An Investigation to Find the Effect of Bile Salts of on the Digestion of Lipids

3023 words 13 pages

I have investigated that if there is an effect of bile salts on the digestion of lipids in the milk. When lipids are broken down in to fatty acids and glycerol (see below), the acid lowers the pH of the mixture. To help me determine and measure the digestion of lipids, a pH indicator phenolphthalein has been used to measure the pH of the mixtures. The pH indicator will change the colour from pink to either white (if bile is not contained) or brown (if bile is contained), this will indicate that the solution is changing from alkaline to acidic. So if I want to use phenolphthalein, I will have to firstly make the mixtures alkaline. This will be achieved by
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After calculating, I can see that there a difference in the reaction times. This is because bile salts are alkaline providing alkaline conditions for the lipase to work in (optimum conditions) so the more bile added, the more alkaline the conditions, therefore the optimum pH is reached. The pH in which an enzyme works is very important, and even slight changes in pH can affect the rate at which an enzyme works dramatically. So bile has a big effect for this reason. When bile salts are added into the mixture, the digestion of lipid would happen much more quickly than without bile. Also Bile salts have detergent action on particles of fat, which causes them to break down or be emulsified into minute, microscopic droplets called micelles, which are only 0.5- 1.0 μm in diameter. These, however, are still not small enough to pass though the membranes, and need to be broken down further. This emulsification creates a greater surface area of fat on which the lipase can work. Effectively there is