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bio food test help
- Thread starter robinho10
- Start date
- Messages
- 4,291
- Reaction score
- 6,457
- Points
- 523
Starch:
Iodine, observe a colour change from brown to blue-black.
Reducing Sugars:
Cut or grind off a small sample and add it to water to attempt to dissolve it. Then add Benedict's solution and heat using a waterbath. Observe a colour change from blue to brick-red.
Protein:
Cut or grind off a small sample and add it to water to attempt to dissolve it. Add potassium hydroxide and copper sulphate. Observe a colour change from blue to purple.
Fat:
Cut or grind off a small portion. Place in a test tube of ethanol and shake. Add the liquid part of this mixture to a test tube containing water. Observe a cloudy emulsifying change.
Iodine, observe a colour change from brown to blue-black.
Reducing Sugars:
Cut or grind off a small sample and add it to water to attempt to dissolve it. Then add Benedict's solution and heat using a waterbath. Observe a colour change from blue to brick-red.
Protein:
Cut or grind off a small sample and add it to water to attempt to dissolve it. Add potassium hydroxide and copper sulphate. Observe a colour change from blue to purple.
Fat:
Cut or grind off a small portion. Place in a test tube of ethanol and shake. Add the liquid part of this mixture to a test tube containing water. Observe a cloudy emulsifying change.
- Messages
- 1,136
- Reaction score
- 12,982
- Points
- 523
reducing sugar:
-equal volumes of sugar and benedict reagent(2 or 3 cm^2 )
-shake well.
-heat in water bath (minimum 80 degree Celsius)
-heat for 2 mins.
if the colour changes from blue to red then it's reducing sugar, if not then non reducing sugar is present
non reducing test:
-2 cm^2 of sugar and 1 cm^2 of HCl(take half the volume of acid, you have taken for sugar)
-heat until it starts to boil (takes about 5 mins) (it's better to heat it directly)
-allow it to cool
-after cooling neutralize it with sodium bicarbonate powder. check it with litmus paper.
-then follow the steps for reducing sugar above.
proteins:
-1 cm^2 of copper sulfate, 1 cm^2 of potassium hydroxide, 1 cm^2 of sample solution.(take equal volumes of the three)
colour changes from blue to purple.
-equal volumes of sugar and benedict reagent(2 or 3 cm^2 )
-shake well.
-heat in water bath (minimum 80 degree Celsius)
-heat for 2 mins.
if the colour changes from blue to red then it's reducing sugar, if not then non reducing sugar is present
non reducing test:
-2 cm^2 of sugar and 1 cm^2 of HCl(take half the volume of acid, you have taken for sugar)
-heat until it starts to boil (takes about 5 mins) (it's better to heat it directly)
-allow it to cool
-after cooling neutralize it with sodium bicarbonate powder. check it with litmus paper.
-then follow the steps for reducing sugar above.
proteins:
-1 cm^2 of copper sulfate, 1 cm^2 of potassium hydroxide, 1 cm^2 of sample solution.(take equal volumes of the three)
colour changes from blue to purple.