Fat Digestion-Which Fat is broken down the fastest?

[Ben Gee]

I am doing a science fair on the digestion rate of unsaturated, saturated, and hydrogenated fats. I want to know which type of fat is the easiest to digest and why. I also want to know what a trans fat is.

[donnahardy2]

Hi,

This is a great topic for a science fair project, however, I am wondering how you are going to set up an experiment with measurable results. This will be very challenging.

First, you need to learn all about your subject. I am assuming that you have had a basic chemistry class and know something about the structure of organic molecules, but let me know if this is not the case. Here is a website with basic information about the structure of fatty acids.

http://en.wikipedia.org/wiki/Fatty_acid

This website includes a table comparing various features of saturated and unsaturated fat:

http://www.diffen.com/difference/Satura ... rated_Fats

This website shows the structural difference between a saturated fat and a trans fat molecule. The double bond in the trans fat molecule makes the molecule stiff and this difference in structure is what causes the health problems in humans.

http://en.wikipedia.org/wiki/Trans_fat

Now, the problem with your project idea is that any type of fat is equally digestible and a good source of energy. The structures of all of the fats contains carbon and hydrogen bonds and the presence of single or double bonds in the carbon chains won’t make a difference in the rate of digestion, so it is going to be difficult to design an experiment with measureable results.

For your science project, you need to set up an experiment that will answer your questions about the topic. I recommend that you do more background reading and develop your topic. The chart on the second website above might give you some inspiration. The following projects on fat from the Science Buddies website are also a good source of ideas; although it you decide to do the iodine project, let me know because I have some suggestions for this experiment.

https://www.sciencebuddies.org/science- ... p048.shtml

https://www.sciencebuddies.org/science- ... p055.shtml

https://www.sciencebuddies.org/science- ... p062.shtml

Please do let me know you have any questions.


Donna Hardy

[Ben Gee]

Hi,
I will set up my experiment by preparing a solution of pancreatin, bile, and sodium bicarbonate. To measure how much a fat is digested, I will measure how much the pH goes down. This works because fatty acids
are broken from gylcerols when hydrolyzed, and the fatty acids cause the pH to go down. A new variable for my expiriment could be testing vegetable oil such as olive oil and animal fat such as cholesterol and seeing which is broken down faster. I want to know if cholesterol or fatty acids are broken down easier or if there is no difference. I am also interested in the iodine project if the vegtable oil vs. animal oil idea does not work.

[donnahardy2]

Hi,

I understand what you are trying to do now. I think you have a good experimental design because you have one independent variable and something to measure. The lipases in pancreatin are very sensitive to pH, so you will have to make sure the samples are all at the optimum pH at the beginning of the experiment. How are you measuring pH? Cholesterol has a different structure compared to triglycerides, and I'm not sure how it is metabolized. Have you checked to make sure its breakdown products are acidic? Do you have samples that are primarily saturated, unsaturated, and trans fats?

Donna Hardy

[Ben Gee]

Hi,
Thank you for your help. I am not planning on using cholesterol if saturated, unsaturated, and trans fats work. The idea is not about wether there are double bonds or not, but which fat has the highest surface area. I read that the higher the surface area, the faster the fat is broken down. I would like to know which type of fat has the highest surface area. I read the pH of the small intestine is 8.5. I can create this pH using sodium bicarbonate solution. I will be using an electronic pH meter to test the pH. The samples I am using are palm oil as a control (51.4% unsaturated, 48.6% saturated), sunflower oil (68.2% polyunsaturated), olive oil (71.1% monounsaturated), margerine (a hydrogenated oil), and coconut oil (81.1% saturated).

[donnahardy2]

Hi,

You have a good selection of samples to test.

The surface area of the fat is determined by the emulsification of the fats by the bile acids. Here are a couple of websites from college courses that explain this process:

http://courses.washington.edu/conj/bess/fats/fats.htm

http://www.vivo.colostate.edu/hbooks/pa ... /bile.html

I am a little confused about your objective. If you want to investigate the effect of the fat structure (saturated, unsaturated, trans) you would have samples with different types of fats (palm oil, sunflower, olive, and margarine, )
If you want to study the effect of surface area, you would use different concentrations or composition of the bile. It is good that you are spending some time thinking about this phase of your project, because you do want to design an experiment that will prove or disprove your hypothesis. Here is the information from the Science Buddies website on variables, developing your hypothesis and designing an experimental procedure.

https://www.sciencebuddies.org/science- ... bles.shtml

https://www.sciencebuddies.org/science- ... esis.shtml

https://www.sciencebuddies.org/science- ... dure.shtml

At this point, your independent variable is fat composition, and you should plan to keep the concentration of bile in the sample and all other parameters of the experiment identical. Your dependent variable is the pH, which will presumably reflect the rate of fat digestion If you want to investigate the effects of surface area, that would be a another experiment.

Donna Hardy

[Ben Gee]

I am almost ready to start my expiriment. I need to know the composition of pancreatic juice. I know it varies between people but I want to know the composition of an avearge person. I want to know the concentration levles of enzymes, bicarbonate, and water.

[donnahardy2]

Hi,

Here is a general recipe that you could use from the following website:

http://chestofbooks.com/health/nutritio ... stion.html
2. Preparation
To make artificial pancreatic juice take one volume of the glycerin extract, add 5 or 6 volumes of water and sufficient sodium carbonate to give the mixture a distinctly alkaline reaction.


Donna Hardy

[Ben Gee]

This juice does not contain enzymes. I can obtain enzymes such as lipase, protease, and amylase. I want to know how much % water there is, how much % enzymes, and how much %sodium bicarbonate.

[donnahardy2]

Hi Ben,

I can't find information on the concentration of enzymes right now. I can see references for artificial pancreatic juice, but I can't find the concentrations of enzymes. This may one of the independent variables that researchers use. I will keep looking, but you may have to improvise. You can start by adding 1 part of glycerin plus 5 parts water and adding 0.1 M (or other defined concentration) of sodium bicarbonate. You should document the quantity of enzymes you add to this solution.

Donna Hardy

[Ben Gee]

I want to know if this is an effective data table for my science fair or if it is too confusing
pH over time (minutes)
0 5 10 15 20 25 30 35 40 45 50 55 60
coconut oil
palm oil
olive oil
sunflower oil
margerine

[donnahardy2]

Hi,

Excellent! This would be a good data table for your science project. The table should be titled so your readers will understand what has happened. You should also plan to present a line graph of the results with pH on the y axis and time on the x axis. Each type of fat should be represented by a different type of line and labeled. Which presentation do you think would be easier for your readers to interpret? Feel free to attach the data when you get results; I am very interested to see what will happen.

Donna Hardy

[Ben Gee]

I was reading on the internet that NaOH should be used for fat digestion expiriments. I am wondering if using NaOH would increase the amount of pH going down.

[donnahardy2]

Hi,

NaOH is a stronger base than sodium bicarbonate and would increase the pH significantly, but the high pH would be more effective in hydrolyzing the fat. It might be difficult to measure the decrease in pH if the concentration of NaOH is too high. Also, I thought your experiment included using the enzymes and these would be denatured at a very high pH. Can you send a link so I can understand what you are looking at? It sounds like two different types of fat hydrolysis experiments.


Donna Hardy

[Ben Gee]

I used
http://eve.kean.edu/~breid/enzyme/enzyme.html
"In the following experiment you will use a solution of commercially available pancreatic lipase to study the hydrolysis of milk fat. To follow the reaction, you will make use of the fact that fats are neutral, while fatty acids are acidic. The release of fatty acids from fats by hydrolysis will increase the acidity (lower the pH) of the reaction mixture. This change can be observed by using the indicator dye, phenol red, which is useful for measuring pH values between 6.8 and 8.4."
"Phenol Red Indicator Dye
The indicator dye, phenol red, is useful for measuring pH values between 6.8 and 8.4. You will use phenol red to observe changes in pH that result from the acidity of the fatty acids that are formed as the triglycerides in cream are digested forming fatty acids and glycerol. You will add NaOH (sodium hydroxide) to all tubes at the start making all tubes initially alkaline. The more enzyme activity, the more fatty acids, the more acid (lower pH), the more "yellow" the tube will become. "

[Ben Gee]

Attached is the data for my expiriment. I have a lot of tables and graphs and was wondering which ones to put on my display board. Should I put just the average ones or all of them?

[donnahardy2]

Hi,

Your data is very great! Three trials with extremely reproducible results. The science fair judges will be impressed. Your most important graph is the bar graph showing the change in pH with the 3 different trials, so I would put this graph in the middle of you board. I would include the line graphs of the change in pH over time for the 3 trails if you have room, or just the average if you don’t have room for all of the graphs. The percentage of change in pH could be included in your notebook. You want to present a clear picture of what happened in your project and just the few graphs will do that.

I recommend that you include one more analysis in your data. Since you have 3 separate trials, you can do the student’s t-test to check to see if there is a statistically significant difference between different sets of data.


Here is a calculator you can use:

http://www.graphpad.com/quickcalcs/ttest1.cfm

Put your data in using the unpaired t-test in the data table. If you compare the 3 pH change results of coconut with palm oil, for example, you will find that the results are not significantly different. However all of the oil results, there is a statistically significant difference compared to the margarine results. Here is information on the student’s t-test if you are not familiar with this test. Let me know if you have any questions about this analysis. Doing this will give you a good basis for completing your conclusion.

http://en.wikipedia.org/wiki/Student's_t-test

This is really good. Congratulations on an outstanding project!


Donna Hardy