Akio Tanaka

Isolation of methyl ferulate from rice bran oil

An unknown ferulate in rice bran oil was isolated by column chromatography. The ferulate was identified as methyl ferulate by TLC, GLC, UV, IR, NMR and mass spectrometry.

4-Desmethylsterol composition of steryl glycoside in oil palm leaf

4-Desmethylsterols of steryl glycoside (SG) of oil palm leaves were separated and analyzed by GLC on both OV-1 (0.5 μm) and OV-17 (0.25 μm) capillary columns of the same size (25 m × 0.25 mm i.d.) under the same conditions. The extent of separation of each 4-desmethylsterol of SG was essentially the same on both columns. Campesterol, stigmasterol, sitosterol, 7-stigmastenol and avenasterol were found, in addition to a traces of cholesterol and brassicasterol. The compositions of these sterols by the OV-17 column were 4.8, 8.9, 84.2, 1.1, and 1.0 %, respectively

Thermal Properties of Several Ferulates

The thermogravimetric analyses, changes of ultraviolet spectra by heating, and thermal transitions of several ferulates were investigated.The results of thermogravimetric analyses of cholesteryl ferulate, sitosteryl ferulate, and trimethylysteryl ferulate showed that the thermal stabilities of sitosteryl ferulate and trimethylsteryl ferulate were little inferior to that of cholesteryl ferulate. Although, the thermogravimetric analysis curves of sitosteryl ferulate and trimethylsteryl ferulate were similar to that of cholesteryl ferulate.Under various conditions of heating, the stabilities of ferulates were examined by determining the intensity of absorption at 315nm. Sitosteryl ferulate was more unstable than campesteryl ferulate, stigmasteryl ferulate, and trimethylsteryl ferulate, and cholesteryl ferulate was most stable among the five kinds of ferulates. When the ferulates were heated at 200°C for 4 h in the air atmosphere, the decrease of their absorption by heating was as follows : Cholesteryl ferulate, 35%; sitosteryl ferulate, 65%; campesteryl ferulate, 55%; stigmasteryl ferulate, 50%; and trimethylsteryl ferulate, 55%. The thermal decomposition products of cholesteryl ferulate that was heated at 200°C for 4 h in the air atmosphere were investigated. Cholesterol, vanillin and ferulic acid from the decomposition products were confirmed by TLC, GLC, UV, and mass spectrometry. When a crude rice bran oil containing the ferulates was heated at 180°C for 2 h in the air atmosphere, the absorption maximum of the oil at 291nm was disappeared, and shown newly at 270nm.The heats of transition of four steryl ferulates, trimethylsteryl ferulate and their acetyl derivatives, and oryzanol which is a mixture of ferulates have been evaluated. The order of increase to heats of fusion for steryl ferulates were sitosteryl ferulate, stigmasteryl ferulate, cholesteryl ferulate and campesteryl ferulate, and the result indicates that is in proportion to melting point of each ferulates. The heats of fusion of acetyl derivatives of ferulates were higher than those of corresponding ferulates. There are presence of shoulders in the peak of the melting curves of acetyl derivatives of cholesteryl ferulate and stigmasteryl ferulate, and the melting curves differ from those of corresponding ferulates.