Raman spectroscopic techniques for detecting structure and quality of frozen foods: principles and applications.

Frozen foods are among the most popular food products and the development of techniques for the rapid detection of their structures and quality is important for the frozen food industry. In the current review, the principles and applications of Raman spectroscopic techniques in detecting and evaluating the structure changes and quality of frozen foods are discussed and merits and drawbacks of each Raman type are presented. These techniques include dispersive, Fourier transform, spatially offset, micro Raman spectroscopies. Raman spectroscopy can assess the compositional, physicochemical, and sensory characteristics of the frozen foods without any pretreatment. It can also be applied to investigate the structural alterations of protein, lipid, water and other components. Further trends of developing the Raman spectroscopy in monitoring the frozen foods should focus on reducing overlapping signals, achieving real noninvasive detection, eliminating misclassification and quantification errors, establishing standardized Raman database, and controlling cost.