新型食品营养强化剂-共轭亚油酸

共轭亚油酸 (Conjgatedlinoleicacid ,CLA)是一类含有共轭双键的亚油酸的异构体 ,由于具有特殊的脂肪链结构使得其具有多种生理功能。c9t11和t10cl2异构体是共轭亚油酸的主要活性异构体。本文对共轭亚油酸的生理功能、代谢、安全性等进行综述。     

共轭亚油酸异构体生理功能的差异

介绍了共轭亚油酸不同异构体在降低机体脂肪积累、抗肿瘤、抗动脉粥样硬化以及免疫调节方面的研究,讨论了不同共轭亚油酸异构体,尤其是顺9,反11-共轭亚油酸(c9,t11-CLA)和反10,顺12-共轭亚油酸(t10,c12-CLA)在生理功能上的差异,以期更有效地利用不同CLA异构体实现特有的生理功能。     

共轭亚油酸生理功能及其合成方法

共轭亚油酸（CLA）为亚油酸（LA）的异构体,具有抗癌、降脂、调节免疫、抗粥样硬化等重要的生理功能,目前共轭亚油酸（CLA）的生产大都是利用碱催化亚油酸异构而成,但其异构体繁多。利用微生物转化生产的共轭亚油酸（CLA）,异构体较少,与天然食品中的CLA异构体组成相似,具有很好的商业前景。     

共轭亚油酸的结构与性质

该文系统地介绍和评述了共轭亚油酸结构和性质。共轭亚油酸与亚油酸不仅在空间结构上不同，而且在理化性质和生理功能等方面也具有显著区别。共轭亚油酸经肠粘膜吸收渗入到血脂、细胞膜及脂肪组织，或者经过代谢进一步合成一系列活性物质而发挥重要生理功能。     

共轭亚油酸对畜禽肌肉品质影响的研究进展

共轭亚油酸(Conjugated linoleic acid,CLA)是亚油酸的一组构象和位置异构体。它作为一种新型功能性脂肪酸,具有许多重要的生理功能,其中调节机体脂肪代谢,降低脂质沉积的功效尤为显著。目前国内外研究人员利用此生物活性在动物饲养方面的研究也日益广泛。文章简要介绍了共轭亚油酸的结构、活性及降脂机制。重点结合近年来国内外在共轭亚油酸和畜禽饲养方面的相关研究报道,从畜禽肌肉品质的主要影响因素展开,综述了共轭亚油酸对畜禽肌肉品质和风味的影响。     

共轭亚油酸的生理功能（Ⅱ）

共轭亚油酸是亚油酸的立体和位置异构体的混合物。动物实验表明,共轭亚油酸是一种很强的抗癌物质,具有抗动脉粥样化形成、抗糖尿病、抗过敏、调节免疫、促进生长、降低身体脂肪并增加瘦肉量及影响骨骼形成等生理功能。     

新型功能性油脂-共轭亚油酸

共轭亚油酸是天然存在于食品中的亚油酸异构体,具有抑制癌症和肿瘤的形成、减肥、抗动脉粥样硬化、改善免疫功能、降低胆固醇、促进生长等多种功能,是一种新型功能性油脂。本文综述了共轭亚油酸的生理功能、来源、合成及纯化方面的研究进展。     

气相色谱-质谱联用法分析苏尼特羔羊肉中共轭亚油酸含量

共轭亚油酸是亚油酸的一组几何和位置异构体，具有多种生理功能。作为瘤胃微生物的产物，反刍动物肉制品是共轭亚油酸异构体较丰富的天然来源，本研究利用气相色谱-质谱联用法分离测定了5月龄苏尼特羔羊肌肉和腹部脂肪中共轭亚油酸总含量，研究结果表明，背最长肌间脂肪中CLA相对百分含量平均为0．83％，腹部脂肪中CLA相对百分含量平均为0．99％。     

共轭亚油酸的生理功能综述

共轭亚油酸(conjugated linoleic acid,CLA)是一类含有共轭双键十八碳二烯酸异构体混合物的统称,以异构体c9, t11-CLA和t10, c12-CLA的研究最为集中,广泛应用于保健品、功能食品及食品添加剂等领域。本文综述了CLA的生理功能及抗病机制的国内外研究进展,通过全面了解共轭亚油酸的生理功能及抗病机制,有助于更科学、更准确地进行研究,对相关保健产品的开发具有一定的意义。     

共轭亚油酸的功能性质及其应用前景

为了让共轭亚油酸在食品工业中被更广泛的应用,系统地介绍和评述了共轭亚油酸的分布及来源、光谱特征、层析、氧化稳定性、抗氧化性、吸收、代谢、转化及安全性,同时介绍了共轭亚油酸在食品工业中的应用前景。共轭亚油酸与亚油酸不仅在空间结构上不同,而且在理化性质和生理功能等方面也具有显著区别,共轭亚油酸经肠粘膜吸收渗入到血脂、细胞膜及脂肪组织,或者经过代谢进一步合成一系列活性物质而发挥重要的生理功能。     

共轭亚油酸的合成

共轭亚油酸(CLA)是亚油酸(LA)的同分异构体,是一种非常重要的功能性油脂,在医药保健、食品工业、饲料等方面的应用有着广阔的应用前景.从CLA的生产方法着手,重点描述了传统CLA的制备方法-化学异构化法、羟基脂肪酸脱水法,生物合成法和光异构化法.并对这些方法的研究手段、国内外研究水平、存在的问题、解决措施、优缺点和应用前景进行了介绍.尤其是生物合成法,由于其产物选择性高、异构体种类少、培养易于控制等,具有很好的商业应用前景.     

共轭亚油酸生物合成及其对肠道菌群影响的研究进展

共轭亚油酸(CLA)是一种人和动物自身无法合成但又不可缺少的脂肪酸,它具有抗癌、抗肥胖、抗动脉粥样硬化、抗糖尿病等潜在生理功能,被广泛用作食品营养补充剂。由于天然CLA来源较少、化学合成副产物较多,而利用乳酸菌生物合成的CLA结构单一且转化效率高,是一种有前景的合成方法。目前微生物将亚油酸(LA)转化为CLA的机制主要有2种,即以瘤胃微生物为主的生物氢化合成和乳酸菌为代表的多酶系合成。现有研究表明,CLA具有调节肠道菌群的作用,并指出其潜在生理功能可能与其对肠道微生态的影响密切相关。文章总结了CLA生物合成和影响因素,分析了CLA的生物合成机制以及其对肠道菌群的调节作用,为进一步筛选出高产CLA菌株和CLA的产业化应用提供理论依据。     

Advances in Research on cis-9, trans-11 Conjugated Linoleic Acid: A Major Functional Conjugated Linoleic Acid Isomer

Conjugated linoleic acid (CLA) consists of a group of positional and geometric conjugated isomers of linoleic acid. Since the identification of CLA as a factor that can inhibit mutagenesis and carcinogenesis, thousands of studies have been conducted in the last several decades. Among the many isomers discovered, cis-9, trans-11 CLA is the most intensively studied because of its multiple, isomer-specific effects in humans and animals. This paper provides an overview of the available data on cis-9, trans-11 CLA, including its isomer-specific effects, biosynthesis, in vivo/in vitro research models, quantification, and the factors influencing its content in ruminant products.     

Optimisation of fermentation variables for conjugated linoleic acid bioconversion by Lactobacillus fermentum DDHI27 in modified skim milk

Effects of fermentation variables on conjugated linoleic acids (CLAs) biosynthesis of Lactobacillus fermentum DDHI27 in modified skim milk were evaluated. A total of 0.5 mg/mL was found to be the optimum linoleic acid concentration for maximum CLA production and this level was used in utilised for all successive experiments. The highest production of CLA isomers was detected at pH 6.0 when compared to other pH levels. Maximum biosynthesis of CLA isomers occurred during stationary growth (48 h) phase at all pH values tested. Validation of CLA isomers produced in selected samples was made by GC‐MS. These results indicate that these parameters strongly influence the CLA production capabilities of the strain.     

Systematic evaluation on the effectiveness of conjugated linoleic acid in human health

The term CLA (conjugated linoleic acid) corresponds to a mixture of positional and geometric isomers of linoleic acid. Two of these isomers (9c, 11t and 10t, 12c) have biological activity. The milk and dairy products are the most abundant source of conjugated linoleic acid, which refers to a group of positional and geometric isomers of CLA (CLA 18:2 cis-9, cis-12). The following research aims to approach aspects regarding the CLA, as well as its relationship with diseases. Conjugated linoleic acids have been studied for their beneficial effects in the prevention and treatment of many diseases, including obesity, cancer, diabetes, and cardiovascular diseases. Scientific information put together the physiological properties of CLA, which serves as inputs to claim their potential as functional ingredients to be used in the prevention and control of several chronic metabolic disorders.     

牛乳中共轭亚油酸（CLA）的研究

共轭亚油酸（CLA）是亚油酸的同分异构体的混合物,主要来源于牛乳、乳制品及反刍物食品的天然成分。本文就CLA的抑癌和降血脂等多种生理功能及其作用机理,阐述了CAL作为一种新型营养物质的潜力。     

Use of conjugated linoleic acid (CLA) enrichments to examine the effects of trans-8, cis-10 CLA, and cis-11, trans-13 CLA on milk-fat synthesis

Conjugated linoleic acid (CLA) supplements have typically been comprised of 4 isomers (trans-8, cis-10; cis-9, trans-11; trans-10, cis-12; and cis-11, trans-13 CLA). Abomasal infusion of pure isomers has shown that trans-10, cis-12 CLA is a potent inhibitor of milk-fat synthesis, whereas cis-9, trans-11 CLA has no effect. However, there appear to be additional fatty acids that inhibit milk-fat synthesis, and the objective of this study was to investigate the effects of additional CLA isomers present in CLA supplements. Four rumen fistulated Holstein cows (141+/-8 DIM, mean+/-SE) were randomly assigned in a 4 x 4 Latin square experiment. Treatments were abomasal infusion of (1) skim milk (negative control), (2) trans-10, cis-12 CLA supplement (positive control), (3) trans-8, cis-10 CLA supplement, and (4) cis-11, trans-13 CLA supplement. Treatments 2 through 4 were targeted to provide 4 g/d of the CLA isomer of interest. The trans-8, cis-10 CLA supplement had no effect on milk-fat yield, whereas the trans-10, cis-12 CLA supplement reduced milk-fat yield by 35%. The cis-11, trans-13 CLA supplement contained some trans-10, cis-12 CLA, and when data were compared to the positive control treatment group, it was obvious that cis-11, trans-13 CLA also had no effect on milk-fat synthesis. Milk-fat content of specific CLA isomers was significantly elevated within respective treatment groups. Milk yield, DMI, and milk protein yield were unaffected by treatment. Overall, trans-10, cis-12 CLA reduced milk-fat synthesis, whereas the other major isomers present in CLA supplements (trans-8, cis-10 CLA and cis-11, trans-13 CLA) had no effect.     

生物合成共轭亚油酸菌种的筛选与鉴定

从传统泡菜和生牛乳中筛选出一株乳酸菌ZS2058能生物合成共轭亚油酸,经API系统鉴定为植物乳杆菌(Lactobacillusplantarum).该菌株在MRS培养基中将质量分数11.6%的亚油酸(1.024mg/mL)转化为共轭亚油酸,经气相色谱分析证实c9,t11 18∶2占75.9%,t10,c12 18∶2占24.1%.     

Conjugated linoleic acid intake in humans: a systematic review focusing on its effect on body composition, glucose, and lipid metabolism

Studies performed on different species show that the consumption of conjugated linoleic acid (CLA) leads to a loss of fat and total body weight, reduces the plasma concentrations of total and LDL cholesterol, and has an antiinflammatory effect. This article reviews the clinical trials on human beings that evaluate how mixtures of CLA isomers administered as supplements or CLA-enriched products can affect total body weight, body composition, plasma lipid profile, glycemia, insulinemia, insulin sensitivity, lipid oxidation, and inflammation. After analyzing the few studies published to date in reduced samples of healthy humans or patients with overweight, obesity, metabolic syndrome, or diabetes, we deduce that there is not enough evidence to show that conjugated linoleic acid has an effect on weight and body composition in humans. However, some of these studies have observed that the administration of various CLA isomers has adverse effects on lipid profile (it decreases HDL cholesterol concentration and increases Lp(a) circulating levels), glucose metabolism (glycemia, insulinemia or insulin sensitivity), lipid oxidation, inflammation, or endothelial function. Therefore, long-term randomized clinical trials, controlled with placebo, need to be made in large samples of patients to evaluate the efficacy and safety of CLA isomers before its indiscriminate use in human beings can be recommended.