Honey grading and the reasons for choosing each test to determination of honey quality
|
| Test |
Unit |
Limit |
Explanation |
| Polyphenols |
g/100g |
0.03-0.1 (Samples greater than 0.1 are of higher quality) |
Polyphenols or active compounds are mainly collected from nectar and bee’s living environment and added to honey. This factor can have a great impact on determining the quality of honey. Therefore, their type and quantity in honey can show the quality of collected nectar and plant diversity of the region. Some of laboratories use this factor and its amount in honey to determine the quality and performance of honey. Honey’s polyphenolic compounds include flavonoids, antioxidants and phenolic derivatives. The amount of polyphenol in honey has been reported in different amounts between 60-460 micrograms per 100 grams of honey. But in Iranian honeys, this number is on average between 30-100 mg per 100 grams.ols |
| Amylase |
Unit/g |
10-100 (Samples greater than 0.1 are of higher quality) |
The first enzyme that is evaluated as the most important enzyme for measuring honey quality is amylase or diastase. This enzyme is produced by bees and added to honey. There is almost no specific document for the specific cause and function of this enzyme in honey, but due to its importance as a biological factor in honey, it is always considered, so its activity in honey is of great importance. Compared to other enzymes in honey, diastase has the longest lifespan, which is nearly 2 years. Any reduction or absence of this enzyme in honey can be a sign of low honey quality or its destruction and inactivation by storage conditions or heat during the packaging process and so on. |
| Glucose oxidase |
Unit/g |
0-10 (For typical samples) |
Glucose oxidase is one of the secreted enzymes of honey bees, which causes the antibacterial effect of honey by hydrolyzing glucose into gluconic acid and hydrogen peroxide. Some honeys have more activity for the gluconic acid. This enzyme is highly sensitive to inactivation in the vicinity of heat, direct light, or energy released in microwaves. Gluconic acid is the main acid in honey and it is usually more than the acidity of honey related to this substance. |
| Reducing sugar |
g/100g |
>65 |
More than 15 types of sugars have been identified in honey, some of them are reducing sugars. These sugars are either brought directly from nectar or processed and produced by bees from other sugars. But more than 95% of reducing sugars are mainly fructose and glucose. |
| Fructose/glucose ration |
Ratio |
>65 |
This calculation and ratio can indicate the establishment of sugar balance in honey that is brought from nectar or produced by bees, and therefore the induction of this ratio indicates the amount of fructose in honey. |
| Sucrose |
g/100g |
<5 |
Sucrose is one of the disaccharide sugars in honey, which can be present in honey in two natural or synthetic forms. Based on the studies of the last two decades, the idea that sucrose is the most disaccharide in honey has been changed and it has been determined that maltose, which is a disaccharide sugar and reducing sugar, can have a higher proportion in natural honey. Bees can produce different enzymes, including invertase, to reduce sucrose in honey and bring this sugar to a balanced ratio in honey. |
| Fructose |
g/100g |
>5 |
Fructose, as the most monosaccharide sugar in honey is always an effective factor in honey evaluation. Of course, if this sugar is produced naturally from nectar or by bees, it can certainly be different from fructose that is used in the industry. |
| Glucose |
g/100g |
20-35 |
Glucose is a monosaccharide sugar as sweetener in honey after fructose. This sugar can be brought from the environment or from the conversion of sugars in honey (conversion of sucrose into fructose and glucose by invertase). |
| Hydroxymethylfurfural (HMF) |
mg/kg (ppm) |
Maximum 40 (temperate areas)
Maximum 80 (tropical areas) |
Hydroxymethylfurfural (HMF) is an indicator regarding the effect of storage or processing temperature. This factor is also very important in honey, which is caused by high temperature. The reason for the toxicity of this substance is the effect on the activity of cells and intracellular signals. This substance can be a precursor of acrylamide, both of which are reported as toxic and carcinogenic compounds. Of course, the reported LD100 for HMF is about 37 grams per kilogram, which is much less than the amount found in conventional honey. |
