For sugars, the rate of the reaction depends on the rate at which the sugar
ring opens to the reducible, open-chained form and this increases with increasing pH
14
(Burton & McWeeny, 1963) . Table 2 shows that the amount of acyclic form is much
higher for pentoses such as ribose than hexoses. Thus, pentose sugars react more
rapidly than hexoses (Reynolds, 1963).