Abstract

• The aim of the study is to isolate and characterize the casein and albumin from selected fresh and packed cow milk samples as well as to determine the minerals and antioxidant activities. Preliminary milk quality tests of both milk samples showed that pH (6.8-6.5) were within normal range in the presence of carbohydrate and reducing sugar gave good quality with alcohol test. The main component of casein I and II (9.11 % and 7.36 %) from both samples were isolated by adjustment of isoelectric point (pH 4.6) with 10 % acetic acid. After removing of casein, 2.2 g of CaCO3 was added to the filtrate (whey solution) to precipitate albumin I and II (2.18 % and 0.21 %). The isolated casein and albumin were characterized by FT IR spectroscopy, amino acid tests (such as Millon’s test, Biuret test, Ninhydrin test, Xanthoproteic test) and protein precipitation tests (salt test, organic solvent test, acidic agent test, heat and acid test and heavy metal ions test) respectively. FT IR spectra of isolated casein I and II illustrate better fit with the reported spectra than those of albumin I and II. Atomic absorption spectroscopy (AAS) of isolated casein and albumin showed sufficient amount of minerals. The isolated casein possessed mild antioxidant activity whereas albumin possessed practically inactive by DPPH assay. Therefore, it may be better to use the fresh cow milk for the production of more nutritious dairy food.