花生四烯酸、二十二碳六烯酸和二十碳五烯酸 在炎症中的作用概述

心脑血管疾病、肿瘤、糖尿病、神经系统疾病、自身免疫等疾病严重危害着人类的生命和健康,并消耗着大量医疗资源。事实上,很多疾病发生和发展的背后都伴随着炎症反应,炎症是众多疾病的病理基础,甚至是导致这些疾病的诱因。炎症本身是机体的防御性反应,但过度的炎症反应和长期慢性炎症会损害机体的稳态。炎症的调节和控制由炎症介质介导,花生四烯酸(arachidonic acid,AA)、二十二碳六烯酸(docosahexaenoic acid,DHA)和二十碳五烯酸(eicosapentaenoic acid,EPA)等长链多不饱和脂肪酸(10ng-chain polyunsaturated fatty acids,LC-PUFAs)的衍生物是一类重要的调控炎症的介质。炎性细胞间的交流和细胞内信号传递与LC-PUFAs有关。AA经环氧酶和脂氧合酶合成的类二十烷酸主要起促炎作用,但有的也有抗炎作用。DHA和EPA在体内起抗炎作用,由它们合成的消退素(resolvins,Rvs)和保护素(protectin,PD)是重要的抗炎活性物质。DHA和EPA还可以干扰炎性细胞内信号传导途径来抑制炎症反应。本文从炎症与疾病的关系、LC-PUFAs的衍生物及其促炎和抗炎机制等方面综述了AA、DHA和EPA在炎症中的作用。     

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.     

酸水解去除谷氨酸母液中的焦谷氨酸

焦谷氨酸没有鲜味,是谷氨酸产品中的无效成分,其安全性尚无定论.控制谷氨酸浓度为16g/100mL、焦谷氨酸的浓度为3.2g/100mL,试验研究了水解温度、硫酸加入量、水解时间等因素对降低谷氨酸母液中焦谷氨酸含量的影响.在保证谷氨酸回收率的基础上,确定出使焦谷氨酸含量达到1.07％及以下的最优水解组合:水解温度(95±5)℃、浓硫酸加入量30％ (v/v)、水解时间2h.在上述试验中,焦谷氨酸的初始含量均为20％.通过改变初始焦谷氨酸氨酸含量20%～35％,最优水解组合下水解后焦谷氨酸含量为0.96％～1.04％,仍可达到1.07％以下.     

气相色谱法同时快速测定食品中丙酸、山梨酸、苯甲酸及脱氢乙酸

通过液液萃取净化样品研究,建立了食品中丙酸、山梨酸、苯甲酸、脱氢乙酸及其盐含量气相色谱同时快速测定方法,适用于固体非酯(脂)类食品的检测。结果表明:丙酸的回收率在85.1%~91.3%之间,其余3种防腐剂的回收率均在95.2%~99.4%之间;实验室内变异系数(CV,n=6)最大值≤4.7%,4种防腐剂检出限均在0.002 g/kg以下。4种目标物在有杂质干扰时,可用不同的极性毛细管柱做进一步的确认。本方法具有适用范围广、检测效率高、重现性好、准确度高、检出限低的特点,推广应用对我国食品安全的监督检验具有重要的意义。     

Short communication: Eicosatrienoic acid and docosatrienoic acid do not promote vaccenic acid accumulation in mixed ruminal cultures

Previous research found that docosahexaenoic acid (C22:6n-3) was a component of fish oil that promotes trans-C18:1 accumulation in ruminal cultures when incubated with linoleic acid. The objective of this study was to determine if eicosatrienoic acid (C20:3n-3) and docosatrienoic acid (C22:3n-3), n-3 fatty acids in fish oil, promote accumulation of trans-C18:1, vaccenic acid (VA) in particular, using cultures of mixed ruminal microorganisms. Treatments consisted of control, control plus 5 mg of C20:3n-3 (ETA), control plus 5 mg of C22:3n-3 (DTA), control plus 15 mg of linoleic acid (LA), control plus 5 mg of C20:3n-3 and 15 mg of linoleic acid (ETALA), and control plus 5 mg of C22:3n-3 and 15 mg of linoleic acid (DTALA). Treatments were incubated in triplicate in 125-mL flasks, and 5 mL of culture contents was taken at 0 and 24 h for fatty acid analysis by gas-liquid chromatography. After 24 h of incubation, the concentrations of trans-C18:1 (0.87, 0.88, and 0.99 mg/culture), and VA (0.52, 0.56, and 0.62 mg/culture) were similar for the control, ETA, and DTA cultures, respectively. The concentrations of trans-C18:1 (5.51, 5.41, and 5.36 mg/culture), and VA (4.78, 4.62, and 4.59 mg/culture) were also similar between LA, ETALA, and DTALA cultures, respectively. These data suggest that C20:3n-3 and C22:3n-3 are not the active components in fish oil that promote VA accumulation when incubated with linoleic acid.     

杂多酸催化合成辛酸蔗糖酯

以蔗糖、辛酸为原料,杂多酸为催化剂合成辛酸蔗糖酯。用L16(45)正交设计优化实验,高效液相色谱法分析反应液组成。考察了催化剂种类和用量、反应温度、原料配比、反应时间等因素对辛酸蔗糖酯产率的影响,发现以二甲基亚砜为溶剂、蔗糖与辛酸摩尔比1∶9、磷钨酸用量为蔗糖质量的2.0%、110℃反应时间6h,蔗糖转化率达60%,产物产要是二酯。动力学研究发现,蔗糖反应级数为一级,反应表观速率常数为0.0059min-1(90℃)、0.0117min-1(110℃),反应表观活化能Ea=39.57kJ/mol。     

气相色谱法测定鱼油中的二十碳五烯酸、 二十二碳六烯酸和二十二碳五烯酸

目的通过优化鱼油中二十碳五烯酸(eicosapentaenoic acid,EPA)、二十二碳六烯酸(docosahexaenoic acid,DHA)和二十二碳五烯酸(docosapentaenoic acid,DPA)的测定条件,建立鱼油中EPA、DHA和DPA气相色谱定量检测分析方法。方法采用正己烷处理样品,经色谱柱(Agilent,Elite-WAX,30 m×0.25 mm,0.25μm)分离鱼油中的EPA、DHA、DPA甲酯标准品,并进行定量检测。结果 EPA浓度在0.36~3.6 mg/m L、DHA浓度在0.37~3.7 mg/m L、DPA浓度在0.16~1.62 mg/m L的范围内与峰面积的线性良好,相关系数r0.999。在80%、100%、120%添加水平下,EPA、DHA和DPA的检出限分别为0.01%、0.03%、0.009%,EPA、DHA和DPA的回收率分别为96.2%、96.4%、95.7%。结论气相色谱法灵敏度高、准确、重现性好,适用于鱼油中EPA、DHA和DPA的含量测定。     

高效液相色谱法检测贝类中的乳酸和琥珀酸

研究探讨利用高效液相色谱测定贝类中乳酸和琥珀酸的样品处理方法和测定方法,结果显示:与乙醇沉淀法、国标法相比,流动相提取法更适合作为样品的提取方法,在检测条件中,流动相为pH2.5的2.0%NH4H2PO4,流速在1.0mL/min,波长为205nm为最优条件。此方法具有较好的线性、较高的准确度和精密度,加标实验回收率为94.0%～99.9%,相对标准偏差为0.09%～0.14%。也测定了两种贝类中乳酸和琥珀酸的含量。     

生活饮用水中乙二胺四乙酸和次氮基三乙酸含量测定

目的：建立一种生活饮用水中乙二胺四乙酸（EDTA）和次氮基三乙酸（NTA）的高效液相色谱测定方法。方法：样品与三氯化铁络合后,以甲醇和0.2 mmol/L四丁基溴化铵—磷酸缓冲溶液（pH 2.5）为流动相,梯度洗脱后经Thermo-C₁₈（4.6 mm×250 mm）色谱柱分离,DAD检测器检测,外标法定量。结果：EDTA和NTA在0.1～2.0 mg/L质量浓度范围内与色谱峰面积线性关系良好,相关系数分别为0.999 5,0.999 2;两者的检出限为0.05 mg/L,定量限为0.1 mg/L,平均加标回收率为93.5%～111.4%,相对标准偏差（RSD）为3.63%～7.39%。结论：该方法操作简便,重复性好,灵敏度高,具有较好的实用性。     

乳酸菌发酵代谢合成叶酸的影响因素

对嗜酸乳杆菌以及乳酸乳球菌发酵合成叶酸的影响因素进行了研究。结果表明,乳酸菌代谢合成叶酸的产率为17~100μg/L,菌种、培养时间、pH值、对氨基苯甲酸(PABA)质量浓度会影响乳酸菌合成叶酸的产量。与乳酸乳球菌乳酸亚种相比,嗜酸乳杆菌CH-2生成的叶酸产量要高。不同菌株生成叶酸的能力与pH值有关,嗜酸乳杆菌在pH值为4.2叶酸产率明显下降,乳酸乳球菌乳酸亚种产叶酸的能力则不受pH值影响。添加PABA可以显著提高乳酸菌的叶酸产率。选择适宜的乳酸菌菌株,优化发酵工艺参数可以提高乳及相关食品中叶酸的质量浓度,达到生物方式强化叶酸的效果。     

芥酸常压催化氢化制取山嵛酸

报告了以Ｎｉ－Ｃｕ为催化剂常压催化氢化芥酸制取山嵛酸的方法，对催化剂的组成和用量、反应温度、反应时间等条件进行了讨论。产率达８０％，产品纯度超过９７％，催化剂的制备与回收方便，适于工业生产应用     

Short communication: docosahexaenoic acid promotes vaccenic acid accumulation in mixed ruminal cultures when incubated with linoleic acid

Previous studies found that feeding dairy cows a blend of fish and soybean oils enhanced milk vaccenic acid (VA) and conjugated linoleic acid (CLA) concentrations more than when the oils were fed separately. In these studies, the authors concluded that a component in fish oil was stimulating ruminal VA production from other sources of unsaturated fatty acids; however, that component was not identified. The objective of this study was to determine whether docosahexaenoic acid (DHA), an omega-3 fatty acid (FA) in fish oil, is the active component that promotes trans-C18:1 FA, VA in particular, accumulation using cultures of mixed ruminal microorganisms. Treatments consisted of control, control plus 5 mg of DHA (DH), control plus 30 mg of soybean oil (SBO), and control plus 5 mg of DHA and 30 mg of SBO (DHSBO). Treatments were incubated in triplicate in 125-mL flasks, and 5 mL of culture contents was taken at 0 and 24 h for fatty acid analysis by gas-liquid chromatography. After 24 h of incubation, the level of trans-C18:1 FA (14.1 and 11.7 mg/culture) and VA (13.0 and 10.2 mg/culture) increased more with added DHA than with added SBO, respectively. Combining DHA and SBO yielded higher quantities of trans-C18:1 FA (21.3 mg/culture) and VA (19.8 mg/culture) in the cultures than either fat source alone. These data suggest that DHA is the component in fish oil that promotes VA accumulation when incubated with linoleic acid.     

高效液相色谱法同时测定食品中安赛蜜、苯甲酸、山梨酸、糖精钠以及脱氢乙酸

建立食品中安赛蜜、苯甲酸、山梨酸、糖精钠、脱氢乙酸等甜味剂和防腐剂的高效液相色谱测定法。方法采用C18(5um,4.6mm×150mmi.d)反相色谱柱,流动相:v(甲醇)∶v(0.02moL/L乙酸铵溶液)=(5∶95),流速1.0mL/min,检测波长230nm,柱温30℃,进样量5μL。样品的检出限1.5～4.4mg/kg,线性范围1～10mg/L,加标回收率95.5%～103.6%,相对标准偏差为0.95%～2.81%(n=6)。该法具有样品预处理简单,灵敏度高,分析时间短等优点,可用于食品样品的直接测定。     

气相色谱法多重检验海豹油中二十碳五烯酸、 二十二碳五烯酸和二十二碳六烯酸方法研究

目的建立多重检验海豹油中二十碳五烯酸(eicosapentaenoic acid,EPA)、二十二碳五烯酸(docosapentenoic acid,DPA)和二十二碳六烯酸(docosahexaenoic acid,DHA)的气相色谱法。方法用氢氧化钾甲醇溶液将样品中EPA、DPA和DHA甲酯化,气相色谱程序升温同时分析3个ω-3多不饱和脂肪酸,分别用外标法和内标法进行定量。结果 3个ω-3多不饱和脂肪酸的外标法定量线性范围为50~5000μg/m L,相关系数均0.999,精密度相对标准偏差均10%,回收率均90%;内标法定量的精密度相对标准偏差均10%,回收率均85%;外标法和内标法对3个ω-3多不饱和脂肪酸的结果比较,CV%均小于10%。结论该方法操作简单快捷,适用于进口海豹油中EPA、DPA和DHA的含量简便和准确的测定。     

乳酸菌的适酸性调节

探讨了乳酸菌适酸机制有助于抗酸菌株的筛选、发酵过程中工序的优化以及培养基的优化等,进而大大提升发酵产品品质.对质子泵、产碱、细胞膜变化、大分子保护修复以及耐酸调节在内的适酸性调节机制进行了一一阐述.     

榅桲委陵菜酸、熊果酸和齐墩果酸等三萜酸类薄层色谱分离鉴别

目的建立榅桲果实和种子中委陵菜酸、熊果酸和齐墩果酸等三萜酸薄层色谱分离鉴定方法。方法以甲醇为溶剂,超声提取榅桲果实和种子,对展开系统、点样量、薄层板、显色剂等薄层色谱条件进行考察,确定最佳薄层鉴定条件。结果以点样量为4μL,将点于高效硅胶GF254板上的样品点浸入1%碘二氯甲烷溶液中预处理,以甲苯:乙酸乙酯:冰醋酸(体积比:14:4:0.5)为展开剂, 10%硫酸乙醇溶液来显色,在366 nm下观察,委陵菜酸、熊果酸和齐墩果酸被同时检识,分离效果好。结论薄层色谱法分辨率高、操作简便、结果可靠,可用于榅桲属中三萜酸类化合物的分离和鉴别。     

氨基磺酸催化合成脂肪酸丁酯的研究

以氨基磺酸为催化剂,油酸及菜籽油与正丁醇分别进行酯化反应与酯交换反应制备脂肪酸丁酯。并利用气相色谱及红外光谱对产物进行分析及结构表征。考察了醇(正丁醇)油(油酸及菜籽油)摩尔比、催化剂用量、反应温度和反应时间对油酸及菜籽油转化率的影响。结果表明,油酸酯化反应的最佳工艺条件为:醇油摩尔比3∶1,催化剂用量为油酸质量的0.8%,反应温度110℃,反应时间1.5 h,此时油酸转化率达到88.6%,产品收率为83.5%;菜籽油酯交换反应的最佳工艺条件为:醇油摩尔比10∶1,催化剂用量为菜籽油质量的1.0%,反应温度115℃,反应时间2.0 h,此时菜籽油转化率达到85.6%,产品收率为80.1%。     

Absorption of folic acid and ascorbic acid from nutrient comparable beverages

One hundred percent fruit juices can help consumers increase the nutrient content of the diet since these beverages can be naturally rich in micronutrients. Micronutrient-fortified low-calorie beverages are an important alternative to those wishing to minimize their calorie intakes. However, little is known about the bioavailability of nutrients from fortified beverages relative to 100% fruit juices. The present study examined the bioavailability of ascorbic acid (AA) and folic acid (FA) in 100% orange juice (OJ) and a low-calorie beverage fortified with these nutrients. In a within-subjects, cross-over design, 12 adult men consumed a 591 mL serving of OJ, a low-calorie beverage fortified with AA and FA, and 1% low fat milk. Participants were aged 20 to 35 y, with body mass indexes between 20 and 30 kg/m(2). Blood plasma concentrations of AA and serum concentrations of FA were assayed by serial blood draws, made at 30 min intervals for 4.5 h. Blood plasma concentration of AA was significantly greater after ingestion of the fortified beverage compared to after OJ ingestion. However, the bioavailability of AA did not significantly differ from that of OJ. Analyses of FA indicated no significant difference between fortified beverage and OJ. Consumption of both vitamin containing beverages led to higher concentrations of AA and FA than the milk control. This study showed that similar levels of AA and FA bioavailability can be attained through ingestion of 100% OJ and a fortified beverage.     

混合溶剂下油酸臭氧化催化氧化裂解合成壬二酸的工艺研究

油酸、水、壬酸和醋酸的混合体系在0~15℃、强烈搅拌下,再通臭氧至反应完全。再通氧气并使体系逐渐升温至85~100℃,向体系加入Mn(Ac)2和CoCl2做催化剂或用微波加热催化,反应2~3h。使用近沸水萃取反应混合物,水相经冷冻、抽滤、重结晶等工艺后得到壬二酸,油相经减压蒸馏得到副产品壬酸。由于采用的溶剂体系优良和选用的催化剂得当,壬二酸的收率达到70%以上(以油酸计),纯度大于98.4%。     

Production of pyroglutamic acid by thermophilic lactic acid bacteria in hard-cooked mini-cheeses

Pyroglutamic acid is present in high amounts (0.5g/ 100g) in many cheese varieties-and particularly in extensively ripened Italian cheeses such as Grana Padano and Parmigiano Reggiano. An in vivo model system for cooked mini-cheese production and ripening acceleration was set up to demonstrate the ability of thermophilic lactic acid bacteria, used as a starter, to produce pyroglutamic acid (pGlu). In mini-cheeses stored at 38 and 30 degrees C for up to 45 d, all starters tested produced different amounts of pGlu. In descending order of pGlu production, the bacteria analyzed were: Lactobacillus helveticus, Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus, and Lactobacillus delbrueckii subsp. lactis. Evidence for the presence of glutamine to pGlu cyclase activity in lactic acid bacteria was provided. Cell lysates obtained from cultures of L. helveticus, L. delbrueckii subsp. bulgaricus, L. delbrueckii subsp. lactis, and S. thermophilus showed the ability to cyclize glutamine to pGlu, resulting in processing yields from 1.4 to 30.3%, depending on the subspecies. Formation of pGlu from free glutamine appeared to be similar to that observed using a glutamine-glutamine dipeptide substrate. Under the experimental conditions applied, pGlu aminopeptidase activity was only detected in L. helveticus. Thus, pGlu formation in long-ripened cooked cheese may depend on the activity of thermophilic lactic acid bacteria.