Reaction Tests

Question 1

Benedicts Test

Answer 1

A simple biochemical reaction to test to detect the presence of sugars

All monosaccharides and some disaccharides eg maltose are reducing sugars. A reducing sugar is one that can donate electrons (reduce) to another chemical- in this case Benedicts reagent.

Benedicts is an alkaline solution of copper II sulfate.

When a reducing sugar is heated with Benedicts reagent it forms an insoluble red precipitate of copper I oxide.

Add equal amount of food and Benedicts solution
Gently heat
If turns orange brown sugar present

Question 2

Biuret yest

Answer 2

Detect the presence of protein
Detects peptide bonds

Place sample of solution in a test tube add equal volume of sodium hydroxide at room temperature

Add a few drops of very dilute copper II sulphate (0.05%) mix gently

A purple colouration indicates presence of peptide bonds
No protein solution remains blue