A new concept for determining triglyceride composition of fats and oils by liquid chromatography

The matrix concept was used to characterize the chromatographic rules in the elution of molecular species of triglyceride. To prove the hypothesis experimentally, cacao butter, palm oil, linseed oil, olive oil, rapeseed oil and triglyceride of “Ogonori” (Gracilaria verrucosa) were examined. A matrix model was suggested to help determine the individual molecular species of naturally occurring triglycerides.     

Immobilized lipase reactors for modification of fats and oils—A review

This review focuses on the use of immobilized lipase technology to effect hydrolysis, ester synthesis, and interesterification reactions. The various immobilization procedures, reactor configurations, and process considerations are all reviewed and discussed.     

The determination of light petroleum residues in refined oils and fats

A rapid, direct injection gas liquid chromatographic (GLC) method for determining residual light petroleum in edible vegetable oils has been developed. The response is linear at levels between 0.05–0.5 mg hexane/kg oil. A sample containing 0.2 mg hexane/kg oil was analyzed for repeatability, giving a standard deviation of 0.008 mg/kg, equivalent to a coefficient of variation of 4%. Separation of pentane, hexane, heptane, octane and decane was obtained by this method. A survey of 23 samples of freshly refined vegetable oils obtained from 13 U.K. refiners in 1981 showed that these all contained less than 0.05 mg hexane/kg oil.     

农药残留检测新方法研究进展

介绍了农药残留检测的步骤与方法.农药残留检测主要分为4个步骤:样品的提取、净化、浓缩和检测.提取方法主要有震荡法、索式提取法,固相微萃取法、超临界流体萃取法、快速溶剂萃取法等.净化方法主要有:液-液分配净化法、柱层析法、磺化法等.浓缩方法主要有:蒸发浓缩、反渗透浓缩、K-D浓缩仪浓缩等.检测方法主要有:气相色谱-质谱联用法、荧光分析法、酶抑制法、免疫分析法、生物传感器检测法、红外光谱法、拉曼光谱法等.评述了这些方法的优点与缺陷,提出了今后的发展方向.     

Organochlorine pesticide residues in 4 types of vegetable oils

The present study had as objectives to identify and to quantify organochlorine pesticide residues (OCP) hexachlorobenzene (HCB), lindane, cis-chlordane, heptachlor, aldrin, dieldrin, endrin and o,p'-DDT in vegetable oils of corn, soybean, sunflower and mixtures of oils, sold in the city of Maracaibo, Venezuela. 30 samples of 4 types of vegetable oils of 10 commercial brands were analyzed. The extraction of OCP residues was done according to the Official Method of AOAC. A gas chromatograph with an electronic capture detector (GC-ECD) was used for identification and quantification of OCP residues and confirmation was done with a gas chromatograph coupled with a mass spectrometer (GC-MS). All the OCP residues investigated were detected in the analyzed samples. Aldrin (0.0088), lindane (0.0054) and o,p'-DDT (0.0035) were the OCP residues detected in higher concentrations (microg/g). The statistical analysis showed significant differences (P<0.05) for the concentration of OCP in the different types and commercial brands of vegetable oils. Lindane concentration in the corn oil (0.0125 microg/g), as well as cischlordane (0.0091 microg/g) and aldrín (0.0287 microg/g) in the soybean oil exceeded maximal residual limits (MRL) established by Food and Agriculture Organization of the United Nations/World Health Organization (FAO/WHO). In conclusion, it was detected a high incidence of OCP residues in vegetable oils analyzed.     

Comparison of SFI,DSC and NMR methods for determining solid-liquid ratios in fats

Dilatometry (SFI) has gained wide acceptance for the characterization of solid-liquid contents of fats over approximately the past 15 years. In more recent times, wide-line nuclear magnetic resonance (NMR) has been used for this purpose. Still more recently the differential scanning calorimetry (DSC) technique has been used to determine solid-liquid contents. These three techniques were used to determine the properties of seven fats and oils which represent a cross section of commercially available materials. These products were blended into 14 different compositions and the solid-liquid contents were determined by the three methods. A comparison is made on the results obtained on the various samples by SFI, NMR and DSC techniques. The results of each procedure are compared according to fat composition. One of 10 papers to be published from the Symposium “Wide-Line Nuclear Magnetic Resonance” presented at the AOCS Meeting, Minneapolis, October 1969.     

Toxic contaminants of thermo‐oxidatively processed edible oils/fats

Processing of edible oils during refining of the crude oil, or when used in frying, often exposes the oils to thermal and oxidative stresses. However, because of weaknesses inherent in their chemical structure, oils subsequently undergo structural decomposition and transformation in response to thermooxidative stresses. Whereas some of the decomposition products from the processed oils confer some value additions to the oils and the foods prepared in them (e.g. flavor, color, texture, and even stability), a number of edible oils' degradation products are known to be potentially toxic, and at reasonably high quantity, can compromise the health and wellbeing of consumers. This article describes the sources and updated knowledge on major toxic compounds that are generated during high temperature processing and usage of vegetable oils.     

Identification of adulterants in olive oils

The application of discriminant analysis for identifying and quantifying adulterants in extra virgin olive oils is presented. Three adulterants were used (sunflower oil, rapessed oil, and soybean oil) and were present in the range 5–95%. Near-infrared spectroscopy and principal components analysis were used to develop a discriminant analysis equation that could identify correctly the type of seed oil present in extra virgin olive oil in 90% of cases. Partial least squares analysis was used to develop a calibration equation that could predict the level of adulteration. Cross validation suggested that it was possible to measure the level of adulteration to an accuracy of ±0.9%. External validation of the derived calibation equation gave a standard error of performance of ±2.77%.     

Annual review of literature on fats,oils, and soaps. Part II

Journal of the American Oil Chemists' Society -     

微生物降解有机磷农药残留的研究进展

从微生物降解有机磷农药的种类、降解机理、降解基因等方面综述了微生物降解有机磷农药近年来的研究进展,探讨了微生物降解有机磷农药研究领域的发展趋势及进一步的研究方向,并提出建议。