Question

please answer questions 1 & 2

If the following mixtures are incubated at 37°C with the addition of enzymes and/or bile salts, predict if the mixtures would increase in acidity and, if so, which samples increased the most. If the lipids are not digested to a great extent, there would be little change in acidity. Table 5: Testing after incubation with pancreatin or pancreatin and bile salts Test tube Substance Enzyme Prediction of drops of NaOH solution to neutralize (no change, small increase, large increase) A Milk (butterfat) B Corn oil Pancreatin TARGE INCREASE Pancreatin Small INCREASE LARGE INCRE ASG с Corn oil Bile salt + Pancreatin D Corn oil Bile salt NO NO CHANGE 1. The corn oil was incubated with and without bile salts, but the milk was only incubated with the pancreatin. Why wasn't it necessary to add bile salts to the milk? 2. What was the basis of your prediction for the corn oil with pancreatin, compared to the corn oil with bile salts and pancreatin?

Answer 1

Fats are hydrophobic (insoluble in water). The pancreatin contains lipase which is a water soluble enzyme and this enzyme can break up the ester bonds in the tricylcerides into fatty acids. And as more fats are digested by the enzyme, fatty acids are formed which reduces the pH of the solution.

1. Corn oil was incubated with and without bile sailts, but the milk was only incubated with panceatin. Why wasn't it necessary to add bile salts to the milk

For the lipase in the pancreatin to be able to break down the fats, the enzyme should be able to access the fat molecules. However fats being water insoluble form large globules and the lipase cannot access the interior of the fat globules.

Bile salts breaks down the large fat globules into smaller droplets in a process called emulsification. With the formation of smaller fat droplets, the surface area on which the lipse can act on has increased and hence more fat is digested.

Milk fat is more emulsified than vegetable fat which makes the lipase effective without the presence of bile salts.

2. What was the basis of your prediction for the corn oil with panceatin compared to the corn oil with bile salts and pancreatin.

The presence of fat globules in corn oil reduces the efficiency with which lipase can digest it. However in the presence of bile salts, the large fat globules are broken down. Therefore we have more amount of fat being digested forming fatty acids, increasing the amount of NaOH needed to neutralize the solution.