Science Buddies: "Ask an Expert"

Hi, I am trying to find an experimental topic that can be done at home. I was reading some research on the effect of cold water and hot water after eating oily/fatty foods. How can I experiment with this? If I mix cold, warm and hot water with various fatty foods (like bacon, cheese, butter, oily thai food etc.) and mix it with acid (what acid can I use that closely resembles stomach acids?) and document results - did the food disintegrate faster with cold, hot or warm? Thanks.

I also found in my research that standardized 0.1 M hydrochloric acid (HCl) is as close as I can get to simulate gastric or stomach acid. So if I can find this in my school lab, I need to set up my procedure along with what am I looking for as a result.

The other question is if this is too simple an experiment for a sophomore?

Hello pjain1998,

You have an interesting question. I think that looking at hot vs. cold water could be seen as rather simple, but the idea of dissolving oils and fats in water is not!

Good job researching stomach acid. Gastric acid is in fact formed by HCl, so this is a very accurate way to simulate stomach acid!

Keep in mind that fats are hydrophobic, and they tend to clump in the presence of water. (This is why oil droplets float on top of water instead of being dissolved.) It is very difficult to dissolve fats in water. Thus, while I would expect hot water to do a better job than cold water (because the molecules are moving more), I think you may not see a measurable difference with temperature alone. Instead, you might try to research making synthetic bile, which is the molecule in our bodies that helps us to dissolve fats for digestion.

I hope this gets you thinking. Please post again (in this same thread) if you have more questions.

Heather

Thanks for your reply. I have since then expanded my topic based on research. I am thinking about using multiple variants such as hot/col/warm water and hot/cold/warm tea on various fatty foods such as bacon, cheese, ice cream, oily chinese food, steak, high fat fast foods etc. First step will be to simulate stomach with gastric acid. I need to research on the temperature and time that food normally spends in the stomach - this is where the proteins get separated. Second step is to replicate small intestine with bile - to separate out fat. I am researching on finding a bile replacement for my experimentation - could you please suggest if you are aware of this? Are bile salts a good substitute for bile? Thanks once again.

I was doing some searching about synthetic bile for you and found this thread from a couple of years ago which might be helpful.
https://www.sciencebuddies.org/science- ... 35&start=0

That led me to search on google for dried bile, and it is fairly cheap and available, so that might be your best bet, rather than attempting to make a synthetic bile. It's available at Sigma-Aldrich and EMD (Merck), but I'm not sure whether an individual can order them. Your teacher might be able to help you there. Otherwise, there are some caplets sold on Amazon as freeze dried ox bile which might work in a pinch, although I'd trust the stuff from the scientific companies first, and it's more likely to come with instructions on how to re-hydrate.

Hello there,

The experts have already given you some great advice. I would like to add in some of my suggestions also.

1. If you are going to be working with acid, make sure that you are adding the acid to the water/food, and not the water/food to the acid. The reason why is because acid reacts violently with water and a large amount of heat is released when you mix strong acids with water. If you add water to concentrated acid, your solution may boil violently and splash concentrated acid out of the container. ALWAYS add acid to water instead (a little at a time) because the solution that is formed is very dilute and the small amount of heat that is released is not enough to cause the acid to splash. Also make sure that you wear gloves and other protective gear--you don't want to get that acid on any part of you! If you are working on this at a school lab, make sure you have a teacher or mentor who can explain the safety procedures in regards to working with acid to you so that you can ensure that you are performing your experiments safely.

2.How are you going to measure how fast the food disintegrates when you add the acid in the presence of hot or cold water? Are you going to check on the food at various time intervals until you no longer see the food? Or are you going to record the size of the food every time point you check (are you going to do that by weight)? If you want to mix the food with hot or cold water, or with hot or cold tea, just make sure that for every food item you test, just make sure you use the same size for every condition. So for example, let's say you want to test how fast steak disintegrates in these conditions. Make sure that you put steak pieces of the same size (and/or the same weight) in hot water, cold water, hot tea, and cold tea because you want all your steak pieces to start at the same size so you can directly compare which of the liquids allows the same sized piece to disintegrate the fastest.

3. Are you going to do this in a school lab? Since you are going to be working with acid, it is not a good idea to work with that at home.

Good luck!

Connie