Title: Alternative Sweeteners

Trehalose 427
Figure 2 Enzymatic production of Hayashibara trehalose from starch. A patented debranching
enzyme is used to produce the amylose substrate.
from starch possessed two novel enzymes, maltooligosyl-trehalose synthase and
maltooligosyl-trehalose trehalohydrolase (22, 23).
HBC has commercialized the latter process using starch to manufacture
trehalose. This new process has reduced the price of trehalose approximately
100-fold. Before this discovery, the cost of trehalose in Japan ranged from
20,000–30,000 Yen (¥) per kilogram ($170–250 USD/kg). Food-grade trehalose
is now sold in Japan for about 300 ¥/kg ($2.50/kg).
The direct conversion of starch to trehalose on a commercial scale depends
on a system in which several enzymes coreact in the same medium (5, 22–24).
Isoamylase debranches the starch, producing amylose (Fig. 2). Amylose is then
converted to amylosyl-trehalose by maltooligosyl-trehalose synthase, which identifies
the reducing end glucose units and catalyzes the conversion of α-1,4 bonds
into α,α-1,1 bonds. In the next step, maltooligosyl-trehalose trehalohydrolase
interacts with amylosyl-trehalose molecules, hydrolyzing the α-1,4 bond between
the amylosyl-moiety and the trehalose, releasing the trehalose into the media.
This reaction terminates when the degree of polymerization of amylose becomes
two or less; that is, when only glucose or maltose remains. This enzymatic system
followed by conventional methods of saccharide production results in high-purity
crystalline trehalose (5, 22–24).
VII. TECHNICAL QUALITIES
In nature, trehalose functions as one of the primary molecules responsible for
maintaining the bioactivity of cell membranes during stress caused by freezing,