Experiment # ___
Analysis of Milk
Nova Isablel Agan March 8, 2013
Alethea Dapac Score:
Apparatus: beaker, stirring rod, graduated cylinder, test tube, water bath, test tube holder, evaporating dish, dropper, filter paper, pH paper, tripod, funnel, Erlenmeyer flask,
Procedure: [Preparation of 100 ml whole milk] * 50 ml of milk was placed in a beaker and was diluted with 50 ml tap water.
I. Physical properties of milk * The color was noted. Specific Gravity (denser or less dense than water and pH.
II. Chemical properties of milk 1.) Action of hot alkali
1 ml of milk was placed in a test tube. NaOH was added drop by drop until yellow color develops that gradually deepens into a brown color.
2.) Saturation with MgSO4
1 ml of milk was placed in a test tube. Solid MgSO4 was added until precipitate formed.
3.) Test for formaldehyde preservative in milk
1 ml of milk was placed in a test tube. 1 ml of the solution containing FeCl3 in HCl was added. it was heated in low flame for 5 ml.
[note: the remaining milk in the beaker was added with 5 ml dilute HAc and was heated to boiling until precipitate was formed. It was cooled and filtered.
III. Chemical test for the different components of milk A. The filtrate from the previous procedure was boiled until it coagulates. It was filtered and reserved for part B. The coagulum was divided into two portions and the Biuret test and heating was performed.
B. The filtrate from III.A was used for the other tests. a.> Test for lactose.
5 drops of the filtrate was added with 3 ml Benedicts’ reagent. It was heated in a water bath. The results were noted. b.> Test for calcium ions.
1ml of the filtrate was added with 1 ml of (NH4)2C2O4 solution.
c.> Test for phosphate.
3 ml of the filtrate was added with a few drops of 6M HNO3