维生素E对镰刀菌毒素的解毒作用

维生素E具有广泛的生物学功能,可应用于美容、保健品及食品添加剂.镰刀菌可产生多种真菌毒素,如玉米赤霉烯酮、T-2毒素,对动物和人类产生严重毒害.本文综述了维生素E对镰刀菌毒素的毒素的解毒功能,保护生物体免受其侵害、或者降低毒害作用,及其可能的作用机理.     

维生素E对镰刀菌毒素的解毒作用

维生素E具有广泛的生物学功能,可应用于美容、保健品及食品添加剂.镰刀菌可产生多种真菌毒素,如玉米赤霉烯酮、T-2毒素,对动物和人类产生严重毒害.本文综述了维生素E对镰刀菌毒素的毒素的解毒功能,保护生物体免受其侵害、或者降低毒害作用,及其可能的作用机理.     

天然维生素E的存在及提取

天然维生素E在生理活性及安全性上与合成维生素E相比有其独特的优点,因此当前国内外对于天然维生素E资源的开发利用已引起极大的重视。基于国内天然维生素E的提取和生产尚属空白,而其在食品及医药上的需要量却与日俱增之现状,在调查研究基础上,本文介绍了天然维生素E在植物油脂中的存在及其提取、浓缩精制的方法,以供深入研究。     

维生素E化学修饰的研究进展

维生素E具有显著的抗氧化、消除体内游离基、预防癌症发生、提高机体免疫力等功能.但由于其苯并二氢吡喃母环上的羟基非常活泼,易被氧化生成醌类物质,使生物活性消失.通过对维生素E苯并二氢吡喃母环上的羟基进行化学修饰,使其生物性能得以保护.综述了维生素E化学修饰的研究进展,对维生素E化学修饰的种类、工艺进行了介绍,对维生素E化学修饰的发展前景进行了预测.     

天然D-α-维生素E

天然D－α－维生素E是一种高品质的天然维生素E。本郑重介绍天然维生素E的分类,天然D－α－维生素E与合成维生素的差异以及天然D－α－维生素E先进的制备技术;国内外天然维生素E技术水平的差异;新昌制药厂在研制开发天然D－α－维生素E上所做的工作。     

天然维生素E的分离纯化研究进展

天然维生素E因具有较好的生物活性和食用安全性,在保健品、化妆品和医药行业的应用愈来愈广泛.随着这些行业对天然维生素E的需求量不断增加,如何制备高纯度的天然维生素E逐渐受到人们的关注.本文综述了国内外天然维生素E的分离纯化研究进展.     

天然维生素E琥珀酸酯的制备

维生素E琥珀酸酯有比维生素E更强的化学稳定性,同时其还有抗癌功效,是水溶性维生素E--TPGS的基本原料.介绍了用天然维生素E酯化制备维生素E琥珀酸酯的方法,选用三乙胺作为催化剂制备维生素E琥珀酸酯.通过实验优化后得到优化的工艺条件为(原料50 g):反应时间为4.0 h、琥珀酸酐用量为原料维生素E的150%(W/W)、催化剂用量为5.0 mL、反应温度为55℃.在优化的工艺条件下,维生素E酯化率为93.91%.     

天然维生素E提取工艺研究进展

天然维生素E是一种具有良好生理功能和药理价值的抗氧化剂,具有广阔的开发前景和市场需求。综述了天然维生素E的性质、应用及提取方法,重点介绍了国内外提取天然维生素E的生产工艺,进展情况,对今后开展天然维生素E的进一步深入研究具有一定参考价值。     

抗氧化剂维生素E及其代谢物的毒理损伤

从维生素E及其在抗氧化历程中产生的代谢物的分子结构与功能入手,综述了新近发现的维生素E及其代谢物的毒理损伤,包括与心肌梗塞、高血压及肝硬化等疾病的产生关系密切.因此,在使用抗氧化剂时,应注意:①重新建立一套安全评估方案;②从分子水平更详尽地了解抗氧化剂的动力学变化和分子转化,以此对其利弊作出正确评估;③从生物动力学与生物效果模型中找出最佳食用剂量.     

天然维生素E中PAHs脱除工艺初探

对天然维生素E中PAHs的脱除方法进行了初步探索.考察了脱除溶剂、吸附剂、搅拌时间、搅拌温度、吸附剂加入量以及脱除次数对天然维生素E中PAHs脱除效果的影响,并且考察了吸附剂对天然维生素E含量的影响.实验结果表明,3倍的天然维生素E体积的乙醇溶解天然维生素E(液固比为3 ∶ 1),加入10%的吸附剂2在40℃下搅拌60min对PAHs可以达到较好的脱除效果(对轻质PAHs的脱除率达到98.2%,对重质PAHs的脱除率达到99.6%,对总的PAHs的脱除率达到99.3%),产品中轻质PAHs的残留量为7.5μg/kg,重质PAHs的残留量为6.4μg/kg.而且采用该工艺不影响天然维生素E的含量,脱除PAHs后的天然维生素E具有良好的纯度和收率.     

维生素E乙酸酯的合成及其在卷烟中的应用

以维生素E和乙酸酐为原料,合成了维生素E乙酸酯,经HPLC分析纯度达98%,结构经1HNMR、13CNMR和EI-MS确征。将合成的维生素E乙酸酯添加至卷烟烟丝中,卷烟烟气分析结果表明,维生素E乙酸酯能增加主流烟气中的维生素E;卷烟评吸实验表明,添加维生素E乙酸酯能减少卷烟的刺激,改善卷烟的柔和口味,具有烟气细腻、提高卷烟品质的效果。     

维生素D缺乏对新生儿健康影响的研究进展

维生素D是一种脂溶性维生素,不仅具有抗菌抗炎、免疫调节的作用,还参与了人体多种细胞的增殖、分化、凋亡。维生素D缺乏已成为全球性的公共卫生问题,孕妇维生素D缺乏对母婴二人均有直接影响,是新生儿健康的危险因素之一。本文主要综述了维生素D的代谢及生理功能、影响新生儿维生素D水平的因素、维生素D缺乏与新生儿疾病的关系、维生素D水平评价标准、维生素Ｄ的推荐剂量及膳食补充。以期达到提高孕妇补充维生素D的意识的目的,为提高我国新生儿生存质量提供保障,同时为新生儿相关疾病的预防和治疗提供新思路。     

维生素E改善畜禽肉质的研究综述

维生素E具有抗氧化功能,能改善畜禽肉的品质.综述了维生素E的抗氧化机理及其在改善畜禽肉质方面的应用.     

The relationship between oxidative damage and vitamin E concentration in blood, milk, and liver tissue from vitamin E supplemented and nonsupplemented periparturient heifers

This study investigated the relationship between oxidative damage and the effect of vitamin E supplementation in blood, milk, and liver tissue in 16 periparturient heifers. The question is whether measurements of oxidative and vitamin E status in blood of a periparturient cow are representative of the total body, given that blood concentrations of both vitamin E and oxidative stress products change around this period. The daily vitamin E intake of the vitamin E-supplemented Holstein-Friesian heifers (n = 8) was 3,000 international units and was started 2 mo before calving; the control heifers (n = 8) were not supplemented. Oxidative damage was determined on the basis of malondialdehyde (MDA) concentrations. Blood was sampled 9 times before calving, on calving day, and twice after calving. Liver biopsies were taken at wk −5, −1, and 2 relative to calving day. Milk was obtained from all heifers immediately after calving, the first 2 milkings and on d 3, 7, and 14 at 0600 h. Serum and liver tissue were analyzed for vitamin E, cholesterol, and MDA; and milk samples were analyzed for vitamin E, MDA, fat, protein, and somatic cell count. The results showed that vitamin E supplements increased both absolute vitamin E concentrations and the ratio of vitamin E to cholesterol in blood and liver tissue. Absolute vitamin E concentration in milk tended to be greater in supplemented cows. Based on the increased MDA blood concentrations at calving, it seems that dairy heifers experience oxidative stress. The effect of vitamin E on MDA differs between the blood, liver, and mammary gland. Vitamin E supplementation could not prevent the increase in blood MDA at calving, but the significantly lower MDA blood concentrations of supplemented cows in the 2 wk after calving suggest that vitamin E has a role in recovery from parturition-related oxidative stress. Vitamin E supplementation reduced oxidative damage in liver, whereas no obvious effect was found on milk MDA concentrations. A strong relationship was found between blood and liver vitamin E and the ratio of vitamin E to cholesterol. Concentrations of MDA in blood and milk were also strongly related. The results show that the relationship between oxidative damage and vitamin E differs within blood, liver tissue, and milk. This implies that oxidative and vitamin E status calculated on the basis of blood values alone should be interpreted with caution and cannot be extrapolated to the whole animal.     

维生素E的研究新进展

维生素E是人体必需的维生素之一。本文介绍了维生素E的由来,类型,结构及理化性质,概述了维生素的生理机能,综述了维生素素E的提取,制备工艺及其新进展,并对维生素E的研究开发前景作了展望。     

钙和磷对小麦胚芽愈伤组织维生素E积累的影响

考查培养基中钙元素和磷元素的含量对小麦胚芽愈伤组织维生素E积累的影响,建立维生素E积累和细胞生长的动力学模型.以次生代谢产物维生素E积累最多为目标,通过实验优化确定钙磷含量的最佳组合.结果表明,当B5培养基中CaCl_2·2H_2O为150mg/L,NaH_2PO_4·H_2O为300mg/L时,有利于维生素E积累.维生素E积累的动力学模型的拟合度为97.96%,细胞干重的动力学模型拟合度为95.57%,非线性关系良好.大量元素钙和磷对小麦胚芽愈伤组织维生素E积累有影响,磷元素较钙元素的影响显著.     

In Vitro Binding of Vitamin E to Selected Dietary Fiber Sources

An in vitro method was used to assess interaction between whole fiber (WF) sources and vitamin E under simulated physiological conditions (pH 2, pH 7, pH 2–7; bile salt 5–15 mM; 37°C). Dose-response and binding characteristics (via Scatchard analysis) were examined. Binding of vitamin E by lupin and gum were higher (p≤0.05) at pH 2 and pH 7 than at the sequential treatment. Oat bran, treated at pH 7 or sequentially, showed increased (p≤0.05) binding of vitamin E as fiber level increased (25 - 100 mg). Scatchard plots revealed two specific noninteracting binding sites for sugarbeet and barley bran. Affinities (K_d) and capacities (n) were compared among fibers. Affinities for vitamin E were: sugarbeet>oat>lupin>barley>gum. Capacities were: barley > gum > lupin > sugarbeet > oat. Vitamin E binding to DF is complex, multifactorial, and not due to a single mechanism.     

Chemical reactivities and physical effects in comparison between tocopherols and tocotrienols: physiological significance and prospects as antioxidants

Vitamin E is a generic term for all tocopherol and tocotrienol derivatives. The most abundant and active form of vitamin E isoforms in vivo is alpha-tocopherol, but recently the roles of other forms of vitamin E have received renewed attention. In this review, we summarize the differences among alpha-, beta-, gamma-, delta-tocopherols and tocotrienols specifically regarding the following points; (i) their radical-scavenging efficacies and chemical reactivity with metal ions in solution, (ii) their physical effects at the liposomal membrane interior, and (iii) their protective effects against cell toxicity. Moreover, the physiological significance and future prospects for using vitamin E, especially tocotrienols, for the prevention and treatment of disease are discussed.     

Display Life and Internal Cooked Color of Ground Beef from Vitamin E-Supplemented Steers

The retail display life of fresh ground meat and the internal color of patties cooked to four endpoint temperatures (55, 65, 71, and 77°C) were determined for ground beef (10% fat) from vitamin E-supplemented (500 and 2000 IU) or nonsupplemented steers. Vitamin E supplementation increased (P < 0.05) the retail dissolve life of the meat by 12 and 42 lir for 500 and 2000 IU, respectively Vitamin E did not akect (P > 0.05) internal cooked color or expressible juice color of the patties, and it did not cause premature browning or persistent redness. Increased levels of vitamin E supplementation decreased (P < 0.05) TBA values but had no effect on total reducing activity or oxidation-reduction potential.     

婴幼儿配方乳粉中维生素A、E检测方法的比较研究

目的 以国家标准GB5009.82-2016第一法(GB方法)和AOAC 2012.10/ ISO20633:2015 (AOAC/ISO方法)为例,通过文本分析和实验数据比较反相液相色谱法(RF-HPLC)和正向液相色谱法(NP-HPLC)检测婴幼儿配方粉中维生素A和维生素E的差异,分析可能导致方法结果产生差异的原因,提出科学建议。方法 通过标准方法文本原理比对,分析两种方法的原理及技术步骤差异;通过质控样检测,分析两组结果的标准偏差、变异系数、95%重复性限、相对重复性限值、平均值、回收率等指标,比对两种方法的精密度和准确度差异;通过市售样品检测,分析两种方法检测结果的系统偏差和比例偏差,判别两种方法对婴幼儿配方乳粉的结果一致性。结果 从方法文本上看,AOAC/ISO方法较 GB方法的步骤更为简便,且标明了方法的适用浓度范围、重复性、重现性等关键指标,标注的检出限及定量限值也较GB方法更低;精密度方面,采用AOAC/ISO方法测得的重复性和重现性标准偏差、变异系数、95%重复性限、相对重复性限值结果,均低于GB方法测得的同类指标。准确度方面,AOAC/ISO方法和GB方法测定维生素AE时均表现出较好的回收率(100±5%);样品对比检测结果表明,维生素A两种方法的检测结果不存在系统偏差和比例偏差,结果一致;维生素E两种方法的结果既有系统偏差也有比例偏差,结果不一致。结论 AOAC/ISO 方法和GB方法原理及操作步骤存在明显不同,可能导致两种方法在测定维生素E含量时,结果呈现统计学显著差异。建议加强国内外检测标准的沟通协调,在检测目标物,样品称量方式,样品适用浓度范围等方面做进一步改进和完善。