本研究利用修正索氏萃取法(MSE)及管柱層析法(CC)從米糠油(RBO)中分離出一文獻未曾報導過之未知物(UC)。MSE可將UC、鯊烯及植物脂肪酸固醇酯濃縮於一非極性部份中。將此一非極性部份以矽膠CC進一步分離UC可得到純度為94.37%之UC。經由TLC、GC、GC/MS及NMR分析得知此UC含苯環並與酯鍵結於鄰位，其分子式暫定為C30H50O4 (分子量474).
與其他植物油比較，RBO含有較多之生物活性物質。本研究利用二階段結晶法從RBO中分離米糠醇。於下述操作條件下：溶劑(甲醇/丙酮, 7/3, v/v) 與RBO比 = 40/1 (mL/g)、溫度 = -60oC、時間15 h, 第一階段結晶可將米糠醇濃度從2.76 %增加至13.68 %。在室溫(20.5 ± 1.5oC) ±下操作第二階段結晶三天可得到純度95.18%、回收率42.40%之米糠醇。若於第二階段結晶時加入己烷及進一步冷卻可將回收率從42.40%增加至58.74%。在從RBO分離米糠醇之過程中可得到一副產物LP2。LP2含59.19%FFAs、19.31%甘油酯及21.5%生物活性物質。將LP2中之FFAs及甘油酯經酸催化與甲醇反應轉化成生質柴油，再將生質柴油分離後可於殘餘物中得到濃縮之生物活性物質。在酸催化與甲醇反應時，催劑量、甲醇與LP2比、反應時間等因素會影響生物活性物質之回收率。

A process which comprises modified soxhlet extraction (MSE) followed by column chromatography (CC) was developed in this work for the isolation of a previously the unknown compound (UC) from rice bran oil (RBO). Modified soxhlet extraction enriched the UC along with squalene, and fatty acid steryl esters (FASEs) in a non-polar lipid fraction. This fraction was then subjected to a silica gel CC to isolate the UC. The unknown compound with a purity of 94.37% was obtained. Results of TLC, GC, GC/MS and NMR analysis indicate that the UC contains benzene ring which binds ester at the ortho position. The molecular formula of UC was tentatively determined as C30H50O4 (M. W. 474).
Compare to other vegetable oils, RBO contains higher level of oryzanol. A two-stage crystallization was used for isolating oryzanol from RBO. The first-stage crystallization operated at a ratio of solvent (methanol/acetone, 7/3, v/v) to RBO = 40/1 (mL/g), temperature = -60oC for 15 h increased oryzanol content from 2.76% to 13.68%. Fractions rich of oryzanol was subjected to a rotary evaporator to obtain supersaturated solution (LP1). This supersaturated solution then applied to the second crystallization. The second-stage crystallization operated at ambient temperature (20.5 ± 1.5oC) for three days, oryzanol with a purity of 95.18% and a recovery of 42.40% was obtained. Adding anti solvent (hexane) of 20 mL in LP1 after crystallization at 20.5 ± 1.5oC for 24 h and further cooling (5oC) for another 48 h can increase the recovery of oryzanol from 42.40% to 58.74%. A side product (LP2) was generated in the isolation of oryzanol from RBO. LP2 contains 59.19% free fatty acids (FFAs), 19.31% acylglycerols (AGs) and 21.5% bioactive compounds. Converting FFAs and AGs into biodiesel (BD) via acid-catalyzed methanolysis, followed by separation of BD enriched bioactive compounds in the residue. Loss of bioactive compounds during acid-catalyzed methanolysis was affected by factors such as amount of catalyst, ratio of methanol to LP2, reaction time etc. As the amount of catalyst increases, the content and recovery of most bioactive compounds decreased. The similar phenomena happened by increasing the mass ratio of methanol to LP2 and prolonged the reaction time. However, loss of bioactive compounds decreased when nitrogen purging during acid-catalyze methanolysis.

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