芝麻油及芝麻木酚素对食用油氧化稳定性的影响研究

研究水代芝麻油、热榨芝麻油、冷榨芝麻油及从这3种芝麻油中提取的芝麻木酚素对食用油氧化稳定性的影响。结果表明:向大豆油、花生油中添加这3种芝麻油进行调和可提高大豆油、花生油氧化稳定性,其中添加热榨芝麻油的效果最好;3种芝麻油提取的芝麻木酚素在63℃加热条件下对提高猪油的氧化稳定性作用不大。     

Impact of polyphenols from banana pseudostem on sunflower oil stability

The present investigation is focused on the potential use of banana pseudostem, which otherwise is disposed off as a waste, as a source of polyphenols or antioxidants. The polyphenols extracted from the outer leaf sheaths of 3 Indian banana (Musa spp.) cultivars namely, ‘Nendhran’, ‘Robusta’, and ‘Kathali’ were tested for antioxidant activities. The extracts showed effective DPPH, hydroxyl, and superoxide radical scavenging ability. Among the banana cultivars, ‘Nendhran’ followed by ‘Robusta’ contained the highest total phenolic (110.45 and 94.03 mg GAE/g extract, respectively) and total flavonoid (49.62 and 38.61 mg QE/g extract, respectively) contents and antiradical activity. Further, the study was aimed to evaluate the protective effects of the polyphenolic extracts in stabilizing sunflower oil, tested in terms of peroxide value, free fatty acid contents, and p-anisidine values in comparison with the synthetic antioxidants, butylated hydroxyanisole and butylated hydroxytoluene. In addition, the antioxidant activity and total phenolic contents of the extract-treated oil samples were also monitored to obtain a complete perspective of the influence exerted by the polyphenols in oil stability. The results demonstrated that polyphenols from pseudostem of banana cultivars are potent source of natural antioxidants and might serve as a substitute for synthetic antioxidants in oil industry.     

葵花籽油的氧化稳定性研究

以葵花籽油的酸值和过氧化值为评价指标,考察了温度、光照、金属离子、氧气、水分对葵花籽油氧化稳定性的影响。结果表明：温度、光照、金属离子、氧气、水分均会引起储藏过程中葵花籽油的酸值和过氧化值的升高,且温度和水分影响较明显;40℃下试样放置24 d后的酸值和过氧化值分别达到1.03 mgKOH/g和19.2 meq/kg;Cu2＋对于葵花籽油过氧化值的影响大于Fe2＋;氧气短期内不会促进葵花籽油酸值的上升;添加了1%和2%水分的葵花籽油的酸值相差不大,均大于未加水样品,且水分含量越高,过氧化值增加越快。     

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.     

Contribution of polyphenols to the oxidative stability of virgin olive oil

Stability, polyphenol, orthodiphenol, tocopherol, oleic/linoleic ratio, chlorophyll, carotenoid, peroxide and acidity values, K₂₃₂, K₂₇₀ and overall sensory score of virgin olive oils from Hojiblanca and Picual cultivars were determined during two consecutive seasons. Changes due to cultivar and season were evaluated, correlations between the changes were studied and their contribution to stability was investigated by multiple regression techniques. Removal of polyphenols from the original samples without altering other antioxidant components has permitted estimating, for the first time, the contribution of these compounds to virgin olive oil. Approximately 50% of the stability is contributed by polyphenols. © 2001 Society of Chemical Industry     

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.     

Use of sesame oil cake (Sesamum indicum L.) on corn expanded extrudates

In the production of oil from sesame (Sesamum indicum L.) seeds, a coproduct is obtained which is rich in protein and fiber contents. Mixtures of semi-defatted sesame cake (SDSC) (0–20%) and corn grits were processed in a single screw extruder at screw speed ranging from 324 to 387 rpm to improve the nutritional value of corn expanded extrudates. Chemical composition of raw and extruded materials, sectional expansion index (SEI), texture properties, color, paste viscosity, microstructure and sensory analysis of the extrudates were performed. The addition of SDSC increased protein, fat and ash content of corn extrudates, whereas carbohydrate content was reduced. The addition of SDSC reduced the sectional expansion of the corn extrudates and increased puncture force. SDSC–corn extrudates were darker than non-SDSC–corn extrudates. Increasing SDSC increased the number of cells similar to those of commercial corn extrudates with small cells. Sensory analysis showed 20% SDSC-corn extrudates to be acceptable and nutritional balanced. The use of SDSC on corn extrudates up to 20% is an alternative to improve nutritional value keeping good sensory characteristics.     

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.     

The increase in oxidative stability of sunflower oil enriched with Nigella sativa L. Seed extracts

Nigella sativa L. seeds are rich sources of phenolic compounds. The aim of this study was to evaluate the efficiency of Nigella seed extract as natural antioxidant compared with butylated hydroxytoluene (BHT) during accelerated oxidation of edible vegetable oils at 120 °C. The modifications during heating were monitored by 3D-front-face fluorescence spectroscopy. The fluorescence spectra were obtained with excitations from 280 to 500 nm and emission wavelengths from 300 to 550 nm and analysed using independent components analysis. Decomposition products formed during heating were also evaluated by means of ¹H-NMR spectroscopy and classic chemical methods such as anisidine value and viscosity. The results of the study clearly indicate that the natural seed extract at a level of 800 ppm exhibited antioxidant effects similar to those of the synthetic antioxidant BHT at a level of 200 ppm and thus contributes to an increase in the oxidative stability of the oil.     

Improving the oxidative stability of sunflower seed kernels by edible biopolymeric coatings loaded with rosemary extract

An optimized combination of whey protein concentrate (WPC), glycerol and carboxymethyl cellulose (CMC) was determined by evaluating the mechanical properties of edible films and coating percentage on sunflower seed kernels (SUKs). The optimal coating solutions with/without rosemary extract (RAE) were used to improve oxidative stability of SUKs. Moreover, the efficiency of the coated SUKs was assessed in a sesame-based product, as a food system. The optimized composite coating (CMC 0.6% and WPC 8% by total solution weight, and glycerol 51% by WPC weight) provided the better color features for SUKs stored at elevated temperature compared to WPC coatings (10 and 11%, w/w) with a Maillard-induced red color, and it was more effective than CMC (4%, w/w) coating to improve the oxidative stability of the nuts. The RAE had a positive effect on the color characteristics of the composite and CMC coatings; however, it enhanced the oxidation of SUKs, which could be due to disruption of coating polymer network, and thus increasing the oxygen diffusion into the product. The food system containing the coated nuts exhibited a lower oxidation extent in comparison to the control formulation prepared by uncoated ones. Therefore, using an optimal composite coating, reddening of WPC at high temperatures and less oxidation protection efficiency of CMC were resolved as the kernels with desirable color and oxidative stability properties were produced, applicable in the formulation of products needing thermal processing.     

Effect of plant extracts on the oxidative stability of sunflower oil and emulsion

The antioxidative activities of six plant extracts (catnip, hyssop, lemon balm, oregano, sage and thyme) were evaluated in sunflower oil and its 20% oil-in-water emulsion in the dark at 60°C. The oxidation process was followed by measuring the formation of primary (conjugated diene hydroperoxides) and secondary (volatile compounds) oxidation products. Sage extracts (600 and 1200 ppm) effectively inhibited the formation of conjugated dienes and volatile compounds (hexanal and pentanal) in oil and emulsion and showed the highest antioxidative activity compared with 300 ppm BHT. Thyme and lemon balm extracts inhibited hexanal generation more than formation of conjugated dienes in both oil and emulsion. Oregano extract was more active in oil than in emulsion. Catnip and hyssop extracts (600 ppm) showed prooxidative action to sunflower oil at 60°C. These two extracts increased the formation of conjugated dienes compared with the control oil. In emulsions, catnip extract (600 ppm) was active and significantly inhibited the formation of conjugated dienes more than BHT (300 ppm) during additional incubation.     

紫苏提取物对裂壶藻油氧化稳定性的影响

目的：探究紫苏提取物对裂壶藻油氧化稳定性的影响。方法：采用强制氧化法,以过氧化值、丙二醛值、茴香胺值、共轭二烯值作为评价指标,探究不同浓度紫苏提取物、0.04%茶多酚与0.02% TBHQ对裂壶藻油氧化稳定性的影响,采用气相—质谱检测裂壶藻油中脂肪酸成分的变化。结果：强制氧化15 d后,0.10%紫苏提取物组不饱和脂肪酸含量相比空白组提高了16.91%,紫苏提取物可以通过延缓不饱和脂肪酸的氧化分解,起到抗氧化效果,紫苏提取物对裂壶藻油的氧化抑制效果略低于TBHQ,不饱和脂肪酸含量仅减少了5.30%,紫苏提取物添加组相比茶多酚添加组不饱和脂肪酸含量增加了12.93%,抗氧化效果明显高于茶多酚。结论：紫苏提取物能够有效提高裂壶藻油的氧化稳定性,且随着提取物剂量的增加,其延缓氧化效果也更加显著。     

Antioxidant activity of ginger extract in sunflower oil

The antioxidant activity of dichloromethane extract from ginger was evaluated during 6 months of storage of refined sunflower oil at 25 and 45 °C. Free fatty acid (FFA) content, peroxide value (POV) and iodine value (IV) were used as criteria to assess ginger extract as an antioxidant. After 6 months of storage at 45 °C, sunflower oil containing 1600 and 2400 ppm ginger extract showed lower FFA contents (0.083 and 0.080%) and POVs (24.5 and 24.0 meq kg^?1) than the control sample (FFA contents 0.380%, POV 198.0 meq kg^?1). Sunflower oil containing 200 ppm butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) showed FFA contents of 0.089 and 0.072% and POVs of 26.5 and 24.7 meq kg^?1 respectively after 6 months of storage at 45 °C. Similarly, after 6 months of storage at 45 °C, IVs of sunflower oil containing 1600 and 2400 ppm ginger extract were 80 and 92 respectively, higher than that of the control sample (53). However, IVs of sunflower oil treated with 200 ppm BHA and BHT were 94 and 96 respectively after 6 months of storage at 45 °C. These results illustrate that ginger extract at various concentrations exhibited very strong antioxidant activity, almost equal to that of synthetic antioxidants (BHA and BHT). Ginger extract also showed good thermal stability and exhibited 85.2% inhibition of peroxidation of linoleic acid when heated at 185 °C for 120 min. Therefore the use of ginger extract in foods is recommended as a natural antioxidant to suppress lipid oxidation. © 2003 Society of Chemical Industry     

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     

磷钨杂多酸催化芝麻林素提高冷榨芝麻油的氧化稳定性

采用向冷榨芝麻油中添加芝麻酚纯品的方式验证芝麻酚的抗氧化活性;采用磷钨杂多酸(HPW)催化冷榨芝麻油中的芝麻林素分解生成芝麻酚和芝麻素酚,探索HPW添加量、反应温度、反应时间对酸催化实验的影响,从而提高冷榨芝麻油的氧化稳定性。结果表明:一定含量的纯品芝麻酚可以有效提高冷榨芝麻油的氧化稳定性,当芝麻酚的添加量达到100 mg/100 g时,冷榨芝麻油的氧化诱导时间(OSI)从原来的4.20 h延长到6.62 h;在HPW添加量0.8%、反应温度80℃、反应时间120 min条件下,芝麻林素完全分解转化,冷榨芝麻油的OSI为9.32 h;经过酸催化处理的冷榨芝麻油酸值、过氧化值、皂化值均有不同程度的上升,色泽变浅,但变化范围不大,均在国标一级芝麻油的标准范围之内,并未对冷榨芝麻油的品质造成较大的影响。     

Enhancing stability and bioavailability of sulforaphene in radish seed extracts using nanoemulsion made with high oleic sunflower oil

Food Science and Biotechnology - The effect of nanoemulsions on the stability and bioavailability of sulforaphene (SFEN) in radish seed extract (RSE) was investigated. Four types of oil were used...     

超声波辅助-HPLC测定芝麻油中木脂素含量

以超临界CO2流体萃取的芝麻油为原料,采用超声波辅助甲醇萃取法对芝麻油进行前处理,并通过高效液相色谱法测定芝麻油中木脂素含量。结果表明,芝麻素和芝麻林素色谱峰分离效果好,干扰峰少,芝麻素与芝麻林素平均加标回收率分别为99.3%、96.2%,相对标准偏差分别为0.87%、1.71%。与皂化法前处理方法相比,此方法的前处理简便快速、结果准确、灵敏度高、稳定性好,适用于芝麻油中芝麻素和芝麻林素含量的测定。