Determination of color, pigment, and phenolic stability in yogurt systems colored with nonacylated anthocyanins from Berberis boliviana L. as compared to other natural/synthetic colorants.

Anthocyanins are of interest to the food industry because of their antioxidant power, attractive color, and stability in high acid foods. Powder from the Peruvian berry Berberis boliviana Lechler, rich in nonacylated anthocyanins (7% to 8% dry weight), was incorporated into yogurt samples containing 3 different fat levels. Color (CIE L, a, b, chroma, and hue angle), pigment (monomeric anthocyanin and polymeric color), and total phenolics were monitored over 8 wk of storage and compared to yogurt treatments containing purple carrot acylated anthocyanins, red beet betalaines, or FD&C Red nr 40. Anthocyanin profiles were analyzed by HPLC coupled to photodiode array and mass detectors. Color of yogurt containing B. boliviana anthocyanins at 20 mg cyanidin-3-glucoside (cy-3-glu) equivalents/100 g yogurt (L*= 65, chroma = 14, and hue angle = 335 degrees ) was similar to commercial blueberry yogurt (L*= 65, chroma = 10.5, and hue angle = 341 degrees ). High color, pigment, and phenolic stability were observed in yogurts colored with B. boliviana, independent of the fat matrix. Acylated anthocyanins from purple carrot extracts exhibited increased stability with higher fat content. Anthocyanin degradation followed 1st-order kinetics. Pigment half-lives were 125 and 104 d for nonacylated anthocyanins at 10 and 20 mg cy-3-glu equivalents/100 g yogurt and 550.2, 232.6, and 128.9 d for acylated anthocyanins at 20 mg of cy-3-glu equivalents/100 g of 4%, 2%, and 0% fat yogurt. Addition of B. boliviana whole berry powder to yogurt matrices produced an attractive, stable anthocyanin-rich product, eliminating the need for industrial colorant extraction.