Physicochemical Study of Palm Ester for Cosmetic Application

Physicochemical Study of Palm Ester for Cosmetic Application 2.0 Introduction Palm oil is extracted from the fruit of oil palm, Elaeis guineensis. Besides, Malaysia is one of the leading exporters and producers of palm oil in the world (Keng et al., 2005 Palm oil has been widely applied in various industrial sectors due to the uniqueness of its composition (Keng et al., 2009). It consists of triglycerides; the combination of glycerol and different fatty acids. Furthermore, other palm oil fractions can be extracted as palm oil is rich in Palmitic acid and Oleic acid (OBrien, 2004). Specifically, in this study, Palm Olein will be used to produce palm ester instead of the other fractions. Wax esters are one of the most important ingredients in cosmetic formulations (Hallberg et al., 1999). The emollient behavior of wax esters makes it applicable for numerous personal care products (Peter Robert, 2001). Besides, synthetic ways to produced ester has been introduced since naturally occurring wax esters are limited and expensive (Keng et al., 2009). Thus, in this study lipase-catalyzed reaction of Palm Olein and Oleyl alcohol by using immobilized lipase will be carried out in order to synthesize wax esters (palm ester). Physicochemical study as well as thermal stability will also be conducted since the characterization of esters is important in order to examine their effectiveness in industrial applications. 3.0 Literature Review 3.1 Waxes In general, the mixture of long-chain of lipid forming a protective coating on plant leaves and animals is waxes (Keng et al., 2005). Besides, it has been used commercially in many areas. Lubricants, polishes, coating materials are some of its applications (Hamilton, 1995; Hallberg et al., 1999). Carnuba wax, beeswax, wool wax and spermaceti wax are some examples of waxes that exist naturally. Animals, plants and minerals are the source of natural waxes (Gunawan et al., 2005). Thus, waxes can be classified into two types which are natural waxes and synthetic waxes. 3.1.1 Natural Waxes Sperm whale oil is one of the natural waxes and it can be found in the open ocean. Years ago, the whale species of P. macrocephalaus was a prime source of wax. This is because of the liquid wax called spermaceti that contained in the head of the whale (Rice, 2009). The liquid wax is present abundantly in the spermaceti organ of the whales. Moreover, manufacturers found that spermaceti is very useful (Whale facts, 10 November 2014). It is a great substance that can be used in many sectors. However, due to the extinction of this species, the government has banned all the whale hunting. Thus, jojoba oil has become the main natural sources of wax since the cessation of whale hunting (Keng et al., 2009). Other than that, Jojoba is a shrub which can be found in Arizona, Mexico and some other areas (Allawzi et al., 1997). The seed of the Simmondsia chinesia (jojoba) plant contain a unique oil which known as jojoba oil. Besides, jojoba oil makes up approximately 50% of the seed’s weight. It is composed of the straight chain monoesters of the monounsaturated C20and C22 alcohols and acids (Wisniak, 1994). Furthermore, the uniqueness of jojoba oil is due to its chemical composition. It contains a little or no glycerin. As the glycerin is almost completely absence, it indicates that jojoba differs from the other seed oil. It is proved that it is a liquid wax not fat. 3.2.2 Synthetic Waxes Day by day, the demands of waxes keep growing. Unfortunately, it is too expensive for large-scale use of natural waxes like jojoba oil. Moreover, it requires up to 5 years for commercial jojoba plantations to start produce seeds (Keng et al., 2009). Thus, ways to synthesize wax with cheaper materials and in shorter time become very crutial (Radzi et al., 2005). In order to synthesize synthetic wax, chemical and enzymatic methods can be used (Keng et al., 2005). However, chemical-catalyzed method may leads to high energy consumption and degradation of esters whereas the enzymatic synthesis offers mild reactions and environmental-friendly process (Yadav Lathi, 2003). Normally, synthetic waxes are used in cosmetics formulations as replacement of natural waxes. Synthetic waxes from natural raw materials have not much different from the natural ones. Synthetic beeswax, synthetic spermaceti, polyethylene waxes and polawax are the examples of synthetic waxes (SpecialChem, 8 November 2014) 3.2.3 Wax Ester The long chain of esters that derived from fatty acids and alcohols are referred as wax esters (Chen Wang, 1997). The chemical structure of wax ester is shown in Figure 1 below. Typically, it is composed of n-alkanoic acids and n-alkan-1-ols with carbon atoms ranging from C12-C32 (Misra Ghosh, 1991). Wax esters are very important in various industries, especially in cosmetic formulations. This is due to its characteristics which are non-irritating and non-greasy feeling when in contact with skin (Peter Robert, 2001). Figure 1: The Chemical Structure of Wax Ester (AOCS lipid library, 10 November) Wax ester can be extracted from animals and plants. Besides, it is a major component of beeswax and jojoba plants. Hence, it’s can’t be deny that the extraction of wax ester from natural sources are expensive for commercial use and it is limited (Keng et al., 2005) 3.2 Palm Oil In early 1870, the oil palm tree (Elaeis guineensis) has been introduced in Malaysia as an ornamental plant by British (Malaysian palm oil council, 11 November 2014). The oil palm tree originates from West Africa (Hartley, 1988). Typically, it has been used as cooking oil. As this plant can be commercialized, it has also been introduced to many other countries. From wild plant, it was developed into an agricultural crop. Moreover, the expansion of its plantation was due to the high demands from the consumers. Figure 2 below shows the oil palm tree as an agricultural crop. Figure 2: The Oil Palm Tree (Wikipedia Palm Oil, 12 November 2014) The first commercial of oil palm in Malaysia was founded on 1917 (Malaysian Palm Oil Council, 11 November 2014). From that onwards, the huge palm oil industry in Malaysia had started. Recently, palm oil, the extraction from the fruit of oil palm is the leading agricultural crop of Malaysia (MPOB, 2004). Besides, Malaysia has been announced as one of the largest producers and exporters of palm oil in the world (Malaysian Palm Oil Council, 11 November 2014). The uniqueness of palm oil composition makes it easy to be commercialized. In addition, it has been applied in many industrial sectors such as pharmaceutical, cosmetic formulations and food manufacturing (Keng et al, 2005). In Malaysia, the oil palm trees planted are the crossbred of dura and pisifera, known as tenera variety (Latiff, 2000). The mature trees will grow up to 20m tall. The size of the palm fruits is approximately the same with the size of the small plum and it’s grow in bunches. The weight of each bunch is between 10-50 kilograms and containing around 2000 individual fruits. Usually, the oil palm tree will start to produce fruits after 30 months. Its productivity will keep growing for the next 3 decades (Palm oil world, 11 November 2014). Normally, the fruits are dark purple and almost black (Malaysian Palm Oil Council, 11 November 2014). The colour will turns to reddish orange when ripe. The fruits consist of an outer pulp and kernels (Gunstone, 2001). The fruit of palm tree is the source of two different oils. Palm oil and palm kernel oil are the types of oil that can be obtained from the fruit of oil palm tree (Malaysian Palm Oil Council, 11 November 2014). The outer pulp contains palm oil while palm kernel oil is obtained from the kernel of the fruit. Even though these two types of oil are derived from the same plant, they are completely different by comparing their characteristics and properties (Keng et al, 2009). Figure 3 below shows the fruit bunches of oil palm tree and its cross section. Figure 3: The Fruit Bunches of Oil Palm Tree and Its Cross Section. (Malaysian Palm Oil Board, 12 November 2014) Furthermore, palm oil consists of triglycerides. Triglycerides are a combination of glycerol and different fatty acids. Palm oil is rich in palmitic acid and oleic acid, while palm kernel oil is rich lauric acid (O’Brien, 2004). Besides, these fats can be fractionated into solid and liquid fractions to produce stearins and oleins, respectively (Keng et al, 2009). Even though Lipase-catalyzed reaction of palm oil and palm kernel oil by using lipase are quite simple, the characterization of long chain esters is significant in order to examine their ability and efficiency in industrial sector. Palm Olein, the liquid fraction of palm oil will be used in the synthesis of palm ester instead of the other fractions (Malaysian Palm Oil Council, 12 November 2014). Thus, the synthesis, physicochemical properties and thermal stability of palm ester will be carried out specifically focusing on alm Olein. 3.3 Enzymes Human body is characterized by complex system of related chemical reaction. Besides, the reaction must be fully controlled in order to maintain life. Thus, enzymes are necessary for many reactions to confirm that it occur at suitable rates (Brown et al., 2012). Enzyme is a substance that speeds up reactions without any permanent changes and also known as catalyst. The building blocks of enzymes are amino acids and they are proteins. Enzyme catalyzes reaction takes place at specific location known as active site. Usually, enzymes are specific according to the reaction they catalyzed and the substrate that involves in the reaction. However, unwelcoming inhibitors are naturally occurring and disturb the enzyme reaction. Since enzymes are flexible, the active site is continuously reshaped. Besides, the combination of enzyme and substrate is called the enzyme-substrate complex. As the enzymes react with many substrates, the rigid lock and key model is not valid. In 1958, the modification of lock and key model has been proposed. Figure 4 below shows the modification of lock and key model (Koshland, 1958). Figure 4: The Lock and Key Model (Wikipedia, 11 November 2014) 3.3.1 Lipases Lipases are water-soluble enzyme and it’s able to catalyze both hydrolytic and synthetic reaction. Lipases are widely used in many sectors. They play an important role in the production of leather, detergent industries and in production of surfactants (Knezevic et al., 2004). Naturally, lipases are used in hydrolysis of acylglycerides. However, they are useful in many other reactions. In fact, lipases are qualified of catalyzing the reverse reaction synthesis Due to its ability to combine with broad range of substrate specificity (Gandhi, 1997). Besides, some lipases are more suited for synthesis than hydrolysis reactions. 3.3.2 Immobilized Lipases Lipases used in detergents and many other applications are not immobilized. However, due to an increasing specialty application of lipases demand an immobilized biocatalyst for efficient use (Sharma et al., 2001). Besides, immobilized lipase can reduce the cost and poor stability of free lipase. Adsorption, covalent binding and entrapping are some of the immobilization techniques (Knezeic et al., 2004). Since the immobilization method is typically accompanied by changes in enzymatic activity, pH, temperature and stability, each of the methods has its advantages and disadvantages. Besides, the used of immobilized lipases are very useful in the pharmaceutical, oleochemical and food industry (Knezevic et al., 2004). 3.4 Lipase-Catalyzed Reaction Lipase-catalyzed reaction can be classified into two main categories which are hydrolysis and synthesis. Synthesis category can be further separated into esterification, interesterification, alcoholysis and acidolysis. Table 1 below shows the classification of lipase-catalyzed reaction. Table 1: The Classification of Lipase-Catalyzed Reaction (Gandhi, 1997) In this experiment, alcoholysis of lipase-catalyzed reaction will be conducted. It is also called enzymatic transesterification as the last three reactions (interesterifiction, alcohoysis and acidolysis) are grouped together into single term which is transesterification (Gandhi, 1997). 3.5 Oleyl Alcohol Oleyl alcohol is long chain fatty acids. Fatty acids can be derived from natural fats and oils. Besides, it can be found I beef fat as well as fish oils. Cis-9-Octadecen-1-ol and Oleo alcohol are the synonyms name of oleyl alcohol. The chemical formula of oleyl alcohol is CH3(CH2)7CH=CH(CH2)7CH2OH. Moreover, oleyl alcohol is a clear oily liquid and insoluble in water (chemicalland21, 10 November 2014). Furthermore, fatty alcohols are emulsifiers and emollients to make skin smoother and prevent moisture loss (chemicalland21, 10 November 2014). Hence, it has been used widely as raw materials in industrial sectors such as cosmetics, pharmaceutical, metal processing and lube additive. In this study, Oleyl alcohol will be used as internal standard of gas chromatography analyses. The chemical structure of oleyl alcohol is shown in Figure 5; Figure 5: The Chemical Structure Of Oleyl Alcohol (chemicalland21, 10 November 2014) 3.6 The Application of Physicochemical Study in Cosmetic Formulations Nowadays, industrial cosmetic has immerged along with the advancement of global technology. The development of new cosmetic formulations is due to the discovery of active component in herbs and other natural sources. Thus, study has been done in order to investigate the chemical composition and characteristics of the active components. 3.6.1 Physicochemical Study According to Brasil (2004), physicochemical study is the determinant step in the development of cosmetic formulations. Physicochemical study is the study of the relations between composition and physical properties of the elements. Besides, this study is significant in order to know the intrinsic properties of elements and their ability to react with specific reagent (High Technology Detection Systems, 12 November 2014). Slip melting point, refractive index, saponification value, iodine value and acid value are the physicochemical measurement that will be analyzed in this study. Slip melting point is one of the physical properties which is useful in identification purposes and assessment of purity. It’s proportional to the increase in chain length and degree of saturation. In addition, slip melting points fats usually contain 5% solid fat; thus slip melting point generally happens at lower temperature than the melting point of the fat itself (Akoh et al., 2004). The ratio of the speed of light in a vacuum to the speed in the medium is known as the refractive index. Besides, refractive index is easily determined characteristics of fats, oils and their derivatives. It is important to obtain an accurate refractive index for the purposes of identification and for the progress of reaction like catalytic and isomerization. Generally, for the liquid oils, the density increases with increase in unsaturation and decreases with the increase in molecular weight at constant temperature. On the other hand, the refractive index will increases with the length of hydrocarbon chain and when the number of double bonds in molecules increase (Formo, 1999). Saponification is hydrolysis of ester under alkaline solution. Saponification value is the measure of chain length of all fatty acids present. The saponification value of an oil or fat is defined as the number of mg of potassium hydroxide required to neutralize the fatty acids resulting from the complete hydrolysis of 1 g of the sample. Besides, low saponification value is found from the long chain fatty acids due to the fewer number of carboxylic functional groups (Virtual Amrita Laboratories Universalizing Education, 13 November 2014). For the Iodine value, it measures the content of unsaturation or double bonds of fats and oils. Besides, it is one of the parameters used to measure the quality of olein (Buana et al., 1998). The iodine value also denotes the percentage by weight halogen, calculated as iodine and absorbed under the condition of the test. It is expressed as the number of iodine (grams) absorbed by the fat (100 grams) under test condition. According to O’Brien (1988), iodine value is a valuable constant that can be easily determined for fats and oils. One of the common parameter used in specification of fats and oils is acid value. It is defined as the number of milligrams potassium hydroxide needed to neutralize the free acid in one gram of sample. Besides, it is a measure of free fatty acids present in the fat or oil (chemprime, 13 November 2014). 3.6.2 Applications in Cosmetic Since ancient times, natural extracts from animals, plants and minerals have been used as special ingredients in cosmetics (Elsner Maibach, 2000). Wax esters are formulated in numerous personal care products due to its emollient behavior. Due to that, proper study on its characteristics is as important as the synthesis reaction (Keng et al., 2009). Besides, one of the most essential phases in development of new cosmetic formulations is the adequate physicochemical characterization to guarantee the identification of new patentable compound (Crystal Engineering, 12 November 2014). Physicochemical study is not a visible nor directly applied in cosmetic. However, the determination of each properties of physicochemical study is important in order to verify the compatibility of the extraction of palm oil for cosmetic application. Besides, it is important to verify whether the cosmetics are safe to be used. Hence, in this study the physicochemical properties of palm oil fraction focusing on palm olein will be carried out. 4.0 Problem Statement Currently, most of the chemical product derived from synthetic origin. However, product produced from chemical synthesis is not pure and involved hazardous chemicals. Thus, enzymatic reaction is preferable due to green synthesis process, environmental friendly and the product is pure. Physicochemical study is important in cosmetic formulations. However, rarely study on physicochemical had been reported in journal and any research paper. Due to that, in this research, a physicochemical study will be carried out such as slip melting point, refractive index, saponification value, iodine value, and acid stability. Besides, thermal stability will also be carried out in this research. Nowadays, a lot of synthesized products had been produce. However, the verification of those products was rarely reported. Hence, in this study, the synthesized product will be verified using spectroscopy methods such as thin layer chromatography (TLC) and gas chromatography (GC). 5.0 Objectives In this study, the synthesis of palm ester will be carried out. Enzymatic synthesis will be applied in order to produce palm ester. Besides, the physicochemical study will be conducted in order to apply palm ester in cosmetics. Therefore, this particular work will be carried out with the following objectives: To synthesize palm ester through enzymatic transesterification. To investigate the physicochemical properties and thermal stability of palm ester. To verify the synthesized palm ester using spectroscopy methods.