Honey


Introduction

external image Honey2.jpg
Honey has been a staple of the kitchen for centuries. It is a natural substance produced by honeybees, Apis mellifera, in almost every country in the world. Honey is essentially a concentrated aqueous solution of inverted sugar, namely fructose and glucose, but it also contains a very complex mixture of other saccharides, enzymes, amino and organic acids, polyphenols, carotenoid-like substances, Mallaird reaction products, vitamins, and minerals (Gheldof, Wang and Engeseth, 2002).

Honey is laid down by bees as a food source, and humans have exploited this. Apiarists (beekeepers) encourage the overproduction of honey within the hive, so that the excess can be extracted. Beekeeping for the purpose of obtaining honey is an ancient art, practiced in societies at least as early as the Egyptians (2000-5000 years ago) who used honey as food, medicine and for embalming. In many cultures, honey has associations that go far beyond its use as a food.


Honey Composition


Honey contains about 181 substances (Al-Manary et al., 2002), including sugars, proteins, water, vitamins, minerals, hydroxymethyfurfural (HMF), enzymes, flavonoids, phenolic acids, volatile compounds, and so on. However, the main constituents of honey (as previously stated) are glucose and fructose, water, maltose, sucrose, mineral matter and proteins.
The specific composition of any batch of honey will depend largely on the floral source available to the bees that produced the honey.
DSCF0084.JPG
Hives at an apiary site on the West Coast of NZ

Component
%
Fructose
38
Glucose
31
Sucrose
1
Other Sugars
9
Water
17
Ash
0.17


Honey Analysis


The types of honey commercially available can either be blends, polyfloral, monofloral, or honeydew. The most common type is blends, where the honey is a mixture of two or more honeys differing in floral source, colour, flavour, density, or geographic origin. Polyfloral honey is derived from the nectar of many floral sources, while monofloral honeys have one principal nectar source. Monofloral honeys generally have a distinct flavour and colour, and are produced when hives are kept in an area where bees have access to one main floral source.



Pollen Analysis
The floral source of honey can be determined microscopically by the study of pollen grains in honey, known as Melissopalynology. Taxa of pollen are used to indicate the principal floral nectar source by bees to produce honey.Therefore, the relative pollen frequency is often used to verify and label a honey sample as to the major and minor nectar sources. This information has important commercial value, as honey from some plants commands premium price. Even non-premium grades of honey require certain types of verification because they must be correctly labeled before being marketed. Identifying and quantifying the pollen in a honey is one of the best ways to determine the range of nectar types used to produce it, and ensure it is correctly labeled based on actual foraging resources.
Because of trade agreements, import tariffs, and legal trade restrictions, most of the leading honey-producing countries of the world require accurate labeling of honey before it can be sold.

Colour Analysis
In addition to pollen analysis, colour is another test that can help classify honey. This is measured on a Pfund grader which gives a result in millimeters following the Pfund scale. The scale is actually a metric ruler measuring the point along a calibrated amber glass wedge where the sample (placed in a glass wedge shaped trough) matches the amber wedge. The scale starts at 0mm (colourless) and finishes at 140mm (black). Some common terms describing the colour of honey actually have specific ranges on the Pfund Scale. These can vary slightly from country to country with the
USA, Canada and Australia all having slight variations. The US scale is used in New Zealand.

Pfund grader and values of some NZ honeys
- courtesy of Airborne Honey Ltd
Pfund Grader
Pfund Grader

Honey type
Pfund reading (mm)
Clover
10-35
Rata
5-25
Manuka
84
Honeydew
87
Thyme
105
Rewarewa
93

Nutritional Benefits


Sweetening


As a carbohydrate, honey supplies 64 kilocalories/268 kilojoules of energy per tablespoon (21 grams). While the consumption of high energy foods is generally discouraged nowadays, honey does not attract negative press because of all of its positive attributes.
Honey is sweeter than table sugar, sucrose, due to its high fructose content. On overage honey is 1 to 1.5 times sweeter than sucrose on a dry weight basis. Liquid honey is approximately as sweet as sugar, yet it contains only 82.4 grams of carbohydrates per 100 grams (as opposed to 100 g/100 g for sucrose) and provides only 304 kilocalories per 100 g (versus 400 Kcal for sucrose). Therefore honey is a healthier option than table sugar as a sweetener.
Honey also has a low glycemic index rating (55) compared to sucrose (GI = 61), meaning it has a slower effect on increasing blood sugar levels.


Sports Nutrition


As an energy source, honey appears to be one of the most effective forms of carbohydrate to ingest after exercise. Many post-workout products on the market combine a large amount of carbohydrate (usually maltodexrin) with protein. In one study (Kreider et al, 2007) subjects were divided into two groups after a resistance training workout, and asked to take either a honey/protein or maltodextrin/protein shake. When the two groups were compared, it appeared as though honey functioned just as well in muscle recouperation and glycogen restoration as other carbohydrates, while also sustaining a favourable blood sugar concentration after training.



Prebiotic Properties


Bifidobacteria are considered important in the health of the gastrointestinal tract. Clinical studies have associated other beneficial effects such as immune enhancement and anti-carcinogencity with the presence of gastrointestinal bifidobacteria.
To increase numbers of these beneficial bacteria, prebiotics may be incorporated into the diet. Currently the most common prebiotics are non-digestible oligosaccharides such as fructooligosaccharides (FOS), galactooligosaccharides (GOS) and inulin.
Honey contains a variety of oligosaccharides varying in degree of polymerisation. A study by Kajiwara, Gandhi & Ustunol (2002) of the department of Food Science and Nutrition, Michigan State University, showed that honey enhanced the growth, activity and viability of commercial strains of bifidobacteria typically used in the manufacture of fermented dairy products. It was shown that the effect of honey on intestinal bifidobacterium species was similar to that of commercial oligosaccharides (FOS, GOS and inulin), and that it was due to the synergistic effect of the carbohydrate components of honey, rather than just a single component.


Antioxidants


In food systems and human health, antioxidants function to reduce oxidative reactions by scavenging and eliminating free radicals. Oxidative reactions have deleterious effects on food products; lipid rancidity for example, and adverse health effects; such as implications in cancer, atherosclerosis and diabetes.
It has been hypothesised that consuming more antioxidant-rich food may help protect against cellular damage and the aid in the prevention of chronic disease development.

Flavonoids are a class of antioxidants which are found in plants as phytochemicals. They are present in nearly all plant-derived foods and beverages, including fruits and vegetables, cereals, grains, nuts, herbs, wines, juices, teas, legumes and honey.
Flavonoids are responsible for colour, enzymatic inactivation, flavour, and inhibition of both vitamin and lipid oxidation. The concentration of flavonoids is largely influenced by genetic factors, plant species, enviromental conditions, ripeness, processing and storage.
The majority of antibacterial characteristic (see below) in honey is due to the hydrogen peroxide content . However, if the hydrogen peroxide is destroyed, residual non-peroxide is observed in several honeys - particularly Manuka honey. Part of this activity appears to be due to high concentrations of pinocembrin, a flavonoid unique to propolis and honey (Hughes, 2002).

Pinocembrin
Pinocembrin

Raw honey is rich in antioxidants. As well as flavonoids, honey contains other antioxidants such as catalase and ascorbic acid (Vitamin C). There have been 33 flavonoids identified in honey, with concentrations ranging from 0.005 to 0.01% (Ferreres et al, 1992).





Other Health Benefits


Antibacterial Properties


From a non-nutritional point of view, honey has been used for years to treat a variety of ailments through topical application. It has been used as a remedy for burns, ulcers and wound healing, simply because it has a soothing effect during its application to open wounds. Given its physical properties, honey provides a protective barrier, and owing to its high osmolarity , creates a moist wound healing environment in the form of a solution that does not stick to wounded tissues. Honey also exhibits antibacterial and anti-inflammatory properties as a result of its low water activity(0.6), high acidity, hydrogen peroxide effect and non-peroxide components (Weston, 2000).

See **Antibacterial Properties of Honey**


Negative Press


Recently, honey has been in the media for all the wrong reasons. Nine people have experienced poisoning due to the consumption of honey contaminated by tutin toxin.
Toxic honey results when bees are in close proximity to tutu bushes (Coriaria arborea) and the vine hopper insect (Scolypopa australis). Both are found throughout New Zealand. Bees gather honeydew produced by the vine hopper insects feeding on the tutu plant, and this introduces the tutin toxin into honey.

Only a few areas in New Zealand; Coromandel Peninsula, Eastern Bay of Plenty and the Marlborough Sound produce toxic honey, and this occurs more frequently in dry years such as this as bees start to run out of other foraging sources
.


In order to reduce the risk of tutin poisoning, honey taken from feral hives in the risk areas of New Zealand should not be consumed. Since December 2001, New Zealand beekeepers have been required to reduce the risk of producing toxic honey by closely monitoring tutu, vine hopper, and foraging conditions within 3 km of their apiary.


Related Articles:
**Background on Toxic Honey**





References

Glossary

Written by Tracey Feary (March 2008)
M.Sc. student
Food and Wine Sciences Group, Lincoln University
external image s551010007_3484096_3479.jpg