Measurement of the Relative Content of Fruit Flavonoids and Anthocyanins

Two grams of fruit tissue was ground thoroughly in 2 ml of 1% pre-chilled HCL–methanol solution. Samples were washed with 5 ml of HCL–methanol solution, incubated on ice for 20 min, and centrifuged at 4°C, 10,000 rpm, for 10 min. The absorbance at 325, 530, and 600 nm, respectively, of the supernatant was measured. The absorbance value of each gram of tissue at a wavelength of 325 nm represented the relative content of flavonoids; the difference between the absorbance values at wavelengths of 530 and 600 nm, respectively, represented the relative content of anthocyanins (U):