Enzymatic Glycerolysis of Palm Kernel Olein and Palm Kernel Stearin in different Ratios for Monolaurin Synthesis

Monolaurin is known as a monoglyceride of lauric acid, which act as an emulsifier and antimicrobial. One potential of monolaurin raw materials is palm kernel oil (PKO), which can be fractionated into palm kernel olein (PKOo) and palm kernel stearin (PKS). This study aims to determine the enzymatic glycerolysis influence of PKOo and PKS mixture in different ratios and time, on monoacylglycerol (MAG), diacylglycerol (DAG), and triacylglycerol (TAG) profiles. The Glycerolysis process of PKOo-PKS fat blends were carried out in different ratios of (60:40, 40:60, and 20:80 w/w) using commercial lipases (Lypozime RM IM) at 50°C, with an oil:glycerol molar ratio of 1:4, in a tert-butanol solvent system, between 3 to 24 hours. The results showed that the glycerolysis of PKOo and PKS in different ratios yielded varying product reactions with similar compositions (1.8-3.9% MAG, 73.2-76.4% DAG, and 20.7-24.2% TAG). A higher and not significant MAG was observed during the period of 24 hours. Also, the monolaurin was obtained at the ratio of 40:60 PKOo:PKS, within the glycerolysis time of 3 to 24 hours, at approximately 2.18±0.59% and 3.47±0.62%, respectively. The FTIR analysis also showed that the monolaurin sample was identical to the standard type, with the formation of OH group at wave number and cluster C=O ester of 3368.64 cm-1 and 1734.03 cm-1, respectively.

Physicochemical Properties of Palm Kernel Oil and Palm Kernel Olein Blends

Palm kernel oil (PKO) and palm kernel olein (PKOo) have limited application due to rapid crystallisation properties and excessive foaming during heating, respectively. In this study, a series of PKO and PKOo blends were prepared at different concentration and analysed for slip melting point (SMP), solid fat content (SFC), triacylglycerols (TAGs) composition, thermal and morphological properties. The addition of 90% RBDPKOo caused the SMP to decrease from 27.8°C to 23.80°C. All the samples show steep SFC melting profile from 0°C to 30°C. The onset crystallisation temperature of RBDPKO was delayed with the addition of 90% PKOo from 9.73°C to 5.80°C and totally melted at lower melting temperatures. It was observed that the addition of RBDPKOo caused the crystals to be spherulitic, scattered and less aggregated with each other. The addition of RBDPKOo reduced the compositions of the main TAG of RBDPKO such as LaLaLa, LaLaM and CLaLa. Therefore, through blending the physicochemical properties of the RBDPKO and RBDPKOo could be changed. Hence, their applications in food could be widened.

KARAKTERISTIK MINYAK CAMPURAN RED PALM OIL DENGAN PALM KERNEL OLEIN (Characteristics of Oil Blends from Red Palm Oil and Palm Kernel Olein)

Characteristics of oil blends has been produced from red palm oil (RPO) and palm kernel olein (PKOo) with seven ratios with a total of 100, namely A (0:100), B (25:75), C (40:60), D (50:50), E (60:40), F (75:25) and G (100:0) v/v investigated with randomized complete block design. The result showed that different of ratio levels RPO and PKOo have some effects on peroxide value, saponification value, melting point, cloud point and β-carotene content from RPO-PKOo oil blends, but has not effect on free fatty acid content. Higher level of PKOo content on formulas oil blends were decreased of saponification value and melting point, but was increased of cloud point. The best of RPOPKOo oil blends has been obtained at ratio 50:50 (v/v), with 459.52 ppm β-carotene, 1.35 meq/kg peroxide value, 0.09 % free fatty acid, 202.60 saponification value, 24.15 oC melting point and 7.15 oC cloud point. Fatty acids composition were 1.24 % capric acid, 29.00 % lauric acid, 10.09 % miristic acid, 23.10 % palmitic acid, 5.84 linoleic acid, 27.30 % oleic acid and 3.43 % stearic acid.Keywords: Red palm oil, palm kernel olein, oil blends, chemical and physical propertiesABSTRAKSifat-sifat minyak campuran yang dihasilkan dari red palm oil (RPO) dan palm kernel olein (PKOo) dengan tujuh tingkat rasio yang totalnya 100, yaitu A (0:100), B (25:75), C (40:60), D (50:50), E (60:40), F (75:25) dan G (100:0) (v/v) dikaji menggunakan rancangan acak lengkap kelompok. Hasil penelitian menunjukkan bahwa rasio RPO:PKOo mempengaruhi angka peroksida, angka penyabunan, melting point, cloud point dan kadar β-karoten dari minyak campuran RPO-PKOo yang dihasilkan, namun tidak mempengaruhi kadar asam lemak bebas. Peningkatan jumlah PKOo yang ditambahkan dalam minyak campuran RPO-PKOo, akan menurunkan angka penyabunan dan melting point, namun akan menaikkan cloud point. Produk minyak campuran RPO-PKOo terbaik diperoleh pada rasio 50:50 (v/v), dengan kadar β-karoten 459,52 ppm, angka peroksida 1,35 meq/kg, asam lemak bebas 0,09 %, angka penyabunan 202,60, melting point 24,15 oC dan cloud point 7,15 oC, serta komposisi asam lemak (kaprat 1,24 %, laurat 29,00 %, miristat 10,09 %, palmitat 23,10 %, linoleat 5,84 %, oleat 27,30 % dan stearat 3,43 %).Kata kunci: Red palm oil, palm kernel olein, minyak campuran, sifat kimia, sifat fisika