The extraction of dehulled ground palm kernel using supercritical carbon dioxide (SC-C02) as a solvent at temperatures of 40 and 80°C and pressures of 20.7,27.6, 34.5, 41.4 and 48.3 MPa was studied. Continuous extraction was fractionated into four fractions and each fraction was collected for every 10 minutes. Thus the total extraction process was performed for 40 minutes extraction time.



Kajian ke atas pengekstrakan isirung sawit tanpa testa hancur menggunakan lampau genting karbon dioksida (LG-C02) sebagai pelarut pada suhu 40 dan 80°C dan tekanan 20.7, 26.7, 34.5, 41.4 dan 48.3 MPa. Pengekstrakan berterusan dipemeringkatkan kepada empat pemeringkat dan setiap pemeringkat dikumpul selarna 10 minit dengan jumlah proses pengekstrakan dibuat selama 40 minit masa pengekstrakan

Sarker, Md. Zaidul Islam

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:SUPERCRITICAL CARBON DIOXIDE FRACTIONATION OF PALM KERNEL OIL AND FORMULATION OF COCOA BUTTER REPLACERS FAT By MD. ZAIDUL ISLAM SARKER Thesis submitted in fulfillment of the requirements for the degree of Doct?r of Philosophy July 2003 Dedicated To My revered parents Alhajj Mohd. Ezahar Ali Sarker & Mrs. Zobeida Begom And my parents-in-law The Late Nazir Hossain & The Late Amina Begom 11 ACKNOWLEDGEMENTS I am especially grateful to my supervisor, Professor Ir. Dr. Mohd. Omar bin Ab. Kadir of the School of Industrial Technology, and my co-supervisor, Associate Professor Dr. Nik Norulaini Nik Abd. Rahman of the School of Distance Education, Universiti Sains Malaysia (USM) for their enthusiasm and invaluable guidance, which has brought this project into a reality. I would also like to thank them for appointing me as a research fellow under IRP A grant No: PTEKIND/30S/61 0636. My thanks are also due to the vice chancellor of USM for providing my tuition fees under the Federation of Universities of the Islamic World (FUIW) fellowship scheme and also to the Dean of the School of Industrial Technology, USM, Associate Professor Dr. Wan Rosli Wan Daud, to the deputy deans, Associate Professor Dr. Abd. Karim Alias and Associate Professor Dr. Rozman, to other lecturers especially to Dr. Azlan Ariffin and staff of School of Industrial Technology, USM, for their direct or indirect help in making this project successful. I would like to express my gratitude and thanks to Associate Prof. Dr. Ataharul Islam of the School of Mathematics, USM for his cordial help in statistically analysing the experimental data of this thesis. Cooperation from laboratory assistants, from my colleagues especially from Anuar Omar, and from my friend Md. Fazlul Bari, PhD student from the School of Chemical Sciences, is also gratefully appreciated. 111 I would like to thank all Bangladeshi and foreign students for their encouragement within the small international community in USM, especially to Md. Mahmudul Hassan (PhD student of the Center for Policy Research, USM) and Mrs. Salma Mahmud (Master Student of the same center, USM) for their suggestions and moral support. I would like to gratefully thank Malpom Sdn. Bhd. (Nibong Tabat, Penang), Wilmer Edible Oil Company (Butterworth, Penang) and Acidchem International (Seberang Prai, Penang) for providing samples for this research. The special gratitude and thanks go to my all teachers, especially Mohd. Abd. Latif Prodhan and Dr. Mohd Shahjahan (Dept. of Biochemistry, Rajshahi University, Bangladesh) and to villagers, relatives and friends left back at home for their encouragement and support. I thank my elder brother Dr. Azim Uddin Ahmed who is waiting to call me Dr., and also my younger brother Md. Shahidul Islam Sarker and my sisters especially Mrs. Jahanara Begom for their encouragement. Finally, I gratefully acknowledge the moral support and perseverance of my dear wife and my best friend Mrs. N azmin Begom who took special care of my physical and spiritual comfort throughout the study. Her continuous support and enthusiasm for my career is most invaluable. iv ABSTRACT The extraction of dehulled ground palm kernel using supercritical carbon dioxide (SC-C02) as a solvent at temperatures of 40 and 80°C and pressures of 20.7,27.6, 34.5, 41.4 and 48.3 MPa was studied. Continuous extraction was fractionated into four fractions and each fraction was collected for every 10 minutes. Thus the total extraction process was performed for 40 minutes extraction time. Solubility of palm kernel oil (PKO) increased and total use of carbon dioxide (C02) decreased with increase in temperature from 40 to 80DC and pressures at 34.5, 41.4 and 48.3 MPa. At lower pressures of 20.7 and 27.6 MPa solubility of oil decreased and use of CO2 increased with increase in temperature (80°C) and this was due to the retrogradation characteristic of supercritical fluid at lower pressure. The highest yield was obtained at 48.3 MPa and 80DC with minimum CO2 used. For fractionations the first fraction gave the highest yield and then gradually decreased till to the last fraction for both temperatures 40 and 80DC. That was due to the low solubility of PKO in the later fraction. This trend had been observed for all the pressures except 20.7 and 27.6 MPa. At 20.7 and 27.6 MPa the yield was found to be almost the same for all fractions. This is due to lower amount of oils were extracted at 20.7 and 27.6 MPa. The three-way analysis of variance (AN OVA) on the yield as a function of pressure, temperature and fractionation showed that the yields were found to be significantly different at different pressures and temperatures indicating a significant difference between the population means (p value::S 0.01). Also the yield at different fractions was significantly different (p S 0.01). The different fatty acid compositions caprylic (C8), capric (ClO), lauric (CI2), myristic (CI4), palmitic (CI6), stearic (CI8:0), oleic (C18:l) and linoleic (C18:2) acid in the SC-xxx C02 fractionated PKO were found to be different at various pressures and temperatures. More C8, CI0, C12 extracted in the first fractions, which gradually declined as extraction period extracted into second, third and fourth fractions. C 14 remained unvaried over the extraction period showing no remarkable difference among the fractions but at 48.3 MPa and 80°C it reduced remarkably in the last fraction. On the other hand more C16, C18 and , unsaturated C 18: 1 and C 18:2 were present in the latter fractions. This trends were found to increase with increase in pressures and temperatures but the difference were not remarkable at lower pressure 20.7 and 27.6 MPa for both temperatures. However, the compositions were found to be statistically significant for pressure and fraction times by type of fatty acid. Blending of palm oil (PO), 4th fraction of palm kernel oil extracted using SC-C02 at 48.3 MPa and 80°C (PKO-SC4), palmac 98-18 (C18 based) and palmac 760 (CI8:1 based) at different ratios were carried out to obtain blends of cocoa butter replacers (CBR). There were 13 blends performed through out the study. ,Blends 1 to 10 were recommended as cocoa butter substitutes (CBS) and blends 11 to 13 were referred as cocoa butter equivalent (CBE) fats. The slip melting point (SMP) for blends 11, 12 and 13 were found to be 33.3, 35.1 and 35.3°C, respectively, whereas for the CB it is 35°C. Also the solid fat content (SFC) of these CBB were found to be higher at 20°C and 0 percent within 37.SoC. This trend is quite similar to commercial cocoa butter (CB). The iodine value, saponification value and acid value of these CBE were found quite similar to CB. Thus it proposed to substitute CB at maximum level of substitution. However, the physico-chemical properties of blends 1 to 10 were not found to be as close as CB but it could be proP9sed as CBS for low level of substitution of CB. XXXI ABSTRAK Pemeringkatan Lampau Genting Karbon Dioksida Minyak Isirung Sawit Dan Formulasi Lemak Pengganti Mentega Koko Kajian ke atas pengekstrakan isirung sawit tanpa testa hancur menggunakan lamp au genting karbon dioksida (LG-C02) sebagai pelarut pada suhu 40 dan 80°C dan tekanan 20.7, 26.7, 34.5, 41.4 dan 48.3 MPa. Pengekstrakan berterusan dipemeringkatkan kepada empat pemeringkat dan setiap pemeringkat dikumpul selarna 10 minit dengan jumlah proses pengekstrakan dibuat selama 40 minit masa pengekstrakan. Kelarutan minyak isirung sawit (PKO) meningkat dan jumlah karbon dioksida (C02) yang digunakan menurun dengan meningkatnya suhu dari 40 ke 80°C dan tekanan pada 34.5, 41.4 dan 48.3 MPa. Pada tekanan rendah 20.7 dan 27.6 MPa kelarutan minyak menurun dan penggunaan CO2 meningkat dengan meningkatnya suhu (80°C) dan ini disebabkan oleh ciri kesan undur (retrogradation) bendalir lamp au genting pada tekanan rendah. Penghasilan minyak tertinggi diperolehi pada 48.3 MPa dan 80°C dengan penggunaan C02 yang minima. Pemeringkatan untuk pemeringkat pertama memberikan hasil yang tertinggi dan kemudian perlahan-lahan menurun pada pemeringkat yang terakhir untuk kedua-dua suhu 40 dan 80°C. lni disebabkan oleh kelarutan PKO yang rendah dalarn pemeringkat yang terakhir. Tren ini diperhatikan pada kesemua tekanan kecuali tekanan 20.7 dan 27.6 MPa. Didapati pada 20.7 dan 27.6 MPa hasil yang diperolehi adalah sarna pada kesemua pemeringkat, ini disebabkan oleh kurangnya arnaun minyak yang diekstrak pada 20.7 dan 27.6 MPa. XXXll Analisis varian 'three-way' (ANOVA) ke atas hasilan sebagai fungsi tekanan, suhu dan pemeringkatan menunjukkan bahawa hasilan berbeza seca signifikan pada tekanan berbeza dengan suhu di antara min populasi (p value:::; 0.01). Begitu juga hasilan pada pemeringkat berbeza berbeza secara signifikan (p value:::; 0.01). Didapati komposisi asid lemak kaprilik (C8), kaprik (CIO), laurik (CI2), miristik (CI4), palmitik (C16), stearik (C18:0), oliek (CI8:I) dan linoliek (C18:2) berbeza di dalam pemeringkatan PKO LG-C02 pada tekanan dan suhu berbeza. Asid lemak C8, CIO dan C12 banyak diekstrak pada pemeringkat pertama dan semakin perlahan-Iahan berkurangan pada pemeringkat kedua, ketiga dan keempat. Komposisi asid lemak C 14 kekal tidak berubah pada kesemua pemeringkat sepanj ang tempoh pengekstrakan tetapi pada tekanan 48.3 MPa dan suhu 80°C ianya berkurangan dengan banyak pada pemeringkat terakhir. Sebaliknya, terdapat peningkatan CI6, CI8:0 dan CI8:1 dan CI8:2 tidak tepu pada pemeringkat terakhir. Tren ini meningkat dengan meningkatnya tekanan dan suhu tetapi perbezaannya tidak begitu ketara pada tekanan rendah 20.7 dan 27.6 MPa pada kedua-dua suhu. Walau bagaimana pun, didapati komposisi signifikan secara statistik untuk tekanan dan masa pemeringkat mengikut j enis asid lemak. Adunan minyak sawit (PO), PKO-SC4, palmac 98-18 (asas C18) dan palmac (asas CI8:1) pada nisbah berbeza dibuat untuk memperolehi adunan pengubah mentega koko (CBR). Terdapat 13 adunan yang dibuat untuk kajian ini. Adunan 1 hingga 10 dicadangkan sebagai gantian mentega koko (CBS) and adunan 11 hingga 13 dirujuk sebagai lemak setara mentega koko (eBE). Takat cair 1010s untuk adunan 11, 12 dan 13 ialah masing-masing XXXl11 33.3, 35.1 dan 35.3°C manakala untuk mentega koko (CB) ialah 35°C. Begitu juga kandungan lemak pepejal (SFC) gantian mentega koko ini tinggi pada 20°C dan 0 peratus diantara 37.5°C dan tren ini adalah hampir menyamai mentega koko komersial. Nilai iodin, nilai saponofikasi dan nilai asid gantian mentega koko ini juga hampir menyamai mentega koko. Oleh itu ianya dicadangkan untuk gantian mentega koko pada paras maksima penggantian. Walau bagaimana pun, cirri fisiko-kimia adunan 1 hingga 10 didapati tidak menghampiri mentega koko tetapi ianya dicadangkan sebagai gantian mentega koko pada paras terrendah penggantian mentega koko. xxxiv CHAPTERl INTRODUCTION 1.1 Preamble Supercritical fluid extraction (SFE) is a new and powerful technique in separation processes and an alternative processing method. Carbon dioxide (C02) is employed as a supercritical fluid because it has a low critical temperature (31.1°C) and critical pressure (7.28 MPa) , which makes it an ideal solvent for extracting thermally sensitive materials. CO2 is also nontoxic, nonflammable, and easily available and relatively low cost. In Malaysia the laboratory grade CO2 is costs about US$ 0.66/ liter (dm3). In addition, products obtained by SC-C02 extraction are completely free of solvent residues. On the contrary, conventionally solvent-extracted products must be desolventized before they are suitable for consumption. SC-C02 defatted meal can therefore be directly used in low-calorie foods. Also, crude oils obtained by SC-C02 extraction are generally more easily refined than conventionally extracted oils as they contain fewer impurities (Devittori et aI., 2000, Bruno & Ely, 1991 & de Castro et aI., 1994). The low critical temperature (31°C), non-toxicity and low cost have long rendered SC-C02 a suitable solvent for food products (McHugh & Krukonis, 1994 & Saldana et aI., 1999). There has been renewed interest in the use and development of supercritical fluid extraction (SFE) methods for industrial applications. Several investigations have been made in recent years on probable industrial applications of the SFE, which offer some preferences over the conventional methods, such as separation by extractive solvents by distillation, especially in the areas of the food, pharmaceutical, chemical and oil industries (Bruno & Ely, 1991). 1 

Supercritical carbon dioxide fractionation of palm kernel oil and formulation of cocoa butter replacers fat.

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Supercritical carbon dioxide fractionation of palm kernel oil and formulation of cocoa butter replacers fat.

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