chemistry nerd alert!

This week's lab for my organic/biochemistry class calls for the analysis of milkfat in several samples of milk. We are studying triacylglycerols, a type of lipid, which is, in turn, simply a type of biochemical which is not soluble in water. Milkfat is a type of triacylglycerol, which you may be familiar with as triglycerides.
The first sample is straight-out-of-the-jug whole milk. The students check its pH (acidity level), then use titration to quantify the concentration of acid in the milk. Just for your information, milk is fairly neutral, having a score of about 7.6 on the pH scale (which runs from 0 to 14).
The next three samples are altered, much as milk becomes in our small intestines when it is being digested. First, the students add pancreatin is added (which is just what the body does). That substance is an enzyme, present only to hasten the hydrolysis of the milkfat, remaining unchanged by the process.
Don't flee just yet! Pancreatin is a natural substance, made by your own body, to digest the foods you ingest, including fats and oils. Hydrolysis, the process used, is simply the use of water - you know, that substance that composes most of your body mass - to break those large molecules (fats and oils and starches and proteins) into smaller ones, so you can get the nutritional benefit of those foods.
See? That wasn't so fearsome after all, was it?
Okay, so let's get back to this week's lab, shall we?
By this time, you must want to know what milkfat breaks down into, right? I know you do! Here's the condensed version:
1 milkfat + 3 water = 1 glycerol and 3 fatty acids
In other words: Each milkfat molecule is broken down by three molecules of water, with the aid of pancreatin and body heat, into one glycerol molecule (a small molecule with three alcohol groups) and three molecules of fatty acids. Why are they fatty acids? Well, when the carboxylic acid molecule contains more than ten carbons - that makes the molecule have a bit of size, hence the term "fatty", since no one thinks of molecules as "hefty" or "stout".
(That's a little biochemistry humor for you!)
Did you see that phrase "body heat"? That means 37 degrees Celsius (98.6 degrees Fahrenheit). That temperature is very important. If the pancreatin gets too hot, it decomposes and can't do its job. As you may have noticed, when you have a fever, you tend to get diarrhea, right? That's because the body's enzymes get killed (denaturated, as scientists say) by the heat.
In the lab, we mimic the action going on in the small intestines with a simple Erlenmeyer flask (the only piece of glassware with hips, as I say to my students) and an ordinary hotplate with a stirrer (to mimic the movements of the intestinal muscles).
So, the milk - which includes the milkfat - is combined with the pancreatin in the flask, then placed on the hotplate. There, it is heated to body temperature and held there for an hour, all with constant stirring. The tricky part is maintaining the temperature, as many a student can attest. Hotplates in freshmen chemistry laboratories aren't known for consistent temperatures, sadly. However, if you succeed, the lab will soon reek with the aroma of... spoiled milk.
Oh, how wonderful.
Truly, the outcome is, if not the odor.
The pH will drop, indicating that more acids are present, which confirms that the milkfat was "digested" in the flask and formed fatty acids. Hooray! The experiment was a success!
The titration will confirm that the acid content has increased by about 300%.
I'll let you think about that last part... you'll get it!