الفهرس 
Physical properties 2.1.1. of cocoa butterOnly 14 pages are availabe for public view
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Abstract
Fats and oils constitute an important component of human diet.besides providing
calories; they act as vehicles for such as vitamins A, D, E and K as well as being a
source of calories. They are also the source of essential fatty acids such as linoliec,
linolenic and arachidonic acids and are a source of antioxidants and bioactive
compounds. Fats are also incorporated as structural components of the brain and cell
membranes and are precursor of prostaglandins, hormone-like compounds. They have
the unique quality of improving the texture and palatability of foods (Hansen, 1990).
Moreover fats and oils are also an important food ingredient and are consumed for
their nutritional and organoleptic properties. Their varied uses necessitate a wide
range of melting and crystallization properties. Therefore, they are extensively used in
a wide variety of foods. These uses demand fat modification for varying fat properties
tailored to suit the requirements of a product can expand the application of vegetable
oils. These changes can be brought about either through simple blending,
hydrogenation and interesterification to produce higher value products. An example
that has been well studied is the modification of oils and fats to cocoa butter-like fats.
The main component of fats and oils is the triester of glycerol (triglycerides). Natural
oils and fats are mixtures of various triglycerides compounds, melt and crystallize
over a wide range of temperature (Long et al., 2003).
Cocoa butter is the only continues fat phase in chocolate (33%) and is therefore
responsible for dispersion of the constituent’s chocolate and other confectionery
industries based on its important organoleptic and physical properties resulting from
its unusual triacylglycerol composition. Its major components are saturatedunsaturated-
saturated triacylglycerols, which make cocoa butter hard, gloss, snap and
brittle at room temperature while melting completely in the human mouth. Cocoa
butter is the main fat source in production of chocolate due to its unique physical
characteristics. Relative to most other vegetable fats, cocoa butter has a relatively
simple chemical composition. The major fatty acids found in cocoa butter are palmitic
(16:0), stearic (18:0), oleic (18:1) and linoleic (18:2) acids. The distribution of fatty
acids on the glycerol backbone forms symmetric mixed triacylglycerol molecules with
saturated fatty acids such as palmitic and stearic in the sn-1 and sn-3 position and
unsaturated fatty acids such as oleic and linoleic in the sn-2 position. Due to its
particular chemical composition cocoa butter has narrow melting point that falls
between 32 to 35 ºC. At room temperature, it is solid and brittle, yet it melts sharply at
body temperature (36-37 ºC). This allows cocoa butter to disperse flavor components
a cross the palate when eaten, producing an even flavor, a creamy texture and pleasant
sensation during consumption (Beckett, 2000).
Cocoa butter is a widely used and much appreciated fat composition produced
from cocoa beans. Cocoa butter is used for its flavor and texture properties in a
variety of edible products, particularly in combination with sugars and other
ingredients to make chocolate. The desirability of the characteristics cocoa butter
flavor and texture have long assured a strong demand for cocoa butter and products
which are made from cocoa butter. The worldwide cocoa bean supply, however,
suffers from significant variability, due to constant and often supplying regions to
deliver enough beans at a consistent price and quality to meet the demand. The
uncertain a variability of cocoa beans and the associated fluctuations in price and