Chemical Tests for Gelatin

Aim

To identify the chemical characters of the given sample.

Principle

Gelatin is occurred in thin sheets, strips or granular powder. High-grade gelatin light yellow, semi-crystalline substance. It is Odourless and tasteless. In cold water, it swells up and slowly dissolves on warming to form a viscous solution.

Chemical Tests

• When gelatin is heated with soda lime in the dry test tube, ammonia is evolved due to the presence of a nitrogenous compound in gelatin.
• Gelatin solution is added to Million’s reagent to give a white ppt, which turns red on heating.
• Gelatin gives buff white ppt with tannic acid solution.
• Biuret test to 3 ml of test solution of gelatin. NaOH (1ml of 5%) is added whereby white to whitish buff coloured ppt is formed which does not dissolve on heating.
• Yellow ppt. is formed on adding picric acid to solution of gelatin.
• Yellow ppt. is formed on adding picric acid to solution of gelatin.

Conclusion

From the above morphological characters and chemical tests, the given crude drug is identified as Gelatin.

References

1.Kokate CK. Practical Pharmacognosy, 4 edition, VallabhPrakashan. Delhi; 1994: 98