Effects of different pasteurizers on the nutritional quality of raw milk samples

Abstract

The difference and changes in the nutritional components (Protein, fat an calcium) of local and exotic cow breeds (White Fulani, New Jersey and Mixture of the two breeds) were investigated before and after pasteurization of milk samples from the breeds in aluminium, stainless  and  galvanized  steel  pasteurizers  that  was designed  and  fabricated,  at temperature-time combinations of 61⁰C for 30minutes, 66⁰C for 15minutes and 71⁰C for 15seconds as well as at an unquantified temperature. Chemical test carried out on the milk samples before and after pasteurization showed significant variation in protein, fat and calcium content (p<0.05) after pasteurization. The protein contents in the unpasteurized samples were 3.65%, 3.49% and 3.62% for White Fulani, New Jersey and heir mixtures respectively. These values decrease to 3.64% in White Fulani but increased to a range of 3.50%-3.64% in New Jersey and the mixture after pasteurization. The values of fat content obtained in the same order were 2.95, 2.85 and 2.85 % while those of calcium were 1227.70, 1117.30 and 1107.70 mg/Kg. Calcium values decreased significantly (p<0.05) with increase in temperature in White Fulani to a least value of 11140 mg/Kg at 71⁰C while it increased significantly as well to a value range of 1120.70 to 1134 mg/Kg in New Jersey and to a value range of 1110.30 to 1140.00 mg/Kg in the mixture at varying temperatures and material. This evaluation shows that the local breed has better nutritional composition than the foreign breed but the mixture of milk of the two breeds is a promising idea that should be further exploited.

Keywords: Pasteurizers, Nutritional, Exotic breed, Raw milk, Calcium, Protein