甜橙油多重乳状液的稳定性研究

多重乳状液的稳定性是影响多重乳化香精效果的主要因素,它决定于体系中不同参数的影响.以多重乳状液相对体积为衡量标准,借助显微镜直接观察,探讨乳化剂的含量、乳化剂的HLB值、亲油亲水乳化剂体积比及油水相比等因素对甜橙油多重乳状液体系稳定性的影响.     

不同乳化剂对油酸和亚油酸乳状液稳定性的影响

本文以粒径、稳定性和流变为考察指标,利用激光粒度仪、食品稳定性分析仪、流变仪等研究不同种类和添加量的食品乳化剂(阿拉伯胶、酪蛋白酸钠、吐温20)对不饱和脂肪酸(油酸和亚油酸)乳状液的制备及其稳定性的影响。结果表明,三种乳化剂均可制备出稳定性较好的乳状液,不同乳化剂的质量分数不同得到乳状液的稳定性不同。较高质量分数的阿拉伯胶(4%,w/v)乳状液,具有最低的澄清指数并且具有最大粘度(0.30~0.40 Pa·s)。当酪蛋白酸钠的质量分数为2%时,制备出的乳状液较稳定,但粒径较大,贮藏稳定性较差。较低质量分数的吐温20(1%,w/v)的乳状液具有最小粒径(0.20~0.21 μm),经过贮藏后变化程度也最小。本文研究了不同食品乳化剂制备的不饱和脂肪酸乳状液及其稳定性,可为不饱和脂肪酸乳状液的制备和应用提供参考。     

核桃油多重乳状液的制备及稳定性研究

以多重乳状液相对体积为衡量标准,借助显微镜直接观察,探讨第一相乳化剂含量、第一相质量分数、亲油亲水乳化剂质量比、体系乳化剂的含量等因素对核桃油多重乳状液体系稳定性的影响,并通过正交试验设计优化了乳化工艺。结果表明,第一相质量分数55％,亲油亲水乳化剂质量比7：1,乳化剂含量11％,第一相核桃油含量66％,体系稳定性最好,相对体积分数达到92．5％。同时,核桃油过氧化值的测量表明,核桃油在多重乳状液中的氧化稳定性较好,并与乳状液体系本身的稳定性相关。     

共轭亚油酸酯类的氧化稳定性研究

本文研究了共轭亚油酸乙酯和共轭亚油酸三甘酯的氧化稳定性,并与富含不饱和脂肪酸的红花籽油比较,探讨了变价金属离子和抗氧化剂对共轭亚油酸乙酯和共轭亚油酸三甘酯的氧化稳定性的影响。结果表明共轭亚油酸三甘酯的氧化稳定性优于共轭亚油酸乙酯的氧化稳定性;加入0.02%VE可明显提高它们的氧化稳定性,而0.02%三氯化铁则减弱了它们的氧化稳定性;VC在共轭亚油酸酯类的油状体系中对抗氧化剂维生素E没有增效作用。     

共轭亚油酸氧化稳定性及其影响因素的研究

研究了共轭亚油酸的氧化稳定性及其主要影响因素。共轭亚油酸氧化稳定性低于相应的油脂。变价金属离子（Fe∧3 能够促进共轭亚油酸氧化。考察了几种抗氧化剂对共轭亚油酸的抗氧化性能,BHT、BHA BHT（1：1）对共轭亚油酸的抗氧化效果优于实验的其他抗氧化剂,添加抗氧化剂可是明显改善共轭亚油酸的氧化稳定性。     

共轭亚油酸微胶囊制备工艺技术研究

共轭亚油酸作为拥有多种有益生理功能的可添加健康油,为解决其易氧化、难保存、有异味的缺点。以共轭亚油酸为芯材,利用喷雾干燥技术,制备共轭亚油酸微胶囊。本实验以制备30%共轭亚油酸含量的微胶囊为研究目的,探究了不同乳化剂、壁材及配比,对共轭亚油酸的包埋效果,通过扫描电子显微镜对微胶囊的微观形貌进行表征,并对微胶囊的各项指标进行检测。结果表明：最佳工艺条件为采用蔗糖酯为乳化剂,乳液固形物含量为30%,均质压力30MPa,均质时间2min,淀粉∶麦芽糊精∶辛烯基琥珀酸淀粉钠=5∶5∶2。     

共轭亚油酸氧化稳定性及其抗氧化性的研究

对由红花籽油制取的共轭亚油酸(CLA)和红花籽油组成脂肪酸(SFA)进行氧化稳定性比较。过氧化值和硫代巴比妥酸反应物的测定结果表明，在实验条件下，CLA的氧化稳定性高于SFA，但CLA并不是一种抗氧化剂。米糠油对于CLA的抗氧化效果与BHT相似。     

共轭亚油酸乙酯微乳液的制备及其氧化稳定性的研究

以二辛基琥珀酸磺酸钠（AOT）为表面活性剂,短链醇乙醇、正丙醇、正丁醇为助表面活性剂,对共轭亚油酸乙酯进行了微乳化实验。结果表明,使用不同结构的醇做助表面活性剂会影响微乳液形成的类型,而不同的Km值（表面活性剂/助表面活性剂）只影响所形成微乳液的面积。比较了共轭亚油酸乙酯和共轭亚油酸乙酯微乳液的氧化稳定性,结果证明微乳液的抗氧化能力更好,向其中增溶进0.1%的VC和0.1%的VE将大大提升产品的氧化稳定性。     

葵花籽油制备共轭亚油酸的研究

葵花籽油是为数不多的高含亚油酸的油脂之一,是很好的生产共轭亚油酸的原料。探讨了反应时间、加碱量等对葵花籽油制备共轭亚油酸共轭化转化率的影响。通过正交试验,确定了最佳试验条件,获得了90%以上的共轭化转化率。     

多重乳状液的稳定性及其在食品工业中的应用

综述了影响多重乳状液稳定性的各种因素，如乳化剂、油水相比、粘度、渗透压、电解质和乳化工艺等。介绍了多重乳状液在食品工业中的应用，主要包括脂肪替代品、乳化液膜、香精香料的缓释和微胶囊技术方面，并指出了其发展前景。     

Spray-drying microencapsulation and oxidative stability of conjugated linoleic acid

Conjugated linoleic acid (CLA) as the free acid was microencapsulated using whey protein concentrate (WPC) as a wall material. An emulsion of CLA was prepared using an emulsifier formulated with a 1:4 (w/w) ratio of a 30% WPC solution and was spray-dried with a laboratory unit. Microcapsules were stored at 35 and 45 °C at different water activities. Oxidation was monitored by measuring the CLA concentration, and peroxide, anisidine and total oxidation values. The encapsulation efficiency was 89.60% with a surface oil concentration of 1.77 g/100 g of sample. Microcapsules stored at a_w=0.743–0.898 had very good stability against oxidation for at least 60 days; therefore WPC is considered as an effective microencapsulating agent.     

π-Complex formation of conjugated linoleic acid with iron

Conjugated linoleic acid (CLA) is known to have several beneficial biological effects in animal models, including anticarcinogenic and antiatherosclerotic effects, antiobesity, and antioxidant activity. However, reports of its antioxidant activities have been inconsistent. In this study, we investigated the possible occurrence of π-bonding between CLA and iron. CLA methyl ester was reacted with triiron dodecacarbonyl and confirmed to form π-complexes with iron tricarbonyl. This study may suggest the possible involvement of CLA in oxidation by way of interacting with iron.     

微生物生产共轭亚油酸的研究进展

共轭亚油酸（CLA）是一种具有多种生理活性的天然脂肪酸,具有抗癌、抗粥状动脉硬化、提高机体免疫力等作用.就CLA的微生物合成、分析方法等方面,对国内外的研究进行了综述.乳酸菌、丙酸菌及丁酸弧菌可以特异性地转化合成CLA,气相色谱法能够对CLA的各种异构体进行分析.     

Anti-obesity effects of conjugated linoleic acid, docosahexaenoic acid, and eicosapentaenoic acid

Obesity has become a prevailing epidemic throughout the globe. Effective therapies for obesity become attracting. Food components with beneficial effects on "weight loss" have caught increasing attentions. Conjugated linoleic acid (CLA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) belong to different families of polyunsaturated fatty acids (PUFA). However, they have similar effects on alleviating obesity and/or preventing from obesity. They influence the balance between energy intake and expenditure; and reduce body weight and/or fat deposition in animal models, but show little effect in healthy human subjects. They inhibit key enzymes responsible for lipid synthesis, such as fatty acid synthase and stearoyl-CoA desaturase-1, enhance lipid oxidation and thermogenesis, and prevent free fatty acids from entering adipocytes for lipogenesis. PUFA also exert suppressive effects on several key factors involved in adipocyte differentiation and fat storage. Despite their similar effects and shared mechanisms, they display differences in the regulation of lipid metabolism. Moreover, DHA and EPA exhibit "anti-obesity" effect as well as improving insulin sensitivity, while CLA induces insulin resistance and fatty liver in most cases. A deeper and more detailed investigation into the complex network of anti-obesity regulatory pathways by different PUFA will improve our understanding of the mechanisms of body weight control and reduce the prevalence of obesity.     

Preparation and properties of probiotic cheese high in conjugated linoleic acid content

The development of probiotic Ras cheese rich in conjugated linoleic acid (CLA) was investigated using probiotic Lactobacillus casei and Lactobacillus acidophilus starters. The cheeses were assessed for composition, proteolysis, fatty acids and fat stability, and microbiology during 3 months of ripening. The cheese made with Lb. casei and Lb. acidophilus retained high counts of the probiotic strains (～log 8) throughout storage. Ripening changes followed the normal pattern of this type of cheese during ripening. Ras cheese made with Lb. casei and Lb. acidophilus contained the highest CLA content (0.84% after 3 months) as compared to control and cheese fat had acceptable oxidative stability.     

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.     

植物乳杆菌转化合成共轭亚油酸的培养基条件优化

生物法转化合成共轭亚油酸,产物中异构体组成单一,具有很好的应用前景。通过一株植物乳杆菌(Lactobacillus plantarum)合成共轭亚油酸的培养基成分进行优化,确定最优的培养基组成:葡萄糖20g/L,酵母浸出物40g/L,硫酸镁0.5g/L,硫酸锰0.5g/L,乙酸钠2g/L,磷酸氢二钾1g/L。优化后,共轭亚油酸产量达到0.259g/L,相比优化前(0.0455g/L)有了较大的提升。      

Influence of sodium glycocholate on production of conjugated linoleic acid by cells of Lactobacillus reuteri ATCC 55739

ABSTRACT:  The possible influence of a bile salt on production of conjugated linoleic acid (CLA) by Lactobacillus reuteri ATCC 55739 was evaluated. Cells of the lactobacilli grown in MRS broth with and without linoleic acid (LA, 0.2%) were harvested and washed. The washed cells were added to buffer containing 0.2% LA and incubated 18 h at 37 °C. The cells, which had been grown without LA, transformed LA into CLA (mainly c9t11-C18:2) better than did those cells grown with it. When sodium glycocholate (0.3%) was added to the washed cell suspensions, about the same level of CLA was formed as in its absence regardless of whether or not the cells had been grown in broth supplemented with free LA. Thus, glycocholate that occurs in humans did not influence production of CLA by resting cells of the lactobacilli.     

一株植物乳杆菌转化生成共轭亚油酸的特性研究

报道了一株植物乳杆菌(L.plantarumLT2-6)发酵转化亚油酸(LA)生成共轭亚油酸(CLA)的特性研究。微氧环境有利于CLA的生成;温度为37℃、初始pH为7.0、底物LA浓度为0.075%时,菌体生长及CLA生成量较高。时间曲线结果表明,接种后8h,CLA开始生成;发酵24h时,CLA生成量达到最高(0.29g/L),LA转化率为387%。生成的CLA产物主要为cis9,trans11/trans9,cis11-CLA。