Lignans and tocopherols in Indian sesame cultivars

Lignan (sesamol, sesamin, and sesamolin) profile was determined in different cultivars (botanically identified or market samples) of sesame seeds and commercial oils procured from different parts of India. The wide variation observed in total lignans from 21 sesame seed and 9 commercial oils was attributed to variations in sesamin and sesamolin contents. Lignan content was high (18 g sesamin/kg, 10 g sesamolin/kg) in seasame cultivars obtained from the northeastern states of India. In two of the commercial oils having the Agmark label, the total lignan content was ∼12 g/kg (7.3 g sesamin, 4.7 g sesamolin), 50% of the maximum permissible levels of unsaponifiable matter. In both the seeds and commercial oils, γ-tocopherol was the only representative of tocopherol isomers identified. Sesamin and sesamolin were isolated and crystallized from high-lignan cultivars, and their purity was confirmed by HPLC and spectral (UV and fluorescence) analysis.     

Examination of the Modified Villavecchia Test for Detecting Sesame Oil

The official methods of the American Oil Chemists’ Society recommend the modified Villavecchia test Cb 2-40 for detecting sesame oil in animal and vegetable fats and oils. The test is based on the reactivity of sesamol and sesamolin to furfural under acidic conditions. Although the contribution of sesamol and sesamolin to the reaction has been reported, little information is available on how the test performed with oils prepared from different sesame varieties or for effects of roasting conditions of seeds. The objective of this study was to clarify the contribution of various lignans to the Villavecchia test results. Chromogenic products of the Villavecchia test with sesame oil prepared from different varieties of sesame seeds gave different absorbance intensities at 520 nm, and the absorbance intensities were positively correlated with the content of sesamolin in sesame oil. Roasting conditions affected the content and concentration of lignans in sesame oil, and consequently the corresponding chromogenicity of the Villavecchia test. Roasting seeds at 230 °C for 5 min caused a significant loss of sesamolin in oil, the level of sesamol increased, and the absorbance intensity at 520 nm of the corresponding Villavecchia testing product also increased. Roasting seeds at 280 °C for 5 min caused loss of sesamin and the disappearance of sesamolin from the resultant oil, whereas the level of sesamol increased. These results provide guidance for determining the utility of the Villavecchia test for detecting sesame oil in mixtures of other foods.     

Effects of processing on oxidative stability of sesame oil extracted from intact and dehulled seeds

Oxidative stability of oils extracted from intact and dehulled sesame seeds was determined by monitoring changes in fatty acid composition, iodine value (IV), peroxide value (PV), conjugated diene (CD), para-anisidine value (p-AV), and 2-thiobarbituric acid (TBA) value and by nuclear magnetic resonance spectroscopy after storage under Schaal oven conditions at 65°C for up to 35 d. The oils from coated seeds were more stable, as reflected in PV, CD, p-AV and TBA values, than those extracted from dehulled seeds after roasting at 200°C, steaming at 100°C, roasting at 200°C plus steaming, or microwaving at 2450 MHz, except for TBA values of oil from microwaved seeds. After 35 d of storage at 65°C, the CD, p-AV, and TBA values of extracted oil from dehulled microwaved seeds were 17.72, 10.20, and 1.22, respectively, while those of their coated counterparts were significantly (P<0.05) different at 14.20, 16.47, and 1.26, respectively. Few significant changes were evident in the fatty acid composition of oil obtained from either coated and dehulled seeds subjected to different treatments. Nuclear magnetic resonance analyses found that R_ao (aliphatic to olefinic protons) and R_ad (aliphatic to diallylmethylene protons) ratios increased steadily over the entire storage period, which indicated progressive oxidation of unsaturated fatty acids.     

Sesamin,sesamolin, and sesamol content of the oil of sesame seed as affected by strain,location grown,ageing, and frost damage

Summary The effect of strain and location grown on the sesmin, sesamolin, and sesamol content of oils from sesame seed chosen to represent a wide variety of genetic material is reported. Only differences in sesamin content due to strain were significant. Three of four oils exposed as the oil to 100°F. became rancid in two to three months. Rancidity of the oil was accompanied by lesser sesamin and sesamolin contents, and the ultraviolet spectrum of the oil was much altered. Oil from seed exposed as the seed to the same conditions for six months did not become rancid even though most of the seeds were damaged in threshing. The sesamol content of all the oils subjected to the accelerated ageing procedure increased, but the increase was greatest in the rancid oils. Frost damage of sesame seed markedly diminished the sesamin and sesamolin content of the oil.     

Lignan contents in sesame seeds and products

Sesame seed (Sesamum indicum L.) is a rich source of furofuran lignans with a wide range of potential biological activities. The major lignans in sesame seeds are the oil‐soluble sesamin and sesamolin, as well as glucosides of sesaminol and sesamolinol that reside in the defatted sesame flour. Upon refining of sesame oil, acid‐catalyzed transformation of sesamin to episesamin and of sesamolin to epimeric sesaminols takes place, making the profile of refined sesame oils different from that of virgin oils. In this study, the total lignan content of 14 sesame seeds ranged between 405 and 1178 mg/100 g and the total lignan content in 14 different products, including tahini, ranged between 11 and 763 mg/100 g. The content of sesamin and sesamolin in ten commercial virgin and roasted sesame oils was in the range of 444–1601 mg/100 g oil. In five refined sesame oils, sesamin ranged between 118 and 401 mg/100 g seed, episesamin between 12 and 206 mg/100 g seed, and the total contents of sesaminol epimers between 5 and 35 mg/100 g seed, and no sesamolin was found. Thus, there is a great variation in the types and amounts of lignans in sesame seeds, seed products and oils. This knowledge is important for nutritionists working on resolving the connection between diet and health. Since the consumption of sesame seed products is increasing steadily in Europe and USA, it is important to include sesame seed lignans in databases and studies pertinent to the nutritional significance of antioxidants and phytoestrogens. It is also important to differentiate between virgin, roasted and refined sesame oils.     

The Contents of Lignans in Sesame Seeds and Commercial Sesame Oils of China

In this study, the concentrations of three lignans in 100 sesame seeds and 56 sesame oils were determined using a newly developed method based on high‐performance liquid chromatography coupled with a UV/Vis detector. Total lignan contents in sesame seed and oil samples ranged from 2.52 to 12.76 and 3.38 to 11.53 mg/g, respectively. Black sesame seeds showed higher sesamin content (range 1.98–9.41 mg/g, mean 4.34 mg/g) and sesamolin content (range 1.06–3.35 mg/g, mean 1.92 mg/g) than the other three varieties of sesame seeds. Black sesame oils had higher contents of lignans than the white sesame oils, although remarkable differences were not observed. Hot pressed and small mill sesame oils expressed higher contents of sesamol, sesamin, and total lignans than the cold pressed and refined sesame oils. The results revealed that there is extensive variability in lignan concentration in sesame oils and seeds.     

Effect of roasting temperature and time on the chemical composition of rice germ oil

Compositional changes of rice germ oils prepared at different roasting temperatures (160–180°C) and times (5–15 min) from rice germ were evaluated and compared with those of unroasted rice germ oil. The color development and phosphorus content of oils increased significantly as roasting temperature and time increased, whereas the FA compositions of rice germ oils did not change with roasting temperature and time. Four phospholipid classes, i.e., PE, PI, PA and PC, were identified. PE had the lowest stability under roasting conditions. There were no significant differences in γ-oryzanol levels of rice germ oils prepared at different roasting temperatures and times. Four tocopherol isomers (α−, β−, γ−, and δ-tocopherol) and three tocotrienol isomers (α−, γ−, and δ-tocotrienol) were identified, but no β-tocotrienol was detectable. The content of α− and γ−tocopherol in rice germ oil gradually increased as roasting temperature and time increased.     

Analysis of Sesamin, Asarinin, and Sesamolin by HPLC with Photodiode and Fluorescent Detection and by GC/MS: Application to Sesame Oil and Serum Samples

New sensitive and specific analytical methods are needed for the analysis of sesamin, asarinin, and sesamolin in sesame seed oils, sesame dietary supplements, as well as in serum samples from clinical studies involving sesamin, asarinin, and sesamolin. The objective of this study was to develop a high performance liquid chromatographic (HPLC) method with photodiode array and fluorescent detectors and a gas chromatography mass-spectrometry (GC/MS) method for the analysis of sesamin, asarinin (episesamin), and sesamolin in sesame oil and in serum samples. Sesame oil samples were extracted with methanol whereas the serum samples were extracted with ethyl acetate or n-hexane. The individual lignans were analyzed by HPLC using reversed phase C18 columns. Analytical recoveries of sesamin, asarinin, and sesamolin from sesame oil were 92–94?% with two extractions. Recoveries from serum ranged from 87 to 97?%. The limit of quantitation with the fluorometric detector was 0.1?ng compared to 0.1?μg with the PDA detector. The concentrations of sesamin, asarinin, and sesamolin in Orchids and Sigma sesame oil were 0.4, 0, and 0.15?% and 0.19, 0.09, and 0?%, respectively. The identities of the individual lignans obtained by HPLC were confirmed by GC/MS and the concentrations of sesamin, asarinin, and sesamolin obtained with the fluorometric detector correlated with those obtained by GC/MS (r ²?=?0.94, P?<?0.001). The HPLC and GC/MS methods permit simple and efficient procedures for the analysis of sesamin, asarinin, and sesamolin in sesame oil samples as well as in serum samples.     

Discrimination of Origin of Sesame Oils Using Fatty Acid and Lignan Profiles in Combination with Canonical Discriminant Analysis

The aims of this study were to investigate total fatty acid composition and lignan contents of Korean, Chinese and Indian roasted sesame oils and to differentiate the geographic origins of the oils using analytical data in combination with canonical discriminant analysis. The analytical data were obtained from 84 oil samples that were prepared from 51 Korean, 19 Chinese, and 14 Indian white sesame seeds harvested during 2010 and 2011 and distributed in Korea during the same period. Six variables selected for the discriminant analysis were the contents of three fatty acids (linoleic, oleic, and palmitic) and three lignans (sesamin, sesamolin, and sesamol). A good discrimination between sesame oils from Korea, China, and India was achieved by applying two canonical discriminant functions, with 97.6 % of the samples correctly classified into the geographic origin. When the origins of five commercial oil samples (one was prepared from Korean sesame seeds and the other four were made from imported sesame seeds) were predicted using discriminant functions, the Korean sesame oil was accurately distinguished from the others.     

Sesame oil. VI. Determination of sesamin

Summary A new method for the determination of sesamin in sesame oils is described. It is based on the measurement of the ultraviolet absorption of sesame oil following the removal of sesamol by treatment with alkali and correction for the absorption resulting from the presence of sesamolin. The advantages of the new method over the previously described colorimetric method are discussed. The accuracy of the method is attested by a comparison of the determined values with those for known added amounts of sesamin in cottonseed and sesame oils. When applied to four crude oils, the content of sesamin was found to range from 0.50 to 0.96%. Ultraviolet absorption spectra curves are reported for sesamin, sesamolin, sesamol, and sesame oil. Rockefeller Foundation Fellow from the Ministerio de Agricultura y Crfa, Division de Quimica, El Valle, D. F. Venezuela. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Sesame seed is a rich source of dietary lignans

The variation in the contents of sesamin and sesamolin was studied in oils extracted from 65 samples of sesame seeds (Sesamum indicum L.) from plants with shattering (n=29), semishattering (n=7), and nondehiscent (n=29) capsules. The oil content ranged from 32.5 to 50.6% and was greater in white than black seeds (P<0.001). The sesamin and sesamolin contents in seeds ranged from 7 to 712 mg/100 g (mean±SD, 163±141 mg/100 g) and from 21 to 297 mg/100 g (101±58 mg/100 g), respectively, with no difference between black and white seeds. Thus, there was a wide variation in the contents of sesamin and sesamolin, which were positively correlated (R ²=0.66, P<0.001). There were negative correlations between the contents of sesamin and the contents of sesaminol (R ²=0.37) and sesamolinol (R ²=0.36) and between the content of sesamolin and those of sesaminol (R ²=0.35) and sesamolinol (R ²=0.46) (P<0.001). Sesame seeds had an average of 0.63% lignans, making them a rich source of dietary lignans.     

Variation of Oil,Sesamin, and Sesamolin Content in the Germplasm of the Ancient Oilseed Crop Sesamum indicum L.

Currently, genetic improvement in oil and lignan content is a major objective in sesame breeding. As a prerequisite to meet the objective, the diversity of these traits of sesame germplasm was examined. Solvent extraction of the harvested seeds demonstrated variation in oil content ranging from 39% to 49% across the sesame accessions tested. High performance liquid chromatography of oil samples showed sesamin and sesamolin as the only lignans present in the oil, with their amount in the range of 2.74–10.55 g L⁻¹ and 2.49–13.78 g L⁻¹, respectively. Coefficient of variation for oil content remained the highest in brown and black seeded accessions, whereas it remained at maximum for sesamin and sesamolin in white seeded ones. Pearson analysis showed a positive correlation between oil and lignan content. It was concluded that Indian sesame accessions exhibit considerable variation in oil and lignans content. The S. indicum varieties with a desirable composition of oil and/or lignans have been identified and recommended for incorporation in breeding programs, as well as for specific human use.     

Oxidative Stability of Crude Mid-Oleic Sunflower Oils from Seeds with High γ- and δ-Tocopherol Levels

In this study, mid-oleic and high-oleic sunflower seeds were developed with high levels of γ- and δ-tocopherols by traditional breeding techniques. Sunflower seeds containing various profiles of tocopherols, ranging from traditional high α, low γ, low δ relative to those with high γ, high δ, and low α, were extracted, and the crude oil evaluated for oxidative stability. After aging at 60 °C, oils were measured for peroxide value and hexanal as indicators of oxidation levels. We found that when the γ-tocopherol content of mid-oleic sunflower oil (MOSFO) (NuSun) was increased from its regular level of 20 to 300–700 ppm, the oxidation of the oil was decreased significantly compared to MOSFO with its regular low γ-tocopherol level. The modified oils had α-tocopherol contents of up to 300 ppm without negatively affecting the stability of the oil. An oil with one of the best oxidative stabilities had a tocopherol profile of 470 ppm γ, 100 ppm δ, and 300 ppm α, indicating that MOSFO could be more oxidatively stable and still be a good source of Vitamin E from α-tocopherol. Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable.     

Using Turmeric Oil as a Solvent Improves the Distribution of Sesamin-Sesamolin in the Serum and Brain of Mice

Accumulation of amyloid-β peptide is associated with Alzheimer's dementia. Previously, we reported that sesamin and sesamolin inhibited β-secretase activity in vitro, and each was transported to the serum and brain in mice after oral administration. However, the bioavailability of sesamin and sesamolin was poor in mice. In this study, we aimed to improve the bioavailability of sesamin and sesamolin. We found that the levels of sesamin and sesamolin in mouse serum and brain were higher after the administration of a mixture of sesame extract and turmeric oil (MST) than those after administering sesame extract alone. Serum sesamin and sesamolin contents in the MST-treated group were 23-fold and 15-fold higher, respectively, than those in the sesame extract-treated group. Brain sesamin and sesamolin contents in the MST-treated group were 14-fold and 11-fold higher, respectively, than those in the sesame extract-treated group. These results suggest that turmeric oil is an effective solvent to enhance the bioavailability of sesamin and sesamolin.     

Pyrethrum synergists in sesame oil. Sesamolin,a potent synergist

Summary By the systematic entomological examination of chromotographic fractions of sesame oil two pyrethrum synergists, sesamin and sesamolin, were found to account for practically all the synergistic activity of the oil. Sesamolin, which had not been known to be synergistic, is about five times as active as sesamin and, even though usually present in smaller amount than sesamin, it is believed to account for most of the synergistic activity in sesame oil. Because of sesamolin’s marked synergistic activity, studies on its chemistry were made, and some of its chemical properties are reported. The studies have indicated a close similarity between sesamin and sesamolin, and a tentative chemical formula for sesamolin has been proposed as a basis for future work. Infrared absorption spectra of sesamin and sesamolin are reported.     

Comparative effects of flaxseed and sesame seed on vitamin E and cholesterol levels in rats

Flaxseed and sesame seed both contain more than 40% fat, about 20% protein, and vitamin E, mostly γ-tocopherol. Furthermore, both contain considerable amounts of plant lignans. However, flaxseed contains 54% α-linolenic acid, but sesame seed only 0.6%, and the chemical structures of flaxseed and sesame lignans are different. In this study, we investigated the differential effects of flaxseed and sesame seed on plasma and tissue γ-tocopherol, TBARS, and cholesterol concentrations. Rats were fed experimental diets for 4 wk: vitamin E-free, (-VE), γ-tocopherol, flaxseed (FS), sesame seed (SS), flaxseed oil (FO), FO with sesamin (FOS), and defatted flaxseed (DFF). SS and FOS diets induced significantly higher γ-tocopherol concentrations in plasma and liver compared with FS, FO, and DFF diets. Groups fed FS, FO, and FOS showed lower plasma total cholesterol compared with the SS and DFF groups. Higher TBARS concentrations in plasma and liver were observed in the FS and FO groups but not in the FOS groups. These results suggest that sesame seed and its lignans induced higher γ-tocopherol and lower TBARS concentrations, whereas flaxseed lignans had no such effects. Further, α-linolenic acid produced strong plasma cholesterol-lowering effects and higher TBARS concentrations.     

Aqueous Enzymatic Extraction of Oil and Protein Hydrolysates from Roasted Peanut Seeds

To evaluate the effects of the roasting process on the extraction yield and oil quality, peanut seeds were roasted at different temperatures (130–220 °C) for 20 min prior to the aqueous extraction of both oil and protein hydrolysates with Alcalase 2.4 L. Roasting temperatures did not significantly affect the yields of free oil, whereas the temperature of 220 °C led to a reduced recovery of protein hydrolysates. The color and acid values of peanut oils did not change significantly with roasting temperatures. The enzyme-extracted oil with roasting at 190 °C had a relatively low peroxide value, a strong oxidative stability, and the best flavor score. Using the same seed-roasting temperature (190 °C), quality attributes such as color, acid and peroxide values, phosphorus content and oxidative stability of the enzyme-extracted oil were better than those of the oil obtained by an expeller. After the peanut seeds were roasted at 190 °C for 20 min, with a seeds-to-water ratio of 1:5, an enzyme concentration of 2%, and an incubation time of 3 h, the yields of free oil and protein hydrolysates were 78.6 and 80.1%, respectively. After demulsification of the residual emulsion by a freezing and thawing method, the total free oil yield increased to 86–90%.     

Sesamin (a compound from sesame oil) increases tocopherol levels in rats fedad libitum

Six groups of rats were fed diets low, but adequate, in α-tocopherol but high in γ-tocopherol. The six diets differed only in their contents (0, 0.25, 0.5, 1.0, 2.0, and 4.0 g/kg, respectively) of sesamin, a lignan from sesame oil. After four weeks ofad libitum feeding, the rats were sacrificed and the concentrations of α- and γ-tocopherols were measured in the plasma, livers, and lungs. Sesamin-feeding increased γ-tocopherol and γ-/α-tocopherol ratios in the plasma (P<0.05), liver (P<0.001), and lungs (P<0.001). The increase was non-significant for α-tocopherol. Thus, sesamin appears to spare γ-tocopherol in rat plasma and tissues, and this effect persists in the presence of α-tocopherol, a known competitor to γ-tocopherol. This suggests that the bioavailability of γ-tocopherol is enhanced in phenol-containing diets as compared with purified diets.     

Variations in the composition of sterols,tocopherols and lignans in seed oils from fourSesamum species

Seeds from different collections of cultivatedSesamum indicum Linn and three related wild species [specifically,S. alatum Thonn.,S. radiatum Schum & Thonn. andS. angustifolium (Oliv.) Engl.] were studied for their oil contents and fatty acid composition of the total lipids. The oils from wild seeds were characterized by higher percentages of unsaponifiables (4.9, 2.6 and 3.7%, respectively) compared toS. indicum (1.4–1.8%), mainly due to their high contents of lignans. Total sterols accounted forca. 40, 22, 20 and 16% of the unsaponifiables of the four species, respectively. The four species were different in the relative percentages of the three sterol fractions (the desmethyl, monomethyl and dimethyl sterols) and in the percentage composition of each fraction. Campesterol, stigmasterol, sitosterol and Δ⁵-avenasterol were the major desmethyl sterols, whereas obtusifoliol, gramisterol, cycloeucalenol and citrostandienol were the major monomethyl sterols, and α-amyrin, β-amyrin, cycloartenol and 24-methylene cycloartanol were the main dimethyl sterols in all species. Differences were also observed among the four species in sterol patterns of the free sterols compared to the sterol esters.Sesamum alatum contained less tocopherols (210–320 mg/kg oil), andS. radiatum andS. angustifolium contained more tocopherols (ca. 750 and 800 mg/kg oil, respectively) than didS. indicum (490–680 mg/kg oil). The four species were comparable in tocopherol composition, with γ-tocopherol representing 96–99% of the total tocopherols. The four species varied widely in the identity and levels of the different lignans. The percentages of these lignans in the oils ofS. indicum were sesamin (0.55%) and sesamolin (0.50%).Sesamum alatum showed 1.37% of 2-episesalatin and minor amounts of sesamin and sesamolin (0.01% each).Sesamum radiatum was rich in sesamin (2.40%) and contained minor amounts of sesamolin (0.02%), whereS. angustifolium was rich in sesangolin (3.15%) and also contained considerable amounts of sesamin (0.32%) and sesamolin (0.16%).     

Effect of Roasting on Flaxseed Oil Quality and Stability

The food industry is interested in the application of roasted flaxseeds because the treatment improves their sensory acceptability. However, it also influences flaxseed oil nutritional quality and stability. The aim of the study was to analyze oxidation changes in situ and in flaxseed oil compounds (fatty acids, phytosterols, tocochromanols) and Maillard reaction products (MRP) after roasting. The effect of the roasting temperature (160–220 °C) and flaxseed cultivars (golden- and brown-seed) was taken into consideration. The results showed that the selection of roasting temperature (<200 °C vs. ≥200 °C) and flaxseed cultivar significantly influenced the nutritional quality and oxidative stability of roasted flaxseed oils. The roasting of flaxseeds did not significantly affect the fatty acid profiles of oil but it influenced the content of the other bioactive compounds. As the roasting temperature increased (≥200 °C), the γ-tocopherol degradation decreased, whereas the content of plastochromanol-8 increased. The total content of phytosterols in the roasted seed samples was higher than in the raw seeds but there was no correlation between the phytosterol content and roasting temperature. The temperature ≥200 °C significantly accelerated in situ oil oxidation during roasting. On the other hand, these conditions favored the MRP formation, which may have slowed down the dynamics of oil oxidation during storage. There was lower oil oxidation in the brown-seed cultivar; in consequence, the tocopherol retention was higher than in the golden-seed cultivars. The results could be useful for the selection of the best cultivars and treatment conditions to decrease unfavorable changes in flaxseed oil nutritional quality and stability.