Stabilizing effect of montmorillonite on acerola juice anthocyanins

Abstract

This study was conducted to evaluate color and anthocyanin stability of clarified acerola juice (CAJ) as affected by montmorillonite (Mnt) at different concentrations (0-6 wt%, dry basis). While non-complexed CAJ suffered noticeable color degradation with time and pH variations, the presence of Mnt (especially at 4-6 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 1530 cm 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.

Montmorillonite as a reinforcement and color stabilizer of gelatin films containing acerola juice

“…No evidence has been found from FTIR spectra to support complexation of anthocyanins with Mt, although a possible band at about 1536 cm −1 could have been masked by the one at 1550 cm −1 . Such a band, not evident in this study but reported in our previous study with Mt-added acerola juice (Ribeiro et al, 2018), is ascribed to complexation of anthocyanins with metals such as iron (Buchweitz et al, 2012). Since the color instability of anthocyanins at weakly acid to neutral pH is ascribed to the hydration of flavylium cation producing the colorless pseudobase, complexation has been demonstrated to improve the pigment stability (Fedenko et al, 2017;Yoshida et al, 2009).…”

“…In a previous study from this group (Ribeiro et al, 2018), Mt was demonstrated to intercalate anthocyanins from clarified acerola juice, which resulted in a dramatic color change (from yellowish to bright red) and color stabilization of the juice. The objective of the present study was to evaluate the effectiveness of Mt to act as both color stabilizer and reinforcing phase to gelatin films containing clarified acerola juice.…”

The Microencapsulation of Maqui (Aristotelia chilensis (Mol.) Stuntz) Juice by Spray-Drying and Freeze-Drying Produces Powders with Similar Anthocyanin Stability and Bioaccessibility

“…Ribeiro et al [ 24 ] indicated that in aqueous solutions, anthocyanins undergo structural rearrangements in response to changes in pH. Anthocyanins are most stable in acidic solutions (pH 1–3), whereas at a pH above 4, anthocyanins undergo chemical degradations to produce phenolic acids.…”

Estimation of Ascorbic Acid in Intact Acerola (Malpighia emarginata DC) Fruit by NIRS and Chemometric Analysis

“…The determination of ascorbic acid in acerola fruit is usually performed by high-performance liquid chromatography (HPLC), HPLC tandem photodiode array and mass spectrometry (MS) detectors (HPLC-PDA-MS/MS), and electrochemical or titrimetric methods [4,5]. Although these analytical methods present high selectivity and sensitivity, there are some difficulties, such as the destruction of the sample, the need for specific reagents and bulky instrumentation that impairs in-field monitoring, as well as the generation of waste.…”