微波预处理对芝麻油中芝麻木酚素含量及油脂品质的影响

为了确定高芝麻酚芝麻油的最适微波预处理条件,将芝麻水分含量调节为5个梯度,在不同微波预处理时间下制得芝麻油样品,对其芝麻木酚素含量、酸值、茴香胺值、氧化诱导时间、脂肪酸组成、生育酚含量、有害物质（多环芳烃和杂环胺）含量及感官品质进行了分析,探究芝麻水分含量和微波预处理时间对芝麻油中芝麻木酚素含量及油脂品质的影响。结果表明：微波预处理时间6 min、芝麻水分含量7%条件下制得的芝麻油芝麻酚含量较高,芝麻油酸值符合国家标准限定要求,氧化稳定性较强,有害物质杂环胺和多环芳烃含量处于适当的可控水平,同时兼顾了芝麻油的固有风味,消费者的喜爱度较高。综上,高芝麻酚芝麻油的最适微波预处理条件为微波预处理时间6 min,芝麻水分含量7%。     

芝麻品种和制油工艺对芝麻油品质的影响

对以黑、白芝麻为原料,采用水代法、螺旋压榨法、液压压榨法工艺所得芝麻油的理化指标、脂肪酸组成、芝麻油中VE、芝麻素、芝麻酚含量和氧化稳定性进行了测定。结果显示:水代法所得芝麻油的酸值(KOH)和磷脂含量最低,而水分及挥发物含量最高;所有芝麻油样品均含有丰富的抗氧化成分芝麻素、芝麻酚和VE;所有芝麻油样品的脂肪酸组成接近,其中油酸和亚油酸含量高达83.4%;白芝麻油氧化稳定性明显优于黑芝麻油,水代法所得芝麻油氧化稳定性最好,液压压榨芝麻油次之,螺旋压榨芝麻油最差。     

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.     

Effect of Infrared Heating on the Formation of Sesamol and Quality of Defatted Flours from Sesamum indicum L.

ABSTRACT:  Infrared (IR) heating offers several advantages over conventional heating in terms of heat transfer efficiency, compactness of equipment, and quality of the products. Roasting of sesame seeds degrades the lignan sesamolin to sesamol, which increases the oxidative stability of sesame oil synergistically with tocopherols. IR (near infrared, 1.1 to 1.3 μm, 6 kW power) roasting conditions were optimized for the conversion of sesamolin to sesamol. The resultant oil was evaluated for sesamol and tocopherol content as well as oxidative stability. The defatted flours were evaluated for their nutritional content and functionality. IR roasting of sesame seeds at 200 °C for 30 min increased the efficiency of conversion of sesamolin to sesamol (51% to 82%) compared to conventional heating. The γ-tocopherol content decreased by 17% and 25% in oils treated at 200 and 220 °C for 30 min, respectively. There were no significant differences in the tocopherol content and oxidative stability of the oil. Methionine and cysteine content of the flours remained unchanged due to roasting. The functional properties of defatted flours obtained from either IR roasted or conventionally roasted sesame seeds remained the same.
Practical Applications: Sesame oil is stable to oxidation compared to other vegetable oils. This stability can be attributed to the presence of tocopherols and the formation of sesamol, the thermal degradation product of sesamolin—a lignan present in sesame. Roasting of sesame seeds before oil extraction increases sesamol content which is a more potent antioxidant than the parent molecule. The conversion efficiency of sesamolin to sesamol is increased by 31% by infrared roasting of seeds compared to electric drum roasting. This can be used industrially to obtain roasted oil with greater oxidative stability.     

Effect of Seed Roasting Conditions on the Antioxidant Activity of Defatted Sesame Meal Extracts

ABSTRACT: Antioxidant activities of defatted sesame meal extract increased as the roasting temperature of sesame seed increased, but the maximum antioxidant activity was achieved when the seeds were roasted at 200°C for 60 min. Roasting sesame seeds at 200°C for 60 min significantly increased the total phenolic content, radical scavenging activity (RSA), reducing powers, and antioxidant activity of sesame meal extract; and several low-molecular-weight phenolic compounds such as 2-methoxyphenol, 4-methoxy-3-methylthio-phenol, 5-amino-3-oxo-4-hexenoic acid, 3,4-methylenedioxyphenol (sesamol), 3-hydroxy benzoic acid, 4-hydroxy benzoic acid, vanillic acid, filicinic acid, and 3,4-dimethoxy phenol were newly formed in the sesame meal after roasting sesame seeds at 200°C for 60 min. These results indicate that antioxidant activity of defatted sesame meal extracts was significantly affected by roasting temperature and time of sesame seeds.     

Influence of seed roasting process on the changes in composition and quality of sesame (Sesame indicum) oil

The composition and quality changes of sesame oils prepared at different roasting temperatures (180–260°C) from sesame seed were evaluated and compared with an unroasted oil sample. There were no apparent differences in characteristics, such as acid value, iodine value, saponification value and refractive index, of sesame oils prepared at a roasting temperature between 180 and 220°C. The colour units and total polar content of oils increased in relation to an increase in roasting temperature. The phospholipid content was reduced from 690 mg kg^?1 in unroasted oil to 0 mg kg^?1 in the oil prepared using a 260°C roasting temperature. The fatty acid content of the oil was reduced markedly, especially in oleic and linoleic acids, when the roasting temperature was over 220°C. The amounts of chlorophyll and sesamolin decreased with increasing roasting temperature. However, the highest level of sesamol and γ-tocopherol was found in oils prepared with a 200–220°C roasting temperature. The sesame oil prepared at a 200°C roasting temperature had the best flavour score when compared with the other samples.     

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.     

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     

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.     

水酶法芝麻油与其他工艺芝麻油品质差异研究

通过对芝麻油外观品质、理化特性、抗氧化成分及脂肪酸组成进行对比,研究了水酶法芝麻油与其他工艺芝麻油(热榨法芝麻油、冷榨法芝麻油、水代法芝麻油)的品质差异。结果表明:水酶法芝麻油的外观品质好,色泽浅,符合一级成品芝麻油标准;水酶法芝麻油的水分及挥发物的含量介于冷榨法芝麻油和水代法芝麻油之间,酸价、过氧化值、不皂化物含量最低;水酶法芝麻油的抗氧化成分(生育酚、芝麻素和芝麻林素)含量最高,但未检出芝麻酚;与热榨法芝麻油、冷榨法芝麻油、水代法芝麻油相比,水酶法芝麻油的饱和脂肪酸含量最高,不饱和脂肪酸含量最低。     

Aqueous enzymatic sesame oil and protein extraction

In the present work we evaluated five enzyme-mixtures (Protex 7L, Alcalase 2.4L, Viscozyme L, Natuzyme, and Kemzyme) for their effectiveness in extracting the oil and protein recovery from sesame seeds during an enzyme-assisted aqueous extraction (EAAE) process. Alcalase 2.4L was found to be the best for attaining a high oil yield (57.4% of the total oil content in the seed), whereas, the maximum amount of protein (87.1% of the total seed protein), was recovered in the aqueous phase with Protex 7L. The quality attributes such as fatty acids profile, density, refractive index, free fatty acid contents, iodine value, colour, saponification number and unsaponifiable matter of the sesame oil, extracted by aqueous enzymatic process, were comparable with that of the control (oil extracted without enzyme treatment) and hexane-extracted oil (HEO), revealing no significant (p > 0.05) variations among oils, produced by either of the methods. The oxidative stability state of the enzyme-extracted oil (EEO) was noted to be considerably improved relative to the control and HEO. The amount of tocopherols for the oils, produced by the enzyme–adjuvant was found to be higher than the control and HEO. An appreciable increase in the antioxidant activity as assessed by determinations of total phenolic contents, DPPH radical scavenging capacity, and inhibition of linoleic acid oxidation of EEO was also established. Overall, the present results revealed improvement in the quality of the EEO while a major portion of the food grade protein was also extracted in the aqueous phase.     

焙炒时间对芝麻油风味及芝麻氨基酸含量的影响

本文主要研究焙炒时间对芝麻油挥发性风味成分及芝麻中氨基酸含量(以芝麻脱脂粕中氨基酸含量为依据)的影响。经过不同时间焙炒的芝麻,用水代法提油,然后采用顶空固相微萃取(HS-SPME)结合GC/MS技术,检测芝麻油中的挥发性风味成分。随着焙炒时间的延长,吡嗪类、吡咯类、吡啶和嘧啶类、含硫类、呋喃类、酚类物质的相对含量逐渐增多,醛类、醇类、烃类和环氧烃类等物质的含量逐渐减少。对芝麻脱脂粕中18种氨基酸含量的检测数据显示,随着焙炒程度加深,氨基酸含量呈总体下降趋势,其中精氨酸、丝氨酸、赖氨酸和胱氨酸的含量减少明显,这4种氨基酸对芝麻油香味的形成可能起到了重要的作用。     

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.     

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.     

Variation of sesamin,sesamolin and tocopherols in sesame (Sesamum indicum L.) seeds and oil products in Thailand

Sesame (Sesamum indicum L.) seed and oil contain abundant lignans, including sesamin, sesamolin and lignan glycosides. The aim of the present study was to determine sesamin, sesamolin and tocopherol contents in sesame seed and oil available in Thailand. The results showed that there was a large variation of sesamin and sesamolin contents in products. The distribution plot of sesamin and sesamolin contents in seeds showed that the mean values of sesamin and sesamolin were 1.55 mg/g (SD = 1.63; range n.d.–7.23 mg/g) and 0.62 mg/g (SD = 0.48; range n.d.–2.25 mg/g), respectively. The range of total tocopherols of these sesame lines was 50.9–211 μg/g seed. In commercial sesame oils, the ranges of sesamin and sesamolin were 0.93–2.89 mg/g oil and 0.30–0.74 mg/g oil, respectively, and tocopherol contents were 304–647 μg/g oil. The study reveals the extensive variability in sesamin, sesamolin and tocopherol contents among sesame products.     

Effect of processing on oxidative stability and lipid classes of sesame oil

Sesame oil and seed products are highly stable against oxidative processes. The effects of sesame seed pretreatment, including roasting (R), steaming (S), roasting plus steaming (RS) and microwaving (M) on crude oil quality from intact Egyptian and Sudanese seeds were investigated. Oxidative stability of seasame seeds was determined by monitoring changes in peroxide value (PV) and para-anisidine value (p-AV). The oils from RW and RS seeds showed higher oxidative stability than other processed oils. In addition, different lipid classes and subclasses present and their fatty acid composition would influence the oxidative status of the oil. Neutral lipids constituted about 91.0% whereas monoglycolipids and diglycolipids each respresented 2.4 and 3.5%, respectively, and finally phospholipids represented 3.0% of the total lipids. Moreover, different processing treatments show considerable effects on lipid fractions. The influence on all components after RS was more pronounced than M treatment.     

Improvement of the yield and flavour quality of sesame oil from aqueous extraction process by moisture conditioning before roasting

This study was to investigate the effect of conditioning and heat-treatments on the yield and quality of sesame oil. Confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM) were used to explore the microstructure of sesame cotyledon cells. It was found that cell microstructure and oil body membrane of sesame seeds underwent high-pressure steaming pretreatment (HPS), roasting pretreatment (RP), moisture-conditioning plus roasting pretreatment (MRP) was all damaged. All these thermal treatments, especially MRP, contributing to increased oil yield from 45.85 (untreated) to 91.69%. Furthermore, RP or MRP yielded a higher content of sesamol than untreated sesame, whereas sesamin and seasamolin content, fatty acid composition, acid value and peroxide value showed no significant changes (P > 0.05) between heat-treatments. MRP increased the type and content of volatile compounds, which was beneficial to the strong nut-like aroma. Additionally, MRP had a positive effect on oxidative oil stability (induction time of 10.80 h) with respect to untreated oil (7.82 h).     

光皮木瓜原花青素提取物对不同饱和度油脂氧化稳定性的影响

以光皮木瓜为原料,采用水、50%乙醇、60%丙酮提取光皮木瓜原花青素。利用超高效液相色谱-质谱联用仪对3种原花青素提取物进行成分分析,同时采用Schaal加速氧化的方法考察其对3种不同饱和度油脂（花生油、葵花籽油、亚麻籽油）氧化稳定性的影响。结果表明：3种原花青素提取物中的原花青素主要由原花青素高聚体和低聚体组成,其中高聚体含量均在90%以上,低聚体以原花青素二聚体为主。在加速氧化过程中,3种原花青素提取物均能有效延缓油脂的氧化。在花生油中,与空白样品相比,水提取物能够使油脂过氧化值下降33.00%,显著高于乙醇提取物（1866%）和丙酮提取物（9.15%）。在葵花籽油和亚麻籽油中,乙醇提取物和丙酮提取物对油脂氧化的抑制能力相似且强于水提取物。光皮木瓜原花青素可以作为一种天然抗氧化剂,用于提高油脂的氧化稳定性。     

芝麻油中掺棉籽油的分光光度法研究

研究了用分光光度法测定麻油的掺假情况，该方法具有操作简单，准确度高等特点，可以定量测定芝麻油的纯度。并对4种掺假芝麻油样品进行了检验验证，其变异系数均小于5％。