Chemical and Functional Properties of Food Saccharides

© 2004 by CRC Press LLC
O
HO OH
O
18.45
+
NH2 O
Dehydration of 1-deoxy-2,3-diuloses at position C-6 leads to acetylformoin
(18.47a,b), another well-known degradation product of hexoses (Reaction 18.12).
CH 3
C
C
O
O
HC OH
HC OH
CH 2 OH
18
Figure 18.12
CH 3
C
C
C
O
OH
OH
HC OH
CH 2 OH
CH 3
C
C
C
C
OH
OH
OH
OH
CH 2 OH
Acetylformoin is highly reactive and easily undergoes further reactions that lead to
the formation of numerous compounds, some of them having flavor-, color- and
taste-active properties. For example, reduction and dehydration of acetylformoin that
leads to 3(2H)-furanone (18.38c) explains the formation of this important odorant
from hexoses (known as furaneol ‚ ). 53 Reaction of glucose in the presence of proline
can yield colorant (18.48a,b) (two forms in equilibrium), via condensation of acetyl-
O
O
formoin with 2-formylpyrrole. Another colorant, compound (18.49), is formed from
acetylformoin and proline via bitter-tasting pyrrolidinohexose reductone (18.50) and
bispyrrolidinohexose reductone (18.51). 54 In the presence of primary and secondary
R
-
O O
H 2 O
18.46
CH 3
O
CH3 C O
C OH
C OH
C OH
CH2 HO O
O
18.48a
O
18.48b
OH
OH O
OH
CH3 CH 3
CH3 C O
C OH
C OH
C O
CH3 47a
C
H 3
HO O
O
47b
OH
CH3