Effect of refining processes on the total and individual tocopherol content in sunflower oil

Total and individual tocopherol contents of sunflower oil, processed either by chemical refining (CR), physical refining (PR) or soft column deodorization (SCD) methods were investigated. Total tocopherol content gradually decreased until the end of the refining process (the deodorization stage). Among the refining methods used CR and PR caused higher losses in the tocopherol content when compared with the SCD method. The content of α-, β-, γ- and δ-tocopherols also decreased as a result of the refining process. These significant losses in β- and γ-tocopherol contents were determined after the deodorization stage.     

以生育酚为目标的油脂脱臭馏出物的生产

近年来 ,富含生育酚的脱臭馏出物具有很高的应用价值。脱臭馏出物中生育酚的含量与油脂精炼工艺、脱臭时间、脱臭温度、捕集器温度、蒸汽用量和系统真空度等因素有关。提出一些建议以提高脱臭馏出物中生育酚的含量 ,但不影响精炼油的质量。     

大豆油精炼过程中生育酚的损失

以国内21家大型油脂精炼厂生产的大豆油为对象,研究了精炼过程中生育酚总量和各单体含量的变化,重点考察了不同脱臭塔设备及脱臭条件与生育酚损失率之间的关系.结果表明,在油厂现有通用精炼条件下,整个精炼过程中生育酚总损失率不超过33%,4种生育酚单体(α,β,γ,δ)的相对比例几乎没有变化.影响生育酚保留率的关键因素为脱臭阶段塔的结构、温度及搅拌蒸汽用量.     

精炼工艺对元宝枫籽油品质的影响

为了对元宝枫籽油的精炼提供指导,分析了精炼过程中元宝枫籽油的基本理化指标、脂肪酸和有益油脂伴随物（植物甾醇、生育酚）的变化情况。结果表明：随着精炼工序的进行,元宝枫籽油的酸值、过氧化值和氧化诱导期显著降低（p<0.05）,脂肪酸组成变化不显著（p>0.05）,植物甾醇和生育酚两种有益油脂伴随物的含量显著降低（p<0.05）,分别由毛油的950.3 mg/kg和1 107.4 mg/kg降至脱臭油的569.9 mg/kg和743.4 mg/kg,损失率分别为40.0%、32.9%。研究结果说明精炼能够显著影响元宝枫籽油的品质,应有效控制脱臭条件,尽量减少有益油脂伴随物的损失。     

γ-Oryzanol and tocopherol contents in residues of rice bran oil refining

Rice bran oil (RBO) contains significant amounts of the natural antioxidants γ-oryzanol and tocopherols, which are lost to a large degree during oil refining. This results in a number of industrial residues with high contents of these phytochemicals. With the aim of supporting the development of profitable industrial procedures for γ-oryzanol and tocopherol recovery, the contents of these phytochemicals in all the residues produced during RBO refining were evaluated. The samples included residues from the degumming, soap precipitation, bleaching earth filtering, dewaxing and deodorisation distillation steps. The highest phytochemical concentrations were found in the precipitated soap for γ-oryzanol (14.2 mg g⁻¹, representing 95.3% of total γ-oryzanol in crude RBO), and in the deodorisation distillate for tocopherols (576 mg 100 g⁻¹, representing 6.7% of total tocopherols in crude RBO). Therefore, among the residues of RBO processing, the deodorisation distillate was the best source of tocopherols. As the soap is further processed for the recovery of fatty acids, samples taken from every step of this secondary process, including hydrosoluble fraction, hydrolysed soap, distillation residue and purified fatty acid fraction, were also analyzed. The distillation residue left after fatty acid recovery from soap was found to be the best source of γ-oryzanol (43.1 mg g⁻¹, representing 11.5% of total γ-oryzanol in crude RBO).     

Determination of the tocopherol content of the nonsaponifiable fraction of lupine oil (L. mutabilis)

The content of individual tocopherols was determined in 11 samples of lupine oil (L. mutabilis) from Peru by GC- and HPLC-procedures. The main component is gamma-tocopherol (42-69 mg/100 g oil); alpha- and delta-tocopherol were found in traces (0.1-0.7 mg/100 g oil). The pretreatment of samples, necessary for the GC-methods leads to tocopherol losses of 30% on average, this loss is mainly caused by the saponification of the samples. The tocopherols are predominantly present in an unesterified state.     

Impact of Crude Oil Quality on the Refining Conditions and Composition of Nutraceuticals in Refined Palm Oil

Palm oil is the major vegetable oil used worldwide due to its unique properties. The effect of crude palm oil acidity on the final free fatty acids (FFA) content, neutral oil loss (NOL), and nutraceutical compounds, such as carotenes, total tocols (tocopherols and tocotrienols), squalene, and phytosterols was investigated. A central composite design was employed to study the influence of the refining conditions: temperature (200 to 260 °C), steam percentage (0.5% to 3.5%), and initial FFA content (2.2% to 6.0%) on the quality of the refined product. The results revealed that initial palm oil acidity is a statistically important parameter to obtain commercially acceptable values for final FFA content. The increase of temperature presented the most important effect on the reduction of all nutraceutical compounds. The highest tocopherols (88%), phytosterols (98%), and squalene retention (84%) was obtained when applying the mildest temperature (200 °C). From the experimental results, 3 equations were generated enabling the prediction of the free fatty acids content, the tocols content, and the losses of neutral oil. Therefore, this work contributes to the understanding and optimization of the process for the production of palm oil with high nutraceutical quality and low free fatty acid contents.     

精炼工艺对玉米油微量成分变化的影响

以在超级脱胶结合白土预脱色-复脱色以及双塔脱臭脱酸工艺生产线上取样的玉米毛油、脱胶油、脱蜡油、脱色油、脱臭油为研究对象,对其游离脂肪酸、磷、金属离子、色素、生育酚含量及过氧化值进行测定,考察精炼工艺对玉米油微量成分变化的影响。结果表明:双塔脱臭脱酸工艺可以明显降低玉米油中游离脂肪酸含量;超级脱胶工艺可去除玉米油中约95%的磷脂;脱胶和脱色可明显降低金属离子含量;大部分色素在脱色工段被去除;经脱臭后,成品油中总生育酚损失19. 9%;脱胶使玉米油过氧化值升高,脱色和脱臭可使过氧化值明显降低。说明应根据玉米毛油品质选择合适的精炼工艺,以最大限度地保留有益微量成分,去除有害成分,做到适度精炼。     

稻米油精炼技术

稻米油因其丰富的营养成分越来越受到人们的青睐。米糠极易酸败造成稻米毛油酸价高、精炼难和得率低,制约了稻米油产业发展。高效去除稻米油中杂质的同时,最大程度保留谷维素、植物甾醇等营养成分,是稻米油精炼加工面临的困难和挑战。传统稻米油加工一般采用碱炼脱酸工艺,近年来稻米油超级脱胶物理精炼、酶法脱胶物理精炼等技术在实践中得到运用。对稻米油精炼的传统化学精炼工艺和现代物理精炼工艺进行了综述,以期为稻米油的精炼提供参考。     

Retaining maximum antioxidative potency of wheat germ oil refined by molecular distillation

A process of physical refining wheat germ oil using the technique of molecular distillation (MD) is presented in this work. Wheat germ oil was obtained from the germ by solvent extraction using hexane and also by cold pressing. The oil extracted with hexane was degummed and bleached before deacidification in order to modify the parameters of phosphorus and color. The goal in carrying out the stage of physical refining by MD was to preserve the maximum amount of original antioxidative potential obtained from extraction of the crude oil. The effect of evaporation temperature of one‐stage MD on the efficiency of free fatty acid elimination was studied. The antioxidant portion was followed by means of analytic determination of tocopherols by high‐performance liquid chromatography. Tocopherol retention up to 98% was achieved in the oil extracted by pressing, and yields of up to 96% were achieved in the oil extracted with hexane. Copyright © 2007 Society of Chemical Industry     

Composition and oxidative stabilities of oils extracted from hybrid hazelnuts grown in Nebraska,USA

Recently, hybrid hazelnuts have emerged as a potential oilseed crop in Nebraska for food and value‐added industrial applications. As with all hazelnuts, Nebraska hybrid hazelnuts were characterised by the high oil content with the average oil content of 54.3%. Oleic acid was the predominant fatty acid. Oleic acid and linoleic acid accounted for more than 90% of the total fatty acid composition, whereas small quantities of palmitoleic and linolenic acids were found. Four major tocopherols (α‐, β‐, γ‐ and δ‐tocopherols) were identified with α‐tocopherol as the most dominant isomer. The average total tocopherol content was 235.4 mg kg^?1 oil with α‐tocopherol constituting approximately 97.5% of the total tocopherols. β‐sitosterol was the most abundant sterol of the three identified sterols representing, on average, 93.1% of total sterols, followed by campesterol and stigmasterol. The oil oxidative stability was affected by the presence of high levels of natural antioxidants and monounsaturated fatty acids (MUFA). Genotype 16–177 was superior to the other genotypes, when combining high levels of MUFA, tocopherols and phytosterols, and high oxidative stability.     

生育酚及甾醇含量对大豆油氧化稳定性及贮藏稳定性的影响

植物油是生育酚、甾醇等活性物质的最主要的膳食来源之一,但现有的过度精炼的工艺造成了生育酚和甾醇的大量损失,大大降低了食用植物油的营养价值。随着人们对营养健康的日益关注,加上行业内对植物油适度精炼工艺的号召,需要提高精炼后植物油中生育酚、甾醇的保留量,但植物油中生育酚和甾醇的最低含量的确定缺乏基础研究依据。因此,本文分别利用Rancimat法和Schaal烘箱法比较了不同生育酚及甾醇含量的大豆油的氧化稳定性和贮藏稳定性的差异,结果表明,生育酚和甾醇能够显著提高大豆油贮藏过程中的稳定性,但并不是剂量越高效果越强。当大豆油中生育酚及甾醇分别保留至0.12%、0.35%时,大豆油的氧化稳定性最强;当大豆油中生育酚及甾醇分别保留至0.12%、1.29%时,大豆油的贮藏稳定性最佳。本文研究结果为植物油适度精炼工艺中相应产品标准（草案）的制修定提供基础数据,为探究以营养物质含量高低作为植物油新分级指标之一的可行性提供理论支撑。     

光皮树油工厂化精炼及理化性质分析

将从于都具收集到的光皮树干果压榨出毛油后,通过工厂化精炼,最终得到光皮树精炼油,并对其脂肪酸成分以及理化进行分析。结果表明,光皮树油最主要的3种脂肪酸为亚油酸(34.69%)、油酸(34.47%)、棕榈酸(22.37%)。对光皮树毛油与精炼油比较发现,毛油颜色深(黄77,红12,蓝8.7),高酸值(15.3mg KOH/g)和高过氧化值(76.9meq/kg),精炼后得到很大程度改善;一些营养成分(碳水化合物、水分、β-胡萝卜素、VE、尼克酸、硫胺素)和微量元素(钾、钠、镁、磷)在毛油中均有存在,经精炼后,碳水化合物、水分、β-胡萝卜素、钾、镁、磷含量显著下降,VE含量变化不大,尼克酸、硫胺素和钾含量均低于检测下限。     

不同加热条件对油茶籽油品质影响的研究

以油茶籽油为原料,研究不同加热处理对油脂的脂肪酸、生育酚、角鲨烯含量的影响。结果表明：油茶籽油中油酸含量随温度的升高及加热时间的延长而增加;不饱和脂肪酸含量总体随加热时间的延长呈上升趋势,饱和脂肪酸含量随加热时间的延长呈下降趋势。高温或长时间加热均导致角鲨烯和生育酚含量的损失。加热后油茶籽油总生育酚平均含量为43.68 mg/kg,较未加热(88.96 mg/kg)降低了50.90 %;加热后角鲨烯平均含量为64.15 mg/kg,较未加热(67.06 mg/kg)降低了4.34 %。     

碱炼脱酸工艺条件对高酸值米糠油碱炼效果的影响

以高酸值米糠毛油为原料,分别采用一次碱炼脱酸和两次碱炼脱酸工艺,以油脂碱炼得率、脱色率、谷维素损失率、甾醇损失率为考察指标,研究碱液浓度对碱炼效果的影响,并对两种碱炼脱酸工艺效果进行比较。结果显示:两次碱炼脱酸与一次碱炼脱酸相比,相同碱液浓度条件下,油脂碱炼得率平均提高4.89%,谷维素损失率平均降低5.87%,甾醇损失率在碱液浓度较低(12°Bè~20°Bè)时,两次碱炼甾醇损失率明显比一次碱炼低(平均低12.64%),但在碱液浓度超过24°Bè之后,两次碱炼的甾醇损失率比一次碱炼高,也即在高浓度碱液条件下,减少碱炼次数对减少甾醇损失是有利的。米糠毛油两次碱炼脱酸时,一道碱炼的碱液浓度为28°Bè,二道碱炼的碱液浓度为12°Bè时谷维素损失率最低,16°Bè时甾醇损失率最低,碱液浓度对碱炼得率和脱色率的影响不显著。     

Effect of genotype and cultivation location on β-sitosterol and α-, β-, γ-, and δ-tocopherols in sorghum

This study aims to examine variations in β-sitosterol and α-, β-, γ-, and δ-tocopherol composition and content in sorghum grains with different genotypes and cultivation areas (Wonju and Miryang in Korea). β-Sitosterol content was found to be higher in Wonju sorghum; however, total tocopherol content was found to be higher in Miryang sorghum. Moreover, the β-sitosterol content did not correlate with physical characteristics, including 100-seed weight and color values (L, a, and b), but it was negatively correlated with total tocopherol content. β-Tocopherol was a major tocopherol in sorghum, constituting approximately 40%–46% of the total tocopherol content, and it was highly correlated with the total tocopherol content. Furthermore, the α-tocopherol content also increased with increasing γ-tocopherol content. Among the 4 tocopherols, only δ-tocopherol content correlated with physical characteristics of sorghum grain. This study deepened our knowledge of the variations in β-sitosterol and α-, β-, γ-, and δ-tocopherol content in sorghum with respect to genotype and cultivation location. In addition, this study demonstrated a correlation between some physical characteristics of sorghum and β-sitosterol/tocopherol content, and this information can be useful for breeding programs that develop or breed sorghum varieties or manufacture sorghum-based foods containing high amounts of β-sitosterol and tocopherols.     

Expression of modified tocopherol content and profile in sunflower tissues

BACKGROUND: Alpha‐tocopherol is the predominant tocopherol form in sunflower seeds. Sunflower lines that accumulate increased levels of beta‐, gamma‐ and delta‐tocopherol in seeds as well as lines with reduced and increased total seed tocopherol content have been developed. The objective of this research was to evaluate whether the modified tocopherol levels are expressed in plant tissues other than seeds. RESULTS: Lines with increased levels of beta‐, gamma‐ and delta‐tocopherol in seeds also possessed increased levels of these tocopherols in leaves, roots and pollen. Correlation coefficients for the proportion of individual tocopherols in different plant tissues were significantly positive in all cases, ranging from 0.68 to 0.97. A line with reduced tocopherol content in seeds also showed reduced content in roots and pollen. CONCLUSION: Genetic modifications producing altered seed tocopherol profiles in sunflower are also expressed in leaves, roots and pollen. Reduced total seed tocopherol content is mainly expressed at the root and pollen level. The expression of tocopherol mutations in other plant tissues will enable further studies on the physiological role of tocopherols and could be of interest for early selection for these traits in breeding programmes. Copyright © 2011 Society of Chemical Industry     

Influence of chemical refining process and oil type on bound 3-chloro-1,2-propanediol contents in palm oil and rapeseed oil

The formation of bound 3-chloro-1,2-propanediol (3-MCPD-ester) in oils during chemical refining process was investigated for two palm oils and one rapeseed oil. Additionally, contents of mono- and diglycerides as well as total chlorine and chloride were determined. For all oils the deodorisation step representing one part of the refining process had the main impact on formation of 3-MCPD-esters whereas a direct effect of the other process steps could be neglected. 3-MCPD values in the range of 4–5 ppm for palm oil and 1 ppm for rapeseed oil were found. The chloride content was below detection limit. However, measurable amounts of total chlorine were found in palm oil with the highest 3-MCPD-ester contents. A considerable part of this total chlorine in the refined palm oil was embedded in the 3-MCPD-esters. On the other hand, content of diglycerides as the other potential pre-cursor was between 1% and 10% exceeding the 3-MCPD-ester contents by up to five magnitudes.     

精炼对菜籽油品质的影响

菜籽油精炼过程是一个发生物理与化学变化的过程,在这一过程中,菜籽油损失了一些天然的微量物质,也引入或产生了多种其他微量物质,而这些微量物质的变化对菜籽油的品质具有决定性影响.对国内6厂家生产的菜籽油进行取样,选取酸值、过氧化值、磷含量、色泽、生育酚含量、植物甾醇含量、反式酸含量这几类对菜籽油品质影响较大的微量物质,对其进行分析测定,以期得到菜籽油精炼各工序中这些微量物质的变化规律,为菜籽油的适度精炼提供依据.     

Tocopherol composition of deodorization distillates and their antioxidative activity

During the last stage of plant oil refining, deodorization distillates containing very important biological substances such as tocopherols, sterols, terpenoids or hydrocarbons are formed as a by-products. This study aimed at evaluating the content and antioxidant capacity of tocopherol concentrates from deodorization distillates obtained after the refining of rapeseed, soybean and sunflower oil. The majority of the matrix substances were eliminated from deodorization distillates by freezing with an acetone solution at -70 degrees C. The tocopherol concentrates obtained in this way contained approximately fivefold more tocopherols than the quantity in condensates after deodorization. Antioxidant activity was investigated by observing the peroxide value at 25 degrees C and using the Oxidograph test. The test medium was lard enriched with the tocopherol concentrates of the three plant oils versus single, synthetic alpha-, gamma- and delta-tocopherols (-T), which served for comparison. In these model systems, all investigated tocopherol concentrates exhibited antioxidant capacity. Their antioxidant effect was significantly lower than that of single delta-T and gamma-T, but significantly higher than alpha-T. The results prove that natural tocopherol concentrates obtained from plant oils are valuable food antioxidants and they also increase the biological and nutritional value of food especially when administered to animal fats or food of animal origin. Tocopherol concentrates can fully replace synthetic antioxidants that have been used thus far.