Infrared Spectra Study Of Artificial Aging Cereal Seeds

Seed aging affects seed quality and eating quality.Therefore,the study of seed aging is of great significance to agricultural production and food safety.In this dissertation,aging wheat,barley,rice,sorghum and corn seeds were studied by Fourier transform infrared spectroscopy（FT-IR）,second derivative infrared spectroscopy（SD-IR）and two-dimensional correlation infrared spectroscopy（2D-IR）combined with curve fitting and multivariate statistical analysis（principal component analysis（PCA）,Hierarchical cluster analysis（HCA））.The results showed that the Fourier transform infrared spectra of artificially aged cereal seeds were similar overall.The Fourier transform infrared spectra of different varieties of cereal seeds are generally similar.In the second derivative infrared spectrum,the absorption peak intensity of artificially aged cereal seeds at around1745 cm^-1showed a weakening trend.The intensity of absorption peaks near 1643,1549,and 1242 cm^-1showed a weakening trend.In the range of 1100-1000 cm^-1,the absorption peak intensity shows a law of decreasing trend.The results showed that the contents of lipids,proteins,sugars,amino acids and aldehydes/ketones in cereal seeds changed during artificial aging.In 2D-IR spectra,the number and intensity of auto-peaks are obvious different in the range of 800-1050,1060-1150,and 1150-1800 cm^-1for artificially aged wheat seeds.The number and intensity of the auto-peaks of the aged barley seeds varied significantly in the range of 800-1160 and 1160-1600 cm^-1.The number and intensity of auto-peaks in artificial aging rice seeds varied significantly in the range of800-1350 cm^-1.The number and intensity of auto-peaks in artificial aging sorghum seeds varied significantly in the range of 800-1160 and 1170-1550 cm^-1.The number and intensity of auto-peaks in artificial aging maize seeds varied significantly in the range of 800-1050 and 1050-1600 cm^-1.The positions and numbers of the strongest auto-peaks and the second strongest auto-peaks of different cereal seeds are obviously different.Multivariate statistical methods show that the infrared spectra of artificially aged cereal seeds in the range of 1800-800cm^-1are used for principal component analysis and hierarchical clustering analysis.Principal component analysis and hierarchical cluster analysis can effectively distinguish wheat,rice,and sorghum seeds with different degrees of aging.Principal component analysis and hierarchical cluster analysis are not ideal for clustering of artificially aged corn seeds and artificially aged barley seeds.The curve fitting of artificially aged cereal seeds is selected in the range of1200-950 cm^-1,and the position of the sub-peaks and the percentage of absorption peak area are analyzed.The results showed that the absorption peak areas of aged wheat seeds and barley seeds in artificially aged wheat seeds showed an increasing trend in the vicinity of 1159,1082 and 1021 cm^-1.The absorption peak area around1109,1054,and 988 cm^-1showed a decreasing trend.The absorption peak area of artificially aged rice,sorghum and corn seeds showed an increasing trend around1109 cm^-1.The absorption peak area around 1163,1081,1054,1019,986 cm^-1showed a decreasing trend.It shows that the relative content of the corresponding peaks of C-O,C-OH,C-H,C-C,and C-O in the polysaccharide region of artificially aged cereal seeds has changed.In summary,it is shown that the use of FTIR,SD-IR,and 2D-IR combined with multivariate statistical analysis can quickly and effectively study artificially aged wheat seeds,barley seeds,rice seeds,and sorghum Cereal seeds such as seeds and corn seeds.