406
lipid modification processes. Target - specific lipid modification process includes
using novel fat sources and altering the concentrations of medium-chain, long-chain
saturated, and long-chain polyunsaturated fatty acids as well as cholesterol.
Lipid modification also includes methods such as genetic modification of oil
seeds, chemical and lipase catalyzed interesterification reactions and fractionation
of fats and oils. However the choice of selecting a suitable modification process
depends largely on the end use and target population and to achieve this, a combination of one or more of these techniques may be needed. The choice of refined commodity oils for the use in food industry is very limited and this has fuelled the need
for modifying oils. It is essential to know why the existing commodity oils are less
suitable than modified oils.
Methods of Modification of Lipids
Methods of lipid modification may be either technological or biological.
Technological procedures include techniques like blending, fractionation, hydrogenation, and interesterification with chemical or enzymatic catalysts. Biological procedures includes development of new crops and hybrids to make them more suitable
for commercial growing and harvesting, seed breeding by conventional or newer
procedures so as to produce oils with a favorable and desired fatty acid composition,
and production of single cell oils rich in valuable polyunsaturated fatty acids not
otherwise easily available (Gunstone 2006).
The usage of the four technological procedures listed above consideration has to
be given to their effectiveness in achieving the desired physical, chemical, and nutritional properties and to their relative costs in production. Among the four methods
blending is the cheapest and hydrogenation is the most expensive in terms of both
equipment and consumable costs for catalyst and hydrogen. Dry fractionation does
not require additional materials and there is no yield loss but there has to be an economic use for all the fractions. Interesterification can be carried out with lower capital cost than fractionation but operating costs are higher because of yield loss.
Enzymatic interesterification is more expensive because the cost of enzyme is still
high. It could be seen that costs rise through the blending, dry fractionation, chemical interesterification, and hydrogenation. It is practically very difficult for smaller
producers to carry out these processes and hence they prefer to buy refined and
modified oils and fats from larger food producers and specialist suppliers. However,
to fully understand the properties of these oils it is essential to know the advantages
and disadvantages of these processes (Gunstone 2009).
In technological procedures, the changes are made only in fatty acid and/or triacylglycerol composition by modifying nutritional, chemical, and physical properties to make them more appropriate for their end-use and by developing improved
techniques and sophisticated equipment. However, in the biological procedures we
interfere at an earlier stage by using conventional techniques of seed breeding or by
exploiting newer methods based on increasing genetic understanding to seek new
S. Asokapandian et al.
lipid modification processes. Target - specific lipid modification process includes
using novel fat sources and altering the concentrations of medium-chain, long-chain
saturated, and long-chain polyunsaturated fatty acids as well as cholesterol.
Lipid modification also includes methods such as genetic modification of oil
seeds, chemical and lipase catalyzed interesterification reactions and fractionation
of fats and oils. However the choice of selecting a suitable modification process
depends largely on the end use and target population and to achieve this, a combination of one or more of these techniques may be needed. The choice of refined commodity oils for the use in food industry is very limited and this has fuelled the need
for modifying oils. It is essential to know why the existing commodity oils are less
suitable than modified oils.
Methods of Modification of Lipids
Methods of lipid modification may be either technological or biological.
Technological procedures include techniques like blending, fractionation, hydrogenation, and interesterification with chemical or enzymatic catalysts. Biological procedures includes development of new crops and hybrids to make them more suitable
for commercial growing and harvesting, seed breeding by conventional or newer
procedures so as to produce oils with a favorable and desired fatty acid composition,
and production of single cell oils rich in valuable polyunsaturated fatty acids not
otherwise easily available (Gunstone 2006).
The usage of the four technological procedures listed above consideration has to
be given to their effectiveness in achieving the desired physical, chemical, and nutritional properties and to their relative costs in production. Among the four methods
blending is the cheapest and hydrogenation is the most expensive in terms of both
equipment and consumable costs for catalyst and hydrogen. Dry fractionation does
not require additional materials and there is no yield loss but there has to be an economic use for all the fractions. Interesterification can be carried out with lower capital cost than fractionation but operating costs are higher because of yield loss.
Enzymatic interesterification is more expensive because the cost of enzyme is still
high. It could be seen that costs rise through the blending, dry fractionation, chemical interesterification, and hydrogenation. It is practically very difficult for smaller
producers to carry out these processes and hence they prefer to buy refined and
modified oils and fats from larger food producers and specialist suppliers. However,
to fully understand the properties of these oils it is essential to know the advantages
and disadvantages of these processes (Gunstone 2009).
In technological procedures, the changes are made only in fatty acid and/or triacylglycerol composition by modifying nutritional, chemical, and physical properties to make them more appropriate for their end-use and by developing improved
techniques and sophisticated equipment. However, in the biological procedures we
interfere at an earlier stage by using conventional techniques of seed breeding or by
exploiting newer methods based on increasing genetic understanding to seek new
S. Asokapandian et al.