ASSESSMENT OF QUALITY PARAMETERS OF LOCAL EDIBLE OILS AVAILABLE IN DINAJPUR
Date
2014-12
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Abstract
In this work, physicochemical parameters (moisture, refractive index, viscosity, color,
free fatty acid, iodine value, peroxide value, and saponification value) of palm, mustard,
soybean and bran oil were studied at room temperature and after heating at 180°C for
various periods (10 min, 15 min and 20 min). There were slightly variation in physical
parameters in moisture content, refractive index color, viscosity, iodine value and
saponification value among four types of oils. Peroxide and acid value were increased in
palm oil and mustard oil with the increase of frying time. Result showed that there was no
significant difference between soybean oil and bran oil during frying time on free fatty
acid value, acid value and peroxide value at 180°C. In sensory evaluation results also
found that soybean oil and bran oil were more preferable to cooking than other two oils.
These results indicated that palm oil and mustard oil were oxidized rapidly than other oil
samples upon heating and become risk for human consumption.
Description
Fats and oils are an essential part of our diet, supplying nutrients, improving flavor, aiding
in the absorption of vitamins, and providing concentrated sources of energy for our body.
Oils are derived from oilseed and animal sources. There is a universal demand for
vegetable oil due to its use in domestic cooking, as an ingredient for other food production
(in baked goods and fried snack foods). Edible vegetable oils are “foodstuffs which are
composed primarily of glycerides of fatty acids phospholipids, sterols, hydrocarbons,
pigments, waxes, and vitamins being obtained only from vegetable sources. Oils and Fats
can also have very negative effects on health (Robert et al., 2003).
The quality of vegetable oil is a measure of identity and edibility. This is also related to
the method of obtaining the oils from the vegetable source (i.e. whether it is virgin oil or
cold pressed oil) both obtained without altering the nature of the oil, by mechanical
procedures (e.g. expelling or pressing), and the application of heat only. The quality of the
oil is determined by its composition, FFA (Free Fatty Acid) content, iodine value,
peroxide value, melting point, etc (Agimark, 2002).
Worldwide, natural vegetable oil and fats are increasingly becoming important in nutrition
and commerce because they are sources of dietary energy, antioxidants, biofuels and raw
material for the manufacture of industrial products. They are use in food, cosmetic,
pharmaceutical and chemical industries (Fasin and Colley, 2008). Vegetable oils account
for 80% of the world's natural oils and fat supply (FAO, 2007).
Keywords
Analysis of commercials oils, Moisture content determination, Refractive index determination, Viscosity determination and Color determination