Published paper 1: ‘ENZYMES:LYPASES’

 SMITHERS G. ROUPAS P. WOONTON B. WIJESUNDERA C. 21 JUL 2010, ‘ENZYMES:LYPASES

Accessed 10th April 2013 http://www.tandfonline.com/doi/full/10.1081/E-EBAF-120043735

As we all know, there are thousands of enzymes. In this review, the enzyme lipase was discussed.

The enzyme that catalyzes the hydrolysis of a lipid or fat is known as a lipase. The process lipolysis, is the reaction that takes place at the lipid/water interface and the common products are triacylglycerols, free fatty acids and partial acylglycerols. It can be noted that lipases also catalyze synthetic reactions such as esterification. 

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So where are these enzymes found and how are they produced?

As like most enzymes, lipases are found in animals, plants and in microorganisms! YES microorganisms as well! Interestingly, the lipases in microorganisms are highly preferred over those that occur in plants and animals. This is so because their lipase contents are more predictable and controllable, cheaper to harvest and can be obtained in bulks. The lipases can be either fungal or bacterial and the process involves fermentation and purification. Reminds you of yeast don’t it? Additionally, the global enzyme market is estimated to be approximately $ 3.7 billion and lipases account for around 5% of this market. Apart from microbials, other important sources of animal lipases are found in the  pancreas of cattle, sheep, hogs, and pigs.

What really is the significance of this enzyme? What is it used for?

Different lipases are found in the human body in places such as inside and outside living cells,the pancreas, stomach and mouth.  They are indispensable for the bioconversion of lipids for example, the biosynthesis of milk fat in the mammary gland. A lack of sufficient lipases in the body can cause diseases. Diseases such as pancreatitis, cystic fibrosis, and celiac disease are associated with low levels of pancreatic lipase. However, lipase supplements are implemented to treat such conditions. For example, there are lipase inhibitors that are used in the  treatment of obesity since  non-hydrolyzed fat cannot be absorbed by the gastrointestinal tract. 

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Lipases are highly used in the food industry especially the dairy one. In contrast, lipolysis also has poor effects on the quality of food. Lypolysis in milk affects flavor production and altered functionality. The free fatty acids that are produced may have rancid flavors which are unwanted. The free fatty acids, are more likely to undergo oxidation rather than the triacylglycerols, increasing problems of rancidity.

Lipases have many uses. They are used in infant formulae, a variety of cheeses, Medium-Chain Triglycerides (MCTs) and Omega-3 Concentrates, Diglyceride Oils, Cocoa Butter Substitutes and as Trans Fat Alternatives.

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Lipolysis also reduces the ability for milk to foam when injected with steam. Hmm now we see the difficulty in producing the desired amounts of foam when making a  cappuccino coffee. This effect occurs because of the production of partial acylglycerols, which are surface active and displace the foam-stabilizing proteins at the air water interface of the foam bubbles. 

Finally, is there any hope for lipases? Yes, there is! The growth in the use of these enzymes in the food industry is likely to continue as there is the development of better and more diverse applications. A clearer understanding of the mechanisms of lipase action in food emulsion systems will be able to assist in the development of food products with improved flavor, shelf life, and nutrition. 

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