1. Introduction
A variety of the instruments that are commonly used to analyze food materials are based on spectroscopy, e.g., UV-visible, fluorescence, atomic, infrared and nuclear magnetic resonance spectroscopies. These instruments utilize interactions between electromagnetic radiation and matter to provide information of the operating principles of these instruments depends on an understanding of the distribution of energy within atoms and molecules, of the characteristics of electromagnetic radiation, and of the interaction of electromagnetic radiation with atoms and molecules.