Effect of chemical interesterification on Some Selected Chemical
Characteristics of blends of Butter and palm olein
A. Khurshid *M. Nadeem1, T.N. Pasha1, M. Abdullah1 and M.A. Jabar1
1
Department of Dairy Technology, University of Veterinary and Animal Sciences, Lahore
(Pakistan)
*Corresponding Author: sheikhnadeem@live.com
Cell #: 0313-4283954
Abstract: A study was carried out to determine the effect of chemical interesterification on some
chemical characteristics of butter and palm olein blends. Butter and palm olein were mixed at
different concentrations i.e. T0 (100% butter) which served as control, T1 (80% butter and 20%
palm olein) T2 (60% butter and 40% palm olein) T3 (50% butter and 50% palm olein) T4 (40%
butter and 60% palm olein) T5 (20% butter and 80% palm olein) T6 (100% palm olein). The
effect of interesterification process on fatty acid composition, triglyceride rearrangement,
melting point and free fatty acids were determined. Incorporation of 50% of palm olein to butter
reduced the level of saturated fatty acids by 20% and increased mono unsaturated fatty acids by
48% and 50% the levels of poly unsaturated fatty acids and increased melting point up to 23.10C.
Free fatty acids decreased in all the treatments including control. Addition of palm olein up to
50% level in butter can be used for the manufacturing of tailored fats that can be used for the
manufacturing of large number of food preparations.
Keywords: Butter, Palm olein, Chemical interesterification, physicochemical properties
INTRODUCTION
The awareness about the benefits to consume low cholesterol foods is mounting across the globe
due to increased interest and consciousness in consumers for food related health disparities. The
fatty acids composition of milk fat is characterized by high proportion of saturated fatty acids
(60-70%), Milk fat is also known to contain certain amount of cholesterol (0.25-0.38 mg/kg)
which posses many health risks Butter is a popular dairy product in this part of world and used in
many food preparations. Milk fat is characterized by high percentages of saturated fatty acids.
Saturated fatty acids increase the LDL cholesterol and decrease the beneficial HDL cholesterol
when metabolized in the body. Palm olein is the liquid fraction obtained by fractionation of palm
oil after crystallization at a controlled temperature. Palm olein has low iodine value and melting
point; pure palm olein cannot be incorporated in butter. However, can be used after some
modification by interesterification with others fats or oils (Aini & Miskandar, 2007, 2006).
Chemical interesterification causes modifications in the properties of natural fats. This means
that fatty acids are not randomly distributed in triacylglycerols of natural fats (Rodrigues &
Gioielli, 2003). Chemical interesterification is less expensive and leads to a random distribution
of fatty acids on the triacylglycerols (Marangoni & Rousseau, 1998). For the reason the present
investigation was planed to evaluate the suitability of chemically interesterified blend of palm
olein butter and appreciable quantity of mono and poly unsaturated fatty acids to prepare
functional butter with increased health benefits.
MATERIALS AND METHODS
Materials: Butter was procured from Haleeb Foods and palm olein was obtained from United
Industries Ltd. Faisalabad. The fats were stored at 0C prior to use. Sodium Methylate (Merck)
was purchased from a scientific store of Lahore. The following treatments were prepared.
Experimental: Palm olein was incorporated in butter at five different levels i.e. T0 (100% butter)
which served as control, T1 (80% butter and 20% palm olein) T2 (60% butter and 40% palm
olein) T3 (50% butter and 50% palm olein) T4 (40% butter and 60% palm olein) T5 (20% butter
and 80% palm olein) T6 (100% palm olein). All the treatments were performed duplicate.
Chemical interesterification: Chemical interesterification of different blends of butter and palm
olein were carried out according to the method of (Sreenivasan, 1978). 500 mL of the samples
were dried in a flask, under reduced pressure, fitted with a vacuum pump in a waterbath at 95 0C.
The portions were mixed with 0.2% (w/w) of sodium methylate. Interesterification reaction was
performed under reduced pressure at 70 0C in a 500 mL stoppered flask in a waterbath with
constant agitation for one hour. To terminate the reaction, 5 mL of distilled water was added.
Fatty acid composition: Fatty acid composition was determined after conversion of fatty acids
into their corresponding methyl esters on a gas chromatograph by the method described by
Hartman and Lago (1973).
Iodine value: Iodine value was calculated from the fatty acid composition, according to the
procedure described in the AOCS official method (AOCS, 1990).
Melting point: Melting point was determined by the closed tube melting point method,
according to the AOCS official method (AOCS,1990). Three replicates of this analysis were
performed.
Triacylglycerol composition: Triacylglycerol compositions of butter and palm olein (blends 1
and 7) were obtained from the literature and were used for the calculation of the blends. For
interesterified blends, the 1, 2, 3 - random theory, for random interesterification, was applied.
Trisaturated, disaturated–monounsaturated and monosaturated–diunsaturated triacylglycerols
percentages were calculated according to the method prescribed by (Chrysam, 1985).
RESULTS AND DISUCSSION
Fatty acid composition: The fatty acid composition of different blends of butter and palm olein
is shown in Table 1. Incorporation of 50% of palm olein to butter reduced the level of saturated
fatty acids in 20% and increased in 48% and 50% the levels of poly unsaturated fatty acids and
mono unsaturated fatty acids, respectively. But, from a nutritional point of view, blends
containing more than 50% of palm olein proved to be interesting to make healthy food and this is
due to the content of poly unsaturated fatty acids and mono unsaturated fatty acids of these
blends (WHO/FAO, 2003). Composition of butter and palm olein are in agreement with the
results published in the literature (Aini & Miskandar, 2007).
Triacylglycerol
composition:
The
trisaturated
(S3),
disaturated–monounsaturated
(S2U),monosaturated–diunsaturated (SU2) and triunsaturated (U3) contents of triacylglycerols
for the non-interesterified (NIE) and interesterified (IE) blends are shown in Table 3. Chemical
interesterification distributes fatty acids equally through in the three positions of the glycerol
backbone (Rodrigues & Gioielli, 2003). In butter, palm olein and their blends, chemical
interesterification
increased
trisaturated
and
decreased
monosaturated–diunsaturated
triacylglycerols, due to the probabilistic distribution of fatty acids. Palm olein showed an
increase in trisaturated and triunsaturated triacylglycerols and decrease in disaturated–
monounsaturated
and
monosaturated–diunsaturaded
triacylglycerols,
accompanied
by
considerable changes in physical characteristics. The triacylglycerol fraction of a fat is
responsible for most of its physical properties that affect lubricity (pourability, holding together
at room temperature or melting in the mouth to give a pleasant cooling effect). Lubricity is
dependent on melting temperature, solid fat content and texture. Fats that have composition with
TAGs predominantly SUU, melt in temperatures between 6 and 23 _C. These products provide
appropriate lubricity at 25 _C and are easy to handle and pour over temperatures ranging from 5
to 25_C. The functional properties of margarine oils, such asholding together at room
temperature and mouth melting characteristics, are all influenced by disaturated and trisaturated
TAGs. These TAGs melt between 27–42 _C and 56–65 _C, respectively. (Liu & White, 1992),
In this study, interesterified fats that have more than 50% of palm olein presented a good relation
between trisaturated, disatu- rated, diunsaturated and triunsaturated TAGs, increasing the
possibilities of use of these fats.
Table 2-Fatty acid composition of butter, palm olein and their blends in various ratios.
Treatments
Fatty acidsc (%)
IV
SFA(%)
PUFA(%)
MUFA (%)
14:0
16:0
18:0
18:1
18:2
T0
2.4 ± 0.3a
64.4 ± 0.1
4.5 ± 0.1
23.8 ± 0.1
4.9 ± 0.0
28.5 ± 0.1
71.3 ± 0.4
4.9 ± 0.1
23.8 ± 0.1
T1
2.0 ± 0.5 a 59.5 ± 0.1
4.3 ± 0.2
27.6 ± 0.3
6.6 ± 0.1
38.0 ± 0.7
66.6 ± 0.1
6.6 ± 0.2
27.6 ± 0.3
T2
1.6 ± 0.4b
54.3 ± 0.4
4.2 ± 0.5
32.9 ± 0.8
7.0 ± 0.6
39.2 ± 0.
9 60.1 ± 0.5
7.0 ± 0.6
32.9 ± 0.8
T3
1.5 ± 0.1c
50.9 ± 0.5 5.7 ± 0.1
34.6 ± 0.5
7.3 ± 0.1
42.5 ± 0.6
58.1 ± 0.6
7.3 ± 0.1
34.6 ± 0.5
T4
1.3 ± 0.4c
48.9 ± 0.7
5.0 ± 0.5
36.4 ± 0.9
8.4 ± 0.7
47.7 ± 0.9
55.2 ± 0.9
8.4 ± 0.7
36.4 ± 0.9
T5
1.1 ± 0.2d
44.9 ± 0.7
4.6 ± 0.4
40.1 ± 0.5
9.4 ± 0.9
50.0 ± 1.1
51.2 ± 0.8
9.4 ± 0.9
40.1 ± 0.5
T6
0.8 ± 0.4e
38.0 ± 0.2
5.0 ± 0.8
45.4 ± 0.2 10.2 ± 0.1
56.7 ± 0.1
43.8 ± 0.4
10.2 ± 0.1
45.4 ± 0.2
Table 3Triacylglycerol composition of non-interesterified and interesterified blends.
Type of triacylglycerol(%)
Butter
NIE
80:20
IE
NIE
IE
60:40
NIE
50:50
40:60
20:80
Palm olein
IE
NIE
IE
NIE
IE
NIE
IE
NIE
IE
S3
34.1
37.2
27.7
28.2
21.3
22.5
18.1
19.1
14.9
16.8
8.5 1
4.6
2.1
8.4
S2U
40.7
43.6
42.2
44.4
43.7
43.5
44.5
42.2
45.3
41.0
46.8
39.3
48.3
32.3
U2S
21.8
17.0
26.0
23.3
30.2
28.0
32.4
31.1
34.5
33.2
38.8
35.5
42.9
41.5
U3
3.4
2.2
4.1
4.1
4.7
6.0
5.1
7.6
5.4
9.0
6.0
10.6
6.7
17.8
S3, trisaturated.
S2U, disaturated–monounsaturated (SSU/USS + SUS).
U2S, monosaturated–diunsaturated (UUS/SUU + USU).
Table 3- Effect of chemical interesterification on melting pointof butter and palm olein
blends.
Treatments
Melting Point (0C)
Before
After
a
To (100%) butter
34.4±0.33
35.6±0.18a
b
T1 (80% butter: 20% palm olein)
30.3±0.18
30.9±0.20b
T2 (60% butter: 40% palm olein)
26.0±0.31c
26.4±0.19c
d
T3 (50% butter: 50% palm olein)
24.2±0.45
24.7±0.34d
T4 (40% butter: 60% palm olein)
22.1±0.23e
27.9±0.48e
f
T5 (20% butter: 80% palm olein)
18.0±0.11
30.5±0.22f
T6 (100% palm olein)
14.2±0.14g
37.3±0.43a
Mean values of duplicate experiment; means with same superscript letter in columns are statistically non significant.
Table 4- Effect of chemical interesterification on free fatty acids of butter and palm olein
blends.
Treatments
To (100%) butter
T1 (80% butter: 20% palm olein)
T2 (60% butter: 40% palm olein)
T3 (50% butter: 50% palm olein)
T4 (40% butter: 60% palm olein)
T5 (20% butter: 80% palm olein)
T6 (100% palm olein)
Free Fatty Acids (%)
After
Before
0.110±0.11a
0.104±0.97a
0.098±0.45b
0.092±0.78b
0.090±0.89b
0.064±0.84d
0.080±0.78c
0.020±0.66a
0.024±0.71a
0.018±0.34a
0.022±0.45a
0.020±0.56a
0.022±0.89a
0.020±0.99a
Mean values of duplicate experiment; means with same superscript letter in columns are statistically non significant.
Melting Point: The melting points of the blends before and after interesterification are shown in
Table 3. The melting point of the blends before interesterification increased with the addition of
butter in a nonlinear relationship. On the other hand, after the interestererification the
relationship was linear. The melting point before interesterification was dependent on butter, on
palm olein and on the positive interactions between them. After interesterification the melting
point were dependent only on butter and palm olein, as a consequence of the randorm
rearrangement, that increased the compatibility between the fats. There were no significant
changes in melting point caused by chemical interesterification for fats with up to 60% of palm
olein. The largest increases were observed for fats with 80 and 100% of palm olein. This
behavior is due to the random distribution of fatty acids in triacylglycerols after
interesterification, causing increase in trisaturated triacylglycerols (Lago & Hartman, 1986). The
addition of over 50% of butter to blends caused an increase in melting point. The observed trend
is consistent with the findings made by other researches which reported that as the percentage of
liquid oil in a blend increases, occurs the dilution and solubilization of the triacylglycerols with
higher melting points (Farmani et al., 2006).
Free Fatty Acids: The results of free fatty acids are given in Table 4. The addition of palm olein
in butter at all concentrations decreased the free fatty acids. This may be due to the reason of
using refined, bleached and deodorized palm olein in this experiment. After interesterification
reaction free fatty acids in all treatments were less than before the reaction. This may be due to
the alkaline nature of catalyst which neutralizes the free fatty acids. The results of this study are
in line with the findings of Erickson (1999) who stated that before the start of interesterification
reaction free fatty acids are neutralized
Conclusions
The main aim of this research work was to develop butter and palm olein blend by the process of
interesterification. Addition of palm olein in butter increased the melting point and unsaturated
fatty acids (Table 2). Free fatty acids decreased after interesterification. Chemical
interesterification is an effective way to modify the physical and chemical properties of butter,
palm olein and their blends. The chemical interesterification allows obtaining fats with various
degrees of plasticity, increasing the possibilities for the commercial use of butter and palm olein.
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