| Osmanthusfragrans(Thunb.)Lour.is one of the traditional flowers. It has a long history ofcultivation in Chinaand according to records there are166cultivars now. O.fragrans is not onlya fine ornamental tree species, but also an important spice plant. With the development ofmodern analytical techniques, gas chromatography mass spectrometry and Fourier transforminfrared spectroscopy has become a common means of recent spice component analysis. Thisassay aims to analyze the differences in aroma components of sweet osmanthus using gaschromatography mass spectrometry, also the infrared spectroscopy inside the sweet osmanthuspetals were collected by Fourier transform infrared spectroscopy. Based on these data, we usedcluster analysis and establish the identification model of sweet osmanthus. We expected todevelop a new method for distinguishing sweet osmanthus cultivars and a rapid identification ofnew cultivars on the basis of the classic classification.1. In this paper, we obtained the aroma components of the21sweet osmanthus cultivarsand other plants of Genus Osmanthus using MonoTrap and steam distillation methods. Theresults showed that there is no significant difference between aroma components of sweetosmanthus trapped by MonoTrap and the extract components obtained by steam distillation.The main aroma components were trans-linalool oxide, cis-linalool oxide, linalool, neroli,dihydro-β-ionone, β-ionone, dihydroactinidiolide lactone. Both of the methods showed thatthere are differences between the group cultival, OsmanthusfragransLuteus Group contain morelinalool compounds; higher content of ionone compounds in O. fragransAlbus Group; O.fragransAurantiacus Group contain trans-geraniol, it was not detected in other groups. Themain aroma components of O. cooperi,O. cooperi 'Xuegui', O. heterophyllus were similarwith the sweet osmanthus, however, the relative contents of ionone compounds weresignificantly less than the sweet osmanthus.2. In this paper, the diurnal variation of aroma components and the changes of aromacomponents after natural dried were analyzed taking the O. fragrans 'BoyeJingui' as anexample. The results showed that the relative contents of aroma components reached to themaximum in the2ndday and then decreased gradually except the dihydroactinidiolide usingMonoTrap. The relative content of dihydroactinidiolide increased gradually and reached to themaximum at the5thday. Therefore, the2ndday is the ideal time to study aroma components ofsweet osmanthus. From the natural the dried O. fragrans 'BoyeJingui' flowers, we detected atotal of14kinds of components, lacking of linalool oxide compared with the fresh sweet osmanthus flowers. Therefore, natural dried O. fragrans 'BoyeJingui' flowers still be able toretain the typical aromatic characteristics of sweet osmanthus.3. Infrared spectral data of the inside petals of the sweet osmanthus were analyzed byMatlab, we select3000cm-1-2850cm-1and1750cm-1-1000cm-1two intervals for qualitativeanalysis and to study the influence of different pretreatment methods on building modeling. Theresults showed that using MSC and SNV scaling followed by calculating first derivative wasthe best pretreatment method. The best predicitive model for flower color value was using PLSregression (RMSEC=0.65852, RMSEP=0.837689), which has higher accuracy and robustdegree of model. Using cluster analysis and principle component analysis got a better clusterresults among the culitvars in each group, however, no significant difference among differentgroups. Calibration employing SVMDA provided the optimum model for distinguishingcultivars.24cultivars of correct identification rate can reach more than75%. Calibrationemploying PLS regression provided the model for predicting flower color value in the basis ofinfrared spectrum and flower color value measuring with Royal Horticultural Society ColourChart. This model can be used infrared spectrum of unknown sweet osmanthus cultivars topredict the corresponding color value. The results showed that the model caneffectively predict the color value amongthe groups which had significant differences in flowercolor, but the model had poor effect in O. fragransAurantiacus Group... |
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