Infrared Spectrum Analysis Of Microwave Heating Food

Microwave oven,with the sound functions of heating,thawing, sterilization and the advantages of fast and convenient heating,has been more and more widely used. Thus the safety of microwave food has become a topic of concern。 Infrared spectroscopy,which with the advantages of rapid, non-destructive, green and accessible online analysis, is good choice to analyze the security of microwave food.In this paper, the basic principles of infrared spectroscopy and the major methods of spectral data analysis are illustrated. Meanwhile, the simulations of spectra characteristics of vibration peak are achieved for the condition that the intensity frequency and linewidth change, which includes the characteristics of the two-dimensional correlation spectroscopy, principal component analysis features. Furthermore, relationship between the slices of two-dimensional correlation spectroscopy and the principal components are demonstrated, contributing to the future spectral analysis.The results of experiments are as follows,(1)Microwave heated water is analyzed by the near infrared spectroscopy methods, containing one-dimensional spectroscopy, differential spectral, two-dimensional correlation spectroscopy, principal component analysis and cluster analysis,and is compared with electrically heated water. The results show that: during the cooling process, the two main near infrared spectrum peaks of water are shifted to lower wave numbers; the differential spectrum analysis, two-dimensional correlation analysis and principal component analysis of the two kinds of water indicate the same structural changes; while the cluster analysis shows the two kinds of water are divided into two groups, indicating that these two types of the structure of water is not the same.(2)The microwave heated vegetable oils are analyzed by the infrared spectroscopy methods, containing two-dimensional correlation spectroscopy, principal component analysis and cluster analysis, and are compared with conventional heated ones. The results show that: according to the two-dimensional correlation spectroscopy, the structure changes are not detected in vegetable oils, however according to the principal component cluster analysis, oil heated by different heating methods can not be distinguished; moreover it is found that the rate of re-heated oil is faster than the rapeseed oil. So it comes to the method to identify drainage or re-heat oil according to the heating speed.(3)The infrared spectroscopy analyzes of different food show that, the spectroscopy of potatoes, carrots and lettuce, which is heated by microwave and traditional methods, are changing with the heating temperature and the two-dimensional correlation spectroscopy are different.(4)The spectroscopy of microwave heated milk changes more than the traditional heated one, but the two-dimensional correlation spectroscopies are approximately the same.