The blueberry fruit (Vaccinium corymbosum L.) exhibits a high content of bioactive compounds, including anthocyanins, that can be used as pigmenting agents, but they are mixed with sugars, which can hinder their utilization. The objective was to evaluate the use of aqueous two-phase extraction aided by centrifugation to separate bioactive compounds, particularly anthocyanins, from blueberry fruits, considering the reduction of sugars, for their use as pigmenting agents in a food product. A mixture of trisodium citrate (Na₃C₃H₅O(COO)₃; Na₃Cit) and polyethylene glycol ([HO-(CH₂CH₂O)n-CH₂OH]; poly (ethane-1,2-diol); PEG) with a molecular weight of 4 kDa was used. Based on the cloud point method, a binodal diagram was developed. After the evaluation of several systems with composition located on a tie line, conditions were identified to form biphasic systems with phases of equal volume. Passive sedimentation for 0, 15, and 30 min, followed by centrifugation and also passive sedimentation for 24 h without centrifugation, were evaluated. A system with 17.73% Na₃Cit, 21.33% PEG, 30 min of passive sedimentation, and 15 min of centrifugation at 2940× g produced an extract with a high concentration of soluble phenols (0.353 mg/mL) and anthocyanins (0.202 mg/mL) and, likewise, high antioxidant activity (910.0 mmol gallic acid equivalents per mL), with reduced sugar content, which demonstrated to have the potential to pigment food beverages with a reddish tone.

The importance of purple corn (Zea mays L.) varieties has increased due to their high anthocyanin contents both in the kernels and the degrained cob. The aim of this work was to separate anthocyanins from degrained purple-corn cobs to assess their pigmentation potential in food matrices. Two populations of purple corn were used, namely, Negro de Ixtenco (NIX) and Negro de Ixtenco x Negro de Perú (PIX), collected in Juchitepec, Mexico. Flours of degrained cob were obtained with average moisture, crude protein, ash, lipid, crude fiber, and carbohydrate contents of 7.06, 3.70, 4.48, 0.76, 37.73, and 46.27%, respectively. Aqueous biphasic systems composed of a mixture of 7.88% trisodium citrate, 2.63% citric acid, and 50.88% ethanol were applied at an atmospheric pressure of 77,993.0 Pa and 25 °C, aided by ultrasound and orbital agitation. Extracts with anthocyanin concentrations of 33.01 and 39.55 mg per gram of degrained corn cob were obtained from NIX and PIX, respectively. Pigmentation kinetics were assessed in yogurt and corn dough, which had a logarithmic tendency towards hue angles of 2.25 and 333.05°, respectively. A 60% pigmentation relative to the limit was suggested, which required 0.45 and 11.65% of the extract in yogurt and corn dough, respectively. Pigmentation stability was verified in refrigerated yogurt and in cooked corn dough.