The influence of the chemical structure and the presence of ascorbic acid on anthocyanins stability and spectral properties

The loss of color pigment is an important quality factor of food products. Anthocyanins are a large group of natural water-soluble pigments that are responsible for red, blue and purple colors in many food products thus their deterioration is an important factor in loss of color. This work aimed to systematically study the influence of anthocyanins structure (by increasing the size of the conjugated sugar) and the presence of ascorbic acid on their stability and spectral properties during storage at two pH levels relevant to medium and high acid foods (1). Anthocyanins (cyanidin, cyanidin 3-O-β-glucoside and cyanidin 3-O-β-rutinoside) displayed first-order degradation rates, presenting higher stability in acidic medium and enhanced stability with increasing size of conjugated sugar. The addition of ascorbic acid resulted in significantly enhanced degradation. Changes in spectral properties presented a decrease in typical color intensity and pointed towards formation of degradation products. Identification and formation kinetics for degradation products were obtained by high performance liquid chromatography system-mass spectrometry.

(1) Levy, R.; Okun, Z.; Shpigelman, A. The Influence of Chemical Structure and the Presence of Ascorbic Acid on Anthocyanins Stability and Spectral Properties in Purified Model Systems. Foods 2019, 8 (6), 207.