The effect of ascorbic acid and H_2O_2 treatment on the stability of anthocyanin pigments in berries

Abstract

Anthocyanins are natural pigments widely distributed in nature. Anthocyanin pigment molecules are a subclass of flavonoids. They are responsible for the red, purple, and blue colors observed in many flowers, fruits, and vegetables. Fruits and berries are the main sources of anthocyanins in nature. Anthocyanins are thought to contribute to the nutritive value of fruits and berries due to their antioxidative, anti-carcinogenic, anti-inflammatory, and anti-angiogenic properties. Anthocyanins can also improve the nutritional value of processed foods by preventing the oxidation of lipids and proteins. As such, identification of agents that can affect the stability of anthocyanins and the protective effect of anthocyanins is very important. In the present study anthocyanin pigment was extracted from 3 different berries (Morus nigra L., Morus alba var. nigra, and Fragaria L.). After soaking and wetting in ethanol (1% acidified), the extracted anthocyanin pigments were exposed to 3 different concentrations of ascorbic acid (AA) (10%, 25%, and 50%) and H_2O_2 (9.31, 18.61, and 27.92 mmol/L). Six groups of anthocyanin solutions were refrigerated and kept in darkness for 63 days, and every 3 weeks anthocyanin absorbance was recorded at 526 nm. AA absorbance decreased relative to the blank in all the treated samples. These results indicate the destructive effect of AA on anthocyanins. In the samples treated with H_2O_2 anthocyanin degradation increased and the intensity of color decreased as the concentration of H_2O_2 increased.