Stability of encapsulated and non-encapsulated anthocyanin in yogurt produced with natural dye obtained from Solanum melongena L. Bark

Abstract

Abstract This research evaluated the stability of non-encapsulated and spray-dried encapsulated anthocyanin from Solanum melongena L. bark as a natural dye in yogurts. Anthocyanin was extracted using 70% cereal alcohol acidified with citric acid at pH 2.0. Extract spray-drying was defined using the experimental design (22), with drying temperature (°C) and carrier concentration (Gum arabic) as independent variables. The response variable adopted was the total monomeric anthocyanin content. The following analyses were performed: color; total monomeric anthocyanins; total phenolic contents; antioxidant activity using the DPPH• (1,1-diphenyl-2-picrylhydrazyl) radical; pH; and acidity. Yogurt degradation constant, half-life, and color retention percentage of anthocyanin added to yogurt were calculated. The total monomeric anthocyanin value found in the extract was 67.21 mg 100g-1 of bark. Natural non-encapsulated and encapsulated dye extract were added to yogurt at concentrations of 1.0; 1.5; and 2 g extract/100 mL yogurt. Average pH values after addition of anthocyanin extract ranged from 3.60 to 3.87. Acidity was 1.04% in natural yogurt (time zero), while 1%; 1.5%; and 2% samples showed 1.4; 1.7; and 2.05% and 1.18; 1.29; and 1.47% acidity in non-encapsulated extract added to yogurt and encapsulated extract added to yogurt, respectively. Anthocyanin content decreased during storage using non-encapsulated extract, remaining constant in encapsulated extract added to yogurt. The three formulations showed increased L* at thirty days, with discoloration being related to decreased anthocyanin content. DPPH• radical scavenging activity decreased during the 30 days of storage. The content of phenolic compounds ranged from 106.01 to 239.90 mg GAE 100 g-1 of yogurt in non-encapsulated extract added to yogurt, and from 225.17 to 291.98mg GAE 100 g-1 of encapsulated extract added to yogurt. Extract encapsulation is indicated because it provides high anthocyanin stability.