Separation of crude palm oil components by semipreparative supercritical fluid chromatography

Successful separation of triglycerides, diglycerides, free fatty acids, carotenes, tocopherol, and tocotrienols from crude palm oil has been achieved by supercritical fluid chromatography (SFC) with a combination of a C18 and a silica gel column. The separation was carried out by the programmed extraction elution method. Free fatty acids were separated into five components by gas-liquid chromatography; tocopherol and tocotrienols were also separated into four components by SFC analysis, and the pure fractionated carotenes were obtained by preparative SFC. Thus, by using supercritical fluid chromatography, crude palm oil components can be separated and fractionated, based on differences in their functional groups.     

Identification of chemical oviposition stimulants from rice grain forSitophilus zeamais motschulsky (Coleoptera,Curculionidae)

Chemical components stimulating oviposition bySitophilus zeamais in rice grain were isolated from rice bran and were found to be a mixture of ferulates, diglycerides, and free sterols. Oviposition preference of the species can be induced by synergistic action of these compounds.     

Glycerolysis of fats and methyl esters

The glycerolysis of methyl esters and triglycerides with crude glycerol, a coproduct from the transesterification of triglycerides, was studied. Three procedures were followed for this conversion. The first procedure was a one-step glycerolysis with methyl esters. The second procedure was a two-step process. This procedure involved an initial partial glycerolysis with methyl esters, followed by fat glycerolysis. The third procedure was a simultaneous glycerolysis with methyl esters and triglycerides. In the glycerolysis with methyl esters, the removal of methanol is vital to the production of mono- and diglycerides. Methanol was removed either by drawing vacuum on the reactor or by stripping methanol out by means of an inert carrier gas (nitrogen). Different molar ratios of methyl esters to glycerol were tested in the first two processes. At low concentration of methyl esters, total conversion of methyl esters to mono- and diglycerides was achieved. As the concentration of methyl esters was increased, the conversion of methyl esters to mono- and diglycerides was decreased. Furthermore, the ratio of mono- to diglycerides was also higher at lower concentrations of methyl esters. The conversion of triglycerides in the two-step process with crude glycerol was similar to a one-step fat glycerolysis with pure glycerol. The composition of different components and the ratio of mono- to diglycerides were also comparable.     

Peculiar properties of lipase fromCandida parapsilosis (Ashford) langeron and talice

A newCandida parapsilosis lipase was isolated and studied. This enzyme was purified by hydrophobic chromatography on a phenyl-sepharose CL4B column followed by gel permeation on a Sephacryl S300 HR column. It was a 160 kg·mol⁻¹ molecular-weight oligomeric enzyme. Optimal activity was obtained at 45°C and pH 6.5. The lipase activity toward various acylglycerols and esters was studied. The hydrolysis rate was greater for secondary acylesters than for primary acylesters. This lipase showed a high specificity for long-chain fatty acids and particularly for polyunsaturated fatty acids. This enzyme was able to catalyze the synthesis of various oleoylesters in aqueous medium.     

鹅油甘油二酯微胶囊化工艺研究

以鹅油甘油二酯为材料,探索鹅油甘油二酯微胶囊的制备工艺,以便减少鹅油甘油二酯氧化,延长产品的货架期。以酪蛋白酸钠和β-环糊精为壁材,鹅油甘油二酯为芯材,羧甲基纤维素钠为乳化剂,通过冷冻干燥法制备鹅油甘油二酯微胶囊;以包埋率为指标,采用响应面法对鹅油甘油二酯微胶囊的制备工艺进行了优化。试验结果表明,壁材:芯材为2.4:1,酪蛋白酸钠:β-环糊精为1:1.2,固形物含量为23%,乳化剂用量为0.7%时,鹅油甘油二酯包埋率达到93.7%。     

酶催化分子蒸馏单甘酯的重相产物制备中、长链甘油二酯及其性质研究

以分子蒸馏单甘酯的重相产物和辛酸为原料,固定化脂肪酶Lipozyme TL IM为催化剂催化酯交换反应制备中、长链甘油酯(M/LCG)。通过单因素实验探究了底物(重相产物与辛酸)摩尔比、反应温度、反应时间、加酶量对产品中含有辛酸的甘油酯成分含量及辛酸插入率的影响,从而选择合适的工艺条件为:反应温度65℃,底物摩尔比6∶4,反应时间6 h,加酶量15%。在选定条件下,产品M/LCG中甘油二酯(DAG)含量为50.73%,辛酸插入率为15.35%。对选定条件下的M/LCG样品经柱层析分离纯化,以硅胶为吸附剂,正己烷-乙醚-甲酸(体积比45∶25∶1)的溶液为洗脱剂,可得到DAG含量为88.24%的中、长链甘油二酯(M/LCD),且主要为sn-1,3 DAG。通过DSC、XRD对纯化的M/LCD进行性质研究,测得其熔点为60.34℃,存在明显同质多晶现象,主要为β与β'晶型共存。M/LCD的热力学性质以及晶型特性将为其在乳液方面的潜在应用提供一定的理论依据。     

Influence of diglycerides on crystallisation of palm oil

Palm oil diglycerides and pure synthetic diglycerides of 1,2‐(2,3‐) and 1,3‐dipalmitoylglycerol, dioleoylglycerol and palmitoyloleoyl glycerol were added to purified triglycerides of palm oil. The crystallisation kinetics of the samples were studied by spectrophotometry, NMR analysis of the solid fat content and by X‐ray diffraction of the crystals obtained at 20°C. Palm oil diglycerides inhibited the nucleation process and retarded the crystal growth rate of palm triglycerides. The effect was less pronounced at a higher degree of supercooling. The extent of inhibition depended on the nature of the diglycerides and the concentration. © 1999 Society of Chemical Industry     

Possibility of improving the quality characteristics of olive‐pomace oil and enhancing its differentiation from refined olive‐pomace oil

An investigation was carried out to evaluate the oxidative and hydrolytic degradation of 37 olive‐pomace oils marketed in southern Italy and to compare the results with those obtained from 10 deodorised olive‐pomace oils representative of large stocks of oil obtained after the final step of refining. One aim of the research was to ascertain the quality characteristics of commercial olive‐pomace oils; another was to verify whether the legally prescribed addition of virgin olive oil to refined pomace oil, so that the final product may be classified commercially as olive‐pomace oil, was actually sufficient to justify upgrading. The analytical methods used were silica gel column chromatography and high‐performance size exclusion chromatography. The data obtained showed that the final retail olive‐pomace oils had a lower degree of oxidative degradation than the refined oils, as indicated by the lower values obtained when summing the proportions of triglyceride oligopolymers and oxidised triglycerides. Conversely, hydrolytic degradation, which was evaluated by determining diglycerides, proved to be the same in the two categories of oil. The proportions of virgin olive oil added are small, as indicated by the statistically indistinguishable values of triglyceride oligopolymers and free fatty acids obtained. The possibility of setting a limit to the amount of triglyceride oligopolymers present in the commercial category of olive‐pomace oil has been considered. This limit would ensure standardisation of the level of oxidation and, consequently, of the quality of marketed oils and would enhance differentiation between olive‐pomace oil and refined olive‐pomace oil. © 2000 Society of Chemical Industry     

食品乳化剂二乙酰酒石酸甘油单、二酸酯的研制

研究了食品乳化剂二乙酰酒石酸甘油单、二酸酯的制备，分析了其组成和质量指标，并作了面包焙烤试验。     

Continuous supercritical carbon dioxide processing of palm oil

Crude palm oil was processed by continuous supercritical carbon dioxide. The process reduces the contents of free fatty acids, monoglycerides and diglycerides, certain triglycerides, and some carotenes. The refined palm oil from the process has less than 0.1% free fatty acids, higher carotene content, and low diglycerides. Solubility of palm oil in supercritical carbon dioxide increased with pressure. A co-solvent improves the refining process of palm oil.