MELTING CHARACTERISTIC AND SOLID FAT CONTENT OF MILK FAT AND PALM STEARIN BLENDS BEFORE AND AFTER ENZYMATIC INTERESTERIFICATION

Melting characteristics and solid fat content of anhydrous milk fat (AMF), soft palm oil stearin (SPOs), hard palm oil stearin (HPOs) and their blends were studied by differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) spectroscopy, respectively. Solid fat contents (SFC) determined by NMR were used to construct isosolid diagrams; these indicated the presence of an eutectic effect along the binary blends of AMF:SPOs which only could be observed at 5 and 10C. The effect was reduced after interesterification by sn-1,3-specific lipase. The modification also reduced the number of the distinct DSC melting peaks, demonstrating a better miscibility among the blended fats. A substantial decrease in DSC melting enthalpy of interesterified blends was found to be parallel to a decrease in SFC that was observed at 25–40C. Fatty acid composition showed that improved functionality of AMF may be due to an enrichment in long-chain saturated fatty acids contributed both by SPOs and HPOs.     

RECOVERY OF PALM CAROTENE FROM PALM OIL AND HYDROLYZED PALM OIL BY ADSORPTION COLUMN CHROMATOGRAPHY

Crude palm oil and crude palm olein were hydrolyzed with lipase from Candida rugosa to produce a free fatty acid (FFA) rich oil. The percentages of FFA produced and carotene degradation after the hydrolysis process were determined. The palm oil and hydrolyzed palm oil were subsequently subjected to column chromatography. Diaion HP-20 adsorbent was used for reverse phase column chromatography at 50C. Isopropanol or ethanol, and n-hexane were used as the first and second eluting solvents, respectively. The objective of hydrolyzing the palm oil was to produce more polar FFA-rich oil in order to enhance the nonpolar carotene bind to the nonpolar HP-20 adsorbent in the column chromatography process. Hydrolyzing palm oil with lipase from Candida rugosa gave 30- and 60-fold, respectively, of FFA in the crude palm oil and crude palm olein in 24 h at 50C. Approximately, 15.56 and 17.48% of carotene degraded in crude palm oil and crude palm olein, respectively. For column chromatography, using isopropanol or ethanol as the first eluting solvent, unhydrolyzed oil and hydrolyzed oil showed the carotene recovery infraction two (carotene-rich fraction) of about 36–37 and 90–96%, respectively. Over 90% of carotene recovery was obtained from     

MONITORING THE ADULTERATION OF VIRGIN COCONUT OIL BY SELECTED VEGETABLE OILS USING DIFFERENTIAL SCANNING CALORIMETRY

The crystallization and melting enthalpy of virgin coconut oil adulterated with palm kernel oil (PKO) and soybean oil (SBO) were studied by using differential scanning calorimetry. Virgin coconut oil was spiked separately with PKO and SBO from 2% to 40% (w/w) of adulterant oils. Fatty acids of all oils were determined to complement the differential scanning calorimetry data. The heating curve of SBO-adulterated samples showed the adulteration peak appearing at the lower temperature region at 10% adulteration level. Regression analyses using stepwise multiple linear regression were used to predict the percentage adulterant with R ² of 0.9490. PKO-adulterated oils did not show any adulteration peak but demonstrated a gradual decrease in the peak height of the major exothermic peak.

PRACTICAL APPLICATIONS

An alternative method for detection of adulteration based on differential scanning calorimetry in virgin coconut oil is presented. Application of differential scanning calorimetry is rapid, does not require sample preparation and does not involve use of solvents or toxic chemicals.     

气相色谱法测定植物油中的苯线磷

植物油中苯线磷用丙酮提取,经液-液分配,用火焰光度检测器（FPD）检测,根据色谱峰的保留时间定性,外标法定量。     

PRODUCTION OF PALM OIL REFERENCE MATERIALS FOR THE DETERMINATION OF SOLID FAT CONTENT

ABSTRACT

Three palm oil reference materials were produced for solid fat content analysis employing the Malaysian Palm Oil Board (MPOB) Test Methods. Thirteen laboratories participated in the characterization study, where the solid fat content in palm oil, palm olein and palm stearin were identified at temperature range from 0 to 45C. The consensus values were calculated based on the acceptability of statistical results from collaborating laboratories. Both of the consensus values and their uncertainties (%) for each reference material are as follows: 71.12 ± 1.82% (0C), 54.07 ± 1.05% (10C), 37.44 ± 0.88% (15C), 24.18 ± 1.09% (20C), 13.32 ± 0.86% (25C), 7.64 ± 0.28% (30C), 4.05 ± 0.14% (35C) and 1.25 ± 0.49% (40C) for SFC of palm oil, 66.32 ± 1.93% (0C), 43.53 ± 1.32% (10C), 22.50 ± 0.78% (15C), 6.68 ± 1.14% (20C) and 1.40 ± 0.35% (25C) for SFC of palm olein, and 78.09 ± 1.23% (0C), 67.66 ± 0.71% (10C), 56.29 ± 1.18% (15C), 44.37 ± 1.13% (20C), 30.22 ± 1.25% (25C), 20.08 ± 0.58% (30C), 13.72 ± 0.32% (35C), 8.97 ± 0.72% (40C) and 5.06 ± 0.41% (45C) for solid fat content of palm stearin.

PRACTICAL APPLICATIONS

The implementation of the ISO 17025 accreditation should be encouraged for testing laboratories to assure the traceability of analysis performed. This accreditation requires the use of certified reference materials to ensure that the analysis performed is parallel to the ISO 17025 standards. However, the unavailability of palm oil reference materials will affect the implementation of such standards for laboratories that are performing palm oil analyses. Hence, this study is aimed to characterize and certify the palm oil reference materials for determination of solid fat content. The establishment of this study is hoped to increase the credibility of laboratories, which are involved in the palm oil analysis. This will also promote the Malaysia Palm Oil Board as a center for the certification of palm oil reference materials.     

CHARACTERIZING QUALITY OF RENDERED DUCK FAT COMPARED TO OTHER FATS AND OILS

The characteristics of rendered duck fat (RDF) were compared to commercial sources of soybean oil, lard, tallow, butter and olive oil. RDF was highly susceptible to lipid oxidation during storage compared to the other fats and oils. However, 0.005% tert‐butyl hydroquinone delayed the onset of lipid oxidation to an extent that was comparable to the lag phase observed in the commercial fats and oils. Positive attributes of RDF included a relatively high oleic acid content and low saturated fat content. Undesirable attributes of RDF included a lack of conjugated linoleic acid (CLA) and intermediate levels of trans fatty acids (TFA) compared to the other lipid sources. Decreasing the time and temperature of rendering decreased the TFA content in RDF. Around one‐half of the TFA content in RDF was vaccenic acid which is converted to CLA after ingestion.     

INTERESTERIFICATION KINETICS OF SOYBEAN OIL

Soybean oil was interesterified at different temperatures, ranging from 10 to 80 C, 600 rpm stirring rate and 0.2–0.5% catalyst (NaOCH₃) concentration. The content of palmitic acid in the 2-position of triacylglycerols was monitored during the reaction by an enzymatic method. The conversion of triacylglycerols to random distribution appeared to be a first order and reaction rate constants (k) were determined between 0.015 and 1.498 min^-1. It was also observed that reaction rate increased about 8 times when catalyst ratio was increased from 0.2 to 0.5% and about 10 times when temperature was raised from 40 to 80C. Activation energy was calculated as 14188 Cal/mole, from plotting of Lnk values against reciprocal of absolute temperature.     

MONITORING OF TRANSESTERIFICATION OF PALM OIL BY DIFFERENTIAL SCANNING CALORIMETRY

Chemical transesterification was conducted to obtain triacylglycerol ( TG) containing maximum concentrations of trisaturated and triunsaturated TG in palm oil. Catalyst (sodium methoxide) concentration of 0.1–0.5%, reaction temperature of 50–92C and reaction time of 30–480 min were applied in 20 treatments. Concentrations of trisaturated and triunsaturated TG, as well as melting points and iodine values were monitored by differential scanning calorimetric (DSC) techniques. The results showed that maximum trisaturated and triunsaturated TG achieved for refined-bleached-deodorized (RBD) palm oil were 17.10 and 7.50%, respectively, using 0.42% catalyst, at 58C in 389 min. These amounts were higher compared to control (untransesterified) RBD palm oil i.e 7.45 and 4.92%, respectively. The melting points of the products were higher compared to the control, while the iodine values were not significantly changed in all of the treatments.     

PROCESSING OF CRUDE PALM OIL WITH CERAMIC MICROFILTRATION MEMBRANE

Membrane separation technology offers a potential application in the processing of crude palm oil. Ceramic membranes with different pore diameters (0.45 and 0.2 micron) were used to conduct the study on micromembrane process. Quality parameters of membrane-processed oils examined included free fatty acid (FFA), carotene, fatty acid composition (FAC), phosphorus and iron contents. The effect of operating parameters such as transmembrane pressure, feed flow and time on permeate flux were evaluated. It was found that 'Ceraflo'ceramic membrane with a pore size of 0.45 micron was only able to reject 14% of phosphorus from the crude oil. Ceramic membrane with pore size of 0.2 micron showed a better phosphorus rejection of 56.8%. The permeate was found to contain 7.13 ppm of phosphorus. The 0.2 micron membrane was also able to remove more than 80% of the iron from crude palm oil. Pore sizes for both membranes were not small enough to remove other components such as FFA, and carotene. Both membranes showed a similar trend in which the permeate flux increased with transmembrane pressure and feed flow until a certain limit where the flux declined with increasing pressure and feed flow. The limits in transmembrane pressures for membrane with pore sizes of 0.45 and 0.2 micron were 1.65 and 1.25 bar, respectively. Whereas the limits in feed flow for 0.45 micron and 0.2 micron membranes were 9.2 and 9.8 L/min     

酶促酯交换桕脂的改性

在脂肪酶 Lipozyme 的作用下,将桕脂与硬脂酸甲酯(SME)或硬脂酸甘油酯(SSS)酯交换,可获得一种可可脂类似物.其三甘酯组成与可可脂极为相似,主要三甘酯为 POS 与 SOS(P:棕榈酸;O:油酸;S:硬脂酸)。在对脂肪酶作用原理讨论之后,给出了其在油脂工程中进一步应用的可能性。     

用植物油制取化工产品的新方法

介绍了以植物油为原料，用生物酶作催化剂来制取3种油脂化工产品的新方法。