Extra‐virgin and refined olive oils decrease plasma triglyceride,moderately affect lipoprotein oxidation susceptibility and increase bone density in growing pigs

The objective of this study was to determine the health benefits of extra‐virgin and refined olive oils, which are high in mono‐unsaturated fatty acids (MUFAs) and polyphenolic compounds using the pig as a model. Thirty‐two cross‐bred pigs were individually penned, allocated to one of four dietary treatments and fed ad libitum for 28 days. Two of the experimental diets consisted of a basal diet containing 12% tallow and either 7% sunflower oil (TSO) or 7% extra‐virgin olive oil (TEVO) on a w/w basis. The remaining diets contained 19% extra‐virgin olive oil (EVO) or 19% of refined olive oil (RO). On days 7, 14 and 28 fasted and 3‐h post‐prandial blood samples were taken. Body composition was measured at the beginning and end of the study using dual energy X‐ray absorptiometry. Daily gain, feed intake and lean and fat deposition were not significantly different between the treatments. However, the daily increase in bone mineral density was higher in pigs fed diets containing olive oil (1.23 vs 2.54, 6.28, 5.20 mg cm^?2 per day for TSO, TEVO, EVO and RO, respectively, P = 0.050). Both fasting and non‐fasting plasma triglycerides were lower (P = 0.003) in pigs fed MUFA‐rich diets, while the cholesterol profile was not significantly different between the treatments. The results from in vitro copper‐induced lipid peroxidation, expressed in terms of conjugated dienes, showed that low density lipoprotein (LDL) particles in postprandial serum from pigs fed olive oil were moderately more resistant to oxidative modification. In conclusion, these data demonstrate that both extra‐virgin and refined olive oils attenuate postprandial hypertriglyceridaemia, moderately affect oxidation susceptibility and increase bone mineral density in growing pigs. Copyright © 2006 Society of Chemical Industry     

不同食材煎炸过程极性组分与聚甘油酯变化的研究

利用花生油对油条、薯条、豆腐和鸡翅4种食材分别进行间歇性煎炸(每天早、中、晚各煎炸1 h,连续5 d,累计煎炸15 h),通过对所取油样极性组分(PC)与甘油三酯聚合物(TGP)的检测分析表明,不同食材煎炸过程中PC与TGP均呈明显的增加趋势。4种煎炸油脂的PC值从初始的3.34%分别增加至煎炸结束时的20.29%、23.84%、14.67%和26.27%,TGP值从初始的0.43%分别增加至10.86%、15.29%、5.68%和15.75%,增幅顺序均为鸡翅薯条油条豆腐。煎炸结束时,4种油脂中PC含量均未超出我国标准限量(27%),但煎炸油条、薯条和鸡翅油脂中TGP已达到欧盟国家如比利时和捷克规定≤10%的限量。此外,不同食材煎炸油的PC与TGP均存在着极显著的相关性,即可根据相关性方程通过PC值快速地判断出TGP的大致含量。     

Effect of cavitation jet on the structural,emulsifying properties and rheological properties of soybean protein-oxidised aggregates

The objective of this study was to investigate the effects of cavitation jets on the structural, emulsifying and rheological properties of soybean protein oxidation aggregates. The results showed that oxidation might induce the formation of larger particle sizes and molecular weight protein aggregates and the decrease of emulsifying properties. The cavitation jet at a short treatment time (<6 min) broke down the disulphide bonds and protein skeleton structures, which reduced the aggregate sizes and molecular weights and increased the emulsion activities, emulsion stabilities, apparent viscosity and elastic modulus. The cavitation jet at a long treatment time (>6 min) supported disulphide bond formation among molecules by intermolecular interactions to form protein aggregates. In addition, the skeleton structure showed cross-linking aggregation. This increased the particle sizes and molecular weights and reduced the emulsion properties, consistency index K and elastic modulus. The findings showed that a cavitation jet at 6 min on oxidised aggregates of soybean protein might enhance the structural, emulsifying and rheological characteristics for the industry.     

甾醇类化合物降低高胆固醇HepG2细胞内胆固醇的作用机制

通过建立HepG2高胆固醇细胞模型，测定细胞总胆固醇、甘油三酯及其胆固醇调控相关蛋白水平，探讨甾醇类化合物的降胆固醇活性及其作用机制。结果表明：4种甾醇类化合物可以降低HepG2细胞内的甘油三酯和总胆固醇水平，改善高胆固醇细胞模型脂质水平的增加和代谢紊乱，其可能机制是下调尼曼-匹克C1型类似蛋白1、胆固醇酰基转移酶2、羟甲基戊二酸单酰辅酶A合成酶和固醇调节元件结合蛋白的表达，上调ATP结合盒转运体G5/8的表达，降低胆固醇的吸收与生物合成，减少胆固醇酯化，促进胆固醇向肠道的排泄。结论：甾醇类化合物通过影响胆固醇吸收以及代谢相关蛋白的表达来改善高胆固醇细胞模型的脂质水平。     

中碳链脂肪酸甘油三酯微胶囊制备优化及性质分析

以乳清蛋白、菊粉为复合壁材，采用喷雾干燥的方法制备中碳链脂肪酸甘油三酯微胶囊。通过单因素实验，考察乳化温度、喷雾干燥进风温度、喷雾干燥进样速度对中碳链脂肪酸甘油三酯微胶囊包埋率的影响，采用Box-Behnken设计响应面试验优化中碳链脂肪酸甘油三酯微胶囊的制备工艺。采用电子扫描显微镜、傅里叶红外光谱、差示扫描量热分析仪及粒度分析仪对中碳链脂肪酸甘油三酯微胶囊进行结构及性质分析，并进行贮藏稳定性及体外消化模拟实验。结果表明：中碳链脂肪酸甘油三酯微胶囊最佳制备工艺条件为乳化温度61.00 ℃、喷雾干燥进风温度185.00 ℃、喷雾干燥进样速度15.00 mL/min，在此条件下制备中碳链脂肪酸甘油三酯微胶囊的包埋率为96.25 %；中碳链脂肪酸甘油三酯微胶囊呈表面较光滑椭球状，其结构完整、粒径大小均一，且具有良好的流动性、溶解性、热稳定性；经过氧化动力学分析，中碳链脂肪酸甘油三酯微胶囊符合一级氧化动力学模型，有良好的贮藏稳定性；中碳链脂肪酸甘油三酯微胶囊体外模拟胃肠道消化后，释放率可达84.53 %，符合Ritger-Peppas释放模型。微胶囊化后中碳链脂肪酸甘油三酯由液态转化为固体粉末方便加工运输，提高贮藏稳定性延长货架期，同时在胃肠道中达到缓释的效果，拓宽其在食品工业应用范围。     

Oxidative stabilisation of synthetic fluids and vegetable oils

The use of ashless antioxidants to increase the useful working life of synthetic fluids, such as polyalphaolefins, polyalkylene glycols and carboxylic acids, is discussed, and some general guidelines are proposed. The application of ashless antioxidants in controlling the oxidative degradation of several different types of biodegradable vegetable oil is illustrated. The action of the naturally occurring antioxidant, vitamin E, in some of these fluids has been examined and some preliminary results are reported.     

Quality control of camellia oil based on HPLC fingerprinting techniques combined with chemometric methods for triglycerides

Triglycerides (TAGs) play an important role in the physiological function of vegetable oils. Camellia oil has a variety of good physiological functions. Therefore, a qualitative and quantitative method for the determination of TAGs in camellia oil by high-performance liquid chromatography-diode array detector/electro spray ionization mass spectrometry was developed. The 16 TAGs that separated were identified and quantified by peak-area normalization. In addition, the major TAGs in camellia oil were OOO (25.25%), OLO (20.72%), POL (9.23%), OLL (8.22%), and OOP (8.22%). Moreover, the content of oleic acid in camellia oil was 81.74%. Using fingerprint techniques, 15 common peaks in 12 samples were selected as characteristic peaks to evaluate the differences in the composition of camellia oil samples. In addition, the samples were further classified by chemometric methods. It is shown that the camellia oil samples with high similarity from two cities in the main producing areas of Zhejiang province could be further classified according to the planting areas by the combination of chromatographic fingerprints and chemometric methods.     

Fast chromatography of pulse triacylglycerols

A short 10-min ultra high performance liquid chromatography (UHPLC) method was used for separation and lipidomic analysis of triacylglycerols (TAGs) in 10 pulses: baby lima beans, black beans, black-eyed peas, butter beans, cranberry beans, garbanzo beans, green split peas, lentils, navy beans, and pinto beans. The lipids extracted using chloroform/methanol averaged 1.9–2.7% across all pulses except garbanzo beans, which gave 6.2% lipids. TAGs were analyzed using dual parallel mass spectrometry (LC1MS2), areas were integrated using LipidSearch 4.2 software, and percent relative TAG compositions were calculated. Fatty acid response factors were calculated by comparison to calibrated GC-FID, which were used to calculate response-factor adjusted TAG compositions. Principal component analysis revealed that the pulses separated into three clusters, which were further highlighted using hierarchical cluster analysis. A subset of TAGs was quantified using calibration curves made from alternating sets of regioisomers in the non-linear high concentration range (~2.5 nMol/ml to ~300 nMol/ml). A linear calibration curve for the sum of tocopherols detected by fluorescence was constructed with a coefficient of determination, r², >0.99 for low concentrations (0.50–50 μg/ml), but tocopherols in pulses appeared to be inefficiently extracted. TAG regioisomers were quantified based on a Critical Ratio (CR), [AA]⁺/[AB]⁺, interpolated between the CRs of two pure regioisomer standards taken from alternating calibration standards. TAG mole percent relative compositions are reported for the first time for most pulses and the compositions are given with more detail and specificity than previously reported.     

GC-MS分析食用油中甘油三酯的研究进展

介绍了GC-MS分析食用油中甘油三酯的几种情况,包括高温气相色谱(300℃)直接进样,将甘油三酯进行甲酯化处理的非高温气相色谱(300℃)非直接进样。并介绍了GC-氢离子火焰检测器直接进样和非直接进样技术。指出了这些技术在食用油甘油三酯的分析上取得的进展和存在的一些问题。