STRUCTURED LIPIDS FROM VIRGIN COCONUT OIL AND OMEGA-3 FATTY ACIDS:
PROCESS OPTIMIZATION
Abstract
Structured lipids (SLs) containing DHA, EPA, and DHA+EPA were
synthesized via enzymatic acidolysis using VCO as the substrate in
n-hexane. Commercially available enzymes Lipozyme TL IM (produced
from Thermomyces lanuginosus, a 1,3-specific lipase), Lipozyme
IM60 (produced from Rhizomucor miehei, a 1,3-specific lipase),
and non-specific lipase from Candida rugosa (powder) were used as
biocatalysts. The T. lanuginosus lipase was chosen to evaluate
the effects of various parameters on the incorporation of PUFAs into VCO
and to optimize the process. As the enzyme load increased from 1 to 4%,
the incorporation of omega-3 PUFAs also increased; however, it decreased
when the enzyme load was further increased to 6%. The incorporation of
these fatty acids increased with reaction time from 12 to 36h but
decreased at 48h. Similarly, the incorporation increased with
temperature from 35 to 45 oC, but decreased at 55 and
65 oC. The highest incorporation rates of DHA
(18.91%), EPA (30.38%), and DHA+EPA (34.64%) were achieved at a mole
ratio of 1:3 (VCO to DHA or EPA) or 1:3:3 (VCO to DHA+EPA), with a 4%
enzyme load, 36h incubation time, and a temperature of 45
oC. A central composite design (CCD) with three levels
and three factors—reaction temperature (35, 45, 55
oC), enzyme amount (2, 4, 6%), and reaction time (24,
36, 48h)—was used to model and optimize the reaction conditions via
response surface methodology (RSM). Under optimal conditions of 3.3%
T. lanuginosus enzyme, 42.22°C, and 33.38h, the incorporation
rates were 32.92% for DHA, 44.48% for EPA, and 47.04% for DHA+EPA in
VCO.