Science Buddies: "Ask an Expert"

First to introduce myself, i m student at university for Food science and technology. I'm compleeting 2. grade now (of 4). This is my first post here and apologise in advance if my english is not that good and my eng. science vocabulary's not that wide yet.

So here comes the prob a faced today: At subject Analysis of food quality we were talking about sugars/carbohydrates and other sweetners etc etc
Profesor gave few example how sweet some carbohydrates are.
For example sucrose 100, sorbitol 50, lactose 27-39, glucose 55-60, aspartam is 160-200 times sweeter then sucrose.
Theese numbers give slight idea how sweet some sugar is and the proportion in sweetnes between them, but doesnt rly answers questions that rose in me.
Here are few:
* How did they measure the sweetnest of carbohydrates?
-as i know u can only measure concentration of sugar using polarimeter, but not the taste of sweetnest using any equipment

* How did they compare the sweetnests of carbohydrates beetwen their sleves?
-i can imagine someone taste a sugar and say: that one is sweeter then the other, but how much more (or less) sweeter the other one is ... that is very abstract to me. And if one sugar is 1000 more sweeter then the other one... hmm i dont think i can taste that much.
maybe they used different concetrations in order to examine the relationship beetwen sweetnest of sugars.. dont know (maybe)

*What was the standard for measuring sweetnest? Was it water? 1 mol/L sucrose?
For measuring any kind of thing u need standard or tool that is calibrated.
What would it be for sweetnest and how did they get all those proportions i wrote up there???


I asked the profesor about theese things but he nodded with head and said he tried to find that out aswell


So, science buddies i hope You can help me with that. I searched the internet to get any starting clue but, didnt find anything that would explain why is one sugar Xtimes weeter then other one.
Thanks for any post, idea, link or article and reading this long post

Astrosyn

Hi Astrosyn,

If you post "how do you measure the sweetness of carbohydrates?" to answers.com, you'll get back a wealth of net resources (though you'll need to do some searching through them). For example the information pages for SPLENDA and EQUAL are at:

SPLENDA:
http://www.splenda.com/page.jhtml?id=sp ... ack.inc#q5
EQUAL:
http://www.mediarelations.k-state.edu/W ... icook.html

Hi Astrosyn,

Two caveats on use of answers.com, or any other search engine:

1. small wording changes can have a big impact on the output. So experimentation is in order.

2. Beware of sites that are just trying to sell you something.

Noone else knows, have a clue ?

Astrosyn wrote:Noone else knows, have a clue ?

Well, the point of this forum is to help kids with their science fairs. As a university student, posting a question out of curiosity, your post is beyond the scope of our board. I'm guessing that most people figure that learning how to search the literature is an important part of the University education.

Most science fair projects are due soon, so we are all really busy with our "real job", helping kids with science fair projects. You may get an answer when someone gets bored, but since you haven't (apparently) looked at the link provided or done any searching yourself, you probably won't.


Louise

Hi Atrosyn,
My guess is that they do subjective taste tests using ranges of concentrations of those chemicals. You can imagine a room full of little paper cups and volunteers repeatedly answering the question - "Do the contents of cup A taste sweeter, less sweet, or the same as those of cup B?"

Well, the point of this forum is to help kids with their science fairs. As a university student, posting a question out of curiosity, your post is beyond the scope of our board. I'm guessing that most people figure that learning how to search the literature is an important part of the University education.

Most science fair projects are due soon, so we are all really busy with our "real job", helping kids with science fair projects. You may get an answer when someone gets bored, but since you haven't (apparently) looked at the link provided or done any searching yourself, you probably won't.

I searched the internet for this theme.. and found nothing that would lead to answer. And yes i know how to search on web, and on science link etc etc.. and i spend many hours...so..

My guess is that they do subjective taste tests using ranges of concentrations of those chemicals. You can imagine a room full of little paper cups and volunteers repeatedly answering the question - "Do the contents of cup A taste sweeter, less sweet, or the same as those of cup B?"

Mhm , it's probably something like that. Using various of concetrations and
testing. (but still the standard is missing, would be probably sucrose as most comon "table" sugar)

Astrosyn wrote:

I searched the internet for this theme.. and found nothing that would lead to answer. And yes i know how to search on web, and on science link etc etc.. and i spend many hours...so..

Okay, I typed 'measuring sweetness of carbohydrates" in google and I found the answer in the third result. First result- this thread. Second result- a scholarly paper which i cannot access from home, but which probably has the answer (you can probably access these types of articles from a university computer) and the third result:

Ch09This paper describes a simple procedure for measuring sweetness that can be used, ... J. Yudkin, "Patterns and Trends in Carbohydrate Consumption and Their ...
http://www.unu.edu/Unupress/food/8F071e/8F071E0a.htm - 10k - Cached - Similar pages

So what were your search terms that you couldn't find this article? Sometimes you have to play around a little bit, but starting with the question directly is usually a good start. (And in this case, obviously worked well)

Now, if you were actually doing this experiment, I would suggest that you read the references cited, particularly reference 4 (from which the procedure is taken). Additionally, I would do a search where you look for all papers that cite reference 4, and then look at the most current one to see if any modern twists have been added (unlikely, but something you should check). I don't know what sciencelink is, but web of science and scifinder both make this very easy to do. Lastly, your school librarian is an excellent resource for this type of query. My university has classes on how to search for scientific information using many special databases. It is a good idea to take such a class if it is offered.

Louise