Experimental 2 Determination of phenolic content
1. Extract juice from plant foods from each treatment in experimental 1.
2. Clarify the juice by centrifuging at 4500 rpm for 10 minutes.
3. Mix 0.5 ml clarified juice, 0.5 Folin–Ciocalteu reagent and 0.5 ml distilled water.
4. Add 2.5 ml of 2% sodium carbonate
5. Incubate 20 minutes at ambient temperature under dark condition.
6. Prepare blank by following the procedure No. 3-4 and use distilled water instead
of juice.
7. Turn on the spectrophotometer at least 20 minutes before use.
8. Measure the absorbance at 725 nm by using spectrophotometer.