The aim of this study
was to prepare electro-activated solutions
(EAS) from calcium lactate, calcium ascorbate, and an equimolar mixture
of these two salts to obtain their corresponding acids and to study
their physicochemical characteristics, in particular, pH, titratable
acidity, pK
a, and antioxidant activity.
Indeed, the solutions were electro-activated in a reactor comprising
three compartments (anodic, central, and cathodic) separated by anionic
and cationic exchange membranes, respectively. The electric current
intensities used were set at 250, 500, and 750 mA for a maximum period
of 30 min. In general, the EAS obtained at 750 mA for 30 min showed
the lowest pH (2.16, 2.08, 1.94) and pK
a (3.13, 3.07, 2.90) values and the highest titratable acidity (0.107,
0.102, 0.109 mol/L) for calcium lactate, the mixture, and calcium
ascorbate, respectively. In addition, the obtained results have demonstrated
that the pH, titratable acidity, and pK
a of the EAS varied proportionally and significantly (p < 0.001) with the duration of the experiment and the intensity
of the electric current applied. To evaluate the migration of calcium
(Ca2+) between the central and the cathodic compartments
of the reactor, the concentration of Ca2+ was determined
especially in the cathodic section by inductively coupled plasma optical
emission spectroscopy (ICP-OES). The results showed that the migration
of Ca2+ varied proportionally with the electric current
intensity. In this context, analysis by Fourier transform infrared
(FTIR) spectroscopy, high-performance liquid chromatography (HPLC),
and differential scanning calorimetry (DSC) have confirmed the production
of lactic acid and ascorbic acid compared to standards. In addition,
analysis by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical
scavenging technique confirmed high antioxidant activities of >90
and >83% for calcium ascorbate and the mixture, respectively, in
comparison
to the standard ascorbic acid (85%). Overall, this research has clearly
demonstrated the eventual potential of electro-activation to produce
highly reactive organic acids from their conjugated salts. These EAS
can become excellent antimicrobial and sporicidal agents in the food
processing industry.