Chemical and Functional Properties of Food Saccharides

© 2004 by CRC Press LLC
TABLE 6.2
Nonsugar Honey Components
Major Groups of Compounds Content
Nitrogen Compounds
Total proteins (mg/100 g) 50–1000
Free proline (mg/100 g) 20–300
Other free amino acids (mg/100 g)
Acids (gluconic, citric, lactic, malic, succinic,
30–700
butyric, propionic, and other) (mg/100g) 10–300
Ash (Mn, Co, Fe, and others) (mg/100 g) 70–900
Essential oils (in fresh honey) (mg/100 g) 30–200
Dyes (carotenoids, anthocyanines, flavones)
(µg/100g)
1.5–180
Vitamins and other active substances (mg/100 g) 0–0.1
β do not refer here to the hydrolyzed glycosidic bond configuration. Enzymes of
both types catalyze hydrolysis of the α-(1→4) bond. α-Amylase, by cleaving some
α-(1→4) bonds of polysaccharides, forms combinations of several monosugar molecules,
and is hence sometimes called the dextrinogenic enzyme (3.2.1.1; α-1,4glucane
4-glucanohydrolase). β-Amylase (3.2.1.2; α-1,4-glucane maltohydrolase)
catalyzes hydrolysis of amylose into maltose.
As other amylases, honey amylases are activated by chloride ions. At a 0.01 M
concentration of Cl − ions, enzyme activity increases by 170%. The optimum pH for
honey amylases is 5.4 whereas human saliva amylases show highest activity at pH
7. Honey amylases originate exclusively from the bee organism.
Activities of both enzymes decrease during storage of honey and heating accompanying
the decrystallization; therefore, the diastase number (the α-amylase activity)
determination was used for a long time to evaluate potential overheating of honey.
Currently, the overheating is evaluated by determining the level of 5-hydroxymethylfurfural
(HMF) in honey. 5 HMF results from dehydration (loss of three water molecules)
of either D-glucose or D-fructose. Because of overheating, the HMF level
can increase from commonly occurring ~1.20 mg/100 g up to 20 mg/100 g, although
a sucrose invert made by hydrolysis with citric acid may contain 170–650 mg
HMF/100 g. Such a difference can be useful in detecting and evaluating honey
adulteration by an admixture of invert. Honey containing over 20 mg HMF/100 g
should be recognized as a product adulterated with invert made by acid hydrolysis
(see Section 6.4).
Several biochemical reactions make the composition of honey labile. During
one-year storage at 20°C, the activities of α-amylase and invertase decrease by
30–50% and 10%, respectively. Simultaneously, honey acidity rises by several
mval/kg. The sugar composition also changes. 6