Fractional extraction of coconut oil by supercritical fluid extraction and its application as cocoa butter substitute in chocolate production
Cocoa butter is generally produced from coconut oil (CNO) and palm kernel oil which has similar physical characteristics as cocoa butter (CB). However, CNO contains high lauric acid which is different from CB and can be reduced by fractional extraction using Supercritical Fluid extraction (SFE...
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| Format: | Thesis |
| Language: | English |
| Published: |
2017
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| Online Access: | http://psasir.upm.edu.my/id/eprint/68887/1/FSTM%202018%2013%20IR.pdf http://psasir.upm.edu.my/id/eprint/68887/ |
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| Summary: | Cocoa butter is generally produced from coconut oil (CNO) and palm kernel oil which
has similar physical characteristics as cocoa butter (CB). However, CNO contains high
lauric acid which is different from CB and can be reduced by fractional extraction using
Supercritical Fluid extraction (SFE). Therefore, aim of this study was to produce CBS
from coconut oil (CNO) by fractional extraction with Supercritical Fluid Extraction (SFE).
The objectives of this study were: i) to determine the effects of different pressures and
temperatures on extraction of CNO and CNO fractions by SFE, ii) to determine the effects
of different level of coconut oil fractions substituted CB in milk chocolate. CNO was
extracted with SFE at four different pressures (27.6, 34.5, 41.4, 48.3MPa) and
temperatures of 60 ºC and 80 ºC. Then, the selected parameter conditions were applied for
fractional extraction of CNO with SFE. The selected F-CNO was applied as CBS in milk
chocolate production at different level. The properties of milk chocolates which include
melting profile, hardness, rheology, consumer acceptance and bloom stability were
analysed to determine the effects of F-CNO substitute in milk chocolate.
The yield of CNO extracted at the highest pressure, 48.3 MPa and temperature, 80 ºC was
significantly (p<0.05) higher (63.1%) and significantly (p<0.05) lower lauric acid
(44.75%) compared to others. The pressure at 48.3 MPa and temperature of 80 ºC was
selected as SFE operating parameter for the fractional extraction of the CNO. The
fractional extraction give four different fractions, F1, F2, F3 and F4. F1 had significantly
highest (p<0.05) yield (48.9%). The F4 contained significantly (p<0.05) lowest short and
medium chain fatty acids while highest long chain fatty acids compared to F1, F2 and F3.
F4 also had significantly (p<0.05) highest Tonset (24.2 ºC) and Tendset (33.6 ºC) which
were close to CB. The solid fat content of F4 was 0% at temperature between 35 ºC to 40ºC. Therefore, F4 was selected as the potential fraction of CNO (F-CNO) to be applied as
CBS due to close properties to CB. The F-CNO (F4) was applied in milk chocolate to
substitute cocoa butter at 1.5% (chocolate A), 3.0% (chocolate B) and 4.5% (chocolate C)
compared with control chocolate (without F-CNO). The different levels of F-CNO
substituted in milk chocolate resulted in different triglyceride composition which affected
the melting profile, hardness and rheology. The melting profile of the milk chocolates A,
B and C decreased significantly (p<0.05) as level of F-CNO added increased. The initial
melting point of the milk chocolate decreased from 30.72 ºC to 28.98 ºC while the end
melting point decreased significantly from 40.31 ºC to 36.36 ºC. The hardness of the milk
chocolate significantly (p<0.05) decreased from control, followed by chocolate A, then,
chocolate B and finally chocolate C. The rheology of the milk chocolate decreased
significantly (p<0.05) when level of F-CNO added increased. Sensory evaluation shown
consumer panelists (52%) significantly most preferred (p<0.05) the chocolate C which
contain 4.5% F-CNO in terms of glossiness (6.72) taste, (6.92) and overall acceptability
(6.60) compared to control (glossiness=5.57, taste=5.70 and overall=5.57). During bloom
stability study, the whiteness index (WI) of control chocolate was higher compared to
chocolate with F-CNO. Based on these findings, the F-CNO has the potential to be applied
as CBS in chocolate based product with high stability. |
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