Triglyceride composition of ewe,cow, and goat milk fat

The separation and identification of the components in milk fat, which are mainly triglycerides, is a challenge due to its complex composition. A reverse-phase high-performance liquid chromatography (HPLC) method with gradient elution and light-scattering detection is described in this paper for the triglyceride analysis in ewes’ milk fat. Triglyceride identification was carried out by combining HPLC, gas-liquid chromatography (GLC), and the calculated equivalent carbon numbers of several triglyceride standards. Quantitation of partially resolved peaks in the HPLC chromatogram was accomplished by applying a peak deconvolution program. Forty-four fatty acids were identified by GLC analysis, but only 19 were used for the following prediction of triglyceride molecular species; 181 triglycerides were identified, some of which were grouped at the same peak and needed application of the deconvolution program. Consequently, coefficients of variation were close to or lower than 5%. Moreover, the triglyceride composition of ewe, cow, and goat milk fat were compared by using these methods. These results show that ewe milk fat is richer in short- and medium-chain triglycerides, and cow milk fat is richer in long-chain and unsaturated triglycerides.     

Hypertension incidence after tap-water implementation: a 13-year follow-up study in the arseniasis-endemic area of southwestern Taiwan

Hypertension is the leading cause of cardiovascular disease worldwide. Long-term arsenic exposure has been linked to increased risk for hypertension; however, little is known whether a previous exposure has lingering effects on hypertension after the exposure being reduced significantly for decades. The study cohort was established in 1990 in an arseniasis-endemic area of 3 villages — Homei, Fuhsin, and Hsinming in Putai Township located on the southwestern coast of Taiwan, where residents were exposed to artesian well water (median level = 700 to 930 μg/L) until early 1970s. The original cohort consisted of 490 non-hypertensive residents over 30-yrs-old and 352 of them were successfully followed up in 2002/03. Arsenic concentrations in the artesian well water consumed by residents during 1960s were used to indicate the previous exposure while urinary arsenic species measured in 2002/3 was used to represent current exposure. Hypertension incidences were 27.4, 65.6, and 69.1, per 1000 person-years for men aged 35-49, 50-64, and 65-74 years, respectively being higher than the corresponding rates of 25.1, 46.1, and 57.2 in a community-based longitudinal study. Cancer was the major cause of the total deaths (17/30 = 57%). Diastolic blood pressure was shown to increase with an increased cumulative arsenic ingestion from drinking water (β = 0.27, p < 0.001). The incidence was increased by 2.43-fold in subjects of As(V) ≥ 2.67 μg/g creatinine as compared to those of As(V) < 1.20 μg/g creatinine (the third vs. first tertile; p = 0.047) after adjustment for conventional risk factors. This study suggests that three decades after cessation of drinking artesian well water, residents of the endemic area are still at increased risk for developing hypertension, particularly those who excrete high amounts of As(V).     

冷榨茶叶籽油甘三酯的组成分析

本文采用气相色谱法测定了茶叶籽油的脂肪酸组成,得出茶叶籽油中不饱和脂肪酸含量在80%以上,主要是以油酸的形式存在,含量为59.84%;采用胰脂酶水解法测定茶叶籽油的Sn-2位脂肪酸分布,并根据1,3-随机-2-随机分布学说计算出茶叶籽油甘三酯组成, 得出主要甘三酯是OOO、OOL、POO、PLO、LLO等,其中三不饱和脂肪酸甘油酯含量在53.5%以上,而三饱和脂肪酸甘油酯含量仅为0.05%左右;由高效液相色谱测定得出茶叶籽油中的维生素E含量为0.18 mg/g;Rancimat仪测定茶叶籽油氧化稳定时间在110 ℃时为6.02 h。茶叶籽油具有很好的食用营养价值和储藏稳定性。     

HPLC分析植物油脂甘油三酯结构组成的研究现状

甘油三酯是植物油脂的主要成分,分析其结构组成可了解植物油脂性质及用途,也可作为鉴别各种植物油脂特征的指纹信息.目前对于植物油脂甘油三酯的高效液相色谱分析在新技术、新方法的基础上获得了很多成就,重点介绍了高效液相色谱法在分析植物油脂甘油三酯结构组成方面的研究现状及进展.     

C. medica cv Diamante peel chemical composition and influence on glucose homeostasis and metabolic parameters

This study evaluated the in vitro inhibition of carbohydrate-hydrolysing enzymes, the stimulation of insulin secretion, and the in vivo metabolic effects in mice of Citrus medica L. cv Diamante peel extract. The quantitative analysis of selected phytochemicals were determined to investigate their relationship with the biological activities. Citrus extract exhibited an inhibitory activity against both α-amylase and α-glucosidase with IC₅₀ values of 258.7 and 263.2 μg/ml, respectively. Measurements of the effects of peel extract on the mouse insulinoma MIN6 β-cells indicated that it did exert direct stimulatory effects on the exocytotic release of insulin in a concentration-dependent manner. The supplementation of the C. medica cv Diamante was able to reduce plasma glucose (GLU) concentration and lowered the levels of plasma cholesterol (COL) and triglycerides (TG). The obtained results underline the potential health benefits as a result of consuming C. medica cv Diamante and suggest that it could be used as new potential source with functional properties for food or nutraceutical products.     

燕麦对高胆固醇血症男性中老年人血脂水平的影响

目的:观察食用燕麦对城市患高胆固醇血症男性中、老年人空腹血脂水平的影响.方法:参考《中国成人血脂异常防治指南》中的判断标准,将65名患高胆固醇血症男性中、老年人随机分为2组,分别为燕麦组(33人),每人每日给予100 g即冲即食燕麦片;对照组(32人),每人每日给予100 g普通挂面,试验周期6周.研究开始前和6周时对两组受试者进行基本健康状况问卷调查、人体测量、血生化检测以及膳食调查.结果:燕麦组和对照组的能量、蛋白质、脂肪、碳水化合物摄入量无显著差异,但燕麦组膳食纤维摄入量明显增加,增幅显著大于对照组,P＜0.05.6周结束时,燕麦组血清总胆固醇(T℃)、低密度脂蛋白胆固醇(LDL-C)、载脂蛋白B(apoB)水平显著降低(P＜0.05);血清TC、LDL-C平均降低幅度分别为7.0％和7.5％.对照组血清胆固醇、脂蛋白及载脂蛋白水平在试验期间未见显著变化.结论:对于我国城市中患高胆固醇血症的男性中、老年人,每日食用一定量的燕麦作为膳食中的粮谷类食物,可有效降低血清TC、LDL-C和apoB水平,减少心脑血管疾病发生的危险.     

甲酯化方法对甘油三脂和游离型脂肪酸混合物的脂肪酸分析的影响

在重组解脂耶氏酵母催化红花籽油合成共轭亚油酸的过程中,大量的红花籽油与游离型亚油酸及共轭亚油酸以混合物的形式存在于发酵液上清。为了通过气相色谱准确分析催化过程中底物及产物的含量,确定甘油三脂和游离型脂肪酸混合物的最佳甲酯化方法至关重要。本文选择盐酸-甲醇法、盐酸-甲醇（甲苯）法、三氟化硼-甲醇法、氢氧化钠-甲醇法、酸碱综合法和重氮甲烷法6种方法,对红花籽油、游离型共轭亚油酸和二者混合物分别进行甲酯化,通过气相色谱定量分析,比较甲酯化效率。结果表明盐酸-甲醇（甲苯）法甲酯化程度高,且操作简便、安全、经济,是样品为甘油三酯和游离型脂肪酸混合物的最适甲酯化方法。     

Effects of supercritical carbon dioxide extraction parameters on virgin coconut oil yield and medium-chain triglyceride content

The extraction of coconut oil has been performed using supercritical carbon dioxide (SC-CO₂). The extractions were performed at pressure and temperature ranges of 20.7–34.5 MPa and 40–80 °C, respectively. It was observed that almost all (more than 99%) of the total oil could be extracted. Response surface methodology (RSM) was applied to evaluate the effects of the parameters (pressure, temperature and CO₂ consumption) on the extraction yield and medium-chain triglycerides (MCTs), in terms of the fatty acid content in the extracted oil. A correlation was established with p-values for both responses significant at the 95% confidence level.     

3种油脂煎炸过程极性组分与甘油三酯聚合物及多环芳烃相关性研究

以花生油、菜籽油和葵花籽油的连续煎炸油条的试验为例,对煎炸过程极性组分(PC)、甘油三酯聚合物(TGP)及多环芳烃(PAHs)形成及相关性进行研究。结果表明:3种油脂中PC、TGP及PAHs含量均随煎炸时间的延长而增加;经过32 h的煎炸,花生油中PC、TGP与PAH16含量分别从未煎炸时的3.34%、0.43%、169.88μg/kg增至29.00%、16.92%、282.66μg/kg,菜籽油中PC、TGP与PAH16含量分别从4.02%、0.51%、18.85μg/kg增至25.80%、15.55%、42.92μg/kg,葵花籽油中PC、TGP与PAH16含量分别从2.43%、0.42%、21.49μg/kg增至34.19%、24.76%、51.95μg/kg;煎炸过程菜籽油PC增幅最小,至32 h煎炸结束,PC含量未超出国标限量(≤27%);煎炸过程中PC与TGP、PC与PAH4含量间均呈显著的正相关,根据相关性方程可以通过PC含量对煎炸油中TGP与PAH4含量进行预测。综合考虑煎炸在用油的安全性,除根据国标对PC含量进行检测和控制之外,还应关注TGP及PAHs在煎炸过程的变化情况。     

A Novel Lipase from Lasiodiplodia theobromae Efficiently Hydrolyses C8-C10 Methyl Esters for the Preparation of Medium-Chain Triglycerides’ Precursors

Medium-chain triglycerides (MCTs) are an emerging choice to treat neurodegenerative disorders such as Alzheimer’s disease. They are triesters of glycerol and three medium-chain fatty acids, such as capric (C8) and caprylic (C10) acids. The availability of C8–C10 methyl esters (C8–C10 ME) from vegetable oil processes has presented an opportunity to use methyl esters as raw materials for the synthesis of MCTs. However, there are few reports on enzymes that can efficiently hydrolyse C8–C10 ME to industrial specifications. Here, we report the discovery and identification of a novel lipase from Lasiodiplodia theobromae fungus (LTL1), which hydrolyses C8–C10 ME efficiently. LTL1 can perform hydrolysis over pH ranges from 3.0 to 9.0 and maintain thermotolerance up to 70 °C. It has high selectivity for monoesters over triesters and displays higher activity over commercially available lipases for C8–C10 ME to achieve 96.17% hydrolysis within 31 h. Structural analysis by protein X-ray crystallography revealed LTL1’s well-conserved lipase core domain, together with a partially resolved N-terminal subdomain and an inserted loop, which may suggest its hydrolytic preference for monoesters. In conclusion, our results suggest that LTL1 provides a tractable route towards to production of C8–C10 fatty acids from methyl esters for the synthesis of MCTs.