Discrimination Of Wild-growing And Cultivated Edible Fungi With Fourier Transformed Infrared Spectroscopy

It’s extremely difficult to discriminate wil-growing and cultivated mushrooms by conventional method based on the morphological inspection of fruiting bodies,which is not good for developing and utilizating them.In these dissertation,wild-growing and cultivated Coprinus comatus,Lentinus edodes,Auricularia auricula and Morchella esculenta were discriminated by using Fourier transformed infrared（FT-IR）spectra,second derivative infrared（SD-IR）spectra,two-dimensional correlation infrared（2D-IR）spectra,curve fitting and hierarchical cluster analysis（HCA）.The results showed that FT-IR spectra of cultivated and wild-growing Coprinus comatus were similar in holistic spectral profile.More significant differences are exhibited in their SD-IR spectra in the range of 3030²830 and 1800²830 cm^-1.In their 2D-IR spectra,the number of auto-peaks was great different in the range of1680¹380 and 1210⁹00 cm^-1.But beyond that,the intensities of auto-peaks and cross-peaks also had obvious distinctions.FT-IR spectra,curve fitting and 2D-IR spectra were used to study the cap of the Coprinus comatus before and after deliquescing into inky liquid.The dispersions of frequency of 3330,1649 and 1145 cm^-1 in their FT-IR spectra were 19,8 and 5 cm^-1respectively.Relatively absorbance of A₁₂₄₅/A₃₃₂₄324 and A₁₁₄₉/A₃₃₂₄324 were 0.669 and0.725 respectively for the non-deliquescing cap,and were 0.410 and 0.499respectively for the deliquescing cap.The amide I band(1683¹616 cm^-1)and the characteristic absorption bands of carbohydrates(1180⁹74 cm^-1)in the original spectra were used for decomposition and curve fitting to evaluate the contents of secondary structure of proteins and polysaccharides.The results showed that proteins and polysaccharides were different between non-deliquescing and deliquescing cap of Coprinus comatus.In 2D-IR spectra,their number,position and intensity of auto-peaks and cross-peaks were obvious different,and the order of changing of groups were learned when environment temperature was being increased in this range.Some differences between wild-growing and cultivated Lentinus edodes were observed in the SD-IR spectra in the range of 1700⁹00 cm^-1.In the 2D-IR spectra,the number of auto-peaks were different in the range of 2970²900,1678¹390,1250¹104 and 1090¹030 cm^-1.In addition,the intensity of auto-peaks and cross-peaks also had obvious differences between them in these regions.The FT-IR spectra of wild-growing and cultivated Auricularia auricula were similar.There were significant differences between them in SD-IR spectra in the range of 1850⁵00 cm^-1.The number,position and intensity of auto-peaks and cross-peaks were obvious differences between them in the range of 1750¹500,1480¹350,1300¹000,990⁸65 and 468⁴10 cm^-1.There were some obvious differences of SD-IR spectra between wild-growing and cultivated Morchella esculenta in range of 1760⁸50 cm^-1.The 2D-IR spectral results show the significant differences of number,intensity and intensity of auto-peaks and cross-peaks in the range of 3732²990,1694¹270,1240⁸72 and480⁴00 cm^-1.Hierarchical cluster analysis was conducted on them with SD-IR spectra in the range of 1690⁹90 cm^-1,and all samples could be distinguished correctly,and the results of curve fitting showed that the contents of secondary structure of carbohydrates were different between them in the range of 1182⁹50cm^-1.We can make a conclusion that FT-IR spectroscopy combined with SD-IR spectroscopy,2D-IR spectroscopy,curve fitting and HCA is a nondestructive,effective method to discriminate wild-growing and cultivated edible fungi.