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sources or to modify the composition of the oils in plants which already produce
large quantities of oil efficiently.
Blending
Blending is the oldest process of mixing of oils and fats to produce blends with
improved nutritional or physical properties. In the preparation of most spreads,
blends of two or more oils are used to achieve desirable nutritional and essential
physical properties. Interesterification is usually carried out on oil blends. Inorder to
obtain oils with desired mix, the oils are blended at minimum cost and by developing computer programs that aid to give the best solution. For example, oil with high
oxidative stability (such as sesame oil or rice bran oil) may be added to a less stable
commodity oil to enhance its stability. Frequently lauric oils are usually blended
with non-lauric oils.
Fractionation
Fractionation is a process by which oil is divided into two or more fractions which
differ in fatty acid and triacylglycerol composition. This is achieved without loss of
material and without need for further refining. The two fractions extend the range of
usage of the original oil. This is achieved by a process called dry fractionation. Dry
fractionation requires slow cooling of liquid oil without solvent followed by efficient separation of the solid (stearin) and liquid phases (olein) by suction or by
pressure. Poor separation leaves olein in the stearin and results in less olein and in
more stearin with higher iodine value than is desired for a stearin. This technique
has wide application and usage in palm oil apart from other applications. However
one of the major drawbacks is the formation of unstable compounds that happens to
minor components and impurities due to changes during fractionation. A simple
form of fractionation is referred to as winterization, which originally consisted of
storing oil such as cottonseed in tanks during the winter. The more saturated triacylglycerols crystallized leaving a more unsaturated liquid fraction less likely to
crystallize when stored in the domestic refrigerator. Some oils like sunflower may
contain wax which makes the oil cloudy during storage, especially at sub-ambient
temperatures. Such oils may be dewaxed by storage at appropriate temperatures and
subsequent filtration before release for sale in order to overcome this.
Hydrogenation
Hydrogenation can be conducted at three different levels depending on the end use
and desired trait. Very light or partial hydrogenation also known as brush hydrogenation is a technique applied to oils containing linolenic acid such as soybean oil
and rapeseed oil inorder to reduce the level of triene acid to about one half its
Lipids and Oils: An Overview
sources or to modify the composition of the oils in plants which already produce
large quantities of oil efficiently.
Blending
Blending is the oldest process of mixing of oils and fats to produce blends with
improved nutritional or physical properties. In the preparation of most spreads,
blends of two or more oils are used to achieve desirable nutritional and essential
physical properties. Interesterification is usually carried out on oil blends. Inorder to
obtain oils with desired mix, the oils are blended at minimum cost and by developing computer programs that aid to give the best solution. For example, oil with high
oxidative stability (such as sesame oil or rice bran oil) may be added to a less stable
commodity oil to enhance its stability. Frequently lauric oils are usually blended
with non-lauric oils.
Fractionation
Fractionation is a process by which oil is divided into two or more fractions which
differ in fatty acid and triacylglycerol composition. This is achieved without loss of
material and without need for further refining. The two fractions extend the range of
usage of the original oil. This is achieved by a process called dry fractionation. Dry
fractionation requires slow cooling of liquid oil without solvent followed by efficient separation of the solid (stearin) and liquid phases (olein) by suction or by
pressure. Poor separation leaves olein in the stearin and results in less olein and in
more stearin with higher iodine value than is desired for a stearin. This technique
has wide application and usage in palm oil apart from other applications. However
one of the major drawbacks is the formation of unstable compounds that happens to
minor components and impurities due to changes during fractionation. A simple
form of fractionation is referred to as winterization, which originally consisted of
storing oil such as cottonseed in tanks during the winter. The more saturated triacylglycerols crystallized leaving a more unsaturated liquid fraction less likely to
crystallize when stored in the domestic refrigerator. Some oils like sunflower may
contain wax which makes the oil cloudy during storage, especially at sub-ambient
temperatures. Such oils may be dewaxed by storage at appropriate temperatures and
subsequent filtration before release for sale in order to overcome this.
Hydrogenation
Hydrogenation can be conducted at three different levels depending on the end use
and desired trait. Very light or partial hydrogenation also known as brush hydrogenation is a technique applied to oils containing linolenic acid such as soybean oil
and rapeseed oil inorder to reduce the level of triene acid to about one half its
Lipids and Oils: An Overview