Oxidative and physical stability of vegetable oil oleogels with a binary
mixture of beeswax and candelilla wax
Abstract
Oxidative and physical stability of 3 and 7% beeswax-candelilla wax
(BW-CDW, 1:1) oleogels prepared with flaxseed (FSO), soybean (SBO), and
olive oils (OO) were evaluated during storage at 25 and 4 °C. Peroxide
values (PV) and conjugated diene values (CDV) of BW-CDW oleogels were
lower than bulk oils after storage at 4 °C for 180 days, and those of
7% wax oleogels were lower than 3% wax oleogels indicating the
protection effect by oleogelation. In contrast, these oleogels had lower
oxidative stability than bulk oils at 25 °C indicating the prooxidant
activity of waxes. PV of 7% BW-CDW SBO oleogel increased slower than
commercial margarine fat (CMF) at both storage temperatures while its
CDV increased faster at 25 °C. Gel strength (firmness and cohesiveness)
of oleogels decreased at both temperatures. Gel strength of CMF
decreased faster than oleogels at 25 °C while it was steady at 4 °C. Gel
strength of OO oleogels dramatically decreased during storage at 4 °C,
which was likely due to large oil crystals formed that broke the wax
crystal network at 4 °C. Solid wax content and melting enthalpy of
oleogels increased indicating that new crystals formed during storage,
which, however, did not provide higher gel strength. New spherulite
crystals appeared during storage at 4 °C, which might be the reason for
decreased gel strength. Overall results indicated that BW-CDW oleogels
had the oxidative and physical stability comparable to CMF except for OO
oleogels stored at 4 °C.