大米中脂肪检测方案(分子荧光光谱)

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Measurement of Rice (3D Fluorescence Spectra) INTRODUCTION Rice， when irradiated by ultraviolet ray， emits a blue fluorescence originating from fat， etc. The fluorescence intensityfrom rice increases as the oxidation progresses due to the deterioration of rice and therefore，the fluorescence isrecently expanding its use as the index to evaluate the freshness. The measurement results of fluorescence spectra ofnew rice and old rice are introduced here. By measuring the 3D fluorescence spectrum， the difference in thefluorescence properties of new and old rice was found.F-7000 fluorophotometer， with the fastest scan speed for the instrument class， allows the high-throughput measurement of the 3D fluorescence spectrum. SAMPLE ACCESSORY SAMPLE NAME：Rice Solid Sample Holder (P/N： 650-0161) S20 Standard Cells with U-Shape BottomProducts of GL Sciences Inc. (GL Sciences Cat. No.6210-21203) INSTRUMENT CONDITIONS INSTRUMENT ： F-7000 RESPONSE ： Auto FULLSCALE ： 150 EX BANDPASS ： 5nm EM FILTER ： 290 DIVISION NUMBER ：1 EM BANDPASS ： 5nm PHOTOMULTIPLIER ： R3788 SCAN SPEED ： 60000nm/min PHOTOMULTIPLIER VOL. ： 400 V Em (nm) Em (nm) 3D Fluorescence Spectrum 3D Fluorescence Spectrum of of New Rice Old Rice KEY WORDS Bio/Medical Science/Food/Pharmaceutical，Food， Food Chemistry， Fluorophotometer (FL) New Rice， Old Rice， Freshness， 3D Fluorescence Spectrum， 3D， FL， F-7000 Sheet No.FL090013-01B Measurement of Rice (Fluorescence Spectra) INTRODUCTION When new rice and old rice were compared， it was found that the fluorescence peak of the old rice at the excitationwavelength of 310 nm shifted to a longer wavelength of 444 nm from 428 nm， the fluorescence peak wavelength ofnew rice. The peak shape of the old rice was also found to be sharper than that of new rice. The measurement wasperformed by placing about 10 grains of the rice in a wide width standard cell with U-shaped bottom (20 mm × 40 mmx 10 mm) and mounting the cell on the solid sample holder. SAMPLE ACCESSORY SAMPLE NAME ： Rice Solid Sample Holder (P/N： 650-0161) S20 Standard Cells with U-Shape Bottom Products of GL Sciences Inc. (GL Sciences Cat. No.6210-21203) INSTRUMENT CONDITIONS PEAKS (nm) INSTRUMENT ： F-7000 RESPONSE ： Auto EM WAVELENGTH ： 310 nm EM FILTER ： 350 EX BANDPASS ： 5 nm PHOTOMULTIPLIER ： R3788 EM BANDPASS ： 5nm PHOTOMULTIPLIER VOL.： 400 V SCAN SPEED ： 240 nm/min New rice 1 ：428 Old rice1：444 400 500 600 300 400 500 600 Em (nm) Em (nm) Fluorescence Spectrum Fluorescence Spectrum of New Rice of Old Rice KEY WORDS Bio/Medical Science/Food/Pharmaceutical，Food， Food Chemistry， Fluorophotometer (FL) New Rice， Old Rice， Freshness， Fluorescence Spectrum， Excitation Spectrum， FL， F-7000 Sheet No. FL090013-02B +Integrating sphere 1st 45.38 2nd 2nd 43.4 3rd 42.05 Mean (GL Sciences Cat. No.6210-21203) 113.3 43.6 SD 1.7 INSTRUMENT ：F-7000 RESPONSE ： Auto EM WAVELENGTH ： 310nm EM FILTER ： 350 EX BANDPASS ：5nm PHOTOMULTIPLIER ： R3788 EM BANDPASS ： 5nm PHOTOMULTIPLIER VOL. ： 400V SCAN SPEED ： 240 nm/min 3.8% Em (nm) Em (nm) Solid Sample Holder (Old Rice) Integrating Sphere Accessory (Old Rice) KEY WORDS Bio/Medical Science/Food/Pharmaceutical， Food， Food Chemistry， Fluorophotometer (FL) New Rice， Old Rice， Freshness， Integrating Sphere， Fluorescence Spectrum， Excitation Spectrum， FL， F-7000 Sheet No. FL090013-03B Hitachi High-Technologies Corporation 大米中的脂肪受到紫外光激发时，会发出蓝色荧光。随着储藏时间增加，大米中的脂肪等物质会发生转化，荧光会产生红移，因此可以用荧光特性作为评价大米新鲜度的指标。