Journal of Oil Palm Research Vol. 25 (2) August 2013 p. 1400-1400 JOURNAL OF OIL PALM RESEARCH 25 (2) (AUGUST 2013) A COMPARATIVE STUDY OF THE EFFECTS OF PROCESSING CONDITIONS AND FORMULATIONS ON THE PHYSICAL AND SENSORY PROPERTIES OF FROZEN NASI LEMAK MADE OF PALM-BASED SANTAN AND COCONUT SANTAN RAFIDAH ABD HAMID*; NUR IZYANI AHAMAD AZAHARI* and MISKANDAR MAT SAHRI* ABSTRACT The objective of the study was to determine the efect of processing conditions on physical characteristics of frozen nasi lemak. Two types of santan that is, palm-based santan and coconut santan were used in this experiment. They were tested at three santan to rice ratios i.e. 1/5, 1.5/5 and 2/5 under diferent freezing rates and thawing processes. The results showed that nasi lemak made of palm-based santan have lower moisture content compared to that made of coconut santan and fast-freezing followed by immediate reheating, was able to retain a higher moisture content in both samples. The water activity of frozen nasi lemak samples ranged from 0.994 to 0.998 at 25.0 ± 0.7°C and was not signiicantly afected by processing conditions and type of santan. An increase in the amount of santan signiicantly increased the amount of lipid-amylose complexes formed in frozen nasi lemak which resulted in high Complexing Index (CI) values. It simultaneously reduced the hardness and increased the stickiness of the rice kernels for both type of santan. The freezing rate inluenced the stickiness of rice. At 1/5 santan to rice ratio, nasi lemak made of palm-based santan was comparable to that of coconut santan in its sensory attributes, except for its colour, odor and overall taste. Keywords: lipid-amylose complexes, thawing, frozen, nasi lemak, palm-based, santan, coconut. Date received: 18 July 2012; Sent for revision: 11 September 2012; Received in inal form: 28 February 2013; Accepted: 22 March 2013. Oil Board (MPOB) developed a palm-based transfree liquid santan in 2008 and it was successfully commercialised in 2010. It has been proven that coconut santan contains higher fat and protein content compared to palm-based santan (Zaida, et al., 2008). Foods that contain santan are always perceived as ‘rich’. Santan gives a unique lavour and taste to the food. Among the popular local dishes that contain santan are nasi lemak and curry. Nasi lemak is one of the most popular Malaysian dishes for INTRODUCTION Santan is a Malay term for coconut milk and is derived from the lesh of coconuts. Due to the increase in demand for santan, palm-based santan has been developed. Researchers at the Malaysian Palm * Malaysian Palm Oil Board, 6 Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia. E-mail: raidah@mpob.gov.my 1 JOURNAL OF OIL PALM RESEARCH 25 (2) (AUGUST 2013) breakfast. Two of the main ingredients in nasi lemak are santan and rice. Recently, instant and frozen nasi lemak was introduced to the market as a ready-toeat meal in order to cater to the busy life-style of the urban community, which requires for meals that can be served fast. Palm-based santan has been tested in many foods, including nasi lemak. However, the usage of palm-based santan in nasi lemak has not been scientiically reported in peer-reviewed journal. In this study, the physical characteristics of frozen nasi lemak made of palm-based and coconut santan were examined. The objective of the study was to determine the efects of processing conditions on the physical characteristics of frozen nasi lemak. Four analyses involved were moisture content, water activity, complexing index and texture analysis. Water content, or moisture content, is a measurement of the total water contained in a food. On the other hand, water activity is a measurement of the availability of water for biological reactions. It determines the ability of microorganisms to grow. If water activity decreases, microorganisms with the ability to grow will also decrease. Water activity can be reduced by freezing, e.g. water is removed in the form of ice. However, Benson et al. (1992) had detected increased amounts of malondialdehyde, a breakdown product of lipid peroxides, in frozen/ thawed rice cells compared to unfrozen controls. They suggested that freezing injury can promote lipid peroxidation. Later, Yu et al. (2010a) found that high quality cooked rice can be produced by combined rapid freezing with frozen storage. They reported that rapid freezing combined with −18°C frozen storage can efectively retard starch retrogradation and maintain the textural properties of cooked rice for at least seven months. Another inding suggested that cooked rice chilled with slower cooling rate retrograded faster than chilled with rapid cooling rate (Yu, et al., 2010b). The texture of a cooked rice is described by the hardness and stickiness values. The textural properties of a cooked rice is afected by the processing conditions and chemical characteristics of the raw kernel (Mestres, et al., 2011). These chemical characteristics may include amylose, protein and arabinoxylan contents. Xie et al. (2008) discovered the hardness and adhesiveness of cooked rice of non-waxy cultivars were due to protein hydration. The cooking method applied in this study was based on the common rice cooking method of households in Malaysia which is boiling followed by slow heating. Another method is by stewing. Ghasemi et al. (2009) reported that stewing of rice grains by steam after boiling in excess water can be used for cooking rice perfectly. It reduced the hardness and increased the adhesiveness of rice grains signiicantly, which means that it produced better gelatinisation and more expansion of starch granules compared to non-stewed rice. MATERIALS AND METHODS Materials White rice (Super Special Jasmine, Selangor, Malaysia) was purchased from a shop. Palm-based santan (Khalis, Premium Food Corporation Sdn Bhd, Selangor, Malaysia) and coconut santan (Ayam Brand, Selangor, Malaysia) were purchased from a nearby supermarket. Ginger, shallots, pandan leaves (screwpine) and salt were bought from a wet market. Filtered tap water was used for cooking. Methods Preparation of frozen nasi lemak. Several formulations were tested as listed in Table 1. All ingredients were put into an automatic rice cooker (Model 18GXN, 1.8L, 220V, 50Hz, Panasonic, Shah TABLE 1. FORMULATIONS FOR ALL LEVELS OF TREATMENTS Santan to rice ratio 1/5 ฀ Rice (500 g) ฀ Water (1000 ml) ฀ Palm-based santan (100ml) ฀ Ginger (5 g) ฀ Shallots (5 g) ฀ Salt (2 g) Ingredients ฀ Pandan leaves (2 pcs) 1.5/5 2/5 1/5 1.5/5 ฀ Rice (500 g) ฀ Water (1000 ml) ฀ Palm-based santan (150ml) ฀ Ginger (5 g) ฀ Shallots (5 g) ฀ Salt (2 g) ฀ Pandan leaves (2 pcs) ฀ Rice (500 g) ฀ Water (1000 ml) ฀ Palm-based santan (200ml) ฀ Ginger (5 g) ฀ Shallots (5 g) ฀ Salt (2 g) ฀ Pandan leaves (2 pcs) ฀ Rice (500 g) ฀ Water (1000 ml) ฀ Coconut santan (100ml) ฀ Ginger (5 g) ฀ Shallots (5 g) ฀ Salt (2 g) ฀ Pandan leaves (2 pcs) ฀ Rice (500 g) ฀ Water (1000 ml) ฀ Coconut santan (150ml) ฀ Ginger (5 g) ฀ Shallots (5 g) ฀ Salt (2 g) ฀ Pandan leaves (2 pcs) 2 2/5 No santan ฀ Rice (500 g) ฀ Rice (500 g) ฀ Water (1000 ฀ Water ml) (1000 ml) ฀ Coconut santan (200ml) ฀ Ginger (5 g) ฀ Shallots (5 g) ฀ Salt (2 g) ฀ Pandan leaves (2 pcs) JOURNAL OF OIL PALM RESEARCH 25 (2) (AUGUST 2013) Alam, Malaysia) and cooked for about 26 min. Cooked samples of 100 g were transferred into labelled 350 ml square microwavable polypropylene plastic container. Every set has seven containers. These containers were labelled A, B, C, D, E, F and G (Table 2). These samples were then subjected to diferent processing conditions, as speciied in Table 2. 12 ml test tube. The sample was then homogenised using a vortex mixer (Barnstead Thermolyne, Dubuque, USA) for 2 min and centrifuged (Model 80-2, Jiangsu, China) for 15 min at 3000 rpm. The supernatant (500 µl) was transferred into a cuvette and iodine solution was added before made up to 2 ml with distilled water. The iodine solution used for this analysis was freshly prepared by dissolving 2 g of potassium iodide (KI) (Systerm, Shah Alam, Malaysia) and 1.3 g iodine (I2) (Systerm, Shah Alam, Malaysia) in 50 ml of distilled water. This solution was allowed to stand for about 2 hr before the inal volume was made up to 100 ml with distilled water. The absorbance was measured using spectrophotometer (Aquamate, Minnesota, USA) at 690 nm. The absorbance represents the portion of starches that formed complexes with iodine. Pure potato starch (98%) was used as control. CI was calculated using the following equation. Storage of frozen nasi lemak. Samples C, F, and G from all treatments were stored at -20°C, straight away after cooking. While, samples B, D and E were frozen using a blast freezer (at -40°C for 2 hr) before storage at -20°C. Samples were stored overnight before further analyses were carried out. Reheat of frozen nasi lemak. On the day of the analysis, samples D and F were directly reheated in the microwave without thawing. Whereas, samples E and G were thawed for 15 min (at room temperature) before they were reheated in the microwave for 5 min. Reheated samples were used for all analyses. CI (%) = Moisture content. The moisture content was determined according to the AOAC International Method 926.08 (AOAC 2007). The 3 g sample was put in a crucible before it was left in an oven (Memmert, Schwabach, Germany) overnight at 105°C. Then it was transferred into an electronic dessicator (Eureka, Taipei, Taiwan) for cooling down before weighing. Total moisture content was calculated using formula: % Moisture content = b - (c – a) b (Absorbance of control – Absorbance of sample) Absorbance of control x 100 Water activity. The sample was placed in a water activity (Aw) meter (AquaLab, Pullman, USA). This instrument has selectable internal temperature control which enables temperature-controlled water activity determination under a temperaturestable sampling environment, without the need of an external waterbath. The measurement was taken directly from the instrument. Textural analysis. The texture of the frozen nasi lemak was determined using a Texture Analyser (TA. XT21, Texture Technologies, Corp, UK) with a 36 mm cylinder probe by using a 5 kg load cell. The analyser was linked to a computer that recorded the data by a software program called Texture Expert Excede version 1.0 (Stable Micro Systems Software, Surrey, UK). A compression force versus time program was used to compress the samples till 90% of the original kernel thickness was achieved. A 36 mm cylinder probe was used to compress three kernels, with pretest speed and test speed of 0.5 mm s-1, and posttest speed 10.0 mm s-1. The texture was expressed as x 100 where, a is weight of empty crucible (g); b is weight of sample (g); and c is weight of inal sample with crucible (g) Complexing index. Complexing index (CI) was determined using method developed by Gilbert and Spragg (1964). Sample of 2 g was mashed into paste and mixed with 10 ml distilled water in the TABLE 2. LABELLING OF NASI LEMAK SAMPLES FOR DIFFERENT PROCESSING CONDITIONS Sample A: freshly prepared nasi lemak. Sample B: freshly prepared nasi lemak – fast freezing (-40°C). Sample C: freshly prepared nasi lemak – slow freezing (-20°C). Sample D: freshly prepared nasi lemak – fast freezing – immediately reheated (5 min). Sample E: freshly prepared nasi lemak – fast freezing – thawed (15 min) prior to reheat (5 min). Sample F: freshly prepared nasi lemak – slow freezing – immediately reheated (5 min). Sample G: freshly prepared nasi lemak – slow freezing – thawed (15 min) prior to reheat (5 min). 3 JOURNAL OF OIL PALM RESEARCH 25 (2) (AUGUST 2013) hardness (peak force of the irst compression) and stickiness (maximum –ve force) of the samples. At least four readings were taken for every sample. Theoretically, slow freezing will result in signiicant lower moisture content than initial value due to the structural damage of the rice which promotes drip when the product is thawed (Redmond et al., 2005). However, in this experiment, samples that went through slow freezing before they were thawed and reheated (sample G) had a higher content of moisture compared to sample that undergone fast freezing (sample E). Most probably the drip loss during thawing was re-absorbed into the kernel during reheating since the packaging was kept intact during thawing. The moisture content of samples E and F were about the same. Fast freezing followed by thawing and reheating seems not to have much efect compared to slow freezing followed by immediate reheating in these frozen nasi lemak samples. It was generally observed that the moisture content of nasi lemak increased as the ratio of santan to rice was increased from 1/5 to 1.5/5. An addition of santan reduces relative water content because the components in santan which are mainly oil would lower the water activity of the cooked rice (El-Bassiouny and Bekheta, 2005). However, at two-ifth santan to rice ratio, the moisture content dropped slightly. This applies to both types of santan as shown in Figure 1. Overall, nasi lemak made of palm-based santan has lower moisture content compared to that made of coconut santan, due to the fact that moisture content of palm-based santan is lower than coconut santan. The moisture content for palm-based santan is 63.1%, while that for coconut santan is 65.3% (Zaida et al., 2008). When the data were analysed using the General Linear Model (GLM), it was observed that the value of R2 of each single factor was just 51.4% and this gave an indication that the single factors (type of santan, santan to rice ratio, freezing rate and reheating condition) did not signiicantly afect the moisture content of frozen nasi lemak. But, the R2 of the interactions of these factors was very high (99.84%). The interactions of these factors signiicantly inluenced the moisture content of samples. The interactions between freezing rate and thawing condition have the highest value of Sequential Sum of Squares (Seq SS) which meant that this interaction highly inluenced the moisture content of frozen nasi lemak. Sensory evaluation. Sensory evaluation was conducted by 32 untrained panellists. Panellists were randomly selected from the Malaysian Palm Oil Board (MPOB) staf and students, without any speciic priority in selection. They were asked to evaluate two samples; 1) nasi lemak made from palmbased santan; and 2) nasi lemak made from coconut santan. Evaluation was based on six attributes that included colour, odour, hardness, stickiness, oiliness and overall taste using a nine-point scale. Scale 1 indicates the least acceptable sample while 9 indicated the most acceptable sample. Samples of frozen nasi lemak made of palm-based santan and coconut santan were immediately reheated in a microwave before they were served to the panellists. Nasi lemak was served warm with hot savoury. Only nasi lemak with one-ifth santan to rice ratio was used in the sensory evaluation. Statistical analysis. Data were evaluated using the analysis of variance (ANOVA) and General Linear Model (Minitab Version 14). Signiicance was established at a level of p < 0.05. RESULTS AND DISCUSSION Moisture Content Moisture content is an important criteria that has a signiicant efect on the freshness and quality of the food. Rice is considered as fully cooked when the inal moisture content is in the range of 58% to 64% (Zheng and Lan, 2007). Figure 1 shows the signiicant diference in moisture content of samples between diferent processing conditions. Samples B and C were not analysed. In sample A, where nasi lemak was freshly prepared and did not undergo any freezing treatment, the lowest value of moisture content was recorded, regardless of type or any santan to rice ratio, due to moisture loss to the surrounding atmosphere during the process of cooling down. Sample D, regardless of type or any santan to rice ratio, has the highest moisture content. Obviously, fast freezing and immediate reheating have signiicant efects on the moisture content of the frozen nasi lemak. Fast freezing formed very small ice crystals in food structure, which provide less damage to the cellular structure when the frozen product is thawed (Ernest, 1999). Thus, water remains within the kernel after reheating. Water Activity It was observed that the range of Aw of nasi lemak samples was from 0.994 to 0.998 at 25.0 ± 0.7°C. Water activity is the range of 0 to 1. The values near to 1 indicated that nasi lemak is classiied under the perishable food category. Theoretically, 4 JOURNAL OF OIL PALM RESEARCH 25 (2) (AUGUST 2013) Palm-based santan Coconut santan No santan Figure 1. Means ± standard deviation of moisture content of nasi lemak made of palm-based and coconut santan under diferent processing conditions. the range of Aw that for perishable food is 1.00 to 0.95. Perishable food needs to be handled with extra care since it can easily be spoilt by microbial contamination due to high water availability. Aw is a very useful parameter to determine the possibility for microbial growth (Subramaniam, 2000). As the Aw gets higher, shelf-life would become shorter. Perishable food should be kept hot (>70°C) or cold (<5°C) to ensure it is safe for consumption. Results showed that there were no signiicant diferences in water activity of all samples. Thus, santan to rice ratio and the rates of freezing and reheating method do not signiicantly inluence the Aw of frozen nasi lemak. On the other hand, there was a slight diference in Aw of rice cooked without an addition of santan, where the Aw was lower compared to other samples. The addition of santan increased the Aw of the rice kernel. Complexing Index Figure 2 shows the means and standard deviations for complexing index (CI) of samples. CI gives the indication of how much starches (i.e. amylose) have formed complexes with lipid in nasi lemak samples. In this context, amylose was from rice, while lipid was from santan that was added in during the preparation of nasi lemak. Amylose helices occupied by lipid reduced its capacity to attach to iodine, and will have a lower absorbance than starch alone Figure 2. Means ± standard deviation of complexing index of nasi lemak made of palm-based and coconut santan under diferent processing conditions. 5 JOURNAL OF OIL PALM RESEARCH 25 (2) (AUGUST 2013) when mixed with iodine. Thus, the CI will increase as the iodine binding capacity decreases (Tang and Copeland, 2007). The control starch used in this analysis is the amylose from potato starch (>98%) and its absorbance was determined to be 0.982. From the results shown in Figure 2, the efect of diferent processing conditions (freezing rate and thawing condition) on CI was negligible. However, there was a clear pattern when the amount of santan was increased. The CI progressively increased when the amount of santan added was increased. This applies to both palm-based and coconut santan. This means that when more santan was added, more amylose-lipid complexes were formed leaving only small amount of free amylose helices that could bind with iodine. Thus, the amount of santan added inluenced the CI value. A higher CI value indicates that there are more lipid-amylose complexes formed and fewer amylose formed complexes with iodine. Theoretically, rice without the addition of santan should have the lowest CI values in all treatments. However, the CI values of sample cooked without santan remained relatively low in all treatments except for B, D, E and G. Rate of freezing afects the CI as well. Fast freezing has resulted in lower CI compared to slow freezing, as indicated by sample B, D and E. The efect of rate of freezing on CI is very signiicant. Immediate reheating resulted in higher CI value compared to thawing prior to reheating as indicated by sample G. When the data were analysed using the GLM, it was observed that the single factors (type of santan, santan to rice ratio, freezing rate and reheating condition) did not have a high impact on the CI of nasi lemak. The value for R2 was just 53.88%. However, the interactions between these factors having R2 of 99.66% really inluenced the CI values. The interaction between type of santan, freezing rate and thawing condition had given the highest impact on CI of frozen nasi lemak. the higher the amount of leached amylose, the harder the inal cooked rice texture. This could explain why rice cooked without santan (sample G) that has undergone slow freezing has higher hardness values compared to that of fast freezing. Slow freezing caused more rupture to cells and more leaching components is released. But this situation could only be noticed easily in rice cooked without santan. When santan was added during cooking and cooked samples were freezed and reheated at diferent conditions, this theory could not be applied. The efect of diferent freezing rates and thawing conditions were not very clear in frozen nasi lemak regardless of the type of santan used. Hardness is generally related to the level of the amylose content. Generally, high amylose rice has high hardness and tensile values (Lu et al., 2009). In this experiment, the same type of rice is used in all samples. Therefore, the diference in hardness values is not due to the diference in amylose content. The addition of santan may contributed to the changes in hardness. According to Kaur and Singh (2000), the addition of fatty acids into food that contains starch will alter the physical and chemical properties of food since starchy food will tend to form complexes between amylose and lipids. These complexes afect the hardness value. Cameron and Wang (2005) reported that protein and crude lipid contents have a negative correlation with hardness of cooked rice. Generally, results in Figure 3 indicate that as the amount of santan increased, the hardness of rice gradually decreased. It is observed that type and amount of santan added afected the hardness of nasi lemak. However, the efect of using diferent types of santan only had a smaller impact on the hardness of the samples. Data analysis using the GLM showed that type of santan, amount of santan, the interaction between the rate of freezing and thawing condition, and the interaction between type, amount and rate of freezing have a signiicant efect on the hardness of frozen nasi lemak. Hardness Stickiness The rice kernels were analysed for its hardness at an ambient temperature and the results are shown in Figure 3. Hardness is related to the hydration process which takes place in starch granules. During cooking, rice granules absorb moisture and swell which provide the increase in volume of cooked rice. While the granule expands, cells will rupture and cause amylose leaching. This may afect the rice texture. Cameron and Wang (2005) reported that the cooked rice texture has strong correlation with the amount of insoluble amylose than did the apparent amylose or leached amylose. They concluded that Stickiness is another important criteria when it comes to cooked rice. Amylose content is not directly related to the stickiness but when the amylose content was high, the stickiness will be low (Ayabe et al., 2009). Figure 4 shows the mean and standard deviation of stickiness of samples. Negative (-ve) sign indicates the stickiness, as measured by the Texture Analyser (TA.XT21, Texture Technologies, Corp, UK). Rice without santan has the lowest stickiness value followed by frozen nasi lemak made of palm-based santan and frozen nasi lemak made of coconut santan. The stickiness of rice was increased 6 JOURNAL OF OIL PALM RESEARCH 25 (2) (AUGUST 2013) Palm-based santan Coconut santan No santan Figure 3. Means ± standard deviation of hardness of nasi lemak made of palm-based and coconut santan under diferent processing conditions. Palm-based santan Coconut santan No santan Figure 4. Means ± standard deviation of nasi lemak made of palm-based and coconut santan under diferent processing conditions. 7 JOURNAL OF OIL PALM RESEARCH 25 (2) (AUGUST 2013) as more santan was added. The amount of santan signiicantly inluenced the stickiness. This applied to both types of santan. The rate of freezing also has signiicant efect on the stickiness of samples. Slow freezing resulted in samples which were less sticky compared to fast freezing and unfrozen rice. Immediate reheating resulted in stickier samples compared to thawing prior to reheating. The stickiness of the rice was not greatly afected by the processing conditions as shown in Figure 4. The trend was not very clear. According to Syamsir et al. (2011), the deformation of the grain and exposed endosperm after the grain splitting sharply changed stickiness values. The addition of santan during cooking and the processing conditions (freezing and thawing) caused some deformations to the rice kernels that vary its stickiness values. However, frozen samples (B and C) had low stickiness values in all formulations. The stickiness value was the highest in samples formulated with two-ifth santan to rice ratio that had undergone fast freezing followed by immediate reheating. The R2 value for the single factor analysis was 64.53%, whereas, in the interactions analysis the R2 value was higher (98.87%). This indicates that interactions between factors (type of santan, santan to rice ratio, freezing rate and reheating condition) has a signiicant efect on the stickiness of nasi lemak. The type and amount of santan have the highest value of sequential Seq SS, thus indicating that these two factors have very signiicant impact in the stickiness of nasi lemak. one-ifth santan to rice ratio is suicient to cook a nasi lemak, and it applies to both types of santan. Results from the sensory evaluation shows that frozen nasi lemak made of coconut santan had higher scores compared to frozen nasi lemak made of palm-based santan for all attributes except for oiliness, hardness and stickiness, where they are not signiicantly diferent, as shown in Table 3. Signiicant diferences were observed for colour, odour and overall taste between the samples. Only eight out of 32 panellists prefered the frozen nasi lemak made of palm-based santan. The majority of the panellists prefered frozen nasi lemak made of coconut santan. Figure 5 further illustrates the values showed in Table 4. From the results it can be concluded that some eforts could be made to improve the colour, odour and overall taste of nasi lemak made of palmbased santan. The performance of palm-based santan should be improved so that it is comparable or better than coconut santan in frozen nasi lemak. By doing this, consumer demand and preferences for palm-based santan can be increased. Sensory Evaluation Nasi lemak is a common food among Malaysians especially for breakfast. Therefore, the use of untrained panellists in this sensory study was suicient to meet the purpose. Only nasi lemak with 1/5 santan to rice ratio was used in the sensory evaluation because results from the previous physical analyses of this experiment showed that Figure 5. Mean values of hardness, stickiness, oiliness, colour, odour and overall taste of frozen nasi lemak made of palm-based and coconut santan. TABLE 3. MEAN ± STANDARD DEVIATION OF SENSORY ATTRIBUTES OF NASI LEMAK MADE OF PALM-BASED AND COCONUT SANTAN Hardness Stickiness Oiliness Colour Odour Overall Taste Preference Coconut santan 6.7813 ± 1.3616a 6.6563 ± 1.3102b 6.5625 ± 1.2165c 7.2813 ± 0.9583d 7.4063 ± 1.1876f 7.5937 ± 0.9108h 24 Palm-based santan 6.4688 ± 1.7410a 6.4375 ± 1.2936b 6.5625 ± 1.1622c 6.3438 ± 1.4505e 6.0938 ± 1.6136g 6.6563 ± 1.4505i 8 Note: Mean values in the same column with diferent letters are difer signiicantly (p<0.05). 8 JOURNAL OF OIL PALM RESEARCH 25 (2) (AUGUST 2013) El-BASSIOUNY, H M S and BEKHETA, M A (20050. Efect of salt stress on relative water content, lipid peroxidation, polyamines, amino acids and ethelyene on two wheat cultivars. International journal of Agriculture and Biology, 7(3): 363-368. CONCLUSION The ratio of palm-based santan to rice of one-ifth is suicient in providing the texture to a frozen nasi lemak. However, nasi lemak made of palm-based santan has a lower moisture content compared to one made of coconut santan. The rate of the freezing and thawing process inluences the moisture content and texture properties of frozen nasi lemak. Fast freezing followed by immediate reheating without thawing resulted in less sticky, irm texture. The water activity of frozen nasi lemak was very high (0.994 to 0.998 at 25.0 ± 0.7°C) and was not signiicantly afected by processing conditions and type of santan. The formation of lipid-amylose complexes was enhanced by increasing the amount of santan and this applies to both types of santan. Increasing of santan to rice ratio led to the reduction of hardness but an increase in the stickiness of the rice kernels, regardless of the type of santan. 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