Interdisciplinary Journal of Contemporary Research in ... - Webs

ijcrb.webs.com
INTERDISCIPLINARY JOURNAL OF CONTEMPORARY RESEARCH IN BUSINESS
The factors affecting adsorption are : the type of adsorbent, the bleaching temperature,
the medium(solvent or oil)and the concentration of the solute to be adsorbed. In general,
the higher the temperature, the smaller the smaller the adsorption and the smaller the
solubility, the more complete the adsorption. All these occur because of the more
favourable condition for attaining equilibrium.
14.1.3 DEODORISATION
This is usually the last stage of oil refining process. The primary objectives of
deodorization process is the removal of residual compound characteristics of the taste and
odor of the seed; odoriferous compounds formed during bleaching and traces of oxidation
products.
Deodorizing is basically a high temperature, high vacuum distillation process. The oil is
heated to 225 o C-260 o C under vacuum and sparging steam applied to remove/ reduce
odors, flavor constituents and other volatile compounds such as free fatty acids to a very
low level. Steam increases the volatility of the compounds and improves the efficiency of
the process. When vegetable oil are physically refined, deodorization serves to remove
the small amount of the free fatty acid in the oil. It is important that the oil be free of
chlorophyll, phosphatides and metallic components prior to deodorization.
Deodorization involves the following stages:
� Oil de-aerating and heating
� Oil deodorizing
� Oil cooling and
� Oil polishing.
14.2 CLAY-HEAT OIL REFINING
Crude fatty substances, including edible and inedible fats and oils and free fatty acids, are
refined by heat treatment in the temperature range of about 121°-260°C in the presence of
a bleaching adsorbent or in the presence of phosphoric acid and a bleaching adsorbent.
This refining can be used in lieu of the conventional alkali-refining of fats and oils.
This a process for the refining of crude fatty substances without the use of alkali. The
crude fatty substance is contacted with an adsorbent, which is preferably an acidactivated
clay, at a temperature in the range of about 121°C to 260 O C in the substantial
absence of air, for a short time. This step is improved by carrying out the heat treatment
process in the presence of a small amount of phosphoric acid, which has the effect of
lowering the temperature of treatment and improving the quality of the product. After this
treatment the adsorbent and impurities adsorbed thereon are removed by filtration.
Treated oils and fats can be deodorized directly or hydrogenated prior to deodorization.
Alternatively, a mixture of oil, adsorbent and acid without filtration and after addition of
a suitable catalyst can be hydrogenated directly; the clay with adsorbent impurities and
spent catalyst are then filtered off, and the filtered oil is finally deodorized. In the course
of these deodorizations the volatiles including the free fatty acids are removed from the
oil.
COPY RIGHT © 2011 Institute of Interdisciplinary Business Research 76
JANUARY 2011
VOL 2, NO 9