William HargisC12713 March 2014Milk Separation and Analysis Objective: This experiment uses natural product separation techniques and basic biochemical qualitative analytical testing in order to identify, separate, and analyze the components main features of whole milk.Introduction:Milk is a natural organic product with a complex chemical composition1,2, it is a colloid made up of proteins, carbohydrates, fats, vitamins and minerals. The proteins present in milk are largely soluble in water thanks to the amine and carboxylic acid side chains, the amines are protonated and therefore positively charged, at a pH close to that of 7.44 or human physiological pH2. Amines remain unprotonated at high pH. Carboxylic acids, however, are protonated at low pH and not protonated at higher pH, such as physiological pH2. Carboxylic acids maintain a negative charge in their unprotonated state, at physiological pH carboxylic acids are negatively charged side chains. Although the protein retains positively or negatively charged side chains, it is soluble in water2. Exploiting the isoelectric point by raising the pH to the point where protein charges are balanced causes a loss of solubility, causing protein precipitation2. The most abundant proteins in milk are water-soluble protein molecules called caseins, caseins can be precipitated from milk by reaching their respective isoelectric point via a change in pH via the addition of an acid, this experiment used acetic acid to lower the pH to around 4.6. Butterfat is also precipitated by this pH change. The resulting solution is precipitated casein and butterfat within an aqueous solution called whey, whey contains water-soluble proteins that do not precipitate... middle of paper... cium tests have confirmed the presence of phosphate and respectively calcium in the liquid whey filtrate, this was as expected, since metal ions are soluble in water. The positive biuret protein test result confirmed that the solid curd contains protein, this is as expected since the curd should mainly consist of insoluble casein protein. Butyric fats added to water were found to be immiscible, indicating that the substance is a non-polar hydrophobic material, which confirms that butyric fats are made up of non-polar fat molecules. The results of these qualitative tests and observations strongly indicate a successful separation of the natural product, whole milk. Conclusion: The separation was successful and produced separate phases consistent with the prediction based on solubility properties. This was indicated by qualitative tests and observations.