Preparation and evaluation of blended and interesterified oils

Vegetable oils are part of traditional diets all over the world. Triglycerides make up the
majority of the lipids in edible fats/oils. The fatty acid composition of the edible oils has been
one of the main focuses in defining nutritional value of dietary fats. Nutritional properties of
dietary lipids are largely influenced by the nature of their constituent fatty acids, degree of
unsaturation, distribution of fatty acid on triglyceride back bone and the composition of nonglyceride
fraction of oil.
Certain saturated fatty acids play an important role in increasing plasma cholesterol
concentrations and determining the risk of coronary heart disease. In contrast, mono
unsaturated fatty acids and polyunsaturated fatty acids have been shown to decrease the
plasma cholesterol concentration in various clinical studies and various animal models.
The majority of the reported adverse effects of fats and oils on health are related to their
excessive consumption. The growing awareness on the impact of dietary saturated fats on
cardiac problems is resulting in the changes in the types of the oils used in our diet. All the
negative effects attributed to fats is slowly leading to great concerns and possible elimination
of fat from diet. However, oils and fats are essential part of balanced diet, as they provide
numerous components needed for maintaining our health.
According to the Indian council of medical research, the desirable proportions of
saturated, mono and polyunsaturated fatty acids in the dietary fats should be in the proportion
of about 1:1:1. According to the American heart association, the optimum intake of fat for an
adult is 30% of total calorie and the ratio of saturated/monounsaturated/polyunsaturated fatty
acid 1:1:1, which was also endorsed by studies in India. Naturally available oils are unique in
its composition. Careful analysis of edible oils available in India indicates an imbalance in their
composition and is not in tune with recommendations made by nutritionists. Some of the
commonly used edible oils in India are Coconut oil, Ground nut oil, Sunflower oil, Mustard oil.
Coconut oil is characterized by high levels of medium chain fatty acids, mainly lauric
acid and small amounts of capric, caprylic and caproic acid. It is deficient in essential fatty
acids which needs to be supplemented. This can be achieved by blending Coconut oil with oil
like ground nut oil containing essential fatty acids. Olive oil which is consumed in
Synopsis
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mediterranian regions is endowed with many health benefits due to the presence of phenolics.
However olive oil is not in the main stream of edible oils in India due to its limited availability
and high cost. Blending of olive oil with coconut oil may be a way of introducing it in Indian
market at affordable cost and providing health benefits of olive oil in Indian population.
However blending of two oils may not provide all the required benefits. They may need to be
further modified by way of rearranging fatty acids in the triacylglycerol molecules of blended
oil. Hence modification of oils and fats is one of the requirements in food processing industry
that demands novel economic and green technologies. In this respect, tailor made vegetable
oils with nutritionally beneficial structural triacylglycerols and altered physicochemical
properties have a potential in the future market. Structured lipids are tailor made fats and oils
with improved nutritional or physical properties. Recent Investigators have demonstrated that
structured lipids have a desirable metabolic actions superior to the physically modified oils with
identical composition but not subjected to interesterification reactions.
In majority of the experiments reported in the literature, the oils containing medium
chain triglycerides are interesterified with polyunsaturated fatty acid containing oils. Structured
lipids of this type have been reported to have beneficial effects on a range of metabolic
parameters including immune function, nitrogen balance and improved lipid clearance from the
blood stream. This interesting observation need to be exploited to develop oils which can
provide superior health benefits.
To provide balanced edible oils to Indian population, the present study aims at the
preparation and evaluation of coconut oil which is blended and interesterified with unsaturated
oils like ground nut oil or olive oil.