CALCIUM TEST IN MILK (EDTA TITRATION)
AIM:
To estimate calcium content in milk.
APPARATUS:
Burette, pipette, conical flask.
REAGENT:
0.01M EDTA, buffer solution (pH 10), Eriochrome Black T.
PRINCIPLE:
EDTA binds calcium ions in presence of indicator, forming a color change at endpoint.
PROCEDURE:
Pipette 10ml of milk (diluted), add buffer and indicator.
Titrate with EDTA until the wine-red color changes to blue.
CALCULATION:
mg Ca²⁺ = Titre value × 40.08 (molar mass of Ca)
ASH CONTENT TEST IN FLOUR
AIM:
To determine the inorganic (mineral) content in flour.
APPARATUS:
Crucible, furnace, balance.
REAGENT:
None.
PRINCIPLE:
Organic matter is burnt off, leaving behind ash (mineral content).
PROCEDURE:
Weigh 5g of flour in a crucible.
Incinerate in furnace at 550°C for 4 hours.
Cool in desiccator and weigh.
CALCULATION:
% Ash = (Weight of ash / Weight of sample) × 100
Molisch’s Reagent
Purpose: A general test for carbohydrates.
Procedure:
Dissolve 5 g of α-naphthol in 100 ml of ethanol (95%).
Store in a dark bottle.
pH TEST OF SOFT DRINKS
AIM:
To measure the pH level of a soft drink.
APPARATUS:
pH meter or pH paper, beaker.
REAGENT:
None (or universal indicator).
PRINCIPLE:
pH indicates the acidity or alkalinity of a solution.
PROCEDURE:
Pour 10ml of the soft drink into a beaker.
Dip pH paper or insert pH meter electrode.
Record the pH value.
RESULT:
Soft drinks usually show pH between 2.5 – 4.5.
Benedict’s Reagent
Purpose: Tests for presence of reducing sugars.
Procedure:
Dissolve 173 g sodium citrate and 100 g anhydrous sodium carbonate in 800 ml distilled water.
Separately dissolve 17.3 g CuSO₄·5H₂O in 100 ml water.
Slowly add the CuSO₄ solution to the carbonate/citrate solution with constant stirring.
Make up the volume to 1000 ml.
STARCH TEST IN FOODS (IODINE TEST)
AIM:
To detect the presence of starch in food items.
APPARATUS:
Test tube, dropper, beaker.
REAGENT:
Iodine solution.
PRINCIPLE:
Iodine reacts with starch to form a blue-black complex.
PROCEDURE:
Add a few drops of iodine solution to the food solution or crushed sample.
Observe for a blue-black coloration.
RESULT:
Presence of starch is confirmed by blue-black color.
