2014 3rd International Conference on Nutrition and Food Sciences
IPCBEE vol. 71 (2014) © (2014) IACSIT Press, Singapore
DOI: 10.7763/IPCBEE. 2014. V71. 18
Influence of Lipid Composition, Solid Fat Content and Temperature
on Hardness of Margarines
Zhili Liang1, Lin Li1, 2, Zhenbo Xu1, Bing Li1+
1
College of Light Industry and Food Science, South China University of Technology, Guangzhou 510640,
China
2
Dongguan University of Technology, Dongguan 523808, China
Abstract: By studying the lipid composition, crystallization behavior on hardness of margarines at
different temperatures, the results generally show that there is no linear correlation between the hardness and
temperature, which is different from the customary view. On the basis of these results, the reasons of
hardness change are discussed, including triacylglycerol (TAG) composition, solid fat content (SFC), the
experimental results reveal that the temperature influences these factors. Hardness is controlled not solely by
any one of the lipid composition, solid fat content, it is the result of combined effects of lipid composition,
solid fat content.
Keywords: margarines, hardness, solid fat content
1. Introduction
Margarine was invented by Me`ge Mourie`s in 1896 to meet the lack of cream resulting from the
population increasing [1]. The original margarine was imitation products of natural cream, not only in taste,
but also in raw materials which were tallow. With the oil refining technology improving, vegetable oil
replaces animal oil in margarine production. Margarine are normally produced by vegetable oil undergone
hydrogenation or fractionation or chemical transesterification or a combination of these methods which offer
the possibility of changing the physical and chemical characteristics of lipids [2]. Hydrogenation allows the
conversion of liquid oils into semisolid fats. These hydrogenated fats are characterized by altered melting
and textural characteristics and a higher oxidative stability. Fractionation is a fully reversible modification
and basically a thermo-mechanical separation process. It allows for different fractions, which will also alter
the textural characteristics. Among the vegetable oils, palm oil has been widely applied in margarines due to
its several advantageous properties, such as high productivity, low price, high thermal-oxidative stability and
plasticity at room temperature [3].
The aim of this work was to compare two typical commercial margarines which respectively were
produced by hydrogenated vegetable oil (denoted by A) and fractionated palm oil (denoted by B) in terms of
lipid composition and SFC, so as to evaluate the relative effects of various factors on margarine hardness.
2. Materials and Methods
2.1. Materials
A: Non-dairy whipped topping (slip melting point (SMP)5.1°C, acid value (AV) 0.34 and iodine value
(IV) 0.76 g I/100 g; B: shortening (SMP47.4°C, AV 0.18 and IV 42.66 g I/100 g). Oil A was provided by
Goldem Diamond Food Industrial Co., Ltd. (Guangzhou, China). B was purchased from PT Salim Ivomas
+
Corresponding author. Tel.: + 86-20-87113252; fax: +86-20-87113252.
E-mail address: [email protected]
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Pratama (Indonesia). All other chemicals were either of analytical or high-performance liquid
chromatography (HPLC) grades.
2.2. Fatty Acid Composition Analysis
Fatty acid methyl esters (FAMEs) were prepared according to the AOCS Official Method Ce 2-66 [4],
and subsequently analyzed on a GC-14B gas chromatograph (GC) equipped with a fused-silica capillary
column (CP-Sil88, 100 m× 0.25 mm × 0.2 mm) and a flame ionization detector (Shimadzu, Tokyo, Japan).
The temperatures of the injection port and detector were both set at 250°C. The column was successively
heated to 50°C and held for 1 min, programmed at 8°C/min to 195°C and held for 2 min, then programmed
at 3°C/min to 250°C and held for 5 min. The fatty acid species was identified by using the retention time of
the FAME standard solution and quantified based on relative peak area
2.3. Triacylglycerol (TAG) Composition Analysis
The sample was melted completely and then dissolved in chloroform with the 0.5 mg/mL concentration
TAGs were separated by reversed-phase high-performance liquid chromatography (HPLC) using a
Symmetry C18 column (250 mm× 4.6 mm, particle size 5 μm) (Waters, Ireland) with A phase: Acetonitrile;
B phase: n-hexane/ isopropanol (4:5, v/v), A/B=50:50, the eluent at a flow rate of 1.0 mL/min and detected
with an sevaporative light scattering detector (ELSD). TAGs were identified by HPLC coupled to
atmospheric pressure chemical ionization mass spectrometry (HPLC/APCI-MS) using same HPLC
conditions as described above. A platform liquid chromatography-tandem mass spectrometry Analysis
(Bruker Daltonics Inc, USA) mass spectrometer (MS) equipped with an APCI interface was run at an APCI
source block temperature of 100°C, probe temperature of 400°C and an MS multiplier voltage of 700 V. The
measurement range was between m/z 200 and 1200 [5]. Quantitative determination of individual TAG in the
fat blends was made by using the HPLC results following the procedures of Chen et al. [6].
2.4. Textural Measurements
Textural measurements of oil were held at -20°C, -10°C, 0°C and 10°C, each for 24 h, respectively, and
then measured via constant speed penetration on an SMS TA.XT2i texturometer (Stable Micro Systems,
Surrey, UK) using a cone probe (P/6). The probe was set to penetrate the product at a constant speed of 2.0
mm/s to a distance of 10 mm. The maximum penetration force and the final penetration force were recorded.
Hardness was reported as the maximum penetration force (kg) based on triplicate measurements.
2.5. SFC Determination
Following the AOCS Official Method Cd 16b-93 [4], the SFC of the samples was determined on a
PC120 pulsed nuclear magnetic resonance (pNMR) spectrometer (Bluker, Karlsrube, Germany). The sample
was placed in the NMR tube and successively melted at 70°C for 30 min, tempered at 0°C for 90 min, and
then kept at the 0°C, 5°C, 10°C, 21.1°C, 26.7°C, 33.3°C, 40°C, 45°C, each temperature for 30 min before
measurement was recorded. Triplicate measurements were obtained.
3. Results
3.1. Hardness of Margarines
There is a direct correspondence between the temperature and hardness, which is considered
accustomedly, but the research result indicates it is not true. Figure 1 illustrates that hardness of A is 0.3499
kg at -20C, then promptly reduces to 0.0028 kg at -10C, next to 0.0030 kg at 0ºC and 0.0035 kg at 10ºC,
hardness of B decreases rapidly from 8.2922 kg at -20ºC to 1.1038 kg at -10ºC, then up to 1.7663 kg at 0ºC
and reduces to 1.6556 kg at 10ºC. In addition, both A and B, hardness has very dramatic changes from -20ºC
to -10ºC. Hardness of the A straight from 0.3499 kg to 0.0028 kg, hardness of B reduces from 8.2922 kg to
1.1038 kg. However, according to the SPSS statistic analysis, both A and B, there is not a significant
difference in hardness range from -10ºC to 10ºC. In other words, from -10ºC to 10ºC, the hardness of both A
and B remain constant.
3.2. Fatty Acid Composition
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Table I gives the major fatty acids composition of A and B. It shows that A mainly contains fatty acid
C14:0, C16:0 and C18:2, B mainly contains C16:0 and C18:0, the saturated fatty acid content of A and B all
more than 60%, but A is mainly dominated by short-chain fatty acids, long and medium chain fatty acids
takes up a large proportion in B.
3.3. TAG Composition
According to the fatty acid compositions of the triglycerides and the distribution of the fatty acids on the
individual triglyceride molecules, Wiederman divided TAGs into four component categories: trisaturated (S3)
TAGs; disaturated-monounsaturated(S2U); monosaturated-diunsaturated (SU2); and triunsaturated (U3) [7].
Fig. 1: Hardness of A and B at different temperature
Table I: Fatty acids composition of A and B
C14:0
C16:0
C18:0
C18:1
C18:2
others
A(%)
39.39
31.32
6.36
5.29
16.20
1.44
B(%)
9.18
49.65
29.96
6.10
3.73
1.37
Table II: Main TAG species present in A and B
TAG species
A(%)
B(%)
S3
MMP
8.43
6.06
PPP
5.44
20.44
PPS
1.42
2.15
PPL
9.91
1.29
PPO
6.72
31.73
PSO
3.45
4.65
SSO
1.67
0.47
PLL
1.93
1.77
PLO
21.98
8.76
POO
9.25
17.33
SOO
6.43
1.21
OLL
0.85
0.11
OOL
6.79
1.32
OOO
15.71
2.72
S2U
SU2
U3
(M, myristic ; L, linoleic ; P, palmitic ; O, oleic; S, stearic)
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As the Table II showed, comparing with A, B contains more S3 and S2U TAGs, the content of PPP is up
to 20.44%, the content of PPO is even as high as 31.73%. S3, S2U, SU2 and U3 TAGs have different
crystallization properties, the lower content of S3 TAGs and higher content of SU2 TAGs make margarine A
crystallize difficultly at body temperature or above. These results can explain why the hardness of A is more
lower than the hardness of B at the same temperature.
3.4. SFC
For the oil products with special purpose, SFC value is an important indicator to discriminate properties,
for example, margarine requires plasticity as much as possible at refrigerator temperature, in order to
maintain its shape and prevent separating out oil at 27~32°C in a few time [8].
At all temperature, SFC values of A are lower than B in Figure 2, with the temperature increasing, SFC
values of both A and B have reduced. According to the AOCS Official Method Cd 16b-93 [4], an SFC value
is determined by detecting the NMR signal from both liquid and solid components in the fat sample, or by
detecting the change in the liquid signal as it is displaced by solid.
Fig. 2: SFC value of A and B
4. Discussion
Environmental effects become even more important (than molecular effects) beyond the microscopic
world, where heat and mass transfer effects will strongly influence the formation of nanostructures,
microstructures, and eventually a network [9], [10]. Figure 1 shows that there is no linear correlation
between the hardness and temperature. According to Narine and Marangoni’s theory, rheology, mechanical
strength and sensory impression of fat are determined by many factors [11]. In Figure 1, from -20ºC to -10ºC,
the hardness of both A and B has very dramatic changes. However, from -10ºC to 10ºC, the hardness of both
A and B remains constant. These results may be due to diversification of molecules at the molecule level
such as lipid composition. Other more important reasons are that different temperatures may influence its
other molecules properties such as solid fat content, polymorphism and microstructure. Deman and
Blackman had made physical and textural evaluation of some shortenings and margarines, their results
showed that the fat crystal network played an important role in the textural properties of the product [12].
Consistency of fats depended on the number, size, and type of crystals [13], as well as on the proportion of
solids in the fat, viscosity of the liquid, treatment temperature, and mechanical working.
Table I shows that A is mainly dominated by short-chain fatty acids, long and medium chain fatty acids
take up a large proportion in B. At the same degree of unsaturation, the long chain fatty acids have higher
SMPs than short chain fatty, which can partial interpret why the SMPs of B higher than A. Besides, in
margarine and shortening, S3 and S2U type TAGs with high SMPs are the main sources of crystal backbone
that provide texture for margarines, thus B has higher hardness than A may be due to B contains more long
and medium chain fatty acids with high SMPs. Furthermore, this difference of fatty acid composition will
result in the complexity of triglycerides. As different triglycerides mixture, oil’s properties are closely related
to the constitution of triglycerides. In margarine and shortening, S3 and S2U type TAGs with high SMPs are
the main sources of crystal backbone that provide texture for margarines. Besides, S2U TAGs are solid at
room temperature and melt at body temperature. SU2 and U3 TAGs serve to promote liquidity and ease of
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handling at low temperatures [7]. Comparing with A, B contains more S3 and S2U TAGs. S3, S2U, SU2 and
U3 TAGs have different crystallization properties, the lower content of S3 TAGs and higher content of SU2
TAGs make margarine A crystallize difficultly at body temperature or above. These results can explain why
the hardness of B is much higher than hardness of A at the same temperature in Figure 1.
From the above discussion, an accurate conclusion can be reached that the hardness is the result of
combined effects of lipid composition, solid fat content and the microstructure of the network of crystalline
particles. At relatively low temperature, the crystal network is compact and stronger, thus it is a key factor to
determine the hardness. However, at relatively high temperature, when the crystal network is not strong, or
even disappeared, the crystal clusters and crystals which are characterized by SFC and polymorphism, they
play important roles in determining the hardness.
5. Conclusions
In this work, the results generally show that there is no linear correlation between the hardness and
temperature, which is different from the customary view. The result is due to the temperature influences the
properties of lipid composition, solid fat content. At relatively low temperature, the crystal network is
compact and stronger, thus it is a key factor to determine the hardness.
6. Acknowledgement
This work is supported by the National Natural Science of China (No. 31130042), the National Key
Technology R&D Program (No. 2012BAD37B01), the Fundamental Research Funds for the Central
Universities, SCUT (No. 2014ZB0006).
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