The use of colors in food industry is essential for the creation of new products or their improvement. As an important pigment group, anthocyanin could be used as a natural coloring pigment in foods. This study aims at exploring strategies that result in color stability of anthocyanin in pear‐shaped variety of blueberry (Cornus mas–Macrocarpa). In this study, the effects of different pH values (1, 2, 3, 4) as well as various concentrations (0, 120, 240, 480, 960 mg/L) of five copigments, including tannic, caffeic, benzoic, and coumaric acids, on anthocyanin copigment complexes (ratio 1:1) were investigated. The studied copigments were tannic, caffeic, benzoic, and coumaric acids. Anthocyanin was influenced by the highest concentration of 960 mg/L copigment in the presence of different pHs. Five groups were considered, one of which contained anthocyanin without copigment and the rest consisted of copigments. To evaluate the response of copigmentation through spectrophotometer, absorbance from samples was measured after 30 min of adding copigment to anthocyanin in the range of 450–600 nm wavelengths. The results showed that caffeic acid possessed the greatest anthocyanin stability compared to other copigments and it was the best copigment. An increase in the concentrations of copigments led to a higher level of anthocyanin stability and changes in hyperchromic and bathochromic. Moreover, the results revealed that the strongest hyperchromic effect for all organic acids was observed in pH 2, and the strongest bathochromic changes were observed in pH 4.

In this study, the effects of different pH values and co-pigments, including tannic, caffeic, benzoic, and coumaric acids, in various concentrations on anthocyanin co-pigment complexes (ratio 1:1) were investigated. The anthocyanin was extracted from a round sweet variety of blueberry and subjected to the highest co-pigment concentration (960 mg/l) at different pH values. The results showed that caffeic acid produced the highest stability of anthocyanin compared to the other co-pigments. In addition, benzoic acid had the lowest hyperchromic and bathochromic changes. A positive correlation was found between the co-pigment concentrations and the stability of anthocyanin as well as hyperchromic and bathochromic changes. The results also demonstrated that higher pH values resulted in further destruction of anthocyanin. Furthermore, the absorption rate of anthocyanin in the anthocyanin-co-pigment complex within lower pH values was more compared with the higher ones. The strongest hyperchromic and bathochromic effects for all organic acids were observed in pH values 1 and 4, respectively. It can be concluded that among the tested copigments, caffeic acid was the best co-pigment, while benzoic acid was the weakest, which was not suitable for anthocyanin in the round sweet variety of blueberry.