| The present problems of flavors and fragrances are heating makes them volatilized,short time on to holding aroma and flavor uneven first-class, which limits its application areas and perfuming effect; Glycosides as a fragrance precursor itself has no aroma,stability, and slowly releases the aroma components at high temperatures, but there are relatively few studies in the past for glycoside degradation mechanism and application of being flavored.Therefore, this paper optimizes the chemical synthesis of geraniol glycosides, improves the yield of the synthesis, studies and optimizes the separation and purification methods, studies the structures and compositions by mass spectrometry, and is identified as the natural equivalent structure, then, the use of modern heating technologies to analysis thermal degradation mechanism for its further exploration, and finally is added to cigarettes to study the thermal cracking transfer rate, and contrast smoking flavored cigarettes to provide some reference for perfuming other glycoside precursor substances in cigarette.The main contents and results are as follows:1.the paper adopts improved methods of Koenigs-Knorr which uses the silicone to hold silver carbonate catalyst to improve the productivity, optimizes the flow mat- ches of silica gel column chromatography technology and HPLC that are based on the theory of isolation which selects the appropriate relative retention α and theoretical plate n to get better degree of separation R.The method of SGCC applies the thin plate chromatography to get the better flow matches which is to make the raw sample flow through the silica gel according to the ethyl acetate and ethanol according to 50:1, 40:1,30:1,and the flow matches of HPLC accords to 45:55.The results shows that the new way of synthsis of product could improve from 61% to 68%,the purity of the final product purifyed by sgcc is 89.12%, and he purity of the final product purifyed by HPLC is 98.66%.The use of FT-IR, NMR, LC-MS is to confirm their compositions and structures;firstly, FT-IR analysis showes that the sample has absorption peaks in 896.57cm-1 which attributes to β- glycosidases characteristic absorption peaks. secondly, the use of 1H NMR is to detect its molecular structure and functional groups, it shows double peaks appear near δ4.3 and its, C1-H and 2-H coupling constants is J1-2 = 7.8H, that is in line with β-glycosidases. Finally, LC-MS to determine its molecular weight is co- nsistent with the theory, and the emergence of belonging to O- glycoside bond chara- cteristic absorption.abovea all, it can be identified as a natural target equivalent geraniol glycosides.2.the DTA/SDTG and DSC techniques were used to study the thermal degradat- ion mechanism,The heating rate was adapted of 5 K/min, 7.5 K/min, 10 K/min, and 15 K/min,and heated the samples from the 30 to 500℃, then the methods of Friedman and Flynn-Wall-Ozawa were applied to calculate the parameters of thermal degradation, at last the parameters was substituted to the methods of Coats-Redfern and Phadnis-Deshpande to get its degradation mechanism equation. The TG-DTG curves shows that with the increasing of heating rate, the geranyl glycoside’s mass of starting loss T0, the biggest rate of mass loss Tp and final mass loss Tf all met the functions: T0=1.5667B+226,Tp=1.5381B+288.15, Tf=3.0524B+307.08, respectively, so that its thermal degradation temperature mainly was influenced by the heating rate B. According to the DSC curve,it could be concluded that the sample for melting and decomposition were at the same time.By Friedman and Flynn-Wall-Ozawa, its thermal degradation of the apparent activation energy Ea was gotten, which was 123.08KJ/mol, 117.05KJ/mol respective, and the correlation was better. By the Coats-Redfern, Phadnis-Deshpande, it also could be concluded that the decomposition of geranylglycoside belonged to the one-dimensional motion, and the degradation mechanism followed the equation g(X)=X2.While taking advantage of the online Py-GC-MS technique to study the geraniol glycosides’ s pyrolysis, the conditions of heating temperatures are 200 ℃, 300 ℃, 400 ℃,500 ℃, 600 ℃ and 700 ℃.The result shows that geraniol glycosides at a temperature in the range of 200 ~ 500 ℃ relatively releases large amounts of geraniol, and with the temperature decreasing, the mass of the releasing geraniol are declining, and when the pyrolysis temperature is about 300 ℃, the release mass of geraniol are the maximum,so it can be recognized as geraniol glycosides optimal pyrolysis temperature. When the pyrolysis temperature is relatively low, it slowly degradates and crackes a little aroma substances, but a relatively high pyrolysis temperature, it degradates too fast and the products will cause cracked second time which will yield more byproducts, while heating geraniol glycosides can release alcohol, citronellaene, β- pinene aroma substances,that addmore flavors to geraniol.3.Adding synthetic geraniol glycosides to particular specification cigarettes, taking advantage of GC-MS to qualitatively and quantitatively analysis the mainstream smoke. It is found that with the adding geraniol and geraniol glycosides cigarettes burning, both of them have released a small amount of geraniol, which improve the quality of cigarettes.Quantitative analysis of flavored cigarettes’ cracking transfer rate, the result shows that geraniol standard curve equation is y = 4.2E + 8x + 1.3E + 5, the correlation coefficient is0.9998.It shows that the concentration of geraniol is 0.75~48μg/mL which woks good.4.Then contrasting adding geraniol and geraniol glycosides cigarettes’ cracking transfer rate,it shows that the transfer rate of adding geraniol Cigarettes is 0.83%, the transfer rate of adding geraniol glycosides Cigarettes is 0.91%,they are close,but the latter are slightly higher.By contransting the sensory evaluation of adding geraniol and geraniol glycosides cigarettes, both of which increase the aroma quality, reduce the irritation of cigarettes and miscellaneous gas, but adding geraniol glycosides is better than geraniol. |
PDF Full Text Request