Study On The Infrared Spectra Of Vicia Faba Seeds

Broad bean diseases seriously affect the production and quality of broad bean. Inorder to achieve sustainable development of crop ecological environment, reasonablepreventive methods should be taken to identify the crop diseases. In this dissertation,FTIR spectroscopy combined with curve fitting was utilized to study broad bean andits diseased leaves.The results showed that the infrared spectra of broad bean leaves were similarand mainly made up of the absorption bands of protein, lipid and polysaccharides.There were only some tiny differences such as the spectral peak position, peak shapeand the absorption intensity in the range of1800~1300cm-1. There were someobvious differences among their second derivative spectra in the range of1800~1300cm-1. After the procedure of the Fourier self-deconvolution and curve fitting ofhealth bean leaf and broad bean diseased leaves in the range of1700~1500cm–1,the ratios of relative areas of the bands of healthy leaf amide Ⅱ are larger than that ofdiseased leaves, while the ratios of relative areas of the bands of lignin are smallerthan that of diseased leaves. For sub-band area ratios A1563/A1605, A1650/A1605andA1563/A1654, those of four kinds of diseased leaves are smaller than that of healthy leaf.The results showed that protein content significantly decreased in diseased leaves.FTIR spectroscopy combined with hierarchical cluster analysis (HCA) and curvefitting was utilized to study the contents of secondary structure of protein in broadbean samples, which were collected in Baoshan city of Yunnan province. The resultsshowe the contents of α-helix, β-turn and unordered structure in green beans arehigher than that in white beans, while the content of β-sheet in green beans less thanthat in white beans. The results showed that protein content in green beans were morethan white beans.The study showed that Fourier transform infrared spectroscopy combined withchemometric methods could be used to detect different kinds of broad bean diseases,and secondary structure of protein in broad bean. These methods also can be used toanalysis the chenical composition changes in broad bean leaves and broad bean.