| The research direction of this thesis is analysis of nutrient component in rice bran and studies on its application. Taken rice bran as the research object, HPLC method had been built up to measure water-soluble vitamins in rice bran; Rice Bran Polysaccharides had been abstracted in rice bran ; a study model of ultraviolet damnification of hair had been build and had usedthis model studying the activity Resisting UVB-UltravioletIn chapter1, High performance liquid chromatography (HPLC) has been applied for the simultaneous determination of four kinds of water-soluble vitamins including vitamin B1, vitamin B6, nicotinic acid, and nicotinamide in rice bran. The separation was performed on a Hypersil C18 column (250 cm×4.6mm i.d., 5.0μm) with a mobile phase of 0.1% H3PO4- methanol (88:12, V/V) at flow rate of 0.6 mL /min, and detection wavelength was 266 nm. Four vitamins had good linearity in the range of 6.0×10-7 g/mL - 8.5×10-5 g/mL, with detection limit of 4.3×10-7 g/mL, 3.4×10-6 g/mL, 3.2×10-7 g/mL and 3.0×10-7 mg/L for vitamin B1, vitamin B6, nicotinic acid and nicotinamide, respectively. Baseline separation of four vitamins can be achieved within 8 minutes. Without complicated pretreatment, four analytes in rice bran samples, as well as extracts from rice with water, were successfully determined with recoveries between 96.0% and 99.9%. The approach could be applied to determine water-soluble vitamins in complicated samples owing to simplicity, convenience, sensitivity and accuracy.In chapter 2, extraction methods including microwave extraction, dedoction and ultrasonic extraction had been studied to extract polysaccharides in rice bran. The methods for removing proteins by trichloroacetic acid and Sevage method, as well as for removing amylum by one step assimilation and two steps were also investigatated. Microwave assistant extraction has been applied for extraction polysaccharides in rice bran. The content of polysaccharides were determined by improved vitriol -phenol method. The optimum technics were the material-water ratio of 1:10, microwave assistant extraction for 30 mins for two times under 50% firepower. It was proved thatα-amylase could wipe off amylum effectively by two steps, and trichloroacetic acid method was appropriate to wipe off albuminoid. And the ethanol concentration was 30%, the extraction rate of the water-soluble polysaccharides of rice bran was 1.41%.In chapter 3, a fluorescence spectrometry method has been developed to determine tryptophan in hair, and applied to evaluate hair damnification under UVB ultraviolet. 5.5 mol L-1 NaOH solution containing 0.5% soluble starch was used for hydrolysis of the hair samples. In pH 10.5 buffer of NaH2PO4-NaOH, the fluorescent intensity of tryptophan was determined at 280 nm as excitation wavelength and 360 nm at emission wavelength. The linear range of tryptophan was from 8.0×10-6 g/mL to1.75×10-6 g/mL. The detection limit of 1.6×10-8 g/mL and the recoveries ranged from 96.3% to 100.3% showed that the method was sensitive and accurate. With the increase of the irradiation time with UVB ultraviolet, tryptophan in hair decreased accordingly. During 28 days irradiation, tryptophan in hair was lost by 18.8%. This method could be recommended to measure ultraviolet damnification of hair. In chapter 4, rice bran polysaccharides were applied for protection hair from UV damnification. Tryptophan in hair was determined with fluorescence spectrometry method, the contents of tryptophan were applied to evaluate hair damnification due to UVB ultraviolet under protection of rice bran polysaccharides. For simulating fixature, hair was besprinkled with mixture solution of Rice Bran Polysaccharides and Tween-80 , naturally dryed, then radiated under UVB ultraviolet. It was shown that though the content of tryptophan in hair with protection of rice bran polysaccharides decreased, it was obviously higher compared with the hair besprinkled only with Tween-80, which prove rice bran polysaccharides might have effect on resisting UVB-Ultraviolet.
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