Chemistry Reference
In-Depth Information
35
30
20:80 Enzyme
30:70 Enzyme
40:60 Enzyme
Reference
25
20
15
10
5
0
0
10
20
30
40
50
60
Temperature (°C)
Fig. 15.7
Optimization of blend composition to match the SFC curve of a CIE fat.
provide a full conversion of the fats. The flow rate through the series reactors is adjusted to
give the same conversion, ensuring the same quality of product is constantly produced. This
is only possible where several reactors are connected in series because with a single reactor,
reduction in flow rate would be required to compensate for loss of enzyme activity. With a
series configuration, no single reactor is responsible for the total conversion and hence flow
can be kept constant, whilst at the same time all the enzyme activity is utilized.
The resulting modified fat will be incorporated into a margarine, shortening or other
food product. It is essential that the product quality of this modified fat is at least as good
as that produced by the alternative technology. EIE is a milder process than either CIE
or hydrogenation and results in better retention of natural anti-oxidants (tocopherols, etc).
This by itself could be expected to improve oxidative stability of the resulting fats but it is
normally the case that additional anti-oxidants are added which may blur this distinction.
However, some studies have reported lower PVs and better colour for margarines pro-
duced with enzymatically modified fats
15
and no observations of poorer quality have been
recorded.
Baking quality of the produced margarines is also a critical parameter and a number
of investigations into this area have been made. Kirkeby
16
made baking tests to produce
puff pastry and commented that the margarine from enzymatically interesterified hardstock
gave superior results to that from CIE. Cowan
et al
.
17
focused on margarine for bread
production and showed that equal bread volume and other characteristics could be obtained
for a shortening made by EIE compared to a commercial product. Finally, Siew
et al
.
18
interesterified different blends of hard palm stearin with canola oil to produce a range of
different margarine and fat products. They observed that by varying the proportions between
the two starting materials, they could produce modified fats with physical properties suitable
for the production of stick margarine, shortenings, puff pastry margarine and vanaspati.
