Food Chemistry

19.2 Honey and Artificial Honey 889

In honey gluconic acid is in equilibrium with its
gluconolactone. The acid level is mostly depend-
ent on the time elapsed between nectar collection
by bees and achievement of the final honey
density in honeycomb cells. Glucose oxidase
activity drops to a negligible level in thickened
honey. Other acids present in honey only in
small amounts are: acetic, butyric, lactic, citric,
succinic, formic, maleic, malic and oxalic acids.

19.2.1.5.7 Aroma Substances

About 300 volatile compounds are present in
honey and more than 200 have been identified.
There are esters of aliphatic and aromatic
acids, aldehydes, ketones and alcohols. Of
importance are especiallyβ-damascenone and
phenylacetaldehyde, which have a honey-like
odor and taste. Methyl anthranilate is typical
of the honey from citrus varieties and lavender
and 2,4,5,7a-tetrahydro-3, 6-dimethylbenzofuran
(Formula 19.4, linden ether) is typical of linden
honey.

(19.4)

19.2.1.5.8 Pigments

Relatively little is known about honey color pig-
ments. The amber color appears to originate from
phenolic compounds and from products of the
nonenzymic browning reactions between amino
acids and fructose.

19.2.1.5.9 Toxic Constituents

Poisonous honey (pontius or insane honey) has
been known since the time of the Greek historian
and general,Xenophon, and the Roman writer,
Plinius. It comes mostly from bees collecting
their nectar from: rhododendron species (Asia
Minor, Caucasus Mountains); some plants of the

familyEricacea; insane (“mad”) berries;Kalmia

evergreen shrubs;Eurphorbiaceae; and honey

collected from other sweet substances, e. g.,

honeydew exudates of grasshoppers. Rhododen-

drons contain the poisonous compounds, andro-

medotoxin (an acetylandromedol) and grayan-

otoxins I, II and III (a tetra-cyclic diterpene)

used in medicine as a muscle relaxant (I: R^1 =

OH, R^2 =CH 3 ,R^3 =COCH 3 ; II: R^1 ,R^2 =CH 2 ,

R^3 = H; III: R^1 = OH, R^2 =CH 3 ,R^3 =H)(see

Formula 19.5).

(19.5)

The poisonous nature of New Zealand honey is

a result of tutin and hyenanchin (mellitoxin) tox-

ins from the tutu shrub (tanner shrub plant,Cori-

aria arbora). Poisonous flowers of tobacco, ole-

ander, jasmine, henbane (Datura metel) and of

hemlock (Conium maculatum) provide nonpoi-

sonous honeys. The production of these honeys

is negligible in Europe.

19.2.1.6 Storage

Honey color generally darkens on storage, the

aroma intensity decreases and the content of hy-

droxymethyl furfural increases, depending on pH,

Fig. 19.16.Hydroxymethyl furfural formation in honey

versus temperature and time (according toWhite, 1978)