Science Buddies: "Ask an Expert"

i need to know how to test the sugar quantity in chewing gum.
i do know that i need benedicts solution to find out whether sugar does infact exist in chewing gum but i need to know how much sugar quantity exists, if at all.

so if anyone knows how i could test it, it would be very very very much appreciated!!!
thanks

Hi,

The first thing you need to decide is exactly what sugar you wish to quantitate. Most people use the word sugar to mean sucrose, or common table sugar. Chemists mean a large class of compounds that contain carbon , oxygen, and hydrogen in the ratio 1 part each carbon and oxygen to two parts hydrogen. Food makers can mean any of several sugar compounds (for example: sucrose, glucose, fructose, lactose, or a few others). These sugars are chemically different and the tests for them vary. The thing most of them have in common is that you will probably need access to a chemistry lab and a knowledgeable mentor to do the tests very successfully.

Benedicts solution is a test for reducing sugars like glucose, but not sucrose. Here is a reference to the method:
http://en.wikipedia.org/wiki/Benedict's_reagent

http://www.chemistry-react.org/go/Faq/Faq_24424.html
Here is a procedure to quantitate sugar by Benedict’s solution titration(It is experiment 2, scroll down the page past experiment 1):
http://www.scribd.com/doc/183215/UNDERG ... ALS-MANUAL

Here is an overview of the application of both types of Benedict’s tests:

http://www.madsci.org/posts/archives/20 ... .Bc.r.html


Another classical test for reducing sugars is the Fehling test:
http://www.uni-regensburg.de/Fakultaete ... ling-e.htm


Here is a test for sucrose, a nonreducing sugar:

http://www.sigmaaldrich.com/etc/mediali ... 299bul.pdf

http://terpconnect.umd.edu/~nsw/ench485/lab9d.htm

http://faculty.ksu.edu.sa/aabulhamd/Doc ... 0(353).pdf

More modern assays for sucrose or glucose use enzymatic methods. Here is one:

http://www.sigmaaldrich.com/catalog/Pro ... =ON&F=SPEC

Note that these methods will not quatitate or probably detect artificial sweeteners like aspartame, etc. which may be used in some chewing gums (see gum package ingredients to check).

One look at these refereces and you will probably see the value of having a mentor and access to a well equipt chemistry lab. Here is Science Buddies advice on finding a mentor:

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

This sounds like a fun project. I wish you success with it!

Best regards,

Barrett L Tomlinson

thankyou very very very much
this will help a lot! i really hope!!!

also, are you suggesting that i should infact include all of these different tests to get a complete and more so, accurate result?

Hi,

I think you want to pick one, or at most two, appropriate technique(s) that you can technically handle with your resources, then focus on doing that analysis really well. That includes calibrating the analysis, analyzing a control sample (where you know what the result should be) and proving that you can get a result that is reproducibly close to that, and that you get a reproducible result on the analysis of your unknown. The Benedict’s quantitative analysis (by titration) might be a good choice as long as you recognize its limitations and interferences. The DNS technique might be an alternate to consider, if you have access to a good lab and technical advice. To do any of these assays well may take a fair amount of time and practice, so don’t get in too far over your head or too far over your budget. You want to be able to get good results, if at all possible to a well defined question of limited scope, and know the limitations of your answer.

Have fun, and good luck! I would leve to hear how the project turns out!

Best regards,

Barrett L Tomlinson

Hi,

Here is a low tech analysis method for measuring sugar in chewing gum:

http://docs.google.com/viewer?a=v&q=cac ... ojw9h1GGFg

http://docs.google.com/viewer?a=v&q=cac ... ZDYxtnXfZg

http://www.teachengineering.org/view_le ... y_less.xml



If you remain intent on using a chemical analysis of sugar in chewing gum you might find this site to be of use:
http://www-unix.oit.umass.edu/~mcclemen ... rates.html

You may find it necessary to do some sample preparation to get the sugar out of the gum before doing the analysis.

Good luck!

Barrett L. Tomlinson

thankyou very much
you have no idea how much this will help me out
i'll let you know how everything goes.
thanks again for your expertise and awesome help!!!!

i was also just wondering, whether you may have a link to a colour chart representing the stages of the benedicts solution as it changes from blue to yellow/red?
for example, does red mean 100% sugar, yellow meaning 50% sugar?
or does the colour change go through stages from, blue (original colour) to yellow to red ?
if that makes any sense at all??


thanks

Hi,

Here is the best description I can find;

http://books.google.com/books?id=lciNs3 ... e&q&f=true

http://teachersites.schoolworld.com/web ... 20text.pdf

Please note that the method of using a color chart would be only semi-quantitative under the best of circumstances, and to achieve even that you should really do your own calibration curve (ie prepare a set of samples with known sugar concentrations/amounts and compare your sample to them. To get even slightly accurate results you will need to do a real titration.. (One problem could be that the color changes may depend on the specific sugar doing the reaction, and the exact way you do the test.)

Barrett L Tomlinson

thankyou very much

i conducted 3 tests today, using benedicts solution
2 of of the chewing gums being the constant (definite to having sugar)
and the other being sugar free.
the 2 constants turned out red and orange.
and the sugar free one actually had a small amount of sugar to it. looking on the colour table you sent me, it was a light green colour which means 0.5%-1.0%!!!! not so sugar free after all

i'm going to do the rest of the experiment tomorrow

thanks for your generous help

lydialollies wrote: the sugar free one actually had a small amount of sugar to it

Careful about making claims beyond what your testing can validate. The artificial sweetener "Splenda" will be detected by benedicts solution as being sugar; however, Splenda isn't a bio-available sugar meaning that most human's digestive tracts can't utilize it and turn it into glucose. From diebetic, caloric, and advertizing standpoints, "Splenda" is "sugar free" even though it is manufactured from sugar.

The wiki claims:
"Benedict's reagent is used as a test for the presence of reducing sugars. This includes all monosaccharides and the disaccharides, lactose and maltose. Even more generally, Benedict's test will detect the presence of aldehydes (except aromatic ones), and alpha-hydroxy-ketones, including those that occur in certain ketoses. Thus, although the ketose fructose is not strictly a reducing sugar, it is an alpha-hydroxy-ketone, and gives a positive test because it is converted to the aldoses glucose and mannose by the base in the reagent.[2]"

The elastomers in most chewing gum will contain some things that a base will split and a portion will turn into various aldehydes. Chewing gum is intended to be used in an acidic environment (saliva and if swallowed, stomach acid) where the aldehydes won't exist and not in a strong base like benedicts solution where they will.

okay. so is there some way i could test for spenda?
thanks

Hi,

Here are the assay methods for sucralose (splenda) found by an internet search:

http://www.fcf.usp.br/Ensino/Graduacao/ ... go%20b.pdf

http://www.ncbi.nlm.nih.gov/pubmed/15949159


http://www.ffcr.or.jp/zaidan/FFCRHOME.n ... /182-5.pdf

http://www.pharmacopeia.cn/v29240/usp29 ... 78575.html

The conclusion: If you have access to Gas Chromatography, Liquid Chromatography, or Thin Layer Chromatography there are established methods to assay sucralose (splenda). If you don’t, you are on your own to develop one.

Best regards,

Barrett L Tomlinson.