不同食用植物油中维生素E组分及含量研究

通过对9个不同品种的138个食用植物油样品中维生素E组分及含量的测定,分析研究不同食用植物油中维生素E组分及含量的分布情况。结果表明:9个油脂品种、101个一级油样品中维生素E含量范围为5.9~1 246.6 mg/kg,平均值652.4 mg/kg,维生素E总量的平均值排序为大豆油棉籽油玉米油葵花籽油菜籽油米糠油花生油芝麻油山茶油;不同油脂样品中维生素E的组分有明显差别,米糠油含有最齐全的8种维生素E组分,并且生育三烯酚含量的平均值占维生素E总量平均值的44.2%;玉米油含有3种生育酚和2种生育三烯酚,棉籽油中含有3种生育酚和1种生育三烯酚,但这两种油脂中生育三烯酚含量平均值分别仅占维生素E总量平均值的5.8%和2.8%;大豆油、菜籽油、花生油、葵花籽油均含有α-、γ-、δ-生育酚3种组分;山茶油中含有α-、γ-生育酚2种组分;芝麻油仅含有γ-生育酚1种组分。除芝麻油之外,所有油脂中均含有α-生育酚和γ-生育酚,其中葵花籽油中α-生育酚含量最高,大豆油中γ-生育酚含量最高。同一油脂品种、不同等级的油脂中维生素E含量也存在差异,总体趋势是维生素E含量随油脂精炼程度的加深而降低,但个别二级菜籽油样品中维生素E含量低于一级菜籽油,这与所采集油脂样品的来源不同有关。不同油脂品种、不同等级的食用植物油中维生素E组分及含量因油料品种、油脂精炼工艺的不同显示出明显差异。     

不同类型大豆萌发期维生素E组分及含量的比较

为了探究大豆萌发期维生素E的变化规律,本实验以8种栽培大豆为实验材料,采用高效液相色谱(HPLC)法测定大豆萌发期维生素E组分及含量,并统计萌发期大豆的发芽率、发芽势以及胚根长。结果表明:HPLC法测定的结果重现性和精密度良好,可以准确定量大豆维生素E组分的含量。3个黄皮黄仁大豆、2个黑皮黄仁大豆和1个绿皮黄仁大豆均表现为γ-生育酚含量大于α-和δ-生育酚含量,且萌发期间变化趋势大致相同;仅绿皮绿仁大豆和黑皮绿仁大豆各组分含量表现为α-生育酚γ-生育酚δ-生育酚。差异显著性分析表明,黄仁大豆在第7天的α-生育酚含量最高,绿仁大豆在第1天含量最高。大豆萌发期间黑皮绿仁大豆SZ910的α-生育酚含量显著高于其他材料,进一步分析表明萌发期绿仁大豆中α-生育酚含量显著高于黄仁大豆,表明萌发期绿仁大豆较黄仁大豆具有更高的营养保健作用。     

HPLC测定纺织品中维生素E含量

通过确定维生素E的3种主要异构体α-生育酚、γ-生育酚和δ-生育酚的液相色谱分析条件，以特征保留时间确定各异构体相应的液相色谱指纹图谱。建立了纺织品中维生素E含量的测定方法：以相同液相色谱分析条件对纺织样品提取液进样分析，根据各异构体指纹图谱以外标法定量求得纺织品中异构体含量，最终获得纺织品中维生素E的含量。测定方法的精密度和回收率均满足相关标准要求，可用于纺织品中维生素E含量的检测。     

氧化油脂日粮中添加RRR-α-生育酚琥珀酸酯对鸡肉品质的影响

探讨RRR-α-生育酚琥珀酸酯(TOS)对饲喂氧化油脂日粮鸡肉品质的影响,选用600只1 d AA肉鸡,随机分为10个处理,每处理6个重复,采用2×5因子设计,即2种油脂类型(新鲜和氧化油脂)和5种α-生育酚的处理,30 mg/kg all-rac-α-生育酚醋酸酯(TOA1)、30 mg/kgRRR-α-生育酚醋酸酯(TOA2)及15、30、60 mg/kgRRR-α-生育酚琥珀酸酯(TOS1、TOS2和TOS3),试验期42 d。结果表明:(1)氧化油脂日粮增加了机体脂质过氧化反应,胸腿肌肉色变差,滴水损失增加,MDA含量升高,SOD活性下降(P0.05);(2)不同的油脂日粮处理中,TOS3组均能降低胸肌48 h滴水损失和烹饪损失(P0.05),腿肌亮度、红色度及滴水损失在TOS2或TOS3组得到改善(P0.05);TOS2和TOS3组胸腿肌MDA含量降低(P0.05或P0.01),胸肌TOS3组SOD活性提高(P0.05);与TOS1相比,TOS2和TOS3组血清及肝脏中α-生育酚含量提高(P0.05)。日粮中油脂氧化导致鸡肉品质降低,添加TOS可通过增加机体α-生育酚含量,提高机体抗氧化能力,改善肌肉品质。     

正相高效液相色谱法测定植物油中维生素E的含量

试验建立了正相高效液相色谱法测定植物油中4种维生素E含量的方法。植物油的最佳取样量为0.20 g,在设定的条件下4种维生素E实现了良好的分离,待测维生素E在0.20～6.00μg/m L质量浓度范围内呈良好的线性关系(R~20.999), 4种维生素E的定量限分别为0.15, 0.15, 0.12和0.15 mg/100 g,加标回收率在95.2%～102.3%之间。对市售(流通领域)植物油中维生素E含量进行了测定,发现植物油中各生育酚的含量为γ-生育酚δ-生育酚α-生育酚β-生育酚;γ-生育酚含量范围在39.2～285 mg/100 g之间,δ-生育酚含量范围在1.1～70 mg/100 g之间,α-生育酚含量范围在3～51 mg/100 g之间,β-生育酚含量范围在0.2～6.7 mg/100 g之间。同时测定了餐饮领域的植物油中维生素E含量,发现煎炸用油的α-生育酚、β-生育酚、γ-生育酚和δ-生育酚含量均普遍较低。     

高d-a-生育酚的研制

为制备高含量d-a-生育酚，采用维生素E与甲醇通过催化法使非α-生育酚转变为α-生育酚。优化的工艺条件为：催化剂用量4％，时间2．5h，温度220℃，搅拌转速700r／min。在此条件进行试验验证，得到产品的α-生育酚含量为93．16％，维生素E的收率为81．68％。     

高效液相色谱法同时测定营养强化面包中脂溶性维生素

本试验建立了高效液相色谱法同时测定营养强化面包中3种脂溶性维生素—维生素A(视黄醇)、维生素E(α-生育酚)和维生素D3含量的方法,采用C18色谱柱,流动相为甲醇-水(98:2),检测波长300nm,流速1.6ml/min,各维生素的线性关系良好(R2≥0.9996),回收率88.5%～107.1%(RSD2.36%～4.14%)。本文详细说明标准品的处理和标定方法,结果表明,该方法准确可行。     

催化甲基化法制备d-α-生育酚

维生素E是由α、β、γ、δ-生育酚及α、β、γ、δ-三烯生育酚等八种化合物组成的混合物,它们的生理活性各异。在构象上,又有d-型和l-型之分,天然的多为d-型而人工合成的则多为d,l-型,天然的d-α-生育酚具有迄今所知的最大的维生素E活性。选用V2O5为催化剂进行了反应条件的优化,得到优化条件为:反应温度250℃、时间1 75h、催化剂用量为维生素E的3 5%、氢气压力0 3mPa(表压)。实验结果为:α-生育酚含量92.31%、维生素E得率为79 83%。     

3种油脂在煎炸过程中维生素E组分及理化指标变化研究

研究了葵花籽油、菜籽油、花生油在连续煎炸油条过程中维生素E含量及酸值、过氧化值、碘值等理化指标的变化情况。结果表明:3种油脂在32 h煎炸过程中维生素E含量皆随时间的延长而降低,煎炸初始时维生素E总量的排序为菜籽油(48.50 mg/100 g)葵花籽油(32.33 mg/100 g)花生油(19.56 mg/100 g),损失率分别为86.5%、64.9%及95.7%,不同油脂中维生素E的特征组分不同,葵花籽油的特征组分为α-生育酚、α-生育三烯酚和β-生育酚;菜籽油的特征组分为α-生育酚、γ-生育酚和δ-生育酚;花生油的特征组分为α-生育酚、β-生育酚和γ-生育酚;3种油脂的酸值随时间的延长而升高,碘值随时间的延长而降低;葵花籽油和花生油的过氧化值随时间的延长呈现出先升高后降低的趋势,而菜籽油的过氧化值逐渐升高。     

高活性α-生育酚的制备及结构鉴定

高活性α生育酚(dα生育酚)具有迄今所知的最大的维生素E活性。采用直接甲基化法进行了实验,得到高活性α生育酚产品。制备后的α生育酚含量为98.91%,浓度为0.34mg/mL。比旋光度为31.52°。甲基化反应前后维生素E的生理活性大多数得以保留。经用核磁共振碳谱作进一步确认,并与标准谱图进行比较。结果十分吻合,特别是三个手性碳的位移值均未发生变化,因此进一步确认甲基化过程中构型未受到破坏。     

Effects of supranutritional dietary vitamin E levels on subcellular deposition of α-tocopherol in the muscle and on pork quality

The influence of three levels of vitamin E in the diet of pigs on the subcellular deposition of α-tocopherol in the muscle and on selected quality characteristics of pork meat (oxidative stability of lipids, colour, drip loss, microbial growth) was studied. The content of α-tocopherol in adipose tissue and L. dorsi muscle as well as in mitochondrial and microsomal fractions of the muscle significantly increased (P < 0.05) with increasing levels of dietary vitamin E. The differences in the concentrations of α-tocopherol in the subcellular fractions were evident in the enhanced stability of the membranes when exposed to metmyoglobin/hydrogen peroxide. The beneficial effect of dietary vitamin E on the oxidative stability of pork lipids during the storage of pork chops and ground pork was also demonstrated. Even though lipid oxidation increased in all cases during storage, the pork products from the pigs receiving the highest level of vitamin E (200 IU kg^?1 feed) exhibited the smallest increase in thiobarbituric acid reactive substances. In addition, increased colour stability and decreased drip loss were observed on keeping pork chops, which had been previously frozen for three months, at 4°C under fluoresent light for 10 days. The possible effect of α-tocopherol on membrane fluidity in this context is discussed.     

Effect of dietary vitamin E supplementation and refrigerated storage on quality of rainbow trout fillets

Rainbow trout were fed a low vitamin E (200 mg/kg; LVE) or a high vitamin E (5000 mg/kg; HVE) diet for 9 wk to characterize the effect of vitamin E supplementation at 5000 mg/kg on fillet quality. Fish were sampled at 2, 3, 4, 5, 7, and 9 wk of the trial. Fillets were stored at 2 °C for 0, 7, and 14 d, and analyzed for pH, psychrotrophic counts, color, cook yield, shear force, crude fat and moisture content, α-tocopherol, fatty acid composition, and lipid oxidation. There was a significant feeding duration by fillet storage time interaction for psychrotrophic counts, crude fat content, cook yield, and shear force. Fillet L* value was not affected by diet, feeding duration or storage time. Fillet a* was lowest at 14-d storage, and b* values increased with fillet storage time. High vitamin E diet increased fillet α-tocopherol from 33 to 155 mg/kg. High vitamin E decreased palmitic acid and increased linoleic acid and omega-6 fatty acids. Feeding through 9 wk increased the relative proportions of unsaturated, polyunsaturated, and omega-3 fatty acids, and decreased saturated and omega-6 fatty acids. At 0-d storage, HVE diet did not affect thiobarbituric acid-reactive substances (TBARS) at any sampling week, and fasted fish generated fewer TBARS compared to non-fasted fish.     

Antioxidant activity of lettuce extract (Lactuca sativa) and synergism with added phenolic antioxidants

Combined antioxidative effects of lettuce extract and α-tocopherol, quercetin or ascorbic acid (AA) were investigated for peroxidation of l-α–phosphatidylcholine liposomes with oxidation initiated by lipophilic or by hydrophilic azo-initiators. Lettuce extract had a clear antioxidative effect as evidenced by a lag phase for formation of conjugated dienes, and α-tocopherol and especially quercetin acted synergistically in prolongation of the lag phase both following initiation in the lipid phase and in the aqueous phase. Combination of AA with lettuce extract showed in contrast a lag phase that was similar to that observed for AA alone. Storage of lettuce extract for 24 h at refrigerator or room temperatures resulted in a decreasing lag phase with increasing storage time for both storage temperatures, an effect not counteracted by addition of quercetin or α-tocopherol. Heating of lettuce extract for 10 min at 80 °C did not affect the lag phase and heating of lettuce extract resulted in an increasing synergism for added quercetin and α-tocopherol indicating that thermal inhibition of polyphenoloxidase (PPO) increases antioxidant potential and interaction.     

Color Stability and Microbial Growth Relationships in Beef as Affected by Endogenous α-Tocopherol

Longissimus muscle from Holstein steers supplemented with vitamin E at 500 or 2000 mg/head/day showed less surface metmyoglobin accumulation than controls during 12 days storage at 4°C. Temperature abuse at 25°C for 24 hr increased metmyoglobin formation; vitamin E supplementation diminished the adverse effect of temperature abuse. No differences (P > 0.05) in bacterial load were observed among the 3 vitamin E treatments during storage. Sensory panelists preferred vitamin E-supplemented beef steaks in visual acceptance. Panelist assessment of discoloration correlated highly with a value and hue angle. In general, elevated α-tocopherol concentrations in beef steaks did not affect panelist assessment of meat spoilage.     

Effect of dietary vitamin E supplementation on the shelf life of cured pork sausage

This study examined the shelf life of cured sausage under different packaging conditions from vitamin E supplemented pigs. One group (n=6) of crossbred pigs received a normal fattening diet containing 20 ppm α-tocopherol for 39 days before slaughter. Another group was fed a diet containing 410 ppm α-tocopherol during the same period. After slaughter, cured sausages were produced, packaged under three different atmospheric conditions, ripened for 4 weeks and then stored for 8 weeks (9?°C; 200 lux). The α-tocopherol content was recorded in the fat, liver, muscles and the sausage. TBARS, L*, a*, b* values and antioxidative capacity were evaluated in the sausage during storage. The results showed a transfer of vitamin E into tissues and sausage but no detectable effect on TBARS and colour stability. However, antioxidative effects of vitamin E were seen by provocation. Probably the effect of vitamin E in the sausage was masked by nitrite in the curing salt. The oxygen content of the packs had an influence on TBARS and colour stability.     

Stability in the rumen and effect on plasma status of single oral doses of vitamin D and vitamin E in high-yielding dairy cows

The ruminal fate of the fat-soluble vitamins D and E was studied in dairy cows. Ten to 15 kg of ruminal contents was taken from each cow through a ruminal fistula. A sample was taken out (0-h sample) and the rest of the contents were mixed with 4,360 mg of all-rac-α-tocopheryl acetate (vitamin E; study 1) or 4,360 mg of all-rac-α-tocopheryl acetate, 250 mg of ergocalciferol (vitamin D₂), and 250 mg of cholecalciferol (vitamin D₃; study 2). After mixing, the ruminal contents were returned to the respective cows. Blood was collected 0, 6, 24, and 30 h after introducing the vitamins into the rumen. Samples of ruminal contents were collected at 0, 1, 2, 4, 6, 24, and 30 h (in vivo). From the 1-h sample, 6 subsamples from each cow were incubated at 37°C and taken out at 2, 4, 6, 12, 24, and 30 h (in vitro). In vivo concentrations of added α-tocopherol, ergocalciferol, and cholecalciferol in the rumen first increased and subsequently declined due to dilution effects of eating and passage out of the rumen. The level of the free-alcohol form of α-tocopherol from the natural content in feed was constant throughout the in vivo study, in contrast to the content of total α-tocopherol, which indicated that no hydrolysis of the acetate form into alcohol form happened in the rumen. In vitro, all added vitamins were found at constant levels; hence, none of the added vitamins were degraded in ruminal contents. The concentration of α-tocopherol in plasma increased at a rate per milligram of ruminally introduced α-tocopherol below the rate of the increase in plasma ergocalciferol or cholecalciferol metabolites per milligram of introduced ergocalciferol or cholecalciferol, respectively, over 24 h. In conclusion, ergocalciferol, cholecalciferol, and α-tocopheryl acetate proved to be stable in the rumen and in ruminal contents from high-yielding dairy cows. Changes in plasma concentrations of the vitamins relative to the amount of vitamin introduced to the rumen indicated a lower effect on plasma status of ergocalciferol than of cholecalciferol, and an even lower effect of α-tocopherol. The limited plasma response after a single dose of α-tocopheryl acetate led to the conclusion that oral single dose therapy with all-rac-α-tocopheryl acetate is of limited physiological value.     

多环境大豆种子维生素E含量遗传分析

利用高效液相色谱测定了三个地点的大豆品种合丰25与Bayfield及其衍生的144个重组自交系种子中的维生素E含量,运用主基因＋多基因混合遗传模型,对三个地点的大豆种子的维生素E进行了遗传分析。结果表明：在哈尔滨地区α-生育酚为2对主基因＋多基因遗传模型;γ-生育酚为1对主基因＋多基因遗传模型;δ-生育酚为2对主基因＋多基因遗传模型;在呼兰地区α-生育酚为3对主基因＋多基因遗传模型;γ-生育酚为2对主基因＋多基因遗传模型;δ-生育酚为2对主基因＋多基因遗传模型;在绥化地区α-生育酚为无主基因＋多基因遗传模型;γ-生育酚为3对主基因＋多基因遗传模型;δ-生育酚为2对主基因＋多基因遗传模型。     

Effect of germination and fermentation on the antioxidant vitamin content and antioxidant capacity of Lupinus albus L. var. Multolupa

The present work studies the antioxidant capacity as well as the vitamin C and E contents of raw, fermented and germinated seeds of Lupinus albus L. var. Multolupa. Vitamin C was quantified by micellar electrokinetic capillary electrophoresis and vitamin E isomers by high performance liquid chromatography. The antioxidant capacity was determined by spectrophotometry and expressed as trolox equivalent antioxidant capacity (TEAC) and by liposome methods using phospholipids bilayers. Germination, in general, brought about an increase in the content of α-tocopherol, a decrease in the content of γ-tocopherol and did not affect the content of δ-tocopherol, which resulted in an increment in the vitamin E activity. Vitamin C increased sharply but gradually after germination. Fermentation caused a drastic reduction in the antioxidant vitamin content, vitamin C was not detected and tocopherol isomers decreased significantly. Germination processes caused a significant increase in antioxidant capacity (TEAC) of both hydrophilic and lipophilic extracts and fermentation produced slight changes or total reduction in TEAC, depending on process conditions. The peroxidation of egg yolk phosphatidyl-choline (PC) was inhibited by all lupin extracts in comparison with control assay. Germination was selected as a good treatment to increase antioxidant capacity and vitamin C and E contents.