Applications of spectroscopic techniques for fat and fatty acids analysis of dairy foods

Fat and fatty acids (FAs) are important quality parameters of dairy foods, characterizing their nutritional value. Efficient routine analyses of their contents are of critical importance for dairy farms and factories. Conventional methods for determining fat and FAs contents of dairy foods are time-consuming, laborious, destructive to samples and often requiring use of hazard solvents, which make it impossible for real-time and on-line measurements. Spectroscopic techniques based on near-infrared spectroscopy (NIRS), Raman spectroscopy (RS), nuclear magnetic resonance (NMR) have been studied extensively for fat and FAs analyses of dairy foods, and promising results have been shown. In this context, this paper summarized the current research progress in application of the three important techniques in predicting fat content and FAs composition of dairy products such as milk, milk powder and cheese. First, the working principles and features of these techniques were described, and then the research advances of each technique for fat and FAs analyses of the dairy foods are presented in detail and the factors influencing their modeling results are discussed. Perspectives on their current situation, future trends and challenges are also discussed.