ABSTRACT
This study was conducted to evaluate color and anthocyanin stability of clarified acerola juice (CAJ) as affected by montmorillonite (Mnt) at different concentrations (0-6â¯wt%, dry basis). While non-complexed CAJ suffered noticeable color degradation with time and pH variations, the presence of Mnt (especially at 4-6â¯wt%) not only changed the initial color of CAJ but also made it more stable with time and pH changes. CAJ/Mnt mixtures were ultracentrifuged in order to separate them into supernatants and anthocyanin-complexed Mnt precipitates. The supernatants presented decreasing anthocyanin contents with increasing Mnt concentrations, indicating pigment retention by the precipitates. X-ray diffraction of precipitates showed that Mnt interlayer spacing was increased by increasing anthocyanin/Mnt ratios, corroborating anthocyanin intercalation. FTIR revealed a band at 1530â¯cm-1 ascribed to formation of anthocyanin-Mnt complexes. Moreover, chromatograms indicated the selective adsorption of two compounds by Mnt, which were identified by LC-MS as cyanidin-3-O-rhamnoside and pelargonidin-3-O-rhamnoside.
