Near Infrared Calibrations for Goat's Milk Components: Protein, Total Casein, αs-, β- and k-caseins, Fat and Lactose

Abstract

A fast and inexpensive method to quantify the main constituents of goat's milk using near infrared (NIR) spectroscopy, is proposed. Since the efficiency of milk-to-cheese transformation depends on the total amount of casein, as well as on the relative proportions of the different types of caseins, it is desirable to quantify not only protein, fat and lactose, as is normally done routinely in the cheese industry and milk recording schemes, but also total casein, αs-, β- and k-caseins. Quantities of these main components have been measured in milk samples of three Spanish breeds of goats, using traditional chemical, electrophoretical and densitometric laboratory methods in order to produce NIR calibrations for total protein, total casein, casein fractions (αs-, β- and k-caseins), fat and lactose. Low standard errors and high coefficients of determinations have been obtained for the calibrations and validations. Goat's milk spectra are described, and the contribution of different components to the observed pattern is discussed. Due to the low cost, facility and rapidity of the analyses after the spectrophotometer has been calibrated for each milk component, the use of near infrared spectroscopy becomes a suitable tool to analyse large numbers of samples and, therefore, very suitable for dairy goat recording schemes.