Chemical test for Agar/Agar-Agar / Japaneese Isinglass

Chemical test for Agar/Agar-Agar / Japaneese  Isinglass

Organoleptic test:

Appearance: Coarse,Crystalline                                              acacia, agar

Colour: Pale yellow                                                                 agar

Odour: Marine algae type                                                       agar

Taste: Mucilaginous                                                                agar

Solubility: Insoluble in coldwater, soluble in hot water         agar

Chemical test:

SI.No.	Test	Observation	Inference
1.	Boil 1gm of agar with 10ml of water until solution is affected, cool to room temperature	A slip jet is formed. (Jelly like mass is formed)	Agar
2.	0.2% solution of agar, + aqueous solution of tannic acid	No Precipitate is formed	Distinction from gelatin
3.	Warm little sample in alcoholic solution of pot. Hydroxide	Canary yellow colour is produced	Agar present
4.	Mount a small quantity of powder in the solution of ruthenium red and examine microscopically	Particles acquire red or pink colour	Presence of mucilage in agar.
5.	Add 1 drop of N/10 solution of iodine to 10ml of decoction of agar. Rapidly cool under tap water to room temperature.	Crimson or Pale yellow colour is produced	Agar is present
6.	Add 0.5ml of conc. HCl to 4ml of 0.5% solution of agar. Heat it on water bath for 30minutes, cool at room temperature and divide into two portions. a)      Add 3ml of 10% NaOH solution and Fehling’s solution A and B in equal quantities and warm over water bath. b)      Add 10% of barium chloride solution.	Red ppt of cuprous oxide is obtained        Slight white ppt of barium sulphate is obtained	Reducing sugars are present Sulphate in agar
7.	Incinerate agar to ash, add a drop of con.HCl observe under microscope	Fragments of diatoms	Agar is present