ABSTRACT:
Anthocyanins stability is enhanced by the formation of complexes with colour free molecules named as copigments. Different organic acids, amongst other groups of compounds, can serve as copigments for anthocyanin moieties. In this paper, the evaluation of tannic acid as a potential anthocyanin copigment was performed on Cabernet Sauvignon grape skins crude extract obtained from Syrian town of Habran in Swiada. Furthermore, the stability of anthocyanins in the grape extract and their interaction with tannic acid were investigated when stored under different conditions in the presence of oxygen (from air) i.e. in the dark at 4±1 °C and 29±2 °C, pH (3.0 and 4.0), and at 29±2 °C, pH (3.0 and 4.0), in the presence of light (2,500 lumens). The half-life of the anthocyanins in all treatments/conditions was estimated. The results of the spectrophotometric study (??, ?A) indicated that a significant interaction between tannic acid and the crude extract of anthocyanins has occurred, suggesting a copigmentation effect. Tannic acid addition at (1:1 w/v, in the studied conditions) increased significantly (p< 0.05) the half-life and therefore the stability of anthocyanins. The findings of this study support the use of tannic acid as a stabilizer and copigment of anthocyanins.