Extraction Method And Process Parameters Of Ginger Oil

Ginger (Zingiber officinale Rosc) was one of the main exports of vegetables in China. Inrecent years, with the development of the vegetables processing industry, the gingerprocessing products which required different processing quality of ginger raw materialincreased gradually. Therefore, the quality of ginger rhizome, the content and chemicalcomposition changes of ginger essential oils and oleoresins in different growth and storageperiod were studied; on this basis, we studied the different extraction method of ginger oils,and focus on the process parameters of ethanol extraction. The main results were as follows:1. The content of ginger rhizome dry matter, soluble sugars, soluble starch, crude fiberand oleoresin increased along with the extension of growth and storage period, while thecontent of soluble protein and free amino acids were higher in the early growth stage, lowerand no significant change in the later growth and storage period. The ginger rhizome withlower dry matter and ginger oleoresin, lighter spicy taste, and less crude fiber, which attainedat157days ago after sowing, was suitable for pickling processing. In91days after sowing，the yield of ginger only8541.4kg/hm2and the average fresh weight of single plant only109.7g, although the rhizome was fresh and tender, the value of commodity production waslittle. After sixty days of storage, dry matter content, soluble starch and ginger oleoresin ofginger rhizome maintained stable, which was suitable for ginger dehydration, starchprocessing and ginger oleoresin extraction.2. With the growth of ginger, new compounds were synthesized, which made thechemical composition of ginger oleoresin increased. Although new compounds weresynthesized during ginger storage period, trace volatile components disappeared with theextension of storage period, which led to the species of chemical composition reduced. butthe major chemical composition of ginger oleoresin was kept steadily at different periods.This study also showed that the relative content of α-Curcumene was high at different periods,which indicated that α-Curcumene was the ginger inherent matter, rather than generated at thestorage process.3. The essential oil content of fresh ginger and seed-ginger increased gradually with theextension of growth period; the content of seed-ginger essential oils higher than fresh ginger at each growth period, while the difference reduced with the extension of growth period, andbasically same at harvest time. The content of ginger essential oil has an increasing trendwithin storage60days, and gradually decreased after storage60days. With the growth ofginger, new compounds were synthesized, which made the chemical composition of freshginger and seed-ginger essential oils increased, and most of the increased chemicalcomposition were monoterpenes with low retention time. During storage of ginger, there wasnot only the disappearance of chemical compositions but also the synthesis of new chemicalcompositions. The essential oil compositions of fresh ginger and seed ginger were basicallysame in each growth period, mainly were α-Curcumene, α-Zingiberene, α-Farnesene,β-Sesquiphellandrene, β-Bisabolol and other sesquiterpene compounds. The main chemicalcompositions of ginger essential oils were same in each storage period, including Camphene,β-Phellandrene, β-Citral, Geranial, α-Curcumene, α-Zingiberene, α-Farnesene andβ-Sesquiphellandrene. The essential oil compositions of fresh ginger and seed ginger indifferent growth stages and the essential oils of different storage time were mainlysesquiterpenes, and the content of α-Zingiberene was the highest.4. The ginger essential oils which extracted by the steam distillation only contained thevolatile aromatic compositions, and the extraction rate was lower, only1.58%. Greasemixture which extracted by the soybean oil, although both contain the volatile aromaticcompositions and the non-volatile gingerol compositions, but less ginger oil compostionswhich not easily separated out. The chemical compositions of ginger oleoresin extracted bysupercritical CO2extraction were rich, not only contained a large number of volatile aromaticcompositions, but also contained a lot of non-volatile gingerol compositions. The gingeroleoresin extracted by ethanol, not only contained the volatile aromatic compositions, butalso contained non-volatile gingerol compositions, but the main compositions wasnon-volatile gingerol compounds.5. The optimum conditions of ethanol extraction were: extraction temperature was60℃,extraction time was5hour, the Solid-liquid rate was1:10, the particle size was40mesh, thevacuum was-0.07MPa. The chemical composition of ginger oleoresin which extracted byethanol at different temperatures was basically same, mainly were: α-Curcumene,α-Zingiberene, Bicyclosesquiphellandrene, β-Sesquiphellandrene, E,E-Farnesal, Zingerone, Acetoxy-6-gingerol,6-Gingerol and other compounds. The chemical compositions of gingeroleoresin increased as the extraction temperature rising, thus, we can deduce that theextraction capacity of ethanol increased as the extraction temperature rising, and the gingeroleoresin contain more extensive chemical composition.