Determination of polyphenol content in grape seeds

Determination of polyphenol content in grape seeds

1. F-D reagent: add 750 mL distilled water to a 1000 mL flask, then add Na 2 WO 4 ? 2H 2 O 100 g, 20 g of phosphomolybdic acid and 50 mL of H 3 PO 4 (85%), stopper tightly with a rubber stopper, insert a clean 50-100 cm long thin glass tube into the stopper, insert the solution into the lower end of the glass tube, and place the flask Place on an adjustable electric furnace (with an asbestos mesh) and fix it on an iron plate. Boil and reflux for 2 hours. After cooling, dilute with distilled water to 1000 mL. China Plant Extract Forum!o'e#O7h8P'}$| w

2. 10% Na 2 CO 3 solution: Weigh 100g Na 2 CO 3, dissolve it in 900ml distilled water to a constant volume, and filter. www.plantextra.com+L1c#Q9v5D.j$Q3O$A)b$u

3. 0.1 mg/mL tannic acid stock solution: accurately weigh 10 mg of tannic acid and dissolve it in distilled water. Then adjust the volume to 100 mL. Ready for use.

;a4M6K9v-U China Plant Extract Forum Experimental Steps

0W3d-s'R9A-c!t$tPlant Extract Home, Plant Extract Space, China Plant Extract Forum, Plant Extraction Forum, Plant Extraction Network 3. Sample Measurement: Weigh an appropriate amount of grape seed extract into a 50ml volumetric flask, add 30ml methanol to dissolve, ultrasonicate for 30 minutes, absorb 1 mL of supernatant, and place in 60 mL of distilled water. In a 100 mL volumetric flask, add 5 mL of F-D reagent and 25 mL of 10% Na 2 CO 3 solution, adjust the volume to 100 mL with distilled water, and shake well. After 30 min, the optical density value was read using a spectrophotometer at a wavelength of 760 nm.

&H$E4N$]:k1I4. To draw the standard curve, take the newly prepared 0.1 mg/mL tannic acid stock solution 0, 1.0, 2.0, 4.0, 6.0 and 8.0 mL and put them into 100 mL respectively. into the volumetric flask, then add 5 mL F-D reagent and 10 mL saturated Na 2 CO 3 solution, adjust the volume to 100 mL with distilled water, and shake well. After 30 min, the optical density value was read using a spectrophotometer at a wavelength of 760 nm. Draw the standard curve with the optical density value as the abscissa and the tannic acid concentration as the ordinate.