Page 340 - Demo

344 PROCEEDINGS OF INTERNATIONAL SCIENTIFIC CONFERENCE ON APPLIED BIOTECHNOLOGYreagent. After 3 min, 1,000 %u00b5L of Na2CO3 (10%) was injected into the mixture and vortex. Cover the solution with foil and kept at room temperature. After 1 hour, absorbance was measured at a wavelength of 700 nm, and the results were expressed as gallic acid equivalents (mg GAE/g) per gram of dry extract.2.4. Total flavonoid contentFlavonoids assay using the aluminum chloride colorimetric method was used to analyze total flavonoid concentration in rice bran extracts. [7, 8]. Quercetin was used as the standard calibration curve. A 1mL of diluted standard quercetin solutions or extracts was mixed with 100%u00b5L of 10% AlCl3, 100%u00b5L of 10% CH3COOK, and 4,300 %u00b5L ethanol. After the vortex, the mixture was incubated at room temperature for 40 minutes, and absorbance was measured at a wavelength of 415 nm against the blank. The outcome data were expressed as quercetin equivalents in milligrams per gram (mg QE/g) of dry extract.2.5. DPPH scavenging activityThe scavenging activity of rice bran extracts against DPPH radical was assessed following the method of Blois [9], with some modifications. Briefly, 200 %u00b5L extracts or positive control (ascorbic acid) were mixed with 2 mL 0.1mM DPPH methanol solution. After the vortexing, the solutions were kept in the dark for 0.5 hours at room temperature. A wavelength of 517 nm was used to measure the absorbance of the mixture. Calculate scavenge DPPH radical using the following equation: DPPH radical scavenging activity % = (Abscontrol - Abssample) x 100 / Abscontrolwhere Abscontrol is the absorbance of DPPH radical in methanol; Abssam]ple is the absorbance of DPPH radical solution mixed with