Potential use of new Colombian sources of betalains. Colorimetric study of red prickly pear (Opuntia dillenii) extracts under different technological conditions

A new source of betalains to be used as natural colorant (Opuntia dillenii) has been studied. The stability of O. dillenii extracts indifferent pHs and temperatures over time has been scrutinized. Our attention was focused on differential tristimulus colorimetry and betalain content related to the color, not previously conducted in conjunction in that raw material. On the basis of the results, cold storage conditions (4 degrees C) were optimal to maintain as possible the initial red color (h(ab)), lightness (L*) and betalain content of the O. dillenii extracts, regardless of pH. Highly-acidic extracts (pH 4) manifested a significantly (p <0.05) lower colorant intensity (C-ab(*)) and betalain concentration (around 25% and 35%, respectively), with a clearer tendency toward yellowish tonalities (values of ha from 45 degrees to 90) over time. Furthermore, visually perceptible color changes (Delta E-ab(*) >3) were induced among very acid (pH 4) and low-acidic (pH 5 and 6) extracts at each temperature. (C) 2015 Elsevier Ltd. All rights reserved.