1. L/O/G/O Antioxidant components and properties of five long-grained rice bran extracts from commercial available cultivars in Thailand from Food Chemistry 111 (2008) 汇报人：胡冬梅 指导老师：薛照辉副教授

2. content 1 2 3 Introduction Materials and methods Results and discussion

3. 1. Introduction 1. Lower of blood cholesterol 2.Decrease atherosclerosis disease 3. Laxative effect 6. Prevent urinary stones 4. Anticancer 5. Restrain the melanin

4. 1. Introduction rice bran higher alcohols sterols gamma-oryzanol tocotrienols phenolic compounds phenolic compounds tocopherols Rice bran powder has a high nutritive value

5. 1 1 Mill rice grain sieve to separate grain from rice bran Rice bran was ground, then passed through sieves heated at 100 ℃ for 15 min to inactivate endogenous lipase Rice bran powder (10.0 g) was extracted with methanol (150 ml) for 12 h in an electrical shaker at room temperature. 2 2 3 3 The extract was filtered through filter paper and the solvent was removed. 2. Materials and methods 4 4 The extracts were combined ， then evaporate under vacuum using a rotary evaporator 5 5 6 6 The residual crude methanolic rice bran extract was weighed and stored at 20 ℃ under a nitrogen gas stream RB-1 RB-2 RB-3 RB-4 RB-5 twice again

6. 2.1 Determination of TPC Rice bran extract was dissolved methanol. Rice bran extract (250 µl) mix with 500µl Folin–Ciocalteu reagent and a further 6.0 ml of distilled water. The mixture was shaken vigorously and 2.0ml Na 2 CO 3 ( 15%w/v ) were added and the mixture was again shaken vigorously for 2 min. The final volume was 10.0 ml with distilled water. The mixture was left to stand for 2 h at room temperature. The absorbance at 750 nm was measured by using a UV– vis spectrophotometer 1 2 3 4

7. Rice bran extract was dissolved in methanol. 250µl+ distilled water 1.25 ml + 75 µl 5%NaNO 2 room temperature for 6 min step 1 step 2 step 3 150µl of 10% AlCl 3 were added. This mixture stand for a further 5 min. 0.5 ml of 1 M NaOH was added. The solution was shaken vigorously. The absorbance at 510 nm was measured with a UV–vis spectrophotometer 2.2 Determination of TFC

8. 2.3 Determination of γ-oryzanol content filter through a syringe filter with PTFE( 聚四氟乙烯 ) Rice bran extract 100.0 mg was dissolved in 1.0 ml of methanol RP-HPLC mobile phase mobile phase 流动相： 甲醇：乙腈：二氯甲烷： 醋酸 (50:44:3:3 v/v/v/v) 流速： 1.0 ml/min UV–vis detector 330 nm

9. 2.4 Determination of total tocopherol, total tocotrienol, tocopherol and tocotrienol isomer contents Tocopherol isomer content of rice bran extract was determined by RP-HPLC Agilent 1100 series RP-18 GP column 流动相： 甲醇：乙腈：二氯甲烷（ 50 ： 44 ： 6 ， v/v/v ） 流速： 1ml/min 荧光检测器 激发和发射波长分别为 290nm 和 330nm

10. 0.5 ml sample solution in methanol was mixed with 2.5 ml 0.5 mM methanolic solution of DPPH. The absorbance was measured at 517 nm against a blank, using a UV–vis spectrophotometer The mixture was shaken vigorously and incubated for 30 min in the dark at room temperature. 2.5 Determination of DPPH radical-scavenging activity DPPH scavenging ability(%) = [1 - Absorbance sample /Absorbance control ]×100

11. Trichloroacetic acid (10%, 5.0 ml) was added to mixture, then centrifuged at 6000 g for 10 min Rice bran extract in methanol (2.5 ml) was mixed with 2.0 M sodium phosphate buffer at pH 6.6 (2.5 ml). The dilute sample was then mixed with 5.0 ml of 1% potassium ferricyanide and the mixture was incubated at 50 ℃ for 20 min. The upper solution (5.0 ml)was mixed with distilled water (5.0 ml) and 1.0 ml ferric chloride (1.0%) was added The absorbance was measured at 700 nm BHT was used for comparison 2.6 Determination of reducing power 1 2 3 4

12. 2.7 Determination of ferrous ion-chelating activity The reaction mixture (2.0 ml) contained hexamine (30 mM), KCl (30 mM) and FeSO 4 (9 mM) was added each rice bran extract in methanol(2.0 ml) and 200µl of 1 mM TMM( 三羟甲基三聚氰胺 ) The mixture was shaken vigorously and left to stand for 3 min at room temperature. Absorbance of the mixture was determined at 485 nm against a blank. (Na 2 EDTA ） was used for comparison.

13. 2 64 5 Rice bran extract in methanol (200 µl) Stand in darkness at 37 ℃ for15 h BHT was used for comparison 6.0 ml of 60% methanol were added 4.0 ml linoleic acid (10 mM) in Na3PO4 buffer (0.2 M) Absorbance measured at 234 nm against a blank 13 2.8 Determination of lipid peroxidation inhibition % of inhibition of lipid peroxidation = [1-Absorbance sample /Absorbance control ]×100

14. 3. Results and discussion ▲ ▼ not significantly different ▲ ▼

15. 3. Results and discussion a mixture of phytosteryl and campesteryl ferulates have antioxidant properties in many types of in vitro model systems Different forms of tocopherol exhibit different antioxidative effects T↑,δ ˃ γ ˃ β ˃ α 生育酚的抗氧化作用是通过 传递一个氢原子到过氧化脂质 自由基从而形成脂质氢过氧化物 和生育酚自由基

16. 3. Results and discussion BHT RB-2 RB-3 RB-5 RB-4 RB-1 ▲ ▼ BHT ˃ RB-2 ˃ RB-1 ˃ RB-3 ˃ RB-5 ˃ RB-4

17. 3. Results and discussion BHT ˃ RB-2 ˃ RB-1 ˃ RB-3 ˃ RB-5 ˃ RB-4

18. 3. Results and discussion EC 50 ，半最大效应浓度 是指能引起 50% 最大效应的浓度。

19. 3. Results and discussion Na 2 EDTA RB-2 RB-1 RB-3 RB-5 RB-4

20. 3. Results and discussion BHT RB-2 RB-4

21. 抗氧化能力的高 低与多酚化合物， 黄酮，生育酚， 生育三烯酚和谷 维素的含量成正 比。 米糠中存在一定量的 多酚化合物，黄酮， 谷维素，生育酚和生 育三烯酚，表现出不 同程度的抗氧化能力。 3. Results and discussion 不同商业品种米糠 中抗氧化物质的含 量有很大差异，这 可以作为食品加工 中原料选择的依据。

22. L/O/G/O Thank You!