Margarine Manufacture
A Brief on Margarine Manufacture
What is margarine:
Margarine manufacture came to light in the 19th century as an alternative to butter. It was a popular substitute for people who could not afford butter
or to whom butter wasn’t available. It can be made from either animal fat or
plant oils. Most manufacturers prefer making margarine from plant oils because
of their low values of saturated fatty acids especially Lauric, Myristic and Palmitic acid.
Margarine plastic fats are normally produced by hydrogenation, fractionation,
or interesterification.
Hydrogenation: During hydrogenation, unsaturated fatty
acids are converted into saturated fatty acids in the presence of a suitable
catalyst. After removal of impurities that may poison the catalyst, the oil
(usually soybean or palm oil) are exposed to hydrogen gas at high pressures
(2-10 atmospheres) and high temperatures (160-2200c). Finely divided
nickel (divided to increase the surface area), at 0.01 – 0.2% serves as a
catalyst. This process of hydrogenation occurs due to isomerization of cis to
trans configuration of fatty acid with the proportion of trans-fatty acids
ranging between 5 – 40% in the final product.
Fractionation: This employs the mechanism of
separation where the lipid is separated into solid and liquid fractions. It is usually
employed in margarine manufacture from palm oil where the oil is separated into
an olein and stearin fractions both of which have applications in certain margarine
blends. Fractionation is limited by the sources of oils and varieties of
products.
Interesterification: Normally includes chemical interesterification and lipase-catalyzed interesterification.
In chemical interesterification, fully
hydrogenated fats are blended with liquid oils as the feed-stocks usually using a lipid soluble catalyst (commonly sodium
methoxide (0.1%)) at temperatures between 800c to 1200c. Chemical
interesterification randomizes the location of the different fatty acids, thereby
improving the utility of the fat. Spreadability, melting point, and solid-fat
content temperature profile are modified by the randomization. The chemical
catalyst produces a darkening of the oil and some by-products, both of which
need to be removed.
On the other hand, enzyme interesterification is a process in which a 1,3 specific lipase
enzyme (from either bacterial, yeast and fungal sources) is used to catalyze
the exchange of fatty acids attached to glycerol backbone of the fat in
position 1 and 3 while leaving fatty acids in position 2 intact. It can achieve
tailor-made fats which might have desired physical or nutritional properties
unattainable by physical mixture or chemical randomization. Lipase-catalyzed
interesterification conditions are mild and the process is more natural and
green and would be better accepted by consumers. Enzymatic interesterification
requires less severe reaction conditions; products are more easily purified, and
it produces less waste than chemical interesterification. However it’s more
expensive although prices for lipases are also gradually coming down, and
lipase stability has been improved hence making the technology economically
attractive.
References
O’Brien. R., 2009. Fats and Oils: Formulating and processing
for applications. Richard D., 3rd edition. ISBN 13:
978-1-4200-6166-6
Zhang. H, Xu. X, Mu. H, Nilsson. J, Adler-Nissen. J, Hoy.
C., 2000. Lipozyme IM-catalyzed
Interesterification for the production of margarine fats in a 1 kg scale
stirred tank reactor. Eur. J. Lipid Sci. Technol. 2000, 102, 411-418.
The American Oil Chemical Society Lipid Library, 2011.
Edible oil processing-Modification. Enzymatic interesterification. Accessed
online on January 22, 2013 from; http://lipidlibrary.aocs.org/processing/enzinter/index.htm
Coultate TP. Food: The Chemistry of its components. Fifth edition, Cabridge U.K; Royal Society of
Chemistry; 2009.
