Lab Cat

27 Jan 2009

Simple Sugars: Fructose, glucose and sucrose

Glucose, fructose, sucrose

Glucose, fructose, sucrose

Simple sugars are carbohydrates. Glucose and fructose are monosaccharides and sucrose is a disaccharide of the two combined with a bond.  Glucose and fructose have the same molecular formula (C6H12O6) but glucose has a six member ring and fructose has a five member ring structure.

Fructose is known as the fruit sugar as its make source in the diet is fruits and vegetables. Honey is also a good source.

Glucose is known as grape sugar, blood sugar or corn sugar as these are its riches sources. Listed in food ingredients as dextrose.

Sucrose is the sugar we know as sugar or table sugar. Typically extracted as cane or beet sugar. If sucrose is treated with acid or heat, it hydrolyzes to form glucose and fructose.  This mixture of sucrose, glucose and fructose is also called invert sugar.

Nutritionally, these sugars are the same as they all provide 4 Cal/g. This is true for starch and other digestible carbohydrates too. Of the three sugars, fructose is the sweetest and glucose the least sweet, so typically less fructose can be used than table sugar (sucrose) – if sucrose has a sweetness of one, fructose is 1.7 and glucose 0.74

Fructose is more soluble than other sugars and hard to crystallize because it is more hygroscopic and holds onto water stronger than the others. This means that fructose can be used to extend the shelf life of baked products more than other sugars.

Wikipedia has lots information on sugars, including information on the three I am interested in fructose, glucose and sucrose.



  1. Do you have any idea how sucralose is made? (the sweetener)

    Comment by James Winsoar — 28 Jan 2009 @ 2:57 pm

    • James

      I don’t know how sucralose is made. Three of the hydroxyl groups (OH) are replaced by chlorine atoms. It is probably patented – a list of patents with sucralose in the title can be found at Patentdocs

      Comment by Cat — 28 Jan 2009 @ 8:00 pm

  2. Just an interesting aside. Fructose upsets some people’s stomachs. I used to get this wretched fruitopia drink back in the 90’s and it consistently upset my stomach, but I never really new why until I started sweetening my coffe with fructose which had exactly the same effect…

    Comment by Justin — 5 Mar 2009 @ 5:04 pm

  3. How many glucose can be produced by one gram sucrose?

    Comment by mehdi Ebrahimi — 12 Jul 2009 @ 1:32 am

    • You would end up with just over half a gram of glucose (0.53 g to be precise) when 1 g sucrose hydrolyzes. You would have the same amount of fructose. It is slightly over 0.5 g because water is added across the bond.

      Comment by Cat — 13 Jul 2009 @ 9:32 am

  4. I guess twice in a row you said glucose when you meant sucrose. You said above “Glucose and fructose are monosaccharides and glucose is a disaccharide of the two combined with a bond. Glucose and fructose have the same molecular formula (C6H12O6) but glucose has a six member ring and fructose has a five member ring structure.”

    So you are wrongly saying that glucose and fructose combined equals glucose.

    Comment by Chuck — 13 Jul 2009 @ 6:13 am

    • Chuck,

      I changed the one time I got it wrong. Thanks for pointing out my error.

      In the second sentence, I am correct to say glucose when I say glucose.

      Comment by Cat — 13 Jul 2009 @ 9:26 am

  5. […] you remember sugar is the common name for sucrose, which has the very confusing chemical name of […]

    Pingback by Tasty Tuesday: Sugar Chemistry « Lab Cat — 18 Aug 2009 @ 7:43 am

  6. I think your structure of sucrose is wrong. Correct me if I’m wrong, but sucrose has only eleven oxygen atoms not twelve like shown here.

    Comment by Patrick — 23 Sep 2009 @ 5:36 pm

    • Corrected now.

      Comment by Cat — 24 Sep 2009 @ 8:58 am

      • Is this an image you created? I’d like to use it in a Biology 101 library guide (for a community college library). Is that ok with you? If so, what sort of attribution would you like?

        Comment by Marci — 25 Feb 2015 @ 12:19 pm

  7. is silver immediately reduce by glucose?

    Comment by gel — 8 Jan 2010 @ 4:32 pm

  8. sugars should gather 4kcal/g not 4cal/g

    Comment by passing by — 26 Jan 2010 @ 2:29 am

  9. what is the best sugar and in what general quantity for flowering and or budding type plants?

    Comment by rich — 26 Aug 2010 @ 12:28 am

  10. great and informative post. thanks for sharing

    Comment by lirik — 9 Jan 2011 @ 12:04 pm

  11. what sugar has the most activity during fermenation glucose,sucrose or fructose?
    What is ease of fermenation?

    Comment by alex — 30 Sep 2011 @ 1:32 pm

  12. da info z gud but need 2 explan mo abt how they bond

    Comment by momo — 4 Nov 2011 @ 3:44 pm

  13. Can I ask?
    What is the simple sugars of Sucrose and Fructose ?

    Comment by Jessa Iguiban Gubalani — 10 Nov 2011 @ 6:49 am

    • They are simple sugars. Please check the text.

      Comment by Cat — 11 Nov 2011 @ 9:40 am

  14. How do corn syrup, table sugar, and water react to form a hard candy?

    Comment by AMiller — 19 Nov 2011 @ 7:02 pm

  15. […] was what kind of sugars were there before the artificial sort? I ended up at a website called Lab Cat which, in a brief verbal and visual format, described the sugars we commonly might ingest. Table […]

    Pingback by What Sweeteners Do You Use? Part 2 | Peter D Springberg, MD, FACP — 16 Jan 2012 @ 9:58 pm

  16. I found an article said that fructose is far deadlier. You can read it here – Do you think it’s true? If it’s true, I think we just have to limit ourselves eating unhealthy foods, eat organic foods instead and exercise everyday.

    Comment by Margaret — 13 Mar 2012 @ 2:28 am

    • Unfortunately, this is a website that is not peer reviewed and selective with the science that it uses. I definitely agree on exercising daily though.

      Comment by Cat — 13 Mar 2012 @ 4:03 pm

    • My question would be, what is the difference between “fructose” and “high fructose corn syrup” and is it acceptable to compare them as the same substance?

      Comment by Dale E. Erickson — 13 Nov 2015 @ 11:32 pm

      • Fructose is a pure compound. High fructose corn syrup is 55% fructose and 45% glucose. They are not the same substance.

        Comment by Cat — 16 Nov 2015 @ 10:58 am

  17. There is also a lot of academic writing about serious health concerns related to fructose excessive consumption.

    Here a (“peer reviewed”) example :

    (Liu et al. ‘Effect of pioglitazone on insulin resistance in fructose-drinking rats correlates with AGEs/RAGE inhibition and block of NAPDH oxidase and NF kappa B activation’. European Journal Of Pharmacology. online:

    Too much fructose is dangerous for your health. Sweetener are not any better. The only healthy choice is getting rid of the sweet-taste addiction.

    Comment by Chem Eng — 13 Apr 2012 @ 9:37 am

  18. a precise brief.I love it

    Comment by chepkwony — 22 Jan 2013 @ 2:55 am

  19. what would the reference to this website be?

    Comment by elliot lee — 29 Jan 2013 @ 4:33 pm

  20. […] Simple Sugars: Fructose, glucose and sucrose | Lab Cat […]

    Pingback by 2 Reasons Simple Sugars Matter — 3 Sep 2013 @ 8:54 pm

  21. all these are true, then why are some sugars reducing while others not?

    Comment by oketcho solomons — 17 Feb 2014 @ 5:19 am

    • aLl those which contain aldehyde groups,ketonic group,in hemiactal nnhemiketal form n reduce tolln reagnt thy R called reducing while othrs in which such proprty absnt they arr called non reducng

      Comment by arushi — 26 May 2014 @ 6:27 am

  22. because fructose is so difficult to crystallize?

    Comment by cristian — 14 Nov 2014 @ 7:09 am

  23. I feel that dextrose(glucose) would be a better sweetener for health reasons, but don’t know a good place to purchase it for home use. Any ideas on where I can buy it?

    Comment by David — 23 Apr 2015 @ 9:00 am

    • I have also concluded that dextrose would be better, but not best.
      Have you searched online for it, or for “corn syrup + (dextrose OR glucose)”? Old-fashioned corn syrup was glucose, aka dextrose.

      I agree with the person who pointed out that curing oneselves of addictions to sweet foods is the best approach to trying to preserve our health.

      Comment by Jane — 19 Jul 2015 @ 5:55 pm

  24. helped!

    Comment by Ria — 22 May 2015 @ 5:10 am

  25. […] Simple Sugars: Fructose, glucose and sucrose source […]

    Pingback by Chemistry Project 2016: Chemical Compounds in Healthy/Junk Food | — 31 Oct 2016 @ 10:49 am

  26. why is fructose regarded as d most sweetest amongst glucose and galactose. ans pls

    Comment by Ofonime umoh — 23 Nov 2016 @ 6:19 pm

  27. What happens to the structure in the example of Apples, which have 29g Fructose / 10g Glucose?

    Comment by Fructose Malabsoption HQ — 23 Jan 2017 @ 5:50 am

  28. […] hybridized to be higher in sucrose compared to its wild counterparts.  Fruit, and some vegetables, taste sweeter when they contain more sucrose than if they were glucose dominated, with fructose being the […]

    Pingback by The Tooth/Body Health Mismatch | The Raw Science — 19 Mar 2017 @ 12:34 pm

  29. hank you for sharing this article that helped me in my essay. And it will be useful information to anyone who is studying medicine just like me. : D

    Comment by jenny pham — 3 Jul 2017 @ 7:13 am

  30. […] Technically, the molecular breakdown of fruit sugars and refined sugars is the same. They both contain fructose and glucose, in varying ratios. Glucose is the most simple, preferred energy source for your body. Fructose is sweeter than glucose, and is not metabolized as easily. Fruits (and sweeteners like honey) have mostly fructose, whereas table sugar is about half fructose and half glucose (which combine as sucrose). (Source). […]

    Pingback by Sugar: A not-so-sweet family story ~ Pure Simplicity — 5 Aug 2017 @ 2:23 pm

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