Effect of Enzymatic Trans- and Interesterification on the Thermal Properties of Groundnut and Linseed Oils and Their Blends

The present study was undertaken to compare
the alterations observed in the triacylglycerol (TAG)
molecular species of blended and interesterified oils containing
groundnut oil (GNO) and linseed oil (LIN). The
blended oil (BLE) was subjected to a lipase catalyzed
reaction to prepare transesterified oil (TRA). A structured
lipid (STR) was also prepared by a lipase catalyzed acidolysis
reaction of GNO and free fatty acids concentrate
from LIN. The changes in the molecular species of modified
lipids were determined by high performance liquid
chromatography. The thermal profiles were determined by
differential scanning calorimetry. In comparison with
GNO, the triunsaturated triacylglycerols were increased
and the disaturated triacylglycerol molecular species were
decreased in TRA and STR. Both BLE and TRA showed a
decrease in the onset temperature for crystallization as
compared to that observed with GNO. The total transitional
enthalpy for crystallization was higher for BLE, TRA and
STR as compared to GNO. The melting temperature of
TRA and STR showed a decrease in comparison to GNO,
reflecting on the changes in the TAG molecules species
present in the oil. Thus, interesterification of oils introduced
changes in the physical properties of oils, even
though the overall fatty acid compositio