Chemical Composition of Honey
Carbohydrates
Unsurprisingly, these comprise the major portion of honey - about 82%. The carbohydrates present are the
monosaccharides fructose (38.2%) and glucose (31%); and
disaccharides (~9%) sucrose, maltose, isomaltose, maltulose, turanose and kojibiose. There are also some
oligosaccharides
present (4.2%), including erlose, theanderose and panose, formed from
incomplete breakdown of the higher saccharides present in nectar and
honeydew.
Proteins and Amino Acids
Honey contains a number
of enzymes, including invertase, which converts sucrose to glucose and
fructose; amylase, which breaks starch down into smaller units; glucose
oxidase, which converts glucose to gluconolactone, which in turn yields
gluconic acid and hydrogen peroxide; catalase, which breaks down the
peroxide formed by glucose oxidase to water and oxygen; and acid
phosphorylase, which removes inorganic phosphate from organic
phosphates.
Honey also contains eighteen free amino acids, of which the most abundant is
proline.
Vitamins, Minerals and Antioxidants
Honey contains trace
amounts of the B vitamins riboflavin, niacin, folic acid, pantothenic
acid and vitamin B6. It also contains ascorbic acid (vitamin C), and the
minerals calcium, iron, zinc, potassium, phosphorous, magnesium,
selenium, chromium and manganese.
The main group of antioxidants in honey are the
flavonoids,
of which one, pinocembrin, is unique to honey and bee propolis.
Ascorbic acid, catalase and selenium are also antioxidants. Generally
speaking, the darker the honey, the greater its antioxidising
properties.
Other compounds
Honey also contains organic acids
such as acetic, butanoic, formic, citric, succinic, lactic, malic,
pyroglutamic and gluconic acids, and a number of aromatic acids. The
main acid present is gluconic acid, formed in the breakdown of glucose
by glucose oxidase. Honey also contains
hydroxymethylfurfural, a natural product of the breakdown of simple sugars below pH 5.
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