Synthesis and analysis of symmetrical and nonsymmetrical disaturated/monounsaturated triacylglycerols

Symmetrical disaturated triacylglycerols of the structure SUS, where S is stearic acid (18:0) and U is an unsaturated fatty acid, either oleic (O; 9cis-18:1), linoleic (L; 9cis,12cis-18:2), or linolenic (Ln; 9cis,12cis,15cis-18:3), are important components providing functionality to interesterified fat blends and structurally modified oils. Nonsymmetrical triacylglycerols of the structure SSU can significantly change melting point and solid fat content profiles. To characterize the physical properties of pure and symmetrical and nonsymmetrical triacylglycerol mixtures, the same reaction sequence has been used to prepare multigram quantities of triacylglycerols SUS and SSU. Tristearin was converted to a mixture of mono-, di-, and triacylglycerols, and the 1,3- and 1,2-diacylglycerol fraction was isolated by silica column chromatography. The 1,3-diacylglycerols were removed by crystallization from acetone and esterified with the appropriate fatty acid to form the symmetrical triacylglycerols with >99% SUS structure. The more difficult to obtain 1,2-diacylglycerols were prepared by esterification of the enriched 1,2-diacylglycerol fraction (80-86% 1,2-diacylglycerols) remaining after removal of much of the 1,3-isomer by crystallization, but silver resin or silver nitrate impregnated silica gel chromatography was required to isolate the nonsymmetrical triacylglycerols. SSL and SSLn were prepared in purities of >98% by this procedure, but not SSO. Silver ion HPLC was found to be as accurate as, and more rapid than, lipolysis/gas chromatography for the determination of the isomeric purities of the synthesized triacylglycerols.     

Antioxidant and cyclooxygenase activities of fatty acids found in food

Several commercially available C-8 to C-24 saturated and unsaturated fatty acids (1-29) were assayed for cyclooxygenase-I (COX-I) and cyclooxygenase-II (COX-II) inhibitory and antioxidant activities. Among the saturated fatty acids tested at 60 microg mL(-1), there was an increase in antioxidant activity with increasing chain length from octanoic acid to myristic acid (C-8-C-14) and a decrease thereafter. All unsaturated fatty acids tested at 60 microg mL(-1) showed good antioxidant activity except for undecylenic acid (12), cis-5-dodecenoic acid (13), and nervonic acid (29). The highest inhibitory activities among the saturated fatty acids tested on cyclooxygenase enzymes COX-I and COX-II were observed for decanoic acid to lauric acid (3-5) at 100 microg mL(-1). Similarly, among the unsaturated fatty acids tested, the highest activities were observed for cis-8,11,14-eicosatrienoic acid (25) and cis-13,16-docosadienoic acid (27) at 100 microg mL(-1).     

Near-infrared spectroscopic technique for detection of beef hamburger adulteration

A near-infrared spectroscopic technique was developed to detect beef hamburgers adulterated with 5-25% mutton, pork, skim milk powder, or wheat flour with an accuracy up to 92.7%. The accuracy of detection increased with the increase of adulteration level. When an adulterant was detected, the adulteration level was further predicted by calibration equations. The established calibration equations for predicting adulteration levels with mutton, pork, skim milk powder, and wheat flour had standard errors of cross-validation of 3.33, 2.99, 0.92, and 0.57% and coefficients of variance of 0.87, 0.89, 0.99, and 1.00, respectively. The results of this study indicate that near-infrared spectroscopy is potentially useful in detection of beef hamburger adulteration.     

Authentication of animal fats using direct analysis in real time (DART) ionization-mass spectrometry and chemometric tools

A combination of direct analysis in real time (DART) ionization coupled to time-of-flight mass spectrometry (TOFMS) and chemometrics was used for animal fat (lard and beef tallow) authentication. This novel instrumentation was employed for rapid profiling of triacylglycerols (TAGs) and polar compounds present in fat samples and their mixtures. Additionally, fat isolated from pork, beef, and pork/beef admixtures was analyzed. Mass spectral records were processed by principal component analysis (PCA) and stepwise linear discriminant analysis (LDA). DART-TOFMS profiles of TAGs were found to be more suitable for the purpose of discrimination among the examined fat types as compared to profiles of polar compounds. The LDA model developed using TAG data enabled not only reliable classification of samples representing neat fats but also detection of admixed lard and tallow at adulteration levels of 5 and 10% (w/w), respectively. The presented approach was also successfully applied to minced meat prepared from pork and beef with comparable fat content. Using the DART-TOFMS TAG profiles of fat isolated from meat mixtures, detection of 10% pork added to beef and vice versa was possible.     

Simple and sensitive analysis of long-chain free fatty acids in milk by fluorogenic derivatization and high-performance liquid chromatography.

A highly sensitive high-performance liquid chromatography (HPLC) method is described for the simultaneous determination of some important saturated and unsaturated fatty acids in milk, including lauric (dodecanoic), myristic (tetradecanoic), palmitic (hexadecanoic), stearic (octadecanoic), palmitoleic (hexadecenoic), oleic (octadecenoic), and linoleic acids (octadecadienoic acids). The fatty acids were fluorogenically derivatized with 2-(2-naphthoxy)ethyl 2-(piperidino)ethanesulfonate (NOEPES) as their naphthoxyethyl derivatives. The resulting derivatives were separated by isocratic HPLC and monitored with a fluorometric detector (lambdaex = 235 nm, lambdaem = 350 nm). The fatty acids in milk were extracted with toluene, and the extract with the fatty acids was directly derivatized with NOEPES without solvent replacement. Determination of long-chain free fatty acids in milk is feasible by a standard addition method. A small amount of milk product, 10 microL, is sufficient for the analysis.     

中国草食牲畜发展战略

未来30年,中国人口15亿时,人口增加需要增加口粮0.4亿t;按现在肉食品生产水平和生产方式发展,届时中国至少需要增加猪肉禽肉蛋生产0.12亿t,需要增加饲料粮0.31亿t,总体增加0.71亿t,加之奶生产增加所需增加的饲料粮,粮食总生产需要达到5.71亿t以上,这是很难实现的目标。改变肉食品生产方式,即减少猪肉生产增加牛羊肉生产,具有节约300亿kg粮食的潜力;提高草食牲畜饲料转化率至5%~6%,并将多生产的牛羊肉替换猪肉生产,具有节约粮食200亿kg的潜力,两项合计可以节约粮食500亿kg。本文分析了发展节粮型草地畜牧业,节约粮食消耗,并保证肉品供应的途径,提出奶类生产通过发展1亿只奶山羊替换1670万头奶牛,以解决农村人口喝奶问题,实现全国奶生产消费与现今世界水平持平的目标。为实现草食牲畜生产增加2倍的目标,需要充分挖掘作物秸秆资源及南方冬闲田、疏林地、草原区的隐域生境等土地资源,同时提高草地和上述资源的优化利用效率;大力发展豆科牧草资源,解决中国粗饲料蛋白含量不足以及调整牲畜分布格局也是关键问题。     

Regional variation in shea butter lipid and triterpene composition in four African countries

The triacylglycerol, fatty acid, and polycyclic triterpene compositions of shea butter were determined for 150 samples from the sub-Saharan countries of Mali, Burkina Faso, Nigeria, and Uganda. The compositional profiles showed high variability in all three classes of compounds. Shea butter is made up mainly of four triglycerides (TAG) differing in carbon number (CN) by two, starting from CN 50 to CN 56. The greatest source of variation was in the CN 54 TAG. Shea butter is characterized by 16 saturated and unsaturated fatty acids in greatly varying proportion, the major ones being the even homologues in the range of C(16)-C(20). Oleic acid is dominant in Ugandan provenances, whereas stearic acid is dominant in West African shea butter. Acetyl and cinnamyl polycyclic triterpene means for countries ranged from 3.69 to 12.57%, with the highest values found in Nigerian provenances. Statistical comparisons of fat composition show that the geographic distance between shea populations is reflected in the degree of separation of their chemical profiles.     

电子鼻在牦牛肉和牛肉猪肉识别中的应用

为了探索电子鼻对肉类掺假识别的可行性,利用电子鼻对牦牛肉、牛肉和猪肉样品进行了分析。通过对所获得的数据进行主成分分析（principal component analysis,PCA）、判别因子分析（discriminant factor analysis,DFA）和偏最小二乘回归分析（partial least-squares analysis,PLS）。结果表明：几种肉类在电子鼻传感器上有不同的特征性响应图谱,电子鼻能够有效识别猪、牛肉;同时电子鼻能够识别不同部位的牦牛肉和普通牛肉;但不能识别不同部位的猪肉。在牛肉馅中掺入不同比例的猪肉馅时,电子鼻也能进行识别。采用偏最小二乘回归分析对数据进行处理,电子鼻响应信号和猪肉馅掺入比例之间有很好的相关性（决定系数R2为0.9762）,PLS模型预测误差在1.27%～7.00%之间。试验证明电子鼻可用于肉类的识别。     

基于差示扫描量热法和热力学模型的生物柴油结晶行为分析

棕榈酸甲酯(C16:0)、硬脂酸甲酯(C18:0)和油酸甲酯(C18:1)是生物柴油的主要组成部分。为了深入探究生物柴油的结晶行为,该文基于差示扫描量热法(differential scanning calorimetry,DSC)分析了这3种脂肪酸酯的物性参数,研究发现饱和脂肪酸甲酯C16:0和C18:0的熔点和熔化焓远远高出不饱和脂肪酸甲酯C18:1的值,C16:0和C18:0的熔点分别为301.57、310.92 K,C18:1的熔点为255.01 K。对脂肪酸酯组成的二元溶液进行DSC扫描,DSC曲线出现了2个放热峰,并且溶液的结晶点要低于首先析出的饱和脂肪酸酯纯物质时的熔点;随着饱和脂肪酸酯质量分数的增加溶液的结晶点温度也相应提高。将生物柴油当作由多元脂肪酸甲酯的混合溶液时,C16:0和C18:0等饱和脂肪酸甲酯作为溶质,C18:1等不饱和脂肪酸甲酯作为溶剂,建立了热力学模型计算溶液的结晶点温度。将脂肪酸甲酯的混合溶液近似为理想溶液时对此模型进一步简化,并利用简化模型计算得到4种生物柴油的结晶温度,与实测值进行比较得到了很好的验证效果。该研究可为优化生物柴油低温流动性的技术措施提供参考。     

鸡油组织中的磷脂对鸡油挥发性风味化合物形成的影响

磷脂是肉类特征性风味的重要前体物质。鸡油具有浓郁的脂香和鸡汤香气，磷脂可能对其风味有重要作用。本文采用去除鸡油组织中的磷脂，以及在鸡油中添加磷脂等处理方法，结合顶空固相微萃取-气相色谱-质谱联用技术和感官评价方法研究经不同处理鸡油中的挥发性风味物质相对含量和风味的变化。结果表明添加了磷脂的鸡油，其特征性风味成分显著增加，特别是（E,E）-2,4-癸二烯醛和1-辛烯-3-酮分别增加了4.5倍和10.4倍；而去除磷脂鸡油的挥发性风味物质种类和丰度显著减少；感官评价结果也表明添加磷脂鸡油的风味最浓郁，而去除磷脂鸡油的风味最弱。因此，该研究证明鸡油组织中的磷脂对鸡油的风味具有重要的贡献作用，添加磷脂可显著增加鸡油的香气。该研究结果为浓香鸡油的开发提供理论依据和参考工艺。     

Hypolipidemic effect of oils with balanced amounts of fatty acids obtained by blending and interesterification of coconut oil with rice bran oil or sesame oil

Blended oils comprising coconut oil (CNO) and rice bran oil (RBO) or sesame oil (SESO) with saturated fatty acid/monounsaturated fatty acid/polyunsaturated fatty acid at a ratio of 1:1:1 and polyunsaturated/saturated ratio of 0.8-1 enriched with nutraceuticals were prepared. Blended oils (B) were subjected to interesterification reaction using sn-1,3 specific Lipase from Rhizomucor miehei. Fatty acid composition and nutraceutical contents of the blended oil were not affected by interesterification reaction. Male Wistar rats were fed with AIN-76 diet containing 10% fat from CNO, RBO, SESO, CNO+RBO blend (B), CNO+SESO(B), CNO+RBO interesterified (I), or CNO+SESO(I) for 60 days. Serum total cholesterol (TC), low-density lipoprotein cholesterol, and triacylglycerols (TAGs) were reduced by 23.8, 32.4, and 13.9%, respectively, in rats fed CNO+RBO(B) and by 20.5, 34.1, and 12.9%, respectively, in rats fed CNO+SESO(B) compared to rats given CNO. Rats fed interesterified oils showed a decrease in serum TC, low-density lipoprotein cholesterol (LDL-C), and TAGs in CNO+RBO(I) by 35, 49.1, and 23.2 and by 33.3, 47, and 19.8% in CNO+SESO(I), respectively, compared to rats given CNO. Compared to rats fed CNO+RBO blended oils, rats on CNO+RBO interesterified oil showed a further decrease of 14.6, 24.7, and 10% in TC, LDL-C, and TAG. Rats fed CNO+SESO interesterified oils showed a decrease in serum TC, LDL-C, and TAG by 16.2, 19.6, and 7.8%, respectively, compared to rats given blended oils of CNO+SESO (B). Liver lipid analysis also showed significant change in the TC and TAG concentration in rats fed blended and interesterified oils of CNO+RBO and CNO+SESO compared to the rats given CNO. The present study suggests that feeding fats containing blended oils with balanced fatty acids lowers serum and liver lipids. Interesterified oils prepared using Lipase have a further lowering effect on serum and liver lipids even though the fatty acid composition of blended and interesterified oils remained same. These studies indicated that the atherogenic potentials of a saturated fatty acid containing CNO can be significantly decreased by blending with an oil rich in unsaturated lipids in appropriate amounts and interesterification of blended oil.     

Multiscale characterization of the organization of triglycerides and phospholipids in emmental cheese: from the microscopic to the molecular level

The chemical composition and properties of lipids, both triglycerides and phospholipids, play a major role in the functional and nutritional properties of food products. In this study, the suprastructure of fat, solid fat content, and crystallographic properties of triglycerides were investigated in hard-type cheeses from the microscopic scale to the molecular level using the combination of relevant techniques. Two industrial cheeses with different oiling off properties were compared with experimental cheeses manufactured in the laboratory. Microstructural analysis performed using confocal laser scanning microscopy showed that milk processing led to the disruption of fat globules with the formation of nonglobular fat. For a similar fatty acid composition, oiling off was mainly related to the fat in dry matter content and to the suprastructure of fat in cheese. An exogenous fluorescent phospholipid permitted the localization of milk phospholipids in the cheese matrix, which mainly remain around fat inclusions after disruption of the milk fat globule membrane, and to show heterogeneities. We also showed using differential scanning calorimetry that the suprastructure of fat did not affect the solid fat content in cheese at 4 degrees C: 71.6 +/- 4.9%. The organization of triglyceride molecules in fat crystals, elucidated at a molecular level using X-ray diffraction, corresponded to the coexistence of 2 lamellar structures (2L 40.5 angstroms and 3L 54.6 angstroms) with four polymorphic forms: alpha, two beta' and beta. A schematic representation of the multiscale organization of triglycerides and phospholipids in cheese is proposed.     

Supercritical fluid extraction of fat from ground beef: effects of water on gravimetric and GC-FAME fat determinations

This study investigated the supercritical carbon dioxide (SC-CO(2)) extraction of fat from ground beef and the effects of several factors on the gravimetric determination of fat. The use of ethanol modifier with the SC-CO(2) was not necessary for efficient fat extraction; however, the ethanol did increase the coextraction of water. This coextraction of water caused a significant overestimation of gravimetric fat. Oven-drying ground beef samples prior to extraction inhibited the subsequent extraction of fat, whereas oven-drying the extract after collection decreased the subsequent gas chromatographic fatty acid methyl ester (GC-FAME) fat determination. None of the drying agents tested were able to completely prevent the coextraction of water, and silica gel and molecular sieves inhibited the complete extraction of fat. Measurements of collection vial mass indicated that CO(2) extraction/collection causes an initial increase in mass due to the density of CO(2) (relative to displaced air) followed by a decrease in vial mass due to the removal of adsorbed water from the collection vial. Microwave-drying of the empty collection vials removes approximately 3 mg of adsorbed water, approximately 15-20 min is required for readsorption of the displaced water. For collection vials containing collected fat, microwave-drying effectively removed coextracted water, and the vials reached equilibration after approximately 10-15 min. Silanizing collection vials did not significantly affect weight loss during microwave-drying. SC-CO(2) can be used to accurately determine fat gravimetrically for ground beef, and the presented method can also be followed by GC-FAME analysis to provide specific fatty acid information as well.     

Evaluation of the key aroma compounds in beef and pork vegetable gravies a la chef by stable isotope dilution assays and aroma recombination experiments

Although the aroma compounds of meat processed as such have been studied previously, data on complete homemade dishes containing beef and pork meat were scarcely studied. Recently, 38 odor-active compounds were characterized in beef and pork vegetable gravies using GC-olfactometry. In the present investigation, the most odor-active compounds were quantitated in a freshly prepared stewed beef vegetable gravy (BVG) as well as a stewed pork vegetable gravy (PVG) by means of stable isotope dilution assays. Calculation of odor activity values (OAVs; ratio of concentration to odor threshold) revealed 3-mercapto-2-methylpentan-1-ol, (E,E)-2,4-decadienal, (E,Z)-2,6-nonadienal, (E)-2-decenal, (E)-2-undecanal, and 3-hydroxy-4,5-dimethyl-2(5H)-furanone as the most potent odorants in both gravies. However, significantly different OAVs were found for 12-methyltridecanal, which was much higher in the BVG, whereas (E,Z)-2,4-decadienal showed a clearly higher OAV in the PVG. Aroma recombination experiments performed on the basis of the actual concentrations of the odorants in both gravies revealed a good similarity of the aromas of both model mixtures containing all odorants with OAVs > 1 with those of the original gravies.     

Chemical composition of Greek avgotaracho prepared from mullet (Mugil cephalus): nutritional and health benefits

Crude composition, lipid composition, and tocopherols, ascorbic acid, cholesterol, phytosterols, and squalene content together with fatty acids and antiplatelet activities of total, neutral, and polar lipids of avgotaracho (wax-covered, dried, and salted Mugil cephalus roe) were studied and compared with those of similar products. Wax and steryl esters accounted for 63.7% of roe lipids followed by phosphatidylcholine (PC), which comprised 20.3%. Wax esters were rich in saturated fatty alcohols, monounsaturated fatty acids, and long chain omega3 highly unsaturated fatty acids (HUFA). The fatty acid distribution in roe total and neutral lipids was similar to that of wax esters, while in polar lipids, the omega3 HUFA predominated. Avgotaracho provides significant amounts of protein, fat, alpha-tocopherol, ascorbic acid, and PC, certain amounts of squalene and phytosterols, and cholesterol at levels comparable to hens' eggs. Total, polar, and neutral lipids of avgotaracho exhibited a strong inhibition of platelet activating factors and thrombin, with polar lipids being more active. The results obtained indicate that avgotaracho is a food of high nutritive value, rich in protein and lipids with a healthy lipid profile in terms of omega3/omega6 ratio and major fatty acid classes, while the antiplatelet activity of its oil indicates a putative antithrombotic potential.     

Dual analysis of triglycerides from certain common lipids and seed extracts

A number of reference oils, two commercial oils, and several oil extracts from seeds of Nicotiana species were analyzed for the fatty acid content and also for triglyceride composition. The seed oils were obtained using an accelerated solvent extraction procedure, which was proven to be very efficient and reproducible. The fatty acids were analyzed after the hydrolysis of the oils, using trimethylsilylation and gas chromatography/mass spectrometry (GC/MS) analysis. The levels of sixteen molecular species of triglycerides in the oils were measured after GC separation using MS for identification and flame ionization detection (FID) for quantitation. The results for the fatty acids and those for triglycerides were combined to generate uniform information regarding the composition of the analyzed oils. For a number of oils, the individual triglyceride quantitation and mass spectra were reported for the first time. The study showed that in some cases, oils with similar fatty acid content do not have the same triglycerides profile. The fatty acids and triglycerides profile for selected Nicotiana species were described for the first time in the literature.     

Influence of time, surface-to-volume ratio, and heating process (continuous or intermittent) on the emission rates of selected carbonyl compounds during thermal oxidation of palm and soybean oils

The aim of this work was to compare the emission rates of selected carbonyl compounds (CC) produced by palm and soybean oils when heated at 180 degrees C in the presence of air, through different time intervals and at different surface-to-volume ratios ( S/ V), in continuous and intermittent processes. The CC were collected and derivatized onto silica C18 cartridges impregnated with an acid 2,4-dinitrophenylhidrazine solution, followed by extraction with acetonitrile and analysis by HPLC-UV and, in some cases, HPLC-MS with electrospray ionization. Among the CC quantified, namely, acetaldehyde, acrolein, propanal, butanal, hexanal, 2-heptenal, and 2-octenal, acrolein was the main emission in both oils and all S/ V ratios, followed by hexanal and 2-heptenal. The soybean oil has presented greater emission rates of acrolein than palm oil. When different S/ V ratios used during the heating process of the oil were compared, the emission rates, in general, were directly related to them, although saturated and nonsaturated CC have had different behaviors toward oxidation reactions. During intermittent heating, there was a trend of increasing emission rates of saturated aldehydes, whereas the opposite was observed with unsaturated aldehydes, probably due to the reactivity of the double bond present in these compounds.     

Analytical evaluation of virgin olive oil of first and second extraction

Virgin olive oils from percolation (first extraction) have been compared with the corresponding oils from centrifugation (second extraction). The former were characterized by (i) higher contents of total phenols, o-diphenols, hydroxytyrosol, tyrosol-aglycons, tocopherols, trans-2-hexenal, total volatiles, and waxes; (ii) higher values of resistance to autoxidation and of turbidity; (iii) higher sensory scores; (iv) higher ratios of campesterol/stigmasterol, trans-2-hexenal/hexanal, and trans-2-hexenal/total volatiles; (v) lower contents of chlorophylls, pheophytins, sterols, and aliphatic and triterpene alcohols; (vi) lower alcoholic index and color indices; (vii) similar values of acidity, peroxide index, and UV (ultraviolet) spectrophotometric indices; (viii) similar percentages of saturated and unsaturated fatty acids, triglycerides, and diglycerides; and (ix) similar values of glyceridic indices. Stigmastadienes, trans-oleic, trans-linoleic, and trans-linolenic acid isomers were not detected in the two genuine oil kinds. Hence, the qualitative level of the first extraction oil was superior to the second extraction one.     

Changes in the fatty acid profile of the subcutaneous fat of swine throughout fattening as affected by dietary conjugated linoleic acid and monounsaturated fatty acids

The fatty acid profile of the subcutaneous fat of pigs and its evolution throughout fattening as affected by dietary conjugated linoleic acid (CLA), monounsaturated fatty acids (MUFA), and their interaction (CLAxMUFA) were studied. Three levels (0, 1, and 2%) of an enriched CLA oil (28% cis-9, trans-11 and 28% trans-10, cis-12 CLA) were combined with two levels of MUFA (low, 19% average; and high, 39% average) for pig feeding (288 gilts). Subcutaneous shot-biopsies were taken from 48 animals at the beginning of the trial (S1, 70 kg), 14 days later (S2, 80 kg), and at slaughter (S3, 107 kg). Inclusion of CLA in the diet caused an increase during fattening in cis-9, trans-11 CLA, trans-10, cis-12 CLA, and saturated fatty acids (SFA) contents of pig backfat and a decrease in MUFA and polyunsaturated fatty acids (PUFA). MUFA supplementation also led to a MUFA enrichment of backfat. The interaction CLAxMUFA affected the SFA content. The rates of accumulation of CLA isomers, SFA, and MUFA throughout the trial did not follow a linear behavior, such rates being higher from S1 to S2 than from S2 to S3. These rates were also influenced by dietary CLA and MUFA levels. The increase in the ratio of saturated to unsaturated fatty acids of backfat caused by dietary CLA might be balanced by supplementation of pig diets with MUFA.     

Ethyl acetate/ethyl alcohol mixtures as an alternative to folch reagent for extracting animal lipids

The lipids of fresh egg yolk, boiled yolk, yolk powder, and raw animal tissues including pork loin, belly pork, and pork fat were extracted with the mixed solvents composed of ethyl acetate (EtOAc) and ethyl alcohol (EtOH) at 2:1 and 1:1 volume ratios, and the results were compared with those obtained with Folch reagent, that is, a mixture of chloroform and methyl alcohol (2:1, v/v). Extraction yields, lipid profiles, and fatty acid compositions were determined by weighing, TLC-FID, and GC, respectively. Data of the extracts obtained with the mixtures of EtOAc and EtOH were not significantly different from those obtained with Folch reagent, implying that the mixed solvent composed of EtOAc and EtOH (1:1 to 2:1, v/v) may replace Folch reagent, which is considered to be toxic and mutagenetic due to its component of CHCl3, for lipid extraction.