Abstract:
In this study, the effect of three amplitudes of Ultrasound
-
Assisted Solvent Extraction
(UASE) (0, 20 and 40%; 100W, 30 kHz; the 0% treatment serving as control) on kinetics,
thermodynamic, rosmarinic acid content,
total phenolics, antioxidant activity, and
antimicrobial activity of
Ocimum basilicum
L
.
(basil) extract at different temperatures
(25, 35 and 45°C) was evaluated. Increases in ultrasound amplitude and temperature
increased yields and biological activitie
s of extracts. The highest rosmarinic acid content,
total phenolics, antioxidant and antimicrobial activity were obtained for samples treated
with UASE at 40% amplitude and 45°C. The kinetics of extraction were evaluated based
on a second order mechanism.
Increases of amplitude and temperature significantly
increased saturated extraction Capacity (C
s
), initial extraction rate (h), and rate constant
of extraction (k). The thermodynamic aspects of the extraction process showed that
samples treated with UASE a
t 40% amplitude had higher activation Energy (Ea),
frequency factor (A), enthalpy
(ΔH
++
) and entropy (ΔS
++
) than control. UASE at 40%
amplitude and control did not significantly differ in thermodynamic parameters. Results
also showed very good linear relationships with high correlation coefficients between
E
a
and
ΔH
++
and,
A
and
ΔS
++
. T
herefore, ultrasound can affect thermodynamic aspects and
kinetics of extraction of basil extract and improve its biological activity.
Keywords:
Antimicrobial activity, Antioxidant activity, Basil extract, Extraction kinetics,
Extraction thermodynamic, Ro
smarinic acid
