i. Cover Story & Editorial 78. H Sauthoff - Laurics and the Oleochemical Industry 84. M Kellens - Process Evolution to Technological Revolustion 95. MR Chandran and SHGoh - Palm Oil Prices 99. J Fry - Impact of Sustainability and Biofuel Prices on Oil Price Relativities 103. PW Sylvester - Recent Advances in Tocotrienol Research 109. PT Gee - Tocotrienols for Chemo-Prevention 116. YM Choo and CW Puah - Life Cycle Assessment of Palm Biodiesel vi. Talking Points vii. Lighter Note ix. "Calendar" Calendar 2011 Vol. 19 No. 1 (2010) Preprint titles i. Cover Story & Editorial 1. 63. 66. 68. 71. 81. 91. 93. Vol. 18 No. 2 (2009) Preprint titles i. Cover Story & Editorial 57. J Fry - The Outlook for Palm Oil in the Context of Global Commodity Markets 63. Dorab Mistry - Short-Term Forecasting Palm & Lauric Oil Price Outlook 66. MR Chandran - Visionary Concepts in Palm Oil Processing 68. J Fry - Contribution of Palm Oil to Development 71. KG Berger - Fats and Foods 81. SH Goh - Triacylglycerol Stereo-structures and Lipase Action: Consequences on Nutrition 88. Summary of Some Nutrition Papers from PIPOC2009 91. PT Gee - Chemical Analysis: Glycidol Esters and Possible Mutagens from B20 Biodiesel Exhausts 93. SH Goh and MR Chandran - Plantations Update - December 2009 Vol. 18 No. 1 (2009) Preprint titles iv. Cover Story & Editorial 1. J Fry - Prices of Vegetable Oils: Learning the Lessons of 2008 2. Dorab Mistry - Price Outlook with Special Reference to India 3. T Mielke - The Golbal Supply, Demand and Price Outlook of Palm and Lauric Oils 4. R Kastilani - Price Outlook: An Indonesian Perspective 5. A Frick - Price Drivers in Vegetable Oils 6. H Sauthoff - 2009: Year One After the Commodity Storm; Are there any Specifics for Laurics? 7. A Misra - The Metabolic Syndrome in Asian Indians:Implications for Dietary Oils&Fats 8. MR Chandran - Plantation Notes Vol. 17 No. 2 (2008) Preprint proofs Cover Story & Editorial 34. "Musa Hitam" Challenges and Opportunities 39. "J Fry" Logistics, Fuels Costs and Palm Oil Prices 44. "B Dyer - Certifiable and Sustainable Palm Oil" 59. "A Green - Designer Crops for Renewable Resources" 66. "R Yap - New Uses for Bio-Diesel Glycerin" 74. "K Doll - Emerging Technologies for Development of Green Industrial products from Natural Oils" 80. "F Kosmala - Global Overview of Bio-Fuels: Availability and Sustainability" 86. "MR Chandaran - Oils and Fats: The Way Forward for Palm Oil" 95. "Bangun et al - Glycerol to 1,2-Propanediol" 40. "SC Cheah - Sustainable Biofuels; The Role of Biotechnology" vi. "Talking Points" Talking Points viii. "On a lighter note" On a Lighter Note Vol. 17 No. 1 (2008) Preprint unedited proofs Editorial 1. S.E. Asian Plantations S.E. Asian Plantations: Palm Oil Prices Have Corrected 3. "J Fry" J Fry 7. "Laurics" 10. "Chandran - Green Revolution" 14. "Forecast - CPO Price Target" 16. "Gee - Uniqueness of Palm Oil" 21. "Zhang - Nutritional Benefits from PO Minor Components" 24. "Phytosterols" 26. "Dorab Mistry" 28. "RoundUp" Round Up v "Talking Points" Talking Points vi. "On a lighter note" On a Lighter Note Vol. 16 No. 2 (2007) Preprint unedited proofs Editorial 16-1 1. "J. Fry" Has Agricultural Markets Changed Forever? 5. "Wolfgang Biodiesel" 9. "Herrington - Oleochemicals" 12. "Choo - Biodiesel" 21. "Gee - Tocotrienol" 27. "Lavigne - Biodiesel and its impact on oil palm prices" 28. "Carl Bek-Nielsen - Sustainability" 30. "Teoh - RSPO Sustainability" 35. "Long - Trading" 40. "Goh - BiofuelUpdate" Biofuel Update 2007 42. "Talking Points" Talking Points 43. "On a lighter note" On a Lighter Note Vol. 15 No. 2 (2006) Preprint part-edited proofs iv. "Editorial" Editorial 2006 - 2 29. "Biofuels & Biomass" Biofuels & Biomass 43. "TAG Chemistry, Digestion & Metabolism" TAG Chemistry, Digestion & Metabolism 70. "Trade Liberalism: Price Forecasts" Trade Liberalisation: Price Forecasts Vol. 15 No. 1 (2006) Preprint part-edited proofs iv. "Editorial" Editorial 2006-1 8. "Functional Micronutrients" Functional Micronutrients 15. "Diet & Nutrition: General Considerations" Diet & Nutrition; General Considerations Vol. 14 No. 2 (2005) Preprint Proofs iv. "Editorial" Editorial 1. "Structured Lipids" Sructured Lipids 6. "Healthy Fats sans trans" Healthy Fats sans trans xii: "Calendar" Calendar 2006 Vol. 14 No. 1 (2005) Preprint Proofs 1: "Fractional Crystallization - The Fat Modification Process for the 21st Century" by R.E. Timms Fractional Crystallization 17: "Misconceptions and the Need to Re-Look at Clinical Trials for Vitamin E" by P.T. Gee Clinical Trials on Palm Vitamin E viii: "Calendar" Calendar 2005 Vol. 13 No. 2 (2004) Preprint Proofs vi "Talking Points" Talking Points vii "On a Lighter Note" On A Lighter Note viii "Calendar" Calendar 1: "Agricultural Oils & Fats do not meet Nutritional Demands" by F. Gunstone 9: "Malaysian Biofuels" Biofuels by Basiron 11: "World's Oils and Fats Complex" by J. Fry 17: "Sustainability Issues" by M.R. Chandran Sustainability Issues 23: "A Century of Oil Palm in Malaysia: Past, Present and Future" by J. Tek and M.R. Chandran Oil Palm 27: "Triglyceride Structures by Powder X-ray Diffraction" by Peschar et al Vol. 13 No.1 (2004) Preprint Proofs iv: "Editorial: Commodities Boom; In Transition" 1: "Palm Oil: The Cholesterol Dimension" by AS Truswell Palmolein is Better Than Olive Oil 45: "Nutritional Aspects of Canola Oil" by R. Reuss Canola 58: "Cholesterol and Beyond" by SH Goh, NF Hew and HT Khor Cholesterol and Beyond 65:"BEARISH NEW-CROP PROSPECTS" by T Mielke Bearish Medium Term Outlook for Oils and Fats Vol. 12 No. 2 (2003) Preprint Proofs Vol.12 No.1 (2003) Preprint Proofs iv: "Editorial: Malaysian Palm Oil Industry at the Crossroads" Editorial 1: "Global Oils and Fats Business" by J. Fry Global Oils and Fats 13: "Palm Oil, Coconut Oil and Palm Kernel Oil: Issues and Future Prospects" by Yusuf Basiron and S. Ahmad Palm & Coconut Oils 22: "The Uncertain Future of AgBiotech" by D. J. Murphy AgBiotech 59: "A Review of the Digestion and Absorption of Oils and Fats in Feeds for Poultry and Swine" by S. B. Neoh and S. H. Goh Animal Nutrition ix: "The Malaysian Plantation Sector: A Review" By KW Kok Plantation Review Vol.11 No.2 (2002)Preprints iv: "Editorial" Editorial 57: "Concept of Site Yield Potential and Its Applications in Oil Palm Plantations" by KJ Soh et al Site Yield Potential By KJ Soh 64: "Advances in Fertiliser Management in the Oil Palm Industry" by KW Chan et al Fertiliser Management by KW Chan 70: "Mechanisation in Oil Palm Plantations: Achievement and Challenges" by Teo Leng Mechanisation by Teo Leng 78: "Use of Natural Genetic Diversity to Develop Low-Saturated Substitutes for Partially Hydrogenated Soybean Oil" by Richard F Wilson Natural Soybean Diversity by RF Wilson 121: "Report on OFIC2002 Conference" by K.G. Berger Vol.11 No.1 (2002) iv: "Editorial" Editorial 11(1) 1 : "RESURGENCE OF FAT SOLUBLE VITAMIN A: RESEARCH TO PUBLIC HEALTH" by B. A. Underwood Vitamin A by B. Underwood 9 : "OIL QUALITY MANAGEMENT AND MEASUREMENT DURING CRISP/SNACK FRYING IN PALMOLEIN - WHAT IS IMPORTANT TO PRODUCT QUALITY?" by E. W. Hammond E.W. Hammond 14: "DETECTION AND CHARACTERISATION OF UNWANTED OFF-FLAVORS CAUSED BY RANCIDITY THROUGH ANALYSIS OF VOLATILES" by H. Palm H. Palm 19: "AN AUTOMATIC JENSEN COOLING CURVE APPARATUS FOR EVALUATION OF COCOA BUTTER AND COCOA BUTTER EQUIVALENTS" by R. E. Timms, D. Whittingham and S. Darvell R. E. Timms 25: "MEMBRANE FILTRATION APPLIED TO CLARIFIER SLUDGE" by Mukhtiar Singh Gill and S. Singh M.S. Gill and S. Singh 31: "CATALYST RECYCLING - AN ELEGANT LOOP" by C. Cutchey C. Cutchey 38: "OILS AND FATS IN THE NEW MILLENNIUM: THE USE OF TECHNOLOGY TO MEET CONSUMER DEMAND" by K. G. Berger K.G. Berger 46: "APPLICATIONS AND USES OF PALM AND PALM KERNEL OILS IN SPECIALITY PRODUCTS" by E. M. Goh E.M. Goh Vol.10 No.2 (2001) iv: "Editorial" Editorial 10(2) 59: "ASEAN Oleochemicals" by T.K. Soon ASEAN Oleochemicals 128: "Palm Oil Price Behaviour: Retrospect and Prospect" by D. Mistry D. Mistry 133: "Cholesterol Update 2001" by S.H. Goh Cholesterol2001 vi: "On a Lighter Note" On-A-Lighter-Note Vol.10 No.1 (2001) iv: "Editorial" Editorial 1: "cis-trans Isomerism of Carotenoids-In Relation to Nutrition and Health" by Synnřve Liaaen-Jensen, Bjřrn Bjerkeng and Marianne Řsterlie" 1Carot 11: "Global Oils and Fats Business: Challenges in the New Millennium" by Yusof BasironBasiron 17: "New Oil Crops for the 21st Century. What is in the Pipeline and What is Coming in the Future?" by D J Murphy 22: "The Competitiveness of the World's Oils and Fats Complex" by J Fry OilsFatsComplex 31: "Emerging Labeling Standards" by Ahmad Ibrahim 35: "Natural Oils and Fats: Best Choice for Growing Surfactant-Based Consumer Markets" by P. Hovelman 44: "Palm Biodiesel" by Y.M. Choo, A.N. Ma and Yusof Basiron To Be Inserted 49: "Chiral and Dietary Diacylglycerols" by P.T. Gee and S.H. Goh Diacylglycerol Vol.9 No. 2 (2000) Lipid Flavours; Aromatherapy; The Art, Science and Business of Flavours and Fragrances; Essential Oils; Phytochemicals - A New Paradigm; SMEs and Small Countries Vol. 9 No. 1 (2000) Food Safety by Harrison Aziz HACCP and Implementation by Adinan Husin and Zahara Merican International Food Laws by J DeMan Controversies - Cardiovascular Disease by L DeMan Diet by M Rajan Minor Components of Palm Oil by KG Berger Safety Data Sheets by TS Tang Vol. 8 No. 2 (1999) 4 Editorial 6 Oleochemicals From Genetically Engineered Oil Crops: Surinder Singh and Allan Green 10 Olive Oil : The Right Choice: A. P. K. Kiritsakis 16 High Oleic And High Linoleic Sunflower Varieties and Hybrids in Hungary: J. Holló, J. Perédi, K. Kôvári and K. Recseg 23 Oil Palm Biotechnology: Cheah Suan Choo 33 Oil Palm Breeding: N. Rajanaidu 43 Current Status and Strategies of Oil Palm Tissue Culture: C. H. Lee and K. C. Wooi 50 Variation in Oil and Kernel Extraction Rates of Oil Palms in North Sumatra Due to Nutritional and Climatic Factors: N. E. Prabowo and H. L. Foster 57 Maximising Palm Oil Production through Better Oil-Extraction Ratio (OER): T. S. Tang 58 Cholesterol: S. H. Goh 60 Transgenic Crops 62 Potential Perils from the Promise of GM Foods 64 "Pharming" 66 Health & Science 67 Quotable Quotes 68 Books 69 Calendar Index |
Chemistry Dept., NUS, Singapore [Received 11.9.99] Lipid Structure, Not Just Fatty Acids Cholesterol has again come into the limelight as blood cholesterol or more specifically excessive low-density lipoprotein ("bad cholesterol") is a risk factor for coronary heart disease. Apart from endogenous factors (e.g. excessive cholesterol made by the liver or other genetic factors) and contributions from diets (direct intake of high cholesterol foods), the types of edible oils and fats are often highlighted. Oils and fats are partly characterised by the fatty acids comprising them. Certain fatty acids are known to contribute to raising cholesterol levels, e.g. myristic acid (14:0, fourteen denoting the number of carbons in the molecule and zero means saturated). Stearic acid (18:0), although saturated, is considered to be neutral to cholesterol-raising effects while medium chains such as C10:0 behave differently and do not contribute to raising cholesterol. On the other hand, monounsaturated (18:0) and more so polyunsaturated (18:2) acids have the effect of lowering blood-cholesterol levels. Some simplistic equations to estimate the cholesterol-raising or cholesterol-lowering properties were found empirically to sum up the contributions of various fatty acids from dietary oils and fats. It was soon found that such simplistic equations failed when applied to natural oils, particularly palm oil. These anomalies were evident from earlier studies where it was found that it is not sufficient just to consider the overall fatty acids content but that the molecular structures of the triglycerides (or triacylglycerols) from which the fatty acids are derived are important. Text books and obsolete nutritional recommendations continue to cast a poor image for palm oil because of its overall medium to high percentage of saturated fatty acids (49%). This is mainly due to the use of obsolete data of two or three decades ago when the chemical analysis of oils and fats just provided the overall fatty acids content but not the triglyceride structures and compositions. This lack of information (or even misinformation) has caused misunderstandings on the nutritional quality of palm oil. Another factor is that a higher level of understanding is required, e.g. the fatty acids are derived from three different positions of the oil or fat (i.e. the fatty acids have positional and stereochemical relationships in the triglyceride molecular structure, see Figure). It is therefore not appropriate to take an average of the percentage of saturated or unsaturated fatty acids in all three positions of a fat, bearing in mind that the digestion and uptake of the fatty acids of the three positions can be markedly different. In particular, the 2-positional fatty acids as 2-monoglycerides derived from the action of pancreatic enzymes on oils and fats, being 1,3-specific, are the most easily absorbed. Also liberated are fatty acids from the 1,3-positions with the long chain fatty acids (16:0 and 18:0) being poorly absorbed particularly after being converted to calcium or magnesium salts derived from the diet. This means the description of dietary fat must refer to the molecular constitution of the triglycerides and not just the overall fatty acids. A commonly cited comparison is that although the overall fatty acid composition of palm oil and lard is similar, the latter but not the former is cholesterol-raising which of course is a consequence of the different positioning of the saturated fatty acids in the triglyceride molecule. See Figure 1. below. Relationship between S saturated fatty acid content and thrombogenicity (OT) of dietary fats in rats1 [1. Coconut Oil; 2. Triglyceride mixture; 3. Partially hydrogenated coconut oil; 4. Medium chain triglycerides; 5. Whale oil; 6. Palm oil (+ and x are revised values based on triglyceride structure); 7. Olive oils; 8. Partially hydrogenated soyabean oil; 9. Linseed oil; 10. Rapeseed oil (old); 11. Rapeseed oil (new); 12. Sunflower seed oil] Palm Oil: A Naturally Structured Fat Palm oil as with most vegetable oils have a composition of triglycerides in which the 2-position is mainly unsaturated while the 1- and 3-positions are relatively saturated. Remembering that the 1- and 3-positional fatty acids are liberated by the digestive enzymes (which are 1,3-specific), while the 2-monoglyceride remains and this is most readily absorbed. The 1- and 3-positional fatty acids when released have different absorbabilities, the unsaturates are absorbed relatively easily while the long chain saturated acids (or salts derived from them) are poorly absorbed. This has an important consequence in considering the nutrition of edible oils, especially for palm oil. It means the fatty acid profile of the fatty acids absorbed by the body will be mainly the profile of the 2-positional fatty acids and for crude palm oil this is about 11% saturated while the average of 49% is commonly referred to by competitors of palm oil. It would even have a better absorption profile (about 8% saturated) if it is considered that only the unsaturated fatty acids from the 1- and 3-positions are absorbed by the intestine. This situation is somewhat similar to cocoa butter fat which is highly unsaturated at the 2-position while and 1- and 3- positions are almost all saturated. No wonder nobody ever complains of chocolate fat, even though a lot of palm mid-fractions go to this type of fat. There is another important consequence; only slightly more than a third of the calories in palm oil is taken up into the body. It means palm oil is a naturally structured oil so that a large part of the fat will not be absorbed by the body as compared to other fats which may be claimed to be polyunsaturated or monounsturated but can result in the absorption of the dietary fat consumed. Calorie-conscious consumers should realize the better choice of such fats rather than relying on anti-calorie pills which basically try to stop the digestive enzymes which split out the 1- and 3-positional fatty acids. A lot of research effort has been made to design fats, which are modelled from 1-saturated-2-unsaturated-3-saturated type of molecules present in palm oil so that the body absorbs less of the fatty acids and also provide protection from cholesterol elevation. One of the earlier surprise findings which can support the above considerations has been from Hornstra's experiments on animal thrombosis. The Figure shows thrombosis observed as obstruction time (OT) before the artery is clogged up by blood LDL cholesterol when different fatty diets were experimented on. Based on cholesterol-raising effects due to the absorbed fatty acids (and perhaps other effects), saturated fatty acids will raise cholesterol (leading to short OT) while unsaturated fatty acids will lower (longer OT). When the data was published the results for palm oil was most surprising as it did not fall into the usual pattern (Figure). Subsequent testing considered the presence of antioxidants but this not sufficient to explain the "expected" deviation. In the light of the discussion given above, a reinterpretation of this data shows that the results are to be expected of palm oil if one considers that palm oil is actually highly unsaturated due to the 2-positional fatty acids which are to be absorbed as 2-monoglycerides. When replotted considering only 2-positional fatty acids (11% saturated) or inclusive of unsaturates of the other positions which are also preferentially absorbed (8%), the results are as shown in the Figure. A good re-fit can now be seen from the experimental data and this perhaps is the correct interpretation of the data, without even considering the contributions of minor components. Noteworthy from the Figure is that palm oil is superior to almost all other oils, even olive oil, apart from other benefits (mentioned above) that can be derived from it. It would be useful for such related experiments to be performed to throw more light on the importance of triglyceride structure in designing structured lipids and for genetic engineering or crop breeding programmes. Research Notes. The above write up will perhaps help to bring attention to the better lipid structure of palm oil and comes about from several of our studies as well as with reference to the literature on micronutrients, antioxidants and oils/fats' nutrition in animals and humans. Many nutritional studies have been fraught with contradictions and studies using palm oil and their minor components are no exemptions. The metabolic fates of fats and other micro-constituents must also not be ignored2-4 especially as palm oil provides lipid profiles with beneficial triglyceride structures as well as providing several types of antioxidants. In the controversy on fatty acids and hypercholesterolemia, the total structure of palm triglycerides has mostly been overlooked.5 Pancreatic lipase is 1,3-specific and saturated fatty acids of relatively long chains (C16:0 and 18:0) released from the 1,3-positions are poorly absorbed with the 2-acylmonoglycerides being well absorbed. Palm oil is beneficial from the high unsaturation of the 2-positional fatty acids as well as the high content of natural antioxidants. Palm olein and superoleins (liquid fractions with high unsaturates) supplied as cooking oils will be even more beneficial for consumption. From this point of view it is clear which are the fats to be avoided in excess (i.e. milk fat and lard). Lard is 78% saturated at the 2-position while milk fat is similarly more than 70% saturated and notably with a large percentage of the highly atherogenic myristic (14:0) acid. References 1. Hornstra, G (1987). "Dietary lipids and cardiovascular diseases: effect of palm oil". In: Proc. Internat. O.P./P.O. Conference - Technology, Kuala Lumpur, 1987, pp335-339 2. Yap SC, Choo YM, Ong SH, Hew NF, Khor HT and Goh SH (1995). Lipids 30(12): 1145-50. 4. Yap SC, Choo YM, Hew NF and Goh SH (1997). Nutrition Res 17: 1721-31. 3. Goh SH, Low TP, Huang JM, Choo YM and Hew NF (1998). In: Packer L (ed), Antioxidants: Molecular Mechanisms of their Action, Chapter 31, p274-283, AOCS, Champaign. 5. Willis WM, Lencki RW and Marangoni AJ (1998). Crit Rev Food Sci & Nutri 38: 639. 6. S.H. Goh "PAC Lectures", PORIM, 18th Mar. 1999. |
