Composition and Thermal Analysis of Binary Mixtures of Mee Fat and Palm Stearin

Transcription

1 Journal of Oleo Science Copyright 2014 by Japan Oil Chemists Society doi : /jos.ess13193 Composition and Thermal Analysis of Binary Mixtures of Mee Fat and Palm Stearin Yanty Noorziana Abdul Manaf 1, Jalaldeen Mohammed Nazrim Marikkar 1, 2*, Shuhaimi Musthafa 1 and Miskandar Mat Saari 3 1 Halal Products Research Institute, and 2 Department of Biochemistry, Universiti Putra Malaysia, UPM Serdang, Selangor D.E., Malaysia. 3 Malaysian Palm oil Board, P.O. Box 12301, Kuala Lumpur, Malaysia. Abstract: Seed fat of Madhuca longifolia known as mee fat (MF) has been considered as a potential plant fat for producing fat mixture to simulate the properties of lard. A study was carried out to evaluate the effect of addition of palm stearin (PS) on the solidification behavior of MF to formulate a mixture to become similar in solidification characteristics of lard. Three fat mixtures were prepared by blending MF with palm stearin PS in different ratios: MF:PS (99.5:0.5), MF:PS (99:1), MF:PS (98:2) (w/w), and identified by the mass ratio of MF to PS. The fat mixtures were compared with lard in terms of their fatty acid and triacylglycerol compositions, differential scanning calorimetric (DSC) thermal profiles and solid fat content (SFC) characteristics. Results showed that there were considerable differences between lard and MF:PS fat mixtures with regard to fatty acid and triacylglycerol compositions. The increasing proportion of PS in MF:PS fat mixtures caused a general increase in SFC at different temperatures with respect to the SFC profile of native MF. Of the three binary mixtures, MF:PS (99:1) was found to show the least difference to lard in terms of SFC values throughout the temperature range. Key words: DSC, lard, lard substitute, mee fat, palm stearin, thermal analysis 1 INTRODUCTION Blending of oils and fats is one of the common practices adopted by the food industry to formulate various fat products. It is a highly preferred method since it is less expensive and capable to give the desired consistency of the product by choosing the right mixing ratio. In the commercial world, oils and fats of various kinds are blended for different end-user requirements. Generally, adjusting nutritional composition, frying stability, and functional properties are highlighted as reasons for commercial blending. From the nutritional point of view, blending has been profitably used to offer nutritionally important fat products with enriched content of essential fatty acids such as linoleic and linolenic acids. For improvement of oil stability, blending of polyunsaturated oils either with a more saturated or mono-saturated oil is undertaken to adjust the degree of unsaturation of the original oil to become more stable to oxidation 1, 2. Since sunflower oil is a polyunsaturated oil with a tendency to undergo oxidation quickly during frying, Farag et al. 3 attempted to blend sunflower oil with jojoba oil to improve its oxidative stability. For functionality improvement, semi-solid or hard fats are frequently chosen to be blended with soft oils to prepare fat ingredients for product formulations. Jeyarani and Reddy 4 showed that blending of mahua and kokum fats in selected ratios might produce cocoa butter extenders/replacers with temperature-resistant properties. The same authors also studied the preparation of bakery shortenings with zero trans fatty acids by blending the mango and mahua fats and their fractions 5. The blending approach may also be adopted for formulating a fat substitute for lard, which is a prohibitive substance under halal and kosher food regulations 6. In the past, a number of investigations were undertaken to partially substitute lard by oil mixtures prepared using various plant oils such as palm oil, olive oil, sunflower oil, etc. 7. However, there are many unconventional fats from nature, which are yet to be explored for their utilization in fat substitute for lard in food applications. For instance, the seed fat of Madhuca longifolia known as MF is a semi-solid fat, which has been used in medicinal applications for centuries 8. According to past reports, MF has been reported to contain oleic as the major fatty acid followed by stearic and palmitic acids 8. Although some recent studies 8, 9 suggested * Correspondence to: J.M.N. Marikkar, Halal Products Research Institute and Department of Biochemistry, Universiti Putra Malaysia, UPM Serdang, Selangor D.E., Malaysia. nazrim_marikkar@upm.edu.my Accepted December 10, 2013 (received for review November 11, 2013) Journal of Oleo Science ISSN print / ISSN online

2 Y. N. A. Manaf, J. M. N. Marikkar, S. Musthafa et al. that MF could be used as a shortening in confectionary products, its compatibility to the properties of lard has not been known for researchers until recently. According to Yanty et al. 10 the SFC profiles of MF and lard were similar at some temperatures while they were found to differ at certain other temperatures. It has been suggested that the observed differences in the SFC profile can be minimized possibly through the blending of MF with another fat. According to Miskandar and Aini 11, PS is one of the potential hard stocks used for adjusting solid fat contents of semisolid fats. In this study, we intended to investigate the usefulness of a specialty grade PS to improve the solid fat content profile of MF to become similar to that of lard at almost all temperature regions. 2 EXPERMENTAL 2.1 Materials Lard was extracted using three batches of adipose tissues of swine collected from local slaughter houses according to the method described by Marikkar et al. 12. Dried fruit seeds of mee Madhuca longifolia were collected from three different locations in the North Central Province of Sri Lanka. Samples of specialty grade PS were obtained as a generous gift from the Malaysian Palm Oil Board MPOB. All chemicals used in this experiment were of analytical or HPLC grade. 2.2 Methods Fat extraction Extraction of oil from finely ground samples of mee seeds was carried out by soxhlet extraction method using petroleum ether The extracted oil samples were kept in an oven at 60 for 1 h to expel solvent before storing at 20. Before analysis, the oil samples were removed from frozen storage, and left static at room temperature for 1 h and then warmed at 60 until they became completely molten Determination of slip melting point and iodine value SMP and of the fat samples were determined according to AOCS method Cc.3.25, and AOCS method Cd Id 92, respectively Preparation of binary mixture The fat samples were melted at 60 for 1 h before mixing. A total of three mixtures were prepared: MF:PS 99.5:0.5, MF:PS 99:1, MF:PS 98:2 w/w, and identified by the mass ratio of MF to PS. All samples were kept under frozen storage at 20. Prior to analyses, the fat mixtures were removed from frozen storage, and then left static at room temperature for 1 h before being warmed at 60 until they became completely molten Determination of fatty acid composition Fatty acid methyl esters were prepared by dissolving 50 mg portion of oil in 0.8 ml of hexane and adding 0.2 ml portion of 1 M solution of sodium methoxide 15. The top hexane layer was injected on an Agilent 6890 N gas chromatograph Agillent Technologies, Singapore equipped with a polar capillary column RTX mm internal diameter, 30 m length and 0.25 μm film thickness; Restex Corp., Bellefonte, PA and a Flame Ionization Detector FID. Split injection was conducted with a split ratio of 58:1, nitrogen was used as a carrier gas at a flow-rate of 1.00 ml/min. The temperature of the column was 50 for 1 min, and programmed to increase to 200 at 8 /min. The temperatures of the injector and detector were maintained at Determination of triacylglycerol TAG composition The TAG compositions of samples were determined according to the method described by Yanty et al. 10 using Waters Model 510 liquid chromatography equipped with a differential refractometer Model 410 as the detector Waters Associates, Milford, MA. The analysis of TAG was performed on a Merck Lichrosphere RP-18 column 5 μm 12.5 cm 4 mm i.d.; Merck, Darmstadt, Germany which was maintained at 30. The mobile phase was a mixture of acetone:acetonitrile 63.5:36.5 and the flow rate was 1.5 ml/min. The injector volume was 10 μl of 5 w/w oil in chloroform. Each sample was chromatographed three times, and the data were reported as peak area percentages 10. The identification of the peaks of the samples was done using a set of TAG standards purchased from Sigma- Aldrich Deisehofen, Germany as well as the TAG profiles of lard 10, palm stearin 16, and mee fat 8 reported previously Thermal analysis Thermal analysis was carried out on a Mettler Toledo differential scanning calorimeter DSC 823 Model equipped with a thermal analysis data station STARe software, Version 9.0x, Schwerzenbach, Switzerland. Nitrogen purity was used as the purge gas at a rate of 20 ml/min. Approximately 4-8 mg of melted sample was placed in a standard DSC aluminum pan and then hermetically sealed. An empty, hermetically-sealed DSC aluminum pan was used as the reference. The oil/fat samples were subjected to the following temperature program: 70 isotherm for 1 min, cooled at 5 /min to 70. The samples were held at 70 isotherm for 1 min, and heated at 5 / min to reach Determination of solid fat content SFC was measured using a Bruker Minispec Model Mq 20 pulse Nuclear Magnetic Resonance pnmr spectrometer Karlsruhe, Germany, according to AOCS method Cd 16b The sample in the NMR tube was melted at 70 for 15 min, followed by chilling at 0 for 60 min, and then held at each measuring temperature for 30 min prior to measurement. Melting, chilling and holding of the samples were carried out in pre-equilibrated thermostatic glycol containing baths, accurate to 0.1. SFC measurements 326

3 Comparing properties of Mee fat-palm stearin mixtures and lard were taken at 5 intervals over the range of Statistical analysis All analyses were carried out in triplicate and the results were expressed as mean value standard deviation. Data were statistically analyzed by one-way analysis of variance ANOVA, by using Tukey s Test of MINITAB version 15 statistical package at 0.05 probability level. 3 RESULTS AND DISCUSSION 3.1 Basic physico-chemical characteristics SMP and of binary mixtures of MF:PS and lard are presented in Table 1. The SMP and of MF were and 61.1, respectively and the values were in agreement with those reported previously by Yanty et al. 10. Addition of PS into MF in different proportions caused significant p 0.05 changes in the SMP and values when compared to those of the original MF sample. This was due to the fact that PS used in this study was of a specialty grade hard stock whose SMP and were 59.9 and 13.99, respectively. In fact, PS of this study was remarkably different from commercial PS SMP 51.5; 38.6 as reported previously by Marikkar and Ghazali 16 and Tan and Che Man 17. When compared to SMP value of lard, the SMP values of MF:PS mixtures were significantly higher 37. According to previous studies, the SMP of lard was found to be within the range of 27.5 to , 10. With regard to degree of unsaturation, all MF:PS mixtures of this study displayed significantly lower p 0.05 than that of original MF Further, the of binary mixtures of MF:PS to were also found to be lower than that of lard Hence, none of the binary mixtures of MF:PS was found to have a SMP and closely similar to that of lard. 3.2 Fatty acid composition The fatty acid compositional data of MF, PS, lard, and the binary mixtures of MF:PS are presented in Table 1. The major fatty acids of MF were oleic 47.58, palmitic 22.38, stearic and linoleic PS, on the other hand, was found to possess palmitic 78.9 as the most dominant fatty acid followed by oleic 10.6, and stearic 6.32 acids. The fatty acid composition of PS used in this study differed considerably from those of commercial PS since it was of a specialty grade hard stock. According to Marikkar and Ghazali 16, the proportions of palmitic, oleic and stearic content of a commercial PS were 68.3, 20.6, and 4.1, respectively. As shown in Table 1, addition of PS into MF caused slight increment in the proportion of palmitic acid with concurrent decreases in the amounts of stearic, oleic and linoleic acids. However, the increasing proportion of PS in the mixtures caused only slight changes in the contents of the total saturated fatty acid from to and the total unsaturated fatty acid content from to Further, these observations were compatible to the changing values of parameters such as SMP and of these mixtures as shown in Table 1. Although the saturated fatty acid content of MF:PS mixtures were found to be significantly higher p Table 1 Basic physico-chemical characteristics and fatty acid composition (%) of MF, PS, MF:PS mixtures and LD 1. MF PS PS:MF (99.5:0.5) PS:MF (99:1) PS:MF (98:2) LD SMP 35.25±0.35 d 59.90±0.71 a 37.25±0.35 c, d 38.50±0.71 b, c 40.25±0.35 b 27.50±0.71 e IV 61.10±0.14 b 13.99±0.01 e 57.81±0.04 b 56.04±0.11 c 54.27±0.06 d 73.76±0.34 a Fatty acid C12:0 n.d 0.20±0.14 a n.d n.d n.d 0.09±0.01 b C14:0 n.d 1.65±0.07 a 0.01±0.00 c 0.02±0.00 c 0.03±0.00 c 1.24±0.01 b C16: ±0.79 c 78.90±0.28 a 22.75±0.01 c 23.53±0.01 c 25.53±0.01 b 22.68±0.48 c C16:1 n.d n.d n.d n.d n.d 1.42±0.05 a C18: ±0.67 a 6.32±0.17 d n.d n.d n.d 12.70±0.28 c C18: ±0.08 a 10.90±0.00 d n.d n.d n.d 38.24±0.13 c C18:2 8.51±0.04 b 1.58±0.60 d 8.47±0.02 b 8.11±0.03 c 7.38±0.01 d 20.39±0.04 a C18:3 n.d n.d n.d n.d n.d 0.98±0.01 a C20:0 n.d 0.46±0.08 b n.d n.d n.d 0.67±0.01 a Others n.d n.d n.d n.d n.d Each value in the table represents the mean of three determinations. Means within each row bearing different superscripts are significantly (p<0.05) different. Abbreviations: MF, mee fat; PS: palm stearin; MF:PS, mee fat:palm stearin; LD, lard; SMP, slip melting point; IV, iodine value; n.d, not detectable. 327

4 Y. N. A. Manaf, J. M. N. Marikkar, S. Musthafa et al than that of lard, the palmitic acid contents of MF:PS 99.5:0.5 was found to be comparably similar to that of lard. However, other fatty acids of MF:PS 99.5:0.5 such as stearic, and oleic were found to be significantly higher p 0.05 than those of lard. 3.3 TAG composition The TAG composition of MF, PS, lard, and the binary mixtures of MF:PS are compared as shown in Table 2. MF was composed of POO 25.64, StPO 14.86, StOO 12.05, OOO and PPO as dominant TAG molecules. In PS, on the other hand, the major TAG molecules such as PPP 68.66, PPO 15.23, and StOP constituted of the total. The TAG composition of PS used in this study differed considerably from those of a commercial PS as reported previously 16, 17. According to Marikkar and Ghazali 16, the proportions of PPP, PPO and StOP in a commercial PS were 29.2, 29.8, and 3.75, respectively. After addition of PS into MF, some of the TAG molecules were found to increase while others were tended to decrease. According to Table 2, TAG molecules namely PPO to and StPO to were found to increase in greater amounts after MF was added with PS. In addition, the increases in the proportion of other TAG molecular species such as PPP, PPSt and StStSt were relatively smaller. As a result, the disaturated and trisaturated TAG molecules of the binary mixtures were found to increase with respect to the original sample of MF. For instance, the disaturated TAG was increased significantly from to when compared to that of the original sample of MF On the other hand, the trisaturated TAG molecules of the binary mixtures were found to increase only slightly from 1.34 to When compared to lard, the amount of disaturated TAG of the MF:PS mixtures were found to be higher ranging from to with concurrent decreases in the amounts of diunsaturated, and triunsaturated TAG molecules. The increasing proportions of disaturated and trisaturated TAGs in the fat mixtures could have led to the increase in the value of SMP as shown in Table 1. Table 2 TAG composition of MF, PS, MF: PS mixtures and LD 1. TAG MF PS PS:MF (99.5:0.5) PS:MF (99:1) PS:MF (98:2) LD LLLn n.d n.d n.d n.d n.d 1.54±0.21 a LLL n.d n.d n.d n.d n.d 0.68±0.21 a OLL 0.88±0.02 b n.d 0.73±0.03 b 0.51±0.01 c 0.38±0.06 c 4.68±0.08 a PLL 0.83±0.02 b n.d 0.63±0.04 b 0.43±0.01 c 0.33±0.01 c 7.05±0.06 a OOL 5.00±0.14 b n.d 3.49±0.02 b 2.91±0.01 c 2.13±0.10 d 6.93±0.04 a POL 6.72±0.00 b 0.32±0.03 d 6.19±0.05 b 5.11±0.11 c 4.50±0.07 c 20.00±0.27 a PPL 2.08±0.01 b 1.03±0.10 c 1.94±0.08 b 1.66±0.06 b 1.05±0.06 c 2.62±0.04 a OOO 11.06±0.01 a 0.13±0.01 c 9.24±0.32 a 9.11±0.08 a 8.88±0.21 a 4.33±0.21 b POO 25.64±0.04 a 2.22±0.02e 24.46±0.08 a 23.56±0.06 b 21.70±0.08 c 20.67±0.11 d PPO 10.39±0.01 d 15.23±0.03 b 13.96±0.74 b 15.29±0.06 b 18.85±0.01 a 10.63±0.01 c PPP 0.33±0.01 e 68.66±0.13 a 0.98±0.04 d 2.51±0.01 c 3.31±0.05 b 0.38±0.00 e StOO 12.05±0.04 a 0.26±0.06 e 11.85±0.07 a 9.84±0.08 b 8.12±0.02 c 3.62±0.04 d StPO 14.86±0.01 d 11.07±0.01 e 16.30±0.28 c 18.41±0.06 b 19.95±0.09 a 12.52±0.12 d PPSt 0.33±0.01 e 0.68±0.04 c 0.48±0.04 d 0.79±0.01 b 1.14±0.00 a 0.81±0.00 b StOSt 6.36±0.21 a n.d 6.01±0.01 a 5.61±0.13 a 4.91±0.15 b 0.83±0.01 c StStSt 0.23±0.01 e 0.41±0.01 d 0.37±0.01 d 0.59±0.05 c 0.86±0.04 b 1.31±0.01 a Others 3.24±0.03 n.d 3.40± ± ± ±0.33 UUU UUS USS SSS Each value in the table represents the mean of three determinations. Means within each row bearing different superscripts are significantly (p<0.05) different. 2 Abbreviations: TAG, triacglycerol; MF, mee fat; PS, palm stearin; MF:PS, mee fat:palm stearin; LD, lard; O, oleic; P, palmitic; L, linoleic; Ln, linolenic; St, stearic; U, unsaturated; S, saturated; n.d, not detectable. 328

5 Comparing properties of Mee fat-palm stearin mixtures and lard Among the three binary mixtures, MF:PS 99:1 was found to have the amount of PPSt 0.79 comparable to that of lard Thermal characteristics by cooling curve The cooling behaviors of MF, PS and lard are shown in Fig. 1. The cooling curve of MF curve E had three transitions; the low-cooling region consisted of a sharp peak at 24.3 while the high-cooling region consisted of peaks with a maximum at 4.5 and 26. These results were in accordance with the previous report of Yanty et al. 10. According to Fig. 1, the DSC cooling curve of PS curve F was found to show a single sharp thermal transition at 42.8, which was found to differ considerably from those of commercial PS reported previously. For instance, the cooling curves of commercial PS reported by Marikkar and Ghazali 16 and Tan and Che Man 17 were found to have a major thermal transition at and a minor thermal transition at As mentioned earlier, this difference was due to the fact that PS used in this study was of a specialty grade hard stock. The overlay of cooling curves presented in Fig. 1 compares the binary mixtures formed by blending PS with MF with that of lard. The cooling curve of lard curve A was characterized by two widely separated thermal events; a high a , a and a low a temperature transitions. The cooling curves of the MF:PS mixtures curves B, C, and D were consisted of three distinct thermal transitions; a high cooling transition at around 23 b 1, c 1, d 1, middle cooling transition at around 0 b 2, c 2, d 2 and low cooling transition at around 30 b 3, c 3, d 3. Having sharp thermal transitions in the low below 0 region and high-temperature regions above 0 region was a common characteristic feature between lard and MF:PS mixtures. All peak-maxima of the high-cooling thermal transitions were slightly shifted to higher temperature region when the proportion of PS in the binary mixture was gradually increased. In addition, the peak areas of low temperature transitions b 3, c 3, d 3 of the MF:PS mixtures were found to decrease with the concurrent increases in the peak areas of the middle b 2, c 2, d 2 and high temperature transitions b 1, c 1, d 1. These changes were found to be compatible with the changes in SMP values, fatty acid composition Table 1 and TAG composition Table 2. This was because of the fact that the physical properties of lipids are strongly influenced by the changes in their degree of unsaturation 17, 18. As shown in Fig. 1, the on-set of cooling T onset and the positions of thermal transition of lard were found to differ remarkably when compared to those of the thermal transitions of MF:PS mixtures. These differences were generally attributed to the differences in the saturated fatty acid content as well as disaturated/trisaturated TAG contents of the mixtures 17, 18. For instance, the stearic acid content Table 1 and the proportions of disaturated TAG molecules Table 2 in the mixtures were significantly p 0.05 higher than those of lard. 3.5 Thermal characteristics by heating curve The melting behaviors of MF, PS and lard are shown in Fig. 2. The heating curve of MF curve E had three transitions; the low-melting region consisted of a major sharp peak at 5.75 e 1 with a shoulder at 1.88 e 2 while the high-melting region consisted of a broad peak with peak maximum at 35.6 e 3. These results were in accordance with the previous report of Yanty et al. 10. According to Fig. 2, the DSC heating profile of PS curve F was found to show a single sharp thermal transition at As seen before, the nature of the heating profile displayed by PS Fig 1 DSC cooling curves of (A) LD, (B) MF:PS mixture (B=99.5:0.5), (C) MF:PS mixture (C=99:1), (D) MF:PS mixture (D=98:2), (E) MF and (F) PS. Abbreviations: LD, lard; MF, mee fat; PS, palm stearin. Fig 2 DSC heating curves of (A) LD, (B) MF:PS mixture (B=99.5:0.5), (C) MF:PS mixture (C=99:1), (D) MF:PS mixture (D=98:2), (E) MF and (F) PS. Abbreviations: LD, lard; MF, mee fat; PS, palm stearin. 329

6 Y. N. A. Manaf, J. M. N. Marikkar, S. Musthafa et al. differed considerably from that of commercial PS as reported by previous researchers 16, 17. The overlay of heating curves presented in Fig. 2 compares melting behavior of lard with those of the binary mixtures formed by blending PS with MF. The melting transitions of lard represented by curve A could be divided into two distinct regions namely, low-melting region below 0 a , a and high-melting region above 0 a , a , a These results were in accordance with the thermal profile of lard reported previously 12. On the other hand, the DSC melting curves of mixtures of MF:PS could be divided into three regions; one major peak in the low-melting region at around 5 b 1, c 1, d 1, one minor peak at middle-melting region at around 5 b 2, c 2, d 2 and one minor peak at around 37 b 4, c 4, d 4 with a shoulder peak at 30 b 3, c 3, d 3 in the high-melting region. With the increasing proportion of PS in the binary mixtures, all melting peak-maxima were found to have shifted to the higher temperature region resulting in higher endsets of melting T endset. Meanwhile the minor peak of MF at 35.6 tended to form a shoulder peak at a temperature slightly below the peak maxima. This phenomenon implied that the addition of PS into MF would tend to cause increases in the saturated fatty acids Table 1 as well as the disaturated/trisaturated TAG contents Table 2 of the binary mixtures 17, 18. Further, the end-set of melting T endset transitions of the MF:PS mixtures were found to be slightly higher at around 40 than that of lard Despite these differences, the major peak of lard at 3.59 a 2 and the major peaks of MF:PS mixtures b 1, c 1, d 1 were found to occur within a narrow temperature region. Particularly, the major peak of MF:PS 99:1 at 4.10 c 1 was found to be closest to that of lard at 3.6 a Solid fat content The SFC profiles of MF, PS and lard are shown in Fig. 3. SFC value of PS at 0 was 92.5 and tended to become 0 at 65. This showed the hard nature of PS, which was roughly comparable to the nature of engkabang fat extracted from the seeds of Shorea macrophylla 7. In between 0 to 55, the SFC profile was quite smooth since the rate of decrease in the SFC values was low. However, the curve showed a dramatic drop in the SFC values in between This peculiar behaviour of PS was largely in agreement with the observed thermal events in the DSC heating curve where a single sharp peak at 59 indicated that the entire TAG groups of PS tended to melt within a narrow temperature range Fig. 2. On the other hand, the SFC values of lard and MF at 0 were 30.8 and 33.1, respectively and tended to become 0 at 40. Both MF and lard displayed roughly similar SFC values at 5, 20 and 25, but they deviated considerably from each other at 10 to 15 and 30 to 35. According to Fig 3, addition of PS into MF Fig 3 Solid fat content profiles of lard (LD), mee fat (MF), palm stearin (PS) and binary mixtures of mee fat:palm stearin (MF:PS). tended to increase the SFC values of MF slightly at different temperatures. The observed increases in the SFC values were well-correlated to the increasing proportion of di- and tri-saturated TAG molecules PPO, PPP, and StPO in the binary mixtures Table 2. At 0, all three mixtures had SFC values higher than that of lard. While the SFC values of MF:PS 99.5:0.5 and MF:PS 99:1 tended to become 0 at 40, the mixture MF:PS 98:2 tended to become 0 only at 45. This difference could be probably due to the fact that MF:PS 98:2 had a higher proportion of trisaturated TAG molecules than the other two binary mixtures Table 2. Among the three mixtures, MF:PS 99:1 was the mixture, which showed better compatibility to lard at most of the temperatures in the range Fig. 3. This is further confirmed by the calculations presented in Table 3, where MF:PS 99:1 was found to have the least difference to lard in terms of SFC values throughout the temperature range. This was due to the fact that the SFC values of MF:PS 99:1 were found to increase to become closely similar to that of LD at 10, 15, 20, and Conclusions This study demonstrated the possibility of producing a fat mixture to mimic some of the compositional and thermal properties of lard by blending MF with PS. Among the three binary mixtures formulated, MF:PS 99:1 was 330

7 Comparing properties of Mee fat-palm stearin mixtures and lard Table 3 Comparing the least difference of SFC values of lard and MF: PS mixtures. Temp ( ) MF:PS (99.5:0.5) +/- lard MF:PS (99:1) +/- lard MF:PS (98:2) +/- lard Total Abbreviations: MF:PS, mee fat:palm stearin; Temp, Temperature found to show some characteristic similarities to lard. Despite much differences in fatty acid and TAG compositions, MF:PS 99:1 and lard displayed the closest similarity at the peak-maximum of the major peak occurring at 3.59 of the DSC heating curve. In terms of the SFC profile, MF:PS 99:1 showed the least difference to that of lard throughout the temperature range 0 to 40. Because of these reasons, MF:PS 99:1 can be considered as the most compatible to lard in terms of thermal behavior, and could be tested as replacement for lard in moon cake, and meat products such salami, sausage, etc. Acknowledgements Authors gratefully acknowledge the financial support from a research grant RU obtained under the Research University Grants Scheme of Universiti Putra Malaysia. References 1 Anwar, F.; Hussain, A. I.; Iqbal, S.; Bhanger, M. I. Enhancement of the oxidative stability of some vegetable oils by blending with Moringa oleifera oil. Food Chem. 93, Mariod, A.; Mattaus, B.; Eichner, K.; Hussein, I. H. Improving the oxidative stability of sunflower oil by blending with Sclerocarya birrea and Aspongopus viduatus oils. J. Food Lipids 12, Farag, R. S.; Farag, M. M.; Ali, R. F. M. Use of sunflower oil mixed with jojoba and paraffin oils in deep-fat frying process. Int. J. Food Sci. Technol. 59, Jeyarani, T.; Reddy, S. Y. Heat-resistant cocoa butter extenders from Mahua Madhuca latifolia and Kokum Garcinia indica fats. J. Am. Oil Chem. Soc. 76, Reddy, S. Y.; Jeyarani, T. Trans-free bakery shortenings from mango kernel and mahua fats by fractionation and blending. J. Am. Oil Chem. Soc. 78, Regenstein, J. M.; Chaudry, M. M.; Regenstein, C. E. The kosher and halal food laws. Compr. Rev. in Food Sci. Food Safety 2, Nur Illiyin, M. R.; Marikkar, J. M. N.; Shuhaimi, M.; Mahiran, B.; Miskandar, M. S. A comparison of the thermo physical behavior of Engkabang Shorea macrophylla seed fat - canola oil blends and lard. J. Am. Oil Chem. Soc. 90, Marikkar, J. M. N.; Ghazali, H. M.; Long, K. Composition and thermal characteristics of Madhuca longifolia seed fat and its solid and liquid fractions. J. Oleo Sci. 59, Ramadan, M. F.; Moersel, J. T. Mowrah butter: nature s novel fat. Inform 17, Yanty, N. A. M.; Marikkar, J. M. N.; Miskandar, M. S. Comparing the thermo-physical properties of lard and selected plant fats. Grasas Y. Aceites. 63, Miskandar, M. S.; Nor Aini, I. Palm stearin as low trans hard stock for margarine. Sains Malaysiana 39, Marikkar, J. M. N.; Lai, O. M.; Ghazali, H. M.; Che Man, Y. B. Detection of lard and randomised lard as adulter- 331

8 Y. N. A. Manaf, J. M. N. Marikkar, S. Musthafa et al. ants in RBD palm oil by differential scanning calorimetry. J. Am. Oil Chem. Soc. 78, AOAC. Official methods of analysis of AOAC international. 18 th ed.. 14 AOCS. Official methods and recommended practices of the American Oil Chemists Society. 5 th ed.. 15 PORIM Test Methods. Palm Oil Research Institute of Malaysia, Kuala Lumpur, pp Marikkar, J. M. N.; Ghazali, H. M. Effect of Moringa oleifera oil blending on fractional crystallization behavior of palm oil. Int. J. Food Prop. 14, Tan, C. P.; Che Man, Y. B. Differential scanning calorimetry analysis of edible oils: comparison of thermal properties and chemical composition. J. Am. Oil Chem. Soc. 77, De Man, J. M. Lipids, in Principles of Food Chemistry. 3 rd edn.. Springer Science Business Media, Inc. New York. pp