Food Science B

[i8maps]

Does anyone know how to calculate the calorie content in food with the nutrition label? My partner and I have been trying for a while and we always are slightly off.

[triplej]

one question:What's the best way to study for this event because I've made my cheat sheet and i feel like it's pretty good, but my regional competition was a joke because all we did was bake stuff and answer like 8 questions. So, i feel like it's a sort of weird event that's hard to study/practice for

[knittingfrenzy18]

Drill yourself.

There's plenty to know, and it always helps to graph more, practice with Benedict's/Biuret's/Iodine, density measuring, etc.

For example: Tell me how to distiguish a saturated fatty acid from a unsaturated one.

or:

What are the two main functions of different polysaccharides, and name some.

[jgrischow1]

I have read on the Internets that carbs actually have 3.6 calories per gram and the commonly cited 4 is an estimate. Is this true, and if so, will this factor into the event? Does every event supervisor adhere to the same value? Thanks.

[knittingfrenzy18]

Hello,

As a standard, use 4 C/g. If you wish to risk it for some extra points, go for it and explain your answer. Make sure you back it up well, otherwise you may receive no points.

I know 4 is an estimate, but it seems to vary. I read somewhere why it is said as 4, but i forgot why.

[Scipuppy]

one question:What's the best way to study for this event because I've made my cheat sheet and i feel like it's pretty good, but my regional competition was a joke because all we did was bake stuff and answer like 8 questions. So, i feel like it's a sort of weird event that's hard to study/practice for

Well, the rules, (If you don't have one) are very specific, and you can find a lot of things there. Just study the topics it says will be on the test. Also, you can't bring a cheat sheet, all reference stuff should be in a three hole punched binder. (Which is a lot better than a cheat sheet). Good luck at states!

[Scipuppy]

I have a question about the molasses for the viscosity...
We've been testing it over and over, using 3 different brands of molasses, for first-boil molasses we were getting times too low for the curve, for blackstrap we got substantially lower times (30 seconds less that first-boil) which is even farther from the curve. Has anyone else been having this problem? It seems like we can't get the times to be where they should be. According to the rules, it should be more viscous than corn syrup, but it seems to consistently be less viscous. If anyone has a brand of molasses that seems to be working with their standard curve, or knows what kind they used while making the rules (chalker, is there any chance you know what they used?) can you please tell us? Thanks

[knittingfrenzy18]

Room temperature could affect your data.

Try not to warm it up.

Also, I'm not sure why.

Our Hershey's Syrup point is a little out of there, but we'll try to fix that.

[coachmom]

We are trying to get this standard curve together for State and I don't understand your explanation above. We're using the cP numbers from the power point and standard curve example that goes along with the liquids in the rules. Since we were given milk as a liquid at regionals we're also testing other ingredients from the approved ingredients list in the rules. Given our flow times we can't find a way to get a standard cP, we tried setting up a proportion but that doesn't work. Is it a "best guess" sort of thing? Also as others have stated our molasses and honey are no where near what the numbers on the power point are, then we see that the viscometer was made with a different size nail and a ketchup top? I thought the rules seemed fairly explicit in how to make this thing....

[Skink]

I'm not sure you understand what a standard curve is. A standard curve is, in our case, a plot of the times it takes each value of viscosity to either break the flow in your viscometer or to decrease in volume between points A and B in your viscometer, however you set it up. Size of the hole is very variable among teams; just be consistent when testing and remake your plot when using a different viscometer.

But where does the standard curve come from? It comes from known values that we get from the rules. It doesn't matter if they're actual or not because we're measuring this all relative to the "actual" values in the rules. To make the standard curve, you time how long it takes each of the six standard liquids to go through your viscometer and record the times. The is NOT to determine viscosity. This is basically calibration. We already know what the viscosities are. Now, make a plot of viscosity on the horizontal axis and time on the vertical axis using the data points you collected for only the six liquids. Make a regression line/line of best fit/connect the dots. Save and print. This is your standard curve.

Now how about that milk? We don't know the viscosity of milk. We have to measure it. Put the milk through your viscometer, and time it exactly as you did with the standards. Now, take that time and find the point on the graph corresponding to that time. Go straight down to the horizontal axis for the viscosity associated with that point, and you have your viscosity of milk, in centipoise, as determined with your viscometer and standard curve.

I have purposely not explained this in gross detail since I want people to work at it a little, but, if you still have trouble, PM me for more detailed assistance.