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StartMicrobiologyOsazone Check for Carbohydrates Precept, Process, Outcome

Osazone Check for Carbohydrates Precept, Process, Outcome

The Osazone check is a kind of biochemical check which is used to detect decreasing sugars. This check can distinguish between several types of decreasing sugars by the looks time of the advanced. Osazone check can be known as Phenyl hydrozine check relying on the reagent used.


  • To detect decreasing sugars.
  • To differentiate between decreasing and non-reducing sugars.
  • To distinguish totally different decreasing sugars from one another.

Precept of Osazone Check 

Osazones are the attribute derivatives of carbohydrates that outcome from the response of decreasing sugars with Phenylhydrazine. These osazone derivatives are crystallized. This made it doable to establish the carbohydrate kind with ease.

This check doesn’t work for sugars that lack free anomeric hydroxyl teams (non-reducing sugars). Whereas glucose, fructose, and mannose produce related kinds of osazone (glucosazone), The melting level, crystal form, and time of crystallization are all totally different for every osazone crystal.

Principle of Osazone Test 
Osazone formation. D-glucose reacts with phenylhydrazine to provide glucosazone. Picture Supply: Wiki



  • Osazone combination: 0.5 g of phenylhydrazine hydrochloride and 0.1 g of sodium acetate.
  • Glacial acetic acid
  • Check pattern


  • Check tube
  • Check tube holder
  • Dropper
  • Pipette
  • Stand 
  • Spirit or fuel lamp
  • Gentle Microscope
  • Slides
  • Coverslip
  • Answer to be examined


  1. In a small container, take 5 ml of the answer.
  2. To the above-mentioned check tube, add 3 pinches of osazone combination.
  3. Combine totally
  4. Place the flame on the check and boil for 5 minutes
  5. Look out for yellow crystals. If they don’t seem to be fashioned, boil them.
  6. Examine each 5 minutes to make sure yellow crystals usually are not missed.
  7. After the crystals have fashioned, let the answer cool at room temperature.
  8. Take the crystals out and put together slide    
  9. Beneath microscope, look at the slide


Osazone crystals fashioned when examined below the microscope can tackle totally different shapes relying upon the kind of carbohydrate.


The next inferences are drawn from the shapes of osazone crystals.

  1. Needle formed/ broom-stick crystals are fashioned in 5 minutes point out glucose
  2. Needle formed/ broom-stick crystals are fashioned in 2 minutes point out fructose
  3. Cotton ball-shaped crystals are fashioned by lactose in half-hour
  4. Sunflower formed crystals are fashioned by maltose in 30 to 40 minutes
Carbohydrate Time of formation (min) Crystalline construction
Fructose 2 Needle form
Glucose 5 Needle or broomstick form
Galactose 20 Thorny ball or rhombic plate form
Maltose 30-45 Sunflower/ petal formed
Lactose 30-45 puff formed powder or cotton balls
Osazone Test result
Osazone Check outcome

Benefits of Osazone Check

  • This check distinguishes between decreasing and non-reducing sugars. It’s also the most affordable, best to do, and most significantly, interprets properly.
  • This check can be utilized to establish sugars in plant tissues.
  • Completely different decreasing sugars kind totally different osazone compounds. It’s an efficient method to seperate them.

Limitations of Osazone Check

  • Lowering sugars should be current at better portions within the pattern for identification.
  • If heated for longer than half-hour, it may give false-positive outcomes for sucrose (a non-reducing sugar).
  • If multiple decreasing sugars are within the pattern, detection is unimaginable.


  • Tiwari A. (2015). Sensible Biochemistry. LAP Lambert Educational Publishing.
  • Shah, Tejas. (2016). Utility of Osazone Check to Establish Sugars. Journal of Medical Science And scientific Analysis. 04. 14361-14365. 10.18535/jmscr/v4i12.14.
  • Mester, L.; El Khadem, H.; Horton, D. (1970). “Construction of saccharide osazones.” Journal of the Chemical Society C: Natural (18): 2567. doi:10.1039/J39700002567.
  • https://www.topperlearning.com/reply/what-is-osazone-test-please-explain-with-the-help-of-examplepercent20/d1yd9w11
  • https://pubs.acs.org/doi/10.1021/ja01971a011
  • http://ecoursesonline.iasri.res.in/mod/web page/view.php?id=53489
  • https://idswater.com/2019/12/08/what-is-osazone-formation-and-its-significance/
  • https://pdfcoffee.com/osazone-test-pdf-pdf-free.html
  • https://aklectures.com/lecture/reactions-and-disaccharides/osazone-formation-from-d-glucose
  • https://www.jaypeedigital.com/ebook/9788184482591/chapter/ch2
  • https://alevelbiology.co.uk/notes/tests-for-carbohydrates/#64-osazone-test
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