Abstract:
Edible oils are conventionally converted to spreadable form via hydrogenation. However,
hydrogenation leads to the formation of trans-fatty acids that cause metabolic syndrome and
cardiovascular diseases. Oleogelation is an emerging technology that converts liquid oils into
spreadable form without hydrogenation. The present study investigates the possibility of
converting coconut oil and sesame oil into spreadable fat products using milk protein-assisted
emulsion template oleogelation. In this study, oil in water emulsions with a range of milk protein
concentrations (2% (w/w), 3% (w/w) and 6% (w/w) in the aqueous phase) were prepared using
sesame oil, coconut oil and reconstituted milk powder solutions. The emulsions were gelled using
acidification and dewatered by pressing at 2.6 kNm-2 pressure to obtain oleogels. Stability
measurements in room temperature (around 290C) and optical microscopic images revealed that
the stability of oleogels improved with the increase in protein content, due to the formation of a
compact gel network. In coconut oil oleogel samples, the oil separation index was significantly
decreased (p<0.05) from 12.4 to 8.4 as milk protein concentration increased from 2% (w/w) to
6% (w/w). The oil separation indices of sesame oil oleogels made with 2%, 3% and 6% milk
protein concentrations were 4.5, 5.7 and 2.4, respectively. Increase in protein content from 2%
(w/w) to 6% (w/w) led to a significant increase (p<0.05) in the moisture content of oleogels.
Coconut oil oleogels made with 2% (w/w), 3% (w/w) and 6% (w/w) milk protein concentrations
had 20.6% (w/w), 25.7% (w/w) and 33.0% (w/w) moisture, respectively. Similarly, sesame oil
oleogels made with 2%, 3% and 6% milk protein concentrations had 21.0% (w/w), 24.5% (w/w)
and 29.4% (w/w) moisture, respectively. Visual observations of sesame oil oleogels showed
better stability and spreadability than coconut oil oleogels, in all protein concentrations studied.
This study demonstrates the possibility of applying milk protein acid gelation to form spreadable
oleogels using coconut and sesame oil.
