Comparison of fatty acid profile changes between unroasted and roasted brown sesame (Sesamum indicum L.) seeds oil

The conditions of roasting are the key step in manufacturing Sesame (Sesamum indicum L.) oil. Roasting sesame seeds changed its oil, moisture, and ash content. In oils from unroasted and roasted seeds, nine fatty acids analyzed by gas chromatography-mass spectrometry. The fatty acids composition were changed in both oils. Oleic and linoleic changed in large amount, but changes for other fatty acids were small. ¹H and ¹³C NMR analysis showed the frequency changes for both oils, the roasting condition caused to shift the frequency to lower degree.     

Selected functional properties of sesame (Sesamum indicum L.) flour and two protein isolates

Functional properties of sesame flour and protein isolates have been compared with those of some commercial soya products. The sesame products showed better fat absorption, poorer water absorption and overall lower bulk densities than soya products. Emulsifying activities and stabilities were generally lower than soya products. Destabilisation of the emulsion in the presence of NaCl was noted. Sesame products showed better foam expansion, and comparable foam stability and strength to corresponding soya products. Addition of sugar to sesame whips reduced foam expansion and increased foam stability. Acid, neutral and alkaline sesame whips showed distinct whipping properties depending on the product used. Sesame whips resembling those of egg-white could be obtained. The sesame isolate prepared by alkaline extraction was superior to that prepared by salt extraction in terms of their pH-solubility profiles.     

Antioxidant activity of brown pigment and extracts from black sesame seed (Sesamum indicum L.)

The antioxidant activities of brown pigment, extract of n-hexane and extract of supercritical carbon dioxide extraction of black sesame seeds were investigated in this study. Kinetics of anti-radical activity showed that the reaction between DPPH and brown pigment of sesame seed was rapid and reached the steady state in 10 min. Extracts from supercritical carbon dioxide extraction and n-hexane extraction reacted with DPPH slowly and the absorbance became stable after 35 min. However, α-tocopherol and trolox were rapid while the kinetic behaviour of BHA was intermediate. The brown pigment of sesame seed also showed a lower EC₅₀ (13.5 μg ml⁻¹) than the other two extracts and α-tocopherol, which was about 7–10 fold of the antioxidant activity of the supercritical carbon dioxide extract and the n-hexane extract. The ferric thiocyanate (FTC) method also showed that the brown pigment of sesame seed provided higher inhibition activity against lipid peroxidation at 200 μg ml⁻¹ than did the supercritical carbon dioxide extract an n-hexane extract at 1 mg ml⁻¹. However, the activities of the supercritical carbon dioxide extract and n-hexane extracts were significantly higher than that of α-tocopherol. In the linoleic acid system, the brown pigment of black sesame seed showed an equal antioxidant activity to BHA and higher than trolox and α-tocopherol. The results indicated that the brown pigment of sesame seed possessed excellent antioxidant activity.     

Nitrogen extractability of sesame (Sesamum indicum L.) seed and the preparation of two protein isolates

Nitrogen extractability from sesame flour in water is greatest using a flour: solvent ratio of 1:40 and an extraction time of 15 min. At pH 4.0-6.5, <10% nitrogen is extracted, whilst >90% is extracted at pH 11.0. In the presence of NaCl (0.5-1.0M) nitrogen extractability is greatest at pH values > pH 4.0. The two sesame protein isolates produced were bland-tasting, light-coloured and contained approximately 95% protein. The alkali isolate (extracted in water at pH 10.0 and precipitated at pH 4.0) was readily solubilised and showed a good protein recovery (60%). The salt isolate (extracted in 1M NaCl at pH 6.0 and precipitated at pH 4.0) was less soluble and showed a lower protein recovery (50%). The sesame products were extracted sequentially using various solvents. Sesame flour proteins were mainly salt-soluble (67%), alkali isolate proteins mainly water-soluble (41%) and alkali-soluble (41%), and salt isolate proteins mainly alkali-soluble (35%). The amino acid composition of the sesame products is described. Oil-expelled cake showed poor nitrogen extractability (53% at pH 11.0 in water) and was, therefore, a poor source for protein isolate production.     

Microchip capillary electrophoresis (Lab-on-chip®) improves detection of celery (Apium graveolens L.) and sesame (Sesamum indicum L.) in foods

PCR is an usual analytical method applied to the detection of food allergens but sensitivity is a crucial problem in conventional post-PCR detection phase. The multiplex PCR approach often leads to adjunctive loss of sensitivity. The main goal of our study was to improve sensitivity in order to simultaneously detect sesame and celery in foods by mean of an end-point PCR protocol, by replacing conventional agarose gel electrophoresis with a Lab-on-chip® platform (microchip-based capillary electrophoresis). The Lab-on-chip®-based detection allowed to obtain the highest sensitivity in singleplex end-point PCR, for celery and sesame-specific primer pairs, using wheat flour as diluting agent. Moreover, in order to simulate a real system, home-made meat balls and commercial soup were artificially spiked with different percentages of sesame/celery (5% cooked meat balls, w/w and 0.1% soups, w/w), and then analyzed. Limits of detection highlighted in this study using Lab-on-chip® capillary electrophoresis were significantly lower if compared to those obtained with classical agarose gel electrophoresis.     

Optimization of simultaneous recovery of oil and protein from sesame (Sesamum indicum) seed

This study investigated the simultaneous recovery of oil and protein from sesame seeds using aqueous extraction technique by the application of factorial design and central composite design. Solid‐to‐solvent ratio and pH were identified to have the highest significant (p < .05) effects on both oil and protein recovery. High solvent volume and extration temperature favored protein yield. Solvent volume had more influence on the protein yield than the extraction temperature. The significant effect of the extraction temperature was quadratic in nature while solid‐to‐solvent ratio was both linear and quadratic. Optimization of the extraction process showed that the optimal conditions for the process were found to be solid‐to‐solvent ratio, 1:3 (w/v); pH, 11; extraction temperature, 47 °C and surfactant concentration, 0.1 M NaCl with predicted oil and protein recovery of 73.60% and 75.12%, respectively. The validated values for oil and protein recoveries were 75.02% and 73.10%, respectively. The processing steps are readily scalable.

Practical applications

Sesame is an oilseed that contains edible and odorless oil, and with good source of protein for man. The mechanical method of extracting edible oil from oilseeds gives low yield while n‐hexane is flammability, explosiveness, and mild toxicity. Simultaneous recovery of oil and protein from sesame seeds using aqueous extraction technique will reduce production cost and time while maintaining high oil and protein yields. The oil can be used for both domestic and industrial purposes, and the protein in food formulation to combat malnutrition.     

Inhibitory effect of Cynara cardunculus L. extract on aflatoxin B1 production by Aspergillus parasiticus in sesame (Sesamum indicum L.)

Aflatoxin B₁ has been considered as the most potent liver carcinogen for humans. One factor that stimulates the production of aflatoxins in oilseed products, such as sesame seeds and their products is the presence of high levels of fatty acids. This work presents further evidence that sesame is a favorable substrate for aflatoxin B₁ production by Aspergillus parasiticus. Moreover, the use of wild artichoke (Cynara cardunculus L.) extract was examined showing inhibition of aflatoxin B₁ production in both sesame and yeast extract sucrose medium, inoculated with A. parasiticus. More specifically, the inhibition of aflatoxin B₁ production by A. parasiticus in sesame seeds paste was 99.6% and in yeast extract sucrose medium it was 99.4%.     

Antihyperlipidemic effect of sesame (Sesamum indicum L.) protein isolate in rats fed a normal and high cholesterol diet

The dietary influence of sesame protein isolate (protein content 91.5%), produced from dehulled, defatted sesame meal, on blood and tissue lipid profile and lipid peroxidation has been assessed in normal and hypercholesterolemic rats. To evaluate their hypocholesterolemic and antioxidative activity in vivo, we fed 18% sesame protein isolate with or without 2% cholesterol in comparison with casein to rats for 28 d. We determined plasma total protein, total cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, triacylglycerol as well as susceptibility of plasma and erythrocyte membrane lipid to oxidation ex vivo. Liver tissue lipid, cholesterol, phospholipids, and lipid peroxidations were also determined. The total cholesterol, LDL-cholesterol and triacylglycerol levels were significantly reduced in the sesame protein isolate and isolate containing cholesterol group than the corresponding control casein groups. HDL-cholesterol level was also increased in sesame protein isolate (41%) and protein isolate containing cholesterol group (38%) than the corresponding control casein and casein containing cholesterol groups. There was 49% and 64% lowering of plasma lipid peroxidation as well as 36% and 56% lowering of lipoprotein oxidation susceptibility (LOS) in the 2 experimental groups (sesame protein isolate and isolate containing cholesterol group) than the corresponding control (casein and casein containing cholesterol) groups. There was significant lowering of erythrocyte membrane lipid peroxidation (68% and 63% lowering in sesame protein isolate and isolate containing cholesterol groups) and liver lipid peroxidation (61% and 76% lowering in the 2 experimental groups than the corresponding control casein groups). Therefore, our results indicate that sesame protein isolate decreases cholesterol concentration in plasma, increases HDL-cholesterol, and also decreases plasma and erythrocyte membrane lipid peroxidation with or without cholesterol fed diet in rats.     

Effects of seed roasting temperature and time on the quality characteristics of sesame (Sesamum indicum) oil

The quality characteristics and composition of sesame oils prepared at different roasting temperatures (160–250°C) from sesame seeds using a domestic electric oven were evaluated as compared to an unroasted oil sample: only minor increases (P<0·05) in characteristics, such as peroxide value, carbonyl value, anisidine value and thiobarbituric acid reactive substances, of sesame oils occurred in relation to increasing roasting temperature and time between 160 and 200°C, but colour units of oils increased markedly over a 220°C roasting temperature. Significant decreases (P<0·05) were observed in the amounts of triacylglycerols and phospholipids in the oils prepared using a 250°C roasting temperature. The amounts of γ-tocopherol and sesamin still remained over 80 and 90%, respectively, of the original levels after roasting at 250°C. In the oil prepared using a 250°C roasting temperature, sesamol was detected at 3370 mg per kg oil, but sesamolin was almost depleted after 25 min of roasting. Burning and bitter tastes were found in the oils prepared at roasting temperatures over 220°C. The results suggested that a high-quality product would be obtained by roasting for 25 min at 160 or 180°C, 15 min at 200°C and 5 min at 220°C when compared with the other samples. © 1997 SCI.     

Roasting influences on molecular species of triacylglycerols in sesame seeds (Sesamum indicum)

Sesame seeds were roasted at different temperatures (180–220 °C) using a domestic electric oven. Molecular species and fatty acid distributions of triacylglycerols (TAGs) isolated from total lipids in the sesame seeds were analysed by a combination of argentation thin‐layer chromatography (TLC) and gas–liquid chromatography. A modified argentation TLC procedure, developed to optimise the separation of the complex mixture of total TAGs, provided 11 different groups of TAGs, based on both the degree of unsaturation and the total length of fatty acid groups. Fatty acid methyl ester analysis was performed to determine the composition of each zone. Eleven molecular species of TAGs were still detected in the sesame seeds following roasting treatment. Dilinoleolein (33.7–35.8%), palmitoleolinolein (20.3–22.8%), dioleolinolein (15.0–15.4%) and trilinolein (8.8–10.7%) were the main components during roasting. However, roasting for 10 min at 220 °C caused a significant decrease (P < 0.05) not only in molecular species containing more than four double bonds, but also in the amount of diene and triene species present in TAGs (with a few exceptions). These results suggest that no significant changes in molecular species or fatty acid distribution of TAGs would occur within 25 min of roasting at 180 °C, ensuring that a good‐quality product would be attained. © 2000 Society of Chemical Industry     

Triglyceride composition of Sesamum indicum seed oil.

The fatty acid composition of Sesamum indicum seed oil was determined by gas–liquid chromatography. The percentages of individual acids were found to be: palmitic, 11; stearic, 6; arachidic, 1; oleic, 43; linoleic, 39. Triglyceride composition was calculated from the fatty acid compositions of the native oil and of the monoglycerides produced from it by pancreatic lipase hydrolysis. The oil is composed of 8, 41 and 51%, GS₂U, GSU₂ and GU₃ respectively. Analysis by special thin-layer chromatography combined with densitometry also indicated similar triglyceride composition for the sesame seed oil. Changes effected on the triglyceride composition by randomisation were also determined by both methods of analysis.     

Roasting effects on fatty acid distributions of triacylglycerols and phospholipids in sesame (Sesamum indicum) seeds

Sesame seeds were roasted at different temperatures (180–220 °C) using a domestic electric oven. The positional distribution of fatty acids in triacylglycerols (TAGs) and phosphatidylcholine (PC) isolated from total lipids in these seeds was investigated as well as the naturally occurring antioxidants that are present. Major lipid components were TAGs and phospholipids (PLs), while steryl esters (SEs), free fatty acids (FFAs) and sn‐1,3‐ and sn‐1,2‐diacylglycerols (DAGs) were minor ones. Following roasting, a significant increase (P < 0.05) was observed in FFAs and in both forms of DAG (primarily sn‐1,3‐DAG). The greatest PL losses (P < 0.05) were observed in phosphatidylethanolamine (PE), followed by PC and phosphatidylinositol (PI). On the other hand, the amounts of γ‐tocopherol and sesamin remained at over 80 and 90% respectively of the original levels after roasting at 220 °C. The principal characteristics of the positional distribution of fatty acids were still retained after 25 min of roasting: unsaturated fatty acids, especially linoleic and/or oleic, were predominantly concentrated in the sn‐2‐position, and saturated fatty acids, especially stearic and/or palmitic, primarily occupied the sn‐1‐ or sn‐3‐position. The results suggest that unsaturated fatty acids located in the sn‐2‐position are significantly protected from oxidation during roasting at elevated temperatures. © 2001 Society of Chemical Industry     

Duplex real-time PCR method for the detection of sesame (Sesamum indicum) and flaxseed (Linum usitatissimum) DNA in processed food products

The development of a duplex real-time polymerase chain reaction (PCR) method allowing the simultaneous detection of sesame and flaxseed DNA in commercial food products is described. This duplex real-time PCR technique is based in the design of sesame- and flaxseed-specific primers based on the ITS1 region and two TaqMan fluorescent probes. The method was positive for sesame and flaxseed, and showed no cross-reactivity for all other heterologous plant and animal species tested. Sesame and flaxseed could be detected in a series of model samples with defined raw and heat-treated sesame in flaxseed, and flaxseed in sesame, respectively, with detection limits of 1.3 mg kg^?1 for sesame and 1.4 mg kg^?1 for flaxseed. The applicability of the assay for determining sesame and flaxseed in different food matrices was investigated by analysing a total of 238 commercial foodstuffs. This PCR method is useful for highly selective and sensitive detection of traces of sesame and flaxseed in commercial food products.     

芝麻酶解液对浓香芝麻油美拉德反应风味的影响及工艺优化

利用美拉德生香源反应制备浓香芝麻油,并对浓香芝麻油制备工艺进行了优化。正交试验结果表明,浓香芝麻油的最佳制备工艺条件为反应料液比1∶5(g/m L)、料油比1∶10(g/m L),美拉德反应温度120℃、酶添加量2.5%、酶解时间3 h、美拉德反应时间30 min。验证试验表明,在此优化工艺条件下制备所得浓香芝麻油的感官结果综合得分可达到6.95分。探讨了不同原料酶解液对浓香芝麻油美拉德反应风味的影响,结果显示,芝麻粕酶解液是制备浓香芝麻油的最佳反应底物。     

Amino acid composition and antioxidative properties of hydrolysed pumpkin (Cucurbita pepo L.) oil cake protein

Pumpkin oil cake protein isolate (POCPI) was hydrolysed using two food-grade enzymes alcalase and trypsin. Alcalase-hydrolysed POCPI (POCPH₁) was selected as the optimum treatment based on the DPPH radical scavenging, total antioxidative, and ferrous ion chelating activities. Amino acid composition showed a direct relationship between the antioxidative activity of POCPH₁ and the amount of hydrophobic amino acids that formed 33.49% of its total amino acids. Surface hydrophobicity decreased as a result of hydrolysis and potent thermal and pH stability was observed in POCPH₁ (p ? 0.05). In terms of molecular weight distribution, size exclusion chromatogram indicated that the majority of peptides possessed molecular weight less than 6.5 kDa. Based on the results, POCPH₁ could be employed as a natural antioxidative agent with strong pH and thermal stability.