The contents of lignans in commercial sesame oils of Taiwan and their changes during heating

Sesame lignans have multiple functions and were recently reported to have potential as sources of phytoestrogens. Sesame oils used in Taiwan are expelled from roasted sesame seeds with dark colour and strong flavour. This study analyzed lignan contents of 14 brands of sesame oils, and found their mean of total lignans to be 11.5 mg/g; 82% and 15% of the lignans were sesamin, and sesamolin, respectively. Sesamol contents were relatively higher in those with darker colour. In use as a cooking oil, heating at 180 °C for 4 min did not change the content of lignans, but the level of sesamol increased after heating at 180 °C for 20 min. Heating at 200 °C for 20 min caused a significant loss of sesamolin and sesamol. From our calculation, ingestion of 10 g of sesame oil is adequate to provide the level of lignans that might benefit cardiovascular health, as found by other studies. Cooking at temperatures above 200 °C will cause loss of some lignans, but sesamin, a source of phytoestrogen, is relatively heat-stable.     

Effect of refining on the lignan content and oxidative stability of oil pressed from roasted sesame seed

Oxidative stability of pressed and refined sesame oils during seven consecutive months of storage at room temperature was studied comparatively. Lignans, peroxide value (PV), p‐anisidine value (AV) and total oxidation value (TOTOX) were determined as evaluation indices. PV, AV and TOTOX of sunflower, corn and peanut oils were simultaneously monitored to compare their oxidative storage stabilities with the sesame oils. The total amount of lignans in the pressed and refined sesame oils were 1103 and 790 mg per 100 g respectively. The contents of sesamin and sesemolin in the pressed sesame oil were 734 and 369 mg per 100 g respectively. Sesamin and sesamolin content were reduced by 256 and 159 mg per 100 g, respectively, after refining. Nearly 40% of the sesamin epimerised to asarinin after oil refining. The results indicate that sesame oils pressed from roasted seed have far superior storage stability to oxidation than the other vegetable oils. This difference may be due to much higher sesamin and sesamolin contents in the pressed sesame oils. The results suggest lignan compositions and levels could be used as key indicators for evaluating the oxidative storage stability of sesame oil products as well as to differentiate between pressed and refined sesame oils.     

Effects of sesamol, sesamin, and sesamolin extracted from roasted sesame oil on the thermal oxidation of methyl linoleate

This study investigated the effects of lignan compounds extracted from roasted sesame oil, which were sesamol, sesamin, and sesamolin, on oxidation of methyl linoleate (ML) during heating. These compounds were added at 500 or 1000 mg/kg to ML, and α-tocopherol was used as a reference antioxidant. The ML added with lignans or α-tocopherol was heated at 180 °C for 60 min. Thermal oxidation of ML was evaluated by conjugated dienoic acid (CDA) contents, p-anisidine value (PAV), and ML retention. Contents changes of lignan compounds or α-tocopherol in ML during heating were monitored by high-performance liquid chromatography. CDA contents and PAV of samples increased and ML decreased with heating time at 180 °C. Samples added with lignan compounds showed lower CDA contents and PAV but higher ML retention than samples without lignan compounds. The antioxidant activity of sesame oil lignan compounds in ML oxidation during heating tended to be higher than that of α-tocopherol. The contents of lignan compounds in samples decreased with heating time due to their degradation, but the degradation rates were lower than that of α-tocopherol. This study suggested that sesame oil lignan compounds be used as antioxidants in oil at high temperatures for deep-fat frying due to their higher effectiveness and stability than α-tocopherol.     

不同品种类型芝麻品质性状的比较分析

为全面分析不同品种类型芝麻的品质性状及其与重要农艺性状间的关系,筛选294个代表性芝麻品种资源,通过多点种植和测定籽粒脂肪、蛋白质、芝麻素和芝麻林素含量,对不同品种类型芝麻的品质性状进行了差异比较,并对品质性状之间和品质性状与农艺性状的相关性进行了分析。结果表明,294个芝麻品种脂肪、蛋白质、芝麻素和芝麻林素平均含量分别为52.77%、20.41%、310 mg/g和1.92 mg/g。不同株型芝麻,单秆型品种脂肪、芝麻素含量极显著高于分枝型品种,蛋白质含量显著低于分枝型品种,芝麻林素含量差异不显著;不同叶腋花数芝麻,单花型品种脂肪、芝麻素含量极显著低于三花型品种,蛋白质含量极显著高于三花型品种,芝麻林素含量显著低于三花型品种。不同品种芝麻脂肪含量与蛋白质含量呈极显著负相关,与芝麻素、芝麻林素含量呈极显著正相关;蛋白质含量与芝麻素、芝麻林素含量呈极显著负相关;芝麻素与芝麻林素含量呈极显著正相关;脂肪含量与生育期、籽粒颜色L*值、b*值呈极显著正相关,与千粒重、籽粒长度、宽度、长宽比和籽粒颜色a*值呈极显著负相关;蛋白质含量与千粒重、籽粒长度、籽粒宽度、籽粒长宽比呈极显著正相关,与生育期、籽粒颜色L*值及b*值呈极显著负相关,与籽粒颜色a*值相关性不显著;芝麻素含量与生育期呈显著正相关,与籽粒长宽比、籽粒颜色L*值及b*值呈极显著正相关,与千粒重、籽粒长度呈极显著负相关,与籽粒宽度、颜色a*值相关性不显著;芝麻林素含量与生育期、籽粒颜色a*值及b*值呈极显著正相关,与千粒重、籽粒长度、籽粒宽度呈极显著负相关,与籽粒长宽比、籽粒颜色L*值相关性不显著。     

The relationship of antioxidant components and antioxidant activity of sesame seed oil

Although sesame seed oil contains high levels of unsaturated fatty acids and even a small amount of free fatty acids in its unrefined flavored form, it shows markedly greater stability than other dietary vegetable oils. The good stability of sesame seed oil against autoxidation has been ascribed not only to its inherent lignans and tocopherols but also to browning reaction products generated when sesame seeds are roasted. Also, there is a strong synergistic effect among these components. The lignans in sesame seed oil can be categorized into two types, i.e. inherent lignans (sesamin, sesamolin) and lignans mainly formed during the oil production process (sesamol, sesamolinol, etc.). The most abundant tocopherol in sesame seed oil is γ‐tocopherol. This article reviews the antioxidant activities of lignans and tocopherols as well as the browning reaction and its products in sesame seed and/or its oil. It is concluded that the composition and structure of browning reaction products and their impacts on sesame ingredients need to be further studied to better explain the remaining mysteries of sesame oil. © 2014 Society of Chemical Industry     

Tocols in caneberry seed oils

The compositional analysis of tocols in oils extracted from Korean caneberry seeds was compared with commercial soybean, corn, olive, canola, perilla, and grape seed oils. The oils from caneberry seeds of six different species were extracted using either a chloroform–methanol–water system or hot hexane. Tocols from all of the oils were analysed using isocratic HPLC. The contents of total tocopherols in the caneberry seed oils were about 75–290 mg/100 g oil, whereas tocotrienols were not detected. γ-Tocopherol was the most abundant tocopherol (31.8–239 mg/100 g oil) in the caneberry seed oils, followed by α-tocopherol (7.6–58.2 mg/100 g oil). The contents of total tocols in soybean, corn, olive, canola, perilla, and grape seed oils were 99.9, 61.1, 28, 27, 45.4, and 52.2 mg/100 g oil, respectively. Total tocol content was higher in most of the caneberry seed oils including the refined ones than in the commercial vegetable oils.     

Effects of Bleaching on the Properties of Roasted Sesame Oil

ABSTRACT: Improvement in quality of roasted sesame oil was studied. Roasted sesame oil was bleached at 70 °C, 85 °C, or 100 °C for 20 min with acid-activated clay at 0.5%, 1.0%, or 3.0% (w/w) and then centrifuging at 12096 × g at 4 °C for 10 min. The color of the roasted sesame oil became lighter and the viscosity of oil decreased by bleaching. Bleaching caused a significant increase in the smoke point of the oil, from 170 °C to a range of 183 °C to 191 °C. Bleaching increased palmitic acid and decreased linoleic acid contents of roasted sesame oil. Bleaching decreased free fatty acid (FFA) and conjugated dienoic acid (CDA) contents and carbonyl values (CV) of roasted sesame oil. The more the acid clay was used, the lower were the FFA and CDA contents and CV of the oil. Amount of acid clay in bleaching of roasted sesame oil had higher effects on the color, viscosity, smoke point, FFA and CDA contents, and CV of roasted sesame oil than the bleaching temperature. Bleaching did not show a significant effect on tocopherol contents of the sesame oil. Bleaching tended to decrease sesamolin contents and increase sesamol contents in the roasted sesame oil. As the amount of acid clay and the bleaching temperature increased, the contents of sesamin and sesamolin in the oil decreased while sesamol contents increased.     

芝麻油中芝麻素、芝麻林素的研究

本文利用高效液相色谱测定不同芝麻样本提取油以及市购芝麻油中芝麻素、芝麻林素的含量。色谱柱为HibarRT250-4(C18,250mm×4.6mm,填充粒度5μm);流动相:甲醇:水=75:25(V/V);流速:1ml/min;检测波长:280nm。测定结果表明:被测两峰完全分离,且峰形较好,线性范围10～100μg/ml,芝麻素、芝麻林素平均回收率分别为101.1%、100.2%重现性(n=5)分别为芝麻素RSD=2.31%、芝麻林素的RSD=3.05%,最低检出限:芝麻素为1.5μg/ml,芝麻林素为2.5μg/ml(以进量浓度计)。油样中芝麻素的含量范围为0.35%～0.72%、芝麻林素的含量范围为0.32%～0.48%,制油工艺中焙炒工序强度对芝麻林素含量变化具有一定影响。     

Extraction,separation and characterisation of sesame oil lignan for nutraceutical applications

Nutraceutical aspects of sesame oil (SO) are well reported. However, an efficient process for commercial production has not yet been reported. In this study we have aimed at separating lignans from SO aiming at use as nutraceuticals. SO was subjected to sequential extraction with methanol under selected conditions of temperature (70 °C), time (100 min) and solvent:oil ratio (1:1). Under the optimised conditions, the yields of pooled methanolic extract concentrate and residual oil were 10.09 ± 1.0 g and 89.2 ± 1.0 g, respectively. On HPLC analysis, the methanol concentrate showed a total lignan content of 9.32 ± 0.19% (6.54 ± 0.12% sesamin and 2.78 ± 0.31% sesamolin). The concentrate was subjected to low temperature crystallization (4 °C) for the separation of lignan crystals and 51% of the lignans in the oil with 94.4% purity. The crystal-removed methanolic concentrate was saponified and purified; the total lignan content (sesamin and sesamolin) in the unsaponifiable matter (USM) was 64%.The distribution of sesamin and sesamolin in the purified USM was in the proportion 46:54, unlike that in the pure crystals (84:16). Lipid classes (triglycerides, TG; free fatty acids, FFA; diglycerides, DG; monoglycerides, MG; polar lipid, PL) in SO, methanolic extract concentrate and residual oil were separated using thin-layer chromatography (TLC). The amounts of lipid classes were determined by relating the total area of the fatty acid peaks to the area of the peak for internal standard (methyl heptadecanoate), using gas chromatography (GC). The process reported here describes a simple and less cumbersome procedure to produce lignans with high yield and purity for nutraceutical applications.     

Effects of roasting conditions of sesame seeds on the oxidative stability of pressed oil during thermal oxidation

Oxidative stability of sesame oil (SO) prepared from sesame seeds roasted at 213, 230, and 247 °C for each 14, 21, or 28 min was determined at 180 °C heating condition by 2,2-diphenyl-1-picrylhydrazyl (DPPH), conjugated dienoic acid (CDA) value, headspace oxygen analysis, and profile changes of sesamol and sesamolin. As sesame seeds were roasted with longer time and higher temperature, more sesamol was found in SO. SO from sesame seeds roasted at 247 °C for 28 min had the highest oxidative stability based on the results of CDA and headspace oxygen. Absorbance of DPPH from SO roasted at 230 and 247 °C showed different patterns compared to those from SO at 213 °C during thermal oxidation. Sesamol was continuously generated with the decrease of sesamolin in SO from 230 to 247 °C while sesamol in SO from 213 °C did not increase during 180 °C heating. Higher oxidative stability of SO may be related with the continuous generation of sesamol from the degradation of sesamolin during thermal oxidation rather than the initial antioxidant content.     

芝麻中木脂素的组成、结构及其生理功能

介绍了芝麻中木脂素类物质(lignans):芝麻素、芝麻林素、芝麻酚以及芝麻林素酚等生物活性物质的结构、含量以及其所具有的抗氧化、抗癌、保护肝脏、降低血浆中的胆固醇、调节脂质代谢等诸多生理功能特性.     

APPLICATION OF SEMIPREPARATIVE RP-18 HPLC FOR THE PURIFICATION OF SESAMIN AND SESAMOLIN

A relatively simple chromatographic protocol was established to provide good separation of the unsaponifiable constituents from the seed oil of Sesamum indicum Linn. The protocol employs classical column chromatography using alumina and petroleum ether to collect furofuran lignans from sesame oil. Semipreparative RP-18 HPLC was used to separate the sesamin and sesamolin constituents in high purity (> 99%). The purity and identity of the separated compounds was confirmed by rechromatography using an analytical HPLC set up and GC-MS, respectively. The method described offers a means to isolate and collect sesamin and sesamolin in high purity for use as standards in furofuran lignan studies of sesame seed oil.     

Microwave Heating Affects Composition and Oxidative Stability of Sesame (Sesamum indicum) Oil

The effects of microwave heating on antioxidative components and lipid quality of sesame seeds were studied. Amounts of antioxidative components were 576, 18, and 8 mg/kg oil for γ-, δ-, and α-tocopherols; 6,824, 5,642, and 54 mg/kg oil for sesamin, sesamolin, and sesamol, respectively. During microwave treatments, concentrations of tocopherols, sesamin and sesamolin gradually decreased, and ca. 20% of these dominant components was lost after 30 min heating. However, microwave treatments for 16 to 20 min, which would be optimal to prepare sesame oil with better quality, still retained over 85% of the antioxidative components (with few exceptions) and caused no significant chemical changes in lipids.     

芝麻林素的酸催化反应与抗氧化性分析

采用石油醚、甲醇和乙醇溶解芝麻林素,研究不同溶剂体系芝麻林素酸催化反应的现象;以1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除能力评价芝麻林素及其分解产物的抗氧化能力;采用磷钨杂多酸（phosphotungstic heteropoly acid,HPW）催化芝麻油中芝麻林素的转化,研究芝麻林素酸催化对冷榨芝麻油氧化稳定性的影响。结果表明：芝麻林素在3 种溶剂体系中酸催化反应的产物不尽相同,芝麻酚是共同产物,石油醚体系产生Semin和芝麻素酚,甲醇和乙醇体系均出现不同未知物;芝麻林素和芝麻素的DPPH自由基清除能力远低于特丁基对苯二酚、丁基羟基茴香醚、丁基羟基甲苯和芝麻酚,但石油醚体系芝麻林素酸催化产物的DPPH自由基清除能力大幅提高,为HPW催化芝麻林素提高冷榨芝麻油氧化稳定性提供了理论依据;随着HPW催化剂添加量的增加,冷榨芝麻油中的芝麻林素含量逐渐减少,芝麻酚和芝麻素酚的含量逐渐升高,同时冷榨芝麻油的氧化诱导时间逐渐延长,氧化稳定性增强。     

HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC DETERMINATION OF ANTIOXIDANT LIGNAN GLYCOSIDES IN SOME VARIETIES OF SESAME

The difference in the distribution of sesamin, sesamolin, sesaminol glucosides and sesamolinol components in representative varieties of sesame were compared. Quantitation was achieved by HPLC determination using an external standard. The most abundant lignan glucosides in sesame seed were sesaminol triglucoside. The content of sesaminol triglucoside in 100 g seeds ranged from 14.1 to 91.3 mg with an average value of 68.4 mg; that of sesaminol diglucoside from 8.2 to 18.3 mg with an average value of 11.6 mg; and that of sesaminol monoglucoside from 5.4 to 19.5 mg with an average value of 8.3 mg. The total content of sesaminol glucoside was 88.3 mg in 100 g of sesame seeds. Also, the sesamolinol content in 100 g sesame seed ranged from 17.6 to 28.5 mg, the average being 20.5 mg. Within     

Antimicrobial properties and analytical profile of traditional Eruca sativa seed oil: Comparison with various aerial and root plant extracts

The present study investigates the antimicrobial activity of various solvent extracts of Eruca sativa (aerial and root) and seed oil against-antibiotic resistant Gram-negative (Escherichia coli, Pseudomoms aeruginosa and Shigella flexneri) and Gram-positive (Staphylococcus aureus and Bacillus subtilis) bacteria. Among the various preparations, seed oil was the most active, exhibiting a maximum zone inhibition of 97% for Gram-positive bacteria and of 74–97% for Gram-negative bacteria. The MIC of the seed oil was found to be 65–75 and 60–70 μg/ml for Gram-negative and Gram-positive bacteria, respectively. Analytical investigation on main volatile and non-volatile components was performed on seed oil. Among the formers allyl isothiocyanate (40 μg/g), 3-butenyl isothiocyanate (260 μg/g), 4-methylsulfinybutyl isothiocyanate (sulforaphane 743 μg/g), 2-phenylethyl isothiocyanate (159 μg/g) and bis(isothiocyanatobutyl)disulphide (∼5000 μg/g) were determined by head space/SPME/GC–MS analysis. Free fatty acids were 1.6% w/w of the oil and overall 25 fatty acids were identified. Erucic and oleic acids were the main fatty acids both in the free (7.8 and 2.1 mg/ml) and esterified forms (50.6% w/w and 14.9% w/w of total fatty acids). Unsaponifiable fraction was 1.8% w/w.     

芝麻核心种质芝麻素和芝麻酚林的关联分析

选用来源我国黄河流域至长江流域8省215份芝麻核心种质材料,对其种子中芝麻素（sesamin）和芝麻酚林（sesamolin）含量进行测定,芝麻素平均值5．24mg／g,变异范围为0．88～11．05mg／g,变异系数38．56％,芝麻酚林平均值3．30mg／g,变异范围为0．93—6．96mg／g,变异系数22．68％,二者均符合正态分布,且相关分析表明两者间呈极显著正相关;采用标记一性状关联分析法,进行芝麻素和芝麻酚林与SSR、SRAP、AFLP标记的关联分析。利用GLM模型共检测到33个标记与芝麻素和芝麻酚林极显著（P〈0．01）关联,同时与两种成分显著关联的有4个;利用MLM模型共检测到8个显著关联的标记,与两种成分显著关联的分别有4个;其中SSR标记SSll82-3在两种模型中同时极显著关联到芝麻素和芝麻酚林,且解释率较高。该研究将为芝麻功能性成分遗传改良和分子标记研究奠定重要基础。     

Roast effects on the hydrophilic and lipophilic antioxidant capacities of peanut flours,blanched peanut seed and peanut skins

Hydrophilic and lipophilic oxygen radical antioxidant capacity (H&L-ORAC) of peanut flours, blanched peanut seed, and peanut skins were characterised across a range of roast intensities. H-ORAC ranged from 5910 to 7990, 3040 to 3700 and 152,290 to 209,710 μmoles Trolox/100 g for the flours, seed, and skins, respectively. H-ORAC increased linearly with darker seed colour after roasting at 166 °C from 0 to 77 min, whereas skin H-ORAC peaked after roasting for 7 min. Linear correlations with H-ORAC and total phenolic content were observed. Additionally, completely defatted peanut seed were solubilised (5% w/w) in water and H-ORAC measured. For these samples, H-ORAC decreased with roast intensity which correlated with soluble protein. L-ORAC ranged from 620 to 1120, 150 to 730 and 2150 to 6320 μmoles Trolox/100 g for peanut flours, seed, and skins, respectively. L-ORAC increased linearly with both darker seed colour and skin colour across the 77 min range. L-ORACs of roasted peanuts and ingredients are discussed in terms of tocopherol contents and Maillard reaction products.     

Extraction of Lignan Compounds from Roasted Sesame Oil and their Effects on the Autoxidation of Methyl Linoleate

ABSTRACT:  Lignan compounds were extracted from roasted sesame oil and their effects on the autoxidation of methyl linoleate (ML) were studied. Lignan compounds extracted from roasted sesame oil, sesamol, sesamin, and sesamolin, were added to ML, which was then oxidized at 60 ^oC for 18 h in the dark. Alpha-tocopherol was separately added to ML for a reference antioxidant. Degree of ML oxidation was monitored by conjugated dienoic acid (CDA) contents and p -anisidine value (PAV) by AOCS methods, and ML retention by gas chromatography. CDA contents and PAV of samples increased with the oxidation time at 60 ^oC in the dark, and ML decreased. Sesamol-, sesamin-, or sesamolin-added samples showed lower CDA contents, PAV, and ML loss than the samples without lignans during oxidation in the dark, which indicated that lignan compounds lowered the ML autoxidation. The antioxidant activity of sesamol was significantly higher ( P < 0.05) than that of sesamin, sesamolin, or α-tocopherol. Lignan compounds added to ML were degraded during the autoxidation of ML, and the degradation rate was higher in sesamol- than in sesamin-, or sesamolin-added ML, but was lower than in tocopherol-added samples. As the lignan compounds concentration in ML increased, the degradation rate of lignans decreased, and the inhibition of the ML autoxidation by lignan compounds increased. The results strongly suggested that the autoxidative stability of ML could be improved by the addition of sesamol, sesamin, or sesamolin extracted from the roasted sesame oil.     

Fatty acids,tocopherols and proanthocyanidins in bramble seeds

Studies were conducted on the fatty acids, tocopherols and proanthocyanidins in the seeds of 10 bramble varieties from China. The oil yields from these seeds vary from 4.81% to 15.72%. The main fatty acids in bramble seed oils are C18:2 n-6 (51.0–66.1%), C18:3 n-3 (9.70–35.6%), C18:1 n-9 (9.85–16.3%), and C16:0 (2.01–5.73%). The major tocopherol in all seed oils of 10 varieties was γ-tocopherol. The composition (mg/100 g) was as follows: α-tocopherol 7.65–52.6, γ-tocopherol 46.9–106, δ-tocopherol 3.1–9.50, and the active vitamin E 15.9–61.5 among the varieties. The total proanthocyanidin content varies from 6.81 to 17.6 mg/g. The main oligomers in total proanthocyanidins are dimers, and the least are trimers. The contents and composite proportions of fatty acids, tocopherols and proanthocyanidins are different according the varieties, which should be taken into account when the bramble seeds are exploited.