar, which is why a very fresh honey can still have a measurable sucrose figure that falls over the following months. Bees vary in how much they produce, and so do individual colonies.
  2. Diastase — the one that measures honeyAn amylase that breaks starch into simpler sugars. There is essentially no starch in honey, so diastase has no job to do there at all. It survives in the record because it degrades at a predictable rate with heat and storage time, which makes it a proxy for how a honey has been handled. Both the Codex standard and the EU directive set a minimum diastase number.
  3. Glucose oxidase — the one that defends honeyConverts glucose into gluconic acid and hydrogen peroxide. In ripe, concentrated honey it is largely inactive because there is not enough free water for the reaction. Dilute the honey — on a wound, or in a wet cell in the comb — and it starts producing peroxide. Honey's antibacterial activity in the laboratory is mostly this.

Why laboratories care

Diastase and hydroxymethylfurfural are read together. Diastase falls with heat and age; HMF rises with heat, age and acidity. A honey with low diastase and high HMF has been heated hard, stored long, stored warm, or some combination — and none of those can be seen, smelled or tasted with any reliability.

What the enzyme markers do and do not establish
ReadingSupportsDoes not support
High diastase, low HMFGently handled, not old, not stored hotAny conclusion about flavour, floral source or authenticity
Low diastase, high HMFHeated or aged or warm-storedThat the honey is unsafe, or that it is adulterated
Low diastase, low HMFPossibly a naturally low-enzyme honey, such as citrusDeliberate mistreatment — some floral sources start low

What fresh honeys actually measure

The allowance for naturally low-enzyme honeys is not a technicality, and the European reference data show why. Measured on fresh honeys only, diastase activity runs from under 10 Schade units in citrus and rosemary honeys to nearly 40 in Metcalfa honeydew honey — a fourfold natural range before anyone has heated anything. The general legal minimum is 8, lowered to 3 for honeys naturally low in enzymes provided their HMF is no more than 15 mg/kg, and a share of perfectly authentic citrus, rosemary and robinia samples falls below the general figure on its first day in the jar.

Enzyme activity and proline in European honey types, lowest diastase first
Honey typeDiastase activity (Schade units (DN))Invertase activity (U/kg)Proline (mg/kg)
Citrus9.6 ± 2.940 ± 18—
Rosmarinus (rosemary)9.7 ± 3.256.4 ± 17.2271 ± 95
Robinia (black locust, "acacia")10.5 ± 545.5 ± 31.4222 ± 58
Taraxacum (dandelion)11.3 ± 2.3110.7 ± 28.9348 ± 60
Rhododendron (alpine rose)12.1 ± 2.379.6 ± 21.1264 ± 35
Lavandula (lavender)14.1 ± 2.4106.5 ± 44.4—
Tilia (lime, linden)16.8 ± 3.490.6 ± 36.5352 ± 102
Helianthus (sunflower)20.8 ± 5.6117 ± 37.6562 ± 146
Honeydew22.6 ± 5.6139 ± 53.6468 ± 127
Calluna (heather)23.4 ± 6.397.6 ± 34.4646 ± 196
Castanea (chestnut)24.3 ± 5.7152.3 ± 31.2585 ± 167
Eucalyptus25.5 ± 4.8155.3 ± 28.7528 ± 147
Brassica (rape)26.9 ± 5.8103.7 ± 31.7235 ± 49
Thymus (thyme)29.2 ± 7.6121.1 ± 34.7956 ± 196
Metcalfa pruinosa honeydew39.3 ± 7.9172 ± 21.4515 ± 173

Mean ± standard deviation across the samples in the International Honey Commission's European data bank (published 2004). A description of populations of honeys, not a specification for any jar; sample counts for each value are on the individual honey pages. Enzyme values are for fresh honeys. The low diastase of citrus, rosemary, robinia and dandelion honeys is natural, not a sign of heating.

Checked 2026-09-29 against: Main European unifloral honeys: descriptive sheets (Apidologie, 2004); Sensory analysis applied to honey: state of the art (Apidologie, 2004).

Proline, in the last column, is not an enzyme but travels with them in the laboratory. It is the main free amino acid in honey and comes largely from the bee, so it is read as a sign of ripeness — a honey the bees had finished with. Like the enzymes, it varies too much between floral sources to classify a honey on its own: thyme honey averages nearly 1,000 mg/kg in the European samples and robinia honey about 220.

What enzymes are not

The claims on this page

Every substantive claim is placed on a tier, and the top two tiers must also state what they are not claiming.

Commonly claimed, but not supported

Widely repeated and not supported by current evidence. Listed so the correction is here rather than only the claim.

Commonly claimed, but not supported

The enzymes in raw honey aid human digestion.

Honey's enzymes are present in very small quantities, are not human digestive enzymes, and are digested as protein like any other. Their real value is analytical: diastase activity read against HMF is a well-established indicator of heating and storage history, which is why food standards specify it. That is a claim about the honey, not about the eater.

  • HoneyHQ editorial synthesis — HEKNO Ltd · HoneyHQ synthesis
  • Standard for Honey (CXS 12-1981) — Codex Alimentarius Commission, FAO/WHO (1981) · Standards document Link

Sources

  • HoneyHQ editorial synthesis — HEKNO Ltd · HoneyHQ synthesis
  • Composition of American Honeys and related analytical work — United States Department of Agriculture · Peer-reviewed article
  • Standard for Honey (CXS 12-1981) — Codex Alimentarius Commission, FAO/WHO (1981) · Standards document Link
  • The Biology of the Honey Bee — Harvard University Press (1987) · Textbook
  • Main European unifloral honeys: descriptive sheets — Apidologie (2004) · Peer-reviewed article Link
  • Physico-chemical methods for the characterisation of unifloral honeys: a review — Apidologie (2004) · Peer-reviewed article Link
  • Council Directive 2001/110/EC relating to honey — Council of the European Union (2001) · Regulatory guidance Link

How sources are selected and weighted is set out in the sources and evidence policy.

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