2009_Book_FoodChemistry

276 4 Carbohydrates
(4.63)
by reduction at C-1 of the carbohydrate (cf.
Formula 4.56), all these compounds contain
a methyl or acetyl group at position 2 of the
furan or pyran derivatives. The product structures
show that apart from the water elimination at
C-1 leading to 1-deoxyosone, other dehydrations
occurred at C-2, C-5 and/or C-6.
(4.64)
(4.65)
(4.66)
4.2.4.4.4 Secondary Products of 1-Deoxyosones
Unlike the 3-deoxyosones which have been
studied for a long time, the 1-deoxyosones were
detected only a few years ago. Formula 4.67
shows known compounds derived from 1-deoxyosone.
Since 1-deoxyosones formally occur
In the reaction yielding 3-hydroxy-5-hydroxymethyl-2-methyl-(5H)-furan-4-one
(IV in Formula
4.67), this compound can be directly
formed by water elimination from the furanoid
hemiacetal of 1-deoxyosone (Formula 4.68). It
was found that isomerization to the 4-hydroxy-
3-oxo compound does not occur under the
conditions relevant to food. On the other hand,
it is interesting that significant degradation to
norfuraneol occurs (Formula 4.68). Norfuraneol
is also formed as the main reaction product on
the degradtion of the 1-deoxyosones of pentoses.