超高效液相色谱法检测固体粉状保健品中豆甾醇、菜油甾醇、β-谷甾醇的含量

目的 建立超高效液相色谱检测固体粉状保健品中豆甾醇、菜油甾醇、β-谷甾醇含量的分析方法。方法 保健品经过KOH和乙醇的皂化反应, 用乙酸调节pH至6.5~7.5, 使用C18色谱柱(100 mm×2. 1 mm, 1.8 μm), 甲醇为流动相, 等梯度洗脱, 用光电二极管阵列检测器在204 nm进行检测。结果 本方法可以在 10 min内完成3种植物甾醇的分离分析。3种植物甾醇线性范围为10~200 mg/L, 线性相关系数均大于0.99。豆甾醇、菜油甾醇、β-谷甾醇的检出限分别为0.095、0.13、0.13 g/100 g (S/N=3), 定量限分别为0.32、0.43、 0.44 g/100 g (S/N=10), 豆甾醇、菜油甾醇、β-谷甾低中高3种浓度的加标平均回收率分别为98.6%~102.9%、96.1%~101.9%和92.3%~98.7%, 6次重复性实验的相对标准偏差(relative standard deviation, RSD)均小于5%。结论 该方法快速、简便、准确、灵敏, 适合测定保健品中豆甾醇、菜油甾醇和β-谷甾醇的含量。     

特种植物油中甾醇总量及组成分析

通过气相色谱法对牡丹籽油、核桃油、南瓜籽油、葡萄籽油四种特种植物油中的甾醇总量及组成进行分析研究。结果表明,牡丹籽油甾醇总量为240.0 mg/100 g,其主要组分是β-谷甾醇、Δ5,23-豆甾二烯醇和Δ5-燕麦甾烯醇;核桃油甾醇总量为100.5 mg/100 g,其主要组分是β-谷甾醇;南瓜籽油甾醇总量为299.6~358.4 mg/100 g,其主要组分是β-谷甾醇、Δ5,24-豆甾二烯醇和Δ7-燕麦甾烯醇;葡萄籽油甾醇总量为222.5~234.9 mg/100 g,其主要组分是β-谷甾醇、菜油(芸薹)甾醇和豆甾醇。分析结果为特种植物油的开发及加工提供了基础数据及技术支撑。     

气相色谱法测定食用油中的植物甾醇

对食用油进行皂化前处理,以胆甾烷醇为内标,采用气相色谱法测定菜籽甾醇、菜油甾醇、豆甾醇和β-谷甾醇4种植物甾醇含量。结果表明：该方法测定食用油中植物甾醇的专一性强,方法的检出限和定量限分别为3.00～3.30 mg/100 g和9.00～11.00 mg/100 g,精密度(RSD)为0.89%,回收率为90.51%～110.25%。该方法用于测定食用油中4种植物甾醇有效可靠。     

气相色谱法分析不同产地辣木叶中植物甾醇的含量

目的研究西双版纳、韶关、安哥拉、印度和云南辣木叶中菜油甾醇、β谷甾醇和豆甾醇的含量差异。方法样品经50%氢氧化钾皂化后,用乙醚:正己烷(1:1,V:V)萃取游离甾醇并将溶剂蒸干,用N,N-二甲基甲酰胺:六甲基二硅氨烷:三甲基氯硅烷(8:2:1,V:V:V)将游离甾醇硅烷化,然后进行气相色谱分析,并分析各地辣木叶中菜油甾醇、豆甾醇和β谷甾醇含量。结果β谷甾醇在韶关辣木叶中含量为20 mg/100 g左右,在西双版纳辣木叶中含量为40 mg/100 g,在安哥拉、印度和云南辣木叶中含量为30 mg/100 g左右;菜油甾醇在韶关辣木叶中含量为5~7 mg/100 g,在印度辣木叶中含量为8 mg/100 g,在西双版纳、安哥拉和云南辣木叶中均大于10mg/100 g;豆甾醇在各个辣木叶中含量为2~12 mg/100 g。结论西双版纳、云南、安哥拉、印度辣木叶中菜油甾醇、β谷甾醇含量明显高于韶关辣木叶,豆甾醇含量没有明显的地域差异。     

甾醇单体的分离精制研究

本文测定了甾醇单体在不同溶剂中的溶解度数据,在此基础上,利用菜油甾醇、豆甾醇和β-谷甾醇在环己酮中的溶解度随温度变化的差异,用重结晶法提纯β-谷甾醇,经过3次结晶操作,β-谷甾醇的纯度达到86.58%;利用菜油甾醇、豆甾醇在正戊醇和环己酮中溶解度的差异,经过5次重结晶,结晶产品中豆甾醇的纯度分别达到96.1%和93.9%.     

米糠超临界流体萃取物中植物甾醇组分的气相色谱分析

用气相色谱法对米糠超临界流体萃取物中植物甾醇组成及其含量进行分析。结果表明：米糠超临界流体萃取物中含有3 种植物甾醇,即菜油甾醇、豆甾醇和β- 谷甾醇,其中β- 谷甾醇含量最高为8.47mg/g,其次是菜油甾醇含量为1.97mg/g,豆甾醇含量最低为1.23mg/g。气相色谱法检测米糠中植物甾醇种类及含量,可广泛用于植物原料中的植物甾醇的定性、定量分析。     

加工过程对苹果籽油中植物甾醇流向分布影响

采用GC-FIR法对苹果籽加工过程中的植物甾醇进行了成分分析。结果表明,苹果籽油中植物甾醇主要成分为菜油甾醇、豆甾醇和β-谷甾醇,其中以β-谷甾醇含量最高;压榨法制备的苹果籽油植物甾醇的含量(385mg/100g)高于索氏提取(288mg/100g)和超声提取法(318mg/100g);且随着苹果籽油精炼程度提高,油脂中的有益微量成分植物甾醇损失增大。     

黑果枸杞油中脂肪酸、植物甾醇的组成及维生素A、维生素E的分析

对黑果枸杞油中脂肪酸、植物甾醇组成及维生素A、维生素E的含量进行测定。结果表明:黑果枸杞油中不饱和脂肪酸含量为90.0%,其中油酸、亚油酸、亚麻酸含量分别为17.9%、67.6%和4.0%;植物甾醇由β-谷甾醇、菜油甾醇和豆甾醇组成,总含量为489.2 mg/100 g;维生素A和维生素E的含量分别为0.3 mg/100 g和46.3 mg/100 g。黑果枸杞油是一种具有开发价值的新型植物油。     

气相色谱-质谱联用法测定14种食用植物油中的植物甾醇

建立了气相色谱-质谱联用测定植物油中4种植物甾醇(豆甾醇、β-谷甾醇、菜籽甾醇和菜油甾醇)的方法。选用超高惰性J&W DB-5MS UI毛细管色谱柱,50%KOH-乙醇为皂化剂,进样量为1μL,分流比20∶1,程序升温,可在32 min内实现上述4种植物甾醇与其他不皂化组分的分离。豆甾醇、β-谷甾醇、菜籽甾醇和菜油甾醇的检出限分别为4.41、6.09、3.10、8.62 mg/L,线性相关系数R≥0.999 2。运用该法对14种25个植物油样品中4种植物甾醇的含量进行了分析,结果表明:玉米油和菜籽油中植物甾醇总量最高,其次是芝麻油;不同种类植物油中植物甾醇的含量和比例各不相同,同一种类不同品牌植物油中各植物甾醇所占的比例基本接近。     

植物甾醇HPLC-ELSD检测方法研究

建立了反相高效液相色谱-蒸发光散射检测器(HPLC-ELSD)测定植物甾醇含量的方法.结果表明以甲醇-乙腈(75:25,V:V)为流动相,流速1.0 mL/min,可有效分离混合植物甾醇中的豆甾醇、菜油甾醇和β-谷甾醇,它们的标准偏差分别为0.005 7、0.005 6、0.006 6;平均回收率分别为98.2%、101.3%、101.8%;线性范围(线性相关系数)分别为0.016～0.46 mg/mL(r=0.996 8)、0.05～0.45 mg/mL(r=0.999)、0.022～0.45mg/mL(r=0.994 9).用该方法成功检测了豆油脱臭馏出物的维生素E提余物中的植物甾醇.     

Phytosterol Determination and Method Validation for Selected Nuts and Seeds

A method involving alkali and/or acid hydrolysis of phytosterols followed by trimethylsilyl ether derivatization coupled with GC-FID analysis was validated and applied in the analysis of major phytosterols (campesterol, stigmasterol, β-sitosterol, and Δ⁵-avenasterol) in nuts (n = 7), seeds (n = 9), legumes (n = 2), and grain (n = 1). The acid-labile Δ⁵-avenasterol was extracted with alkaline hydrolysis only before derivatization. Quantification of all phytosterols was done using the computed relative response factor of 5α-cholestane (internal standard). Analyses of internal and external phytosterol standards showed good linearity for all phytosterols (R ² of 0.999); LOD and LOQ of phytosterols were determined to be 0.01–0.12 and 0.04–0.40 mg/100 g, respectively. Repeatability and reproducibility precision analyses showed acceptable coefficient of variation of less than 3 and 4%, respectively, and satisfactory Horwitz ratio values of <1.0. Excellent accuracy was proved by the high recovery values of 91.4–106.0% for campesterol, β-sitosterol, and stigmasterol. Δ⁵-Avenasterol, the most oxidation-susceptible sterol, showed a recovery of about 60%. The total phytosterol (sum of major phytosterols quantified) contents in the 19 samples varied from 38.8 mg/100 g (white quinoa seed) to 246.2 mg/100 g (sunflower seed). β-Sitosterol was the predominant phytosterol (54–86.0% of total) among all samples except fennel seed in which stigmasterol was predominant. Analytical quality control chart maintained during the study period showed that assays were performed under control. Method validation indicated that the analytical method can be applied for accurate determination of campesterol, β-sitosterol, and stigmasterol in selected food samples.     

High-Performance Liquid Chromatography with Fluorescence Detection for Simultaneous Analysis of Phytosterols (Stigmasterol, β-Sitosterol,Campesterol, Ergosterol,and Fucosterol) and Cholesterol in Plant Foods

A method based on high-performance liquid chromatography (HPLC) with fluorescence (FL) detection for the simultaneous analysis of phytosterols (stigmasterol, β-sitosterol, campesterol, ergosterol, and fucosterol) and cholesterol was developed. To fluoresceinate the sterols, they were derivatized by 1-anthroyl cyanide to the hydroxyl group at carbon 3 of each sterol skeleton. This HPLC-FL method consists of a C-30 column, an isocratic solution using acetone/acetonitril/hexane/water (71:20:4:5, v/v) as the mobile phase at 1.0 mL min^?1 and fluorescence detection at an excitation of 370 nm and an emission of 470 nm. The separation of five phytosterols, cholesterol, and 1-hexacosanol as an internal standard was achieved with sufficient reproducibility and quantitative ability. Our method could evaluate the sterols of land plants such as wood ear fungus, soybean, and parsley, as well as marine algae such as Hiziki (Phaeophyta), Ogonori (Rhodophyta), and Heraiwazuta (Chlorophyta). As a result of the analysis of land plants, wood ear contained a large amount of ergosterol as a precursor of vitamin D₂. Soybean contained a large amount of stigmasterol, campesterol, and β-sitosterol. Parsley contained small amounts of these sterols compared with wood ear and soybean. Among the marine algae, Hiziki, Ogonori, and Heraiwazuta contained large amounts of fucosterol, cholesterol, and β-sitosterol, respectively. The compositions of marine algae differed from those of land plants.     

A preliminary investigation into the unsaponifiable fraction of donkey milk: Sterols of animal origin,phytosterols, and tocopherols

We investigated the main sterols, phytosterols, and the α- and γ-tocopherol content in donkey milk during the first 2 mo of lactation. Cholesterol was the main sterol in milk (mean ± standard deviation = 0.97 ± 0.443 g/100 g of fat). Lanosterol was the main minor sterol of animal origin, followed by desmosterol (0.003 ± 0.001 and 0.001 ± 0.001 g/100 g of fat, respectively). Of the phytosterols, β-sitosterol was the main sterol of vegetal origin in donkey milk (0.005 ± 0.002 g/100 g of fat), but lower levels of campesterol, brassicasterol, and stigmasterol were also recorded. Mean levels of α- and γ-tocopherol were 0.01 ± 0.007 and 0.003 ± 0.001 g/100 g of fat, respectively. We observed no significant changes in sterol or tocopherol content during the first 2 mo of lactation. The presence of lanosterol in donkey milk is of particular interest, because lanosterol is a potential drug and has important physiological effects. The presence of phytosterols, which are considered nutraceutical molecules, enhances the nutritional quality of donkey milk fat for consumers.     

Development of a Method for the Analysis of Sterols in Sterol-Enriched Deli-Style Turkey with GC-FID

Plant sterols have been recognised by the European Food Safety Authority for their cholesterol-lowering properties and are currently added to several food formulations. The objective of this study was to develop a method based on formation of sterol trimethylsilyl ether derivatives and separation and quantification by GC for the determination of three phytosterols (β-sitosterol, stigmasterol and campesterol) in sterol-enriched deli-style turkey. The assay was linear (concentration range 4.3–172.1 μg/ml, R ²?≥?0.9868) and accuracy and precision were within the acceptance criteria of the U.S. Food and Drug Administration (USFDA) guidelines for method validation, set at <20 % RSD at the lower limit of quantification (LLOQ) and <15 % RSD for all other standards. Accuracy measured by relative response factor (RRF) also met the USFDA validation criteria. No matrix effects were observed. The response factors (RFs) of the three sterols differed significantly to that of the internal standard (ISTD) used, leading to RRF dissimilar to 1 (campesterol?=?1.0167, stigmasterol?=?1.4458, β-sitosterol?=?0.9029). This method is suitable for quantification in meat matrix, and it has been successfully applied to the determination of sterols in sterol-enriched deli-style turkey (21 mg sterols/0.5 g sample).     

气相色谱法同时测定食品中的胆固醇和植物甾醇

建立气相色谱法同时测定食品中植物甾醇和胆固醇含量的分析方法,测定植物甾醇含量较高的常见植物油和同时含有胆固醇及植物甾醇的样品。采用5α-胆甾烷为内标参照物,样品经皂化后提取,浓缩后正庚烷定容上机进样分析。胆固醇和植物甾醇在0.001～2.5 mg/mL质量浓度范围内线性良好,线性相关系数R2均大于0.99。方法的检出限为0.3 mg/100 g,定量限为1.0 mg/100 g,该方法相较于液相色谱法能有效将胆固醇和植物甾醇进行分离,具有步骤简单、重复性好、准确度和灵敏度高等特点。     

UPLC-MS法测定烤后烟叶中的5种游离态甾醇

为考察国内不同类型、品种、产地和部位烟叶样品中游离态甾醇质量分数的分布情况,采用UPLC-MS联用法测定了国内烤烟、雪茄烟和晒烟共47个烟叶样品中5种甾醇(豆甾醇、β-谷甾醇、菜油甾醇、胆甾醇、麦角甾醇)的质量分数。结果表明:(1)烟叶样品中游离态甾醇的总质量分数呈现特定规律,其中豆甾醇质量分数最高,其次是β-谷甾醇、菜油甾醇、胆甾醇和麦角甾醇;(2)烤烟和晒烟中β-谷甾醇的质量分数大于菜油甾醇,而雪茄烟中菜油甾醇的质量分数大于β-谷甾醇;(3)不同品种、部位和产地的烟叶中游离态甾醇的质量分数存在差异。     

造纸法再造烟叶加工过程中5种甾醇的含量变化

为研究造纸法再造烟叶各工艺阶段甾醇类化合物的含量变化,利用超高效液相色谱-串联质谱仪(UPLC-MS/MS)对5种甾醇(麦角甾醇、胆甾醇、菜油甾醇、豆甾醇及β-谷甾醇)进行了测定。结果表明:①烟叶原料中5种甾醇的含量(质量分数)均高于烟梗,且两种烟草原料中的甾醇类化合物均以豆甾醇和β-谷甾醇为主;②在提取和浓缩阶段,甾醇含量均降低,降低量分别占原料中甾醇总量的21.35%和15.13%;③在掺配阶段,低浓浆中甾醇实际增加量占原料中甾醇总量的10.64%;④在打浆和抄造阶段,甾醇含量均降低,降低量分别占原料中甾醇总量的14.06%和14.18%;⑤其余工艺阶段的甾醇含量变化不大,最终再造烟叶产品中甾醇量占原料中甾醇总量的48.67%。      

Phytosterol content of experimental diets differing in fatty acid composition

The goal of this study was to determine the relationship between phytosterol and fatty acid concentrations in experimental diets designed to have particular fatty acid profiles. Diet samples were collected during three National Heart, Lung and Blood Institute sponsored multi-center clinical feeding studies (DELTA and DASH programs). Phytosterols (β-sitosterol, campesterol, stigmasterol, campestanol, sitostanol, avenasterol and brassicasterol) were assayed in the saponified total lipid extracts of diet composites, as trimethylsilyl ether derivatives, by gas chromatography and gas chromatography/mass spectrometry. The predominant phytosterols (>84%) in all diets were β-sitosterol, campesterol and stigmasterol. Regression using a multiple linear model showed an inverse relationship between saturated fat (SFA) and total phytosterols (β₁=−2.55; p<0.001), a positive relationship between polyunsaturated fat (PUFA) and total phytosterols (β₃=6.53; p<0.03), and no association between total phytosterols and monounsaturated fat (MUFA) (β₂=0.55, p<0.40). The results suggest that dietary phytosterol content covaries with changes in PUFA and SFA. Total phytosterol content decreases with increasing SFA and is notably elevated by increasing PUFA. Further studies must elucidate the biological effects of varying phytosterol concentrations as components of different diets. However, clinicians should recognize the likely concurrent variance of phytosterol and fatty acid concentrations in experimental diets, since both have been shown to influence blood cholesterol levels.