Color properties and stability of betacyanins from Opuntia fruits.
The colorant properties of pigments from Opuntia stricta, Opuntia undulata, and Opuntia ficus-indicafruits were studied. The pigments were extracted with different solvents and identified by high-performance liquid chromatography. On the basis of their visible light spectra, the pigments were identified as betalains. In O. undulata and O. ficus-indica fruits, both betacyanins and betaxantins were identified, while in O. stricta fruits only betacyanins (betanin and isobetanin) were detected. O. stricta fruits showed the highest betacyanin content (80 mg/100 g fresh fruit). The thermal stability of the pigment extracts was dependent on the pH, with the maximum stability being at pH 5, as expected for betacyanins. At this value and a storage temperature of 4 degrees C, a deactivation half-life time of more than 1 year, with no added stabilizers, was determined. According to these studies, cactus pears from O. stricta may well be considered as a potential source of natural red colorants.
Castellar
Rosario
R
Department of Chemical Engineering, Higher Technical School of Agronomical Engineering, Polytechnic University of Cartagena, Paseo Alfonso XIII 44, E-30203 Cartagena (Murcia), Spain.
Obón
José M
JM
Alacid
Mercedes
M
Fernández-López
José A
JA
D050858:Betalains; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003116:Color; D005505:Food Coloring Agents / Q000032:analysis / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D029747:Opuntia / Q000737:chemistry*; D010860:Pigments, Biological / Q000032:analysis / Q000302:isolation & purification*; D010936:Plant Extracts / Q000032:analysis; D000644:Quaternary Ammonium Compounds; D013696:Temperature
D005505:Food Coloring Agents; D010860:Pigments, Biological; D010936:Plant Extracts; D000644:Quaternary Ammonium Compounds; D050858:Betalains