Vitamin C content of the samples was evaluated by pouring 20 ml of 0.4% oxalic acid into each of the samples (1 g each). The mixture was filtered and indophenol reagent was reacted with the filtrate in the ratio of 9 to 1 (filtrate: indophenol). Vitamin C standard (ascorbic acid) was prepared using the same procedure for the samples. The final concentration of 1 mg/ml was made for both standard and samples. Serial dilution of the concentration was later done giving concentration levels 1, 0.8, 0.6, 0.4 and 0.2 mg/ml. The absorbance of the resulting sample solution and standard was read at 520 nm. Vitamin C content in milligram ascorbic acid/100 g DW of the each of the samples was extrapolated from the standard curve.
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