呋喃脂肪酸的来源与功能研究进展

呋喃脂肪酸是一组以呋喃环为主体的特殊脂肪酸,多存在于微生物、植物及鱼类中。研究表明,呋喃脂肪酸可以有效地清除活性氧自由基,并且减缓氧化胁迫诱导的损伤。然而,呋喃脂肪酸代谢产物3-羧基-4-甲基-5-丙基-2-呋喃丙酸对糖尿病及慢性肾病病情进展的作用仍存在争议。进一步深入研究呋喃脂肪酸的结构与生理功能,是目前呋喃脂肪酸研究的重要方向。对呋喃脂肪酸的来源、合成代谢及对人体的生理效应研究进展进行综述,为呋喃脂肪酸及其产物的后续研究提供参考。     

多不饱和脂肪酸对大鼠大脑细胞膜脂肪酸组成的影响

研究多不饱和脂肪酸(PUFAs)对发育期大鼠大脑细胞膜脂肪酸类别与含量的变化。将56只初断乳雄性SD大鼠随机分为阴性组、必需脂肪酸(EFA)缺乏组、鱼油组[300mg/(kg·d)]、紫苏组[2.45mL/(kg·d)]、α-亚油酸组[1.32g/(kg·d)]、核桃组[2.45mL/(kg·d)]与红花组[1.65g/(kg·d)]。连续饲养8周,提取大脑组织总细胞膜,并使用气相色谱-质谱联用技术检测其脂肪酸的种类与含量。结果表明,各组大鼠脂肪酸组成无差别;与阴性组比较,各组均能显著提高n-3PUFAs的含量;紫苏组、核桃组和红花组能显著降低n-6PUFAs的含量,增加饱和脂肪酸的含量;紫苏组、核桃组、红花组和鱼油组能显著降低单不饱和脂肪酸的含量。说明PUFAs能改变大鼠大脑细胞膜的含量,但对其类别影响不大;短期缺乏EFA对细胞膜脂肪酸的类别与含量无影响。     

饲喂不同配比油脂饲料对肉鸡肉品质及肌肉中脂肪酸组成的影响

研究日粮中添加不同配比油脂对肉鸡肉品质、肌肉胆固醇含量及脂肪酸组成的影响。选取648只1日龄AA肉鸡,随机分成6组,CON为对照组(饲喂基础日粮),SO为正对照组(日粮中添加豆油),LO为负对照组(日粮中添加猪油),COP、COC、COV组分别在日粮中添加以棕榈油为主的配比油脂、以椰子油为主的配比油脂、多种植物油组成的配比油脂,实验期为42d。结果表明：COP组胸肌24h的滴水损失显著升高(P＜0.05);COC组腿肌烹饪损失显著降低(P＜0.05)。LO组胸肌不饱和脂肪酸/饱和脂肪酸得到提高(P＜0.05);SO、LO、COP、COC组n-3多不饱和脂肪酸含量均得到提高(P＜0.05);SO、COC组n-6多不饱和脂肪酸含量高于CON组(P＜0.05);除COV组外,各组n-6/n-3低于CON组(P＜0.05)。SO组胸肌胆固醇含量低于除LO组外的各组(P＜0.05)。结论：配比油脂组提高了肉鸡肌肉中多不饱和脂肪酸(PUFA)含量,对肉鸡肉品质没有产生不良的影响,豆油组改善了胸肌中脂肪酸比例并降低胆固醇含量,以椰子油为主的配比油脂次之。     

GC/MS分析俄罗斯鲟鱼不同部位脂肪酸组成

通过Folch法提取俄罗斯鲟鱼不同部位总脂,采用GC/MS法对其脂肪酸组成进行分析。通过质谱数据库检索和标准品对照鉴定脂肪酸组成。研究表明,鱼肉、鱼卵、鱼皮、鱼腹中脂肪酸种类及含量类似,多不饱和脂肪酸含量均大于40%,其次为单不饱和脂肪酸(30%左右)和饱和脂肪酸(17%左右),多不饱和脂肪酸以9,12-十八碳二烯酸和DHA为主。鱼肉中总脂含量12.83%,其中,多不饱和脂肪酸为42.37%,EPA+DHA为17.25%;鱼卵总脂含量为14.46%,其中n-3脂肪酸为22.10%;鱼皮含有较高含量的n-6脂肪酸(19.43%);鱼腹总脂含量14.45%,含有较高含量的多不饱和脂肪酸(42.66%)和单不饱和脂肪酸(34.07%),EPA+DHA为17.38%;鱼鳔中未检测到n-3和n-6脂肪酸;鱼肝总脂含量为55.92%,单不饱和脂肪酸含量尤为突出,高达55.81%,以9-十八碳烯酸(49.82%)为主,饱和脂肪酸含量仅为17.24%;椎骨中总脂仅为0.09%。     

糖添加量对广式腊肠脂质降解的影响

研究了不同糖添加量(3%、6%、9%、12%,m/m)对广式腊肠脂质降解的影响规律。将广式腊肠中瘦肉和肥丁分别进行研究,利用固相萃取技术将脂质分为中性脂肪、磷脂和游离脂肪酸,采用气质联用分析中性脂肪和磷脂的脂肪酸组成、游离脂肪酸的组成及含量。结果表明:磷脂是广式腊肠中脂质降解的主要成分,中性脂肪也对游离脂肪酸的释放有一定作用;瘦肉部分的脂质是腊肠脂质降解的主要部分。糖添加量对中性脂肪和磷脂的多不饱和脂肪酸组成比例具有显著影响,糖添加量低时多不饱和脂肪酸组成比例高,尤其是对瘦肉部分的磷脂影响最为显著,糖添加量为12%时其比例为17.88%,而添加量为6%和3%时分别变为36.70%和33.94%;游离脂肪酸含量随糖添加量的减少而降低,表明糖对腊肠的脂质降解具有一定促进作用。由于多不饱和脂肪酸极易氧化导致其组成比例较低。     

Changes of fatty acid composition during the processing of fish

Since the 70's a special attention has been paid to fish oil for its beneficial nutritive effects [1]. Fish products are an important source of polyunsaturated fatty acids (PUFAs) especially n-3 (ω-3) fatty acids - eicosapentaenoic (20:5, n-3) and docosahexaenoic (22:6, n-3) acid which are believed to cause the lowering of the incidence of thrombosis and atherosclerosis [2]. Due to the chemical properties all PUFAs undergo oxidative changes yielding products without any positive nutrition effects. Therefore, the processed fish - preserved, marinated or smoked - differ in the n-3 PUFAs content from the fresh fish meat. The present work aims to compare the effect of smoking and marinating on the n-3 fatty acids content of mackerel meat.     

植物油中脂肪酸成分的调查与分析

通过对植物油中脂肪酸成分的调查,了解多种不同植物油中的脂肪酸含量及组成比,从而为研制符合国家推荐的脂肪酸比例的保健调和油提供数据参考。方法:取一定量的油脂样品,通过碱法甲酯化后用气相色谱分析。结果:实验结果显示,植物油中含有大量的不饱和脂肪酸,主要为油酸和亚油酸,同时还发现存在少量的共轭亚油酸,而饱和脂肪酸则以棕榈酸和硬脂酸为主。在不饱和脂肪酸中n-6/n-3的比值除了亚麻子油和精炼菜子油分别为0.44、2.84以外,其他植物油的比值均较高,从11.15到286.37不等。     

肉类脂肪酸的营养与免疫调节作用

综述了肉类脂肪中饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸及共轭多不饱和脂肪酸构成特性及其对人体的营养与健康功能,以及肉类脂肪中三酰甘油、磷脂、固醇类等的免疫调节作用与疾病的关系。     

Encapsulation of vegetable oils as source of omega-3 fatty acids for enriched functional foods

Polyunsaturated omega-3 fatty acids (PUFAs), a functional component present in vegetable oils, are generally recognized as being beneficial to health. Omega-3 PUFAs are rich in double bonds and unsaturated in nature; this attribute makes them highly susceptible to lipid oxidation and unfit for incorporation into long shelf life foods. The microencapsulation of oils in a polymeric matrix (mainly polysaccharides) offers the possibility of controlled release of the lipophilic functional ingredient and can be useful for the supplementation of foods with PUFAs. The present paper provides a literature review of different vegetable sources of omega-3 fatty acids, the functional effects of omega-3 fatty acids, different microencapsulation methods that can possibly be used for the encapsulation of oils, the properties of vegetable oil microcapsules, the effect of encapsulation on oxidation stability and fatty acid composition of vegetable oils, and the incorporation of long-chain omega-3 polyunsaturated fatty acids in foods.     

3种海洋鱼油脂肪酸组成及其位置分布

采用米黑根毛霉源固定化脂肪酶(Lipozyme RM IM)对常见的海洋鱼油甘三脂进行水解,分析了凤尾鱼、金枪鱼、三文鱼甘三酯中脂肪酸的组成及位置分布。采用硅胶色谱柱分离3种海洋鱼油甘三脂,利用Lipozyme RM IM的sn-1,3特异性,将酯化在sn-1,3位上的脂肪酸(EFA)水解成游离脂肪酸(FFA),然后通过薄层层析(TLC)分离得到sn-2-单甘酯,再甲酯化后利用气相色谱(GC)测定sn-2位脂肪酸组成,并按照脂肪酸的不饱和程度和n-3,6-多不饱和脂肪酸归类分析海洋鱼油甘三酯中各类脂肪酸位置分布的特点。结果表明:3种海洋鱼油(凤尾鱼油、金枪鱼油、三文鱼油)中不饱和脂肪酸含量达到60%以上,其中单不饱和脂肪酸(MUFA)占24.67%~33.51%,多不饱和脂肪酸(PUFA)占26.89%~36.15%,而且一半以上PUFA分布在sn-2位,有利于其吸收和提高其耐氧化性;而SFA和MUFA倾向于分布在sn-1,3位上。n-3与n-6PUFAs之间的比例均10,均符合FAO/WHO推荐摄入的标准(4),是理想的n-3PUFA天然营养补充剂。     

内蒙古放牧和舍饲绵羊肉的脂肪酸特征

内蒙古盛产天然放牧牛羊肉,规模化舍饲也在农区和禁牧地区迅速发展,但不同饲养方式绵羊肉的脂肪酸特征缺乏系统评价。从内蒙古东北部、东中部和西部3 个典型纯牧业和农牧业区的7 个旗县采集草原放牧绵羊肉109 份和舍饲绵羊肉30 份,采用气相色谱法测定脂肪酸并进行主成分分析（principal component analysis,PCA）和描述性统计。结果表明：对各旗县绵羊肉样按放牧和舍饲2 种饲养方式或地域聚类进行PCA,呼伦贝尔和锡林郭勒草原放牧肉样聚集在一起,巴彦淖尔农区舍饲肉单独聚类,放牧和舍饲同地域内各旗县和品种聚类均未能分离;股二头肌和羊肥尾多数脂肪酸含量存在差异,但放牧和舍饲肉样间特征脂肪酸有一致性;羊肥尾脂肪酸对2 种饲养方式的区分效果比股二头肌好;放牧肉n-3多不饱和脂肪酸（polyunsaturated fatty acid,PUFA）、α-C18:3 n-3（α-亚麻酸）、C14:1和C14:0含量显著高于舍饲肉,放牧股二头肌和羊肥尾n-3 PUFA含量为舍饲的6.0 倍和4.2 倍,而α-亚麻酸含量为舍饲的4.6 倍和3.9 倍,舍饲绵羊肉n-6 PUFA、反式脂肪酸和C18:2 n-6c（亚油酸）、C18:1 n-9t（反式油酸）含量显著高于放牧肉。     

Distribution of conjugated linoleic acid in total and subcellular fractions from normal and cancerous parts of human testes

The objective of the present study was to examine differences in the fatty acid composition of subcellular fractions from normal and cancerous parts of human testes. The conjugated linoleic acid (CLA) content was significantly higher in total testicular carcinoma (TC), but significantly lower in the mitochondrial fraction of TC in comparison to normal testicular tissue. The subcellular distribution pattern of CLA was similar to that of monounsaturated fatty acids, but different to that of 18:2n-6 (linoleic acid), underlining the different physiological properties of CLA and 18 : 2n-6. Because polyunsaturated fatty acids (PUFAs) have been suggested to have an effect on cancer risk and previous research has found that CLA inhibits the metabolism of 18 : 2n-6 into 20 : 4n-6, the contents of n-6 and n-3 PUFAs were determined. Significant differences were observed for 18 : 2n-6, 18 : 3n-3, 20 : 5n-3, and 22 : 6n-3, with 18 : 2n-6, 18 : 3n-3, and 20 : 5n-3 contents being higher and 22 : 6n-3 content being lower in TC than in normal testicular tissue. These results indicate a changed availability of substrates for the cyclooxygenase (COX) or lipooxygenase (LOX) pathways generating eicosanoids. Although not statistically significant, the reduced content of 20 : 4n-6 shown in this study might be due to an increased metabolism of this fatty acid into eicosanoids.     

N3系多不饱和脂肪酸膳食参考摄入量的研究进展

近年来n-3系多不饱和脂肪酸（N-3 Polyunsaturated Fatty Acids,n-3 PUFAs）在提高婴幼儿认知及视力发育、增强免疫及预防精神疾病、癌症、炎症、心血管疾病（Cardiovascular Disease,CVD）等方面的作用倍受人们的重视,n-3PUFAs的膳食参考摄入量也成为这些研究领域的重要关注焦点之一。为了更好地发挥n-3 PUFAs在促进人体营养、发育、健康以及疾病预防等方面的重要作用,本文综述了世界上许多知名的研究机构及官方组织关于对不同人群的n-3 PUFAs推荐摄入量（Recommended Nutrient Intake,RNI）及适宜摄入量（Adequate Intake,AI）,以及它们对n-6/n-3脂肪酸的摄入比例以及n-3 PUFAs的可耐受最高摄入量（Tolerable Upper Intake Level,UL）进行的科学研究、探讨,同时还对n-3 PUFAs在使用过程中的不稳定性及注意事项进行了阐述,可以为我国不同人群的n-3 PUFAs膳食参考摄入量、普通食品中应用添加n-3 PUFAs以及n-3 PUFAs摄入补充方面提供更加充分、完整的科学依据和参考。      

Effect of rancidity of Lupinus albus protein-concentrate-based diets on food intake and growth of Wistar rats

The organoleptic properties of a diet are influenced by technological processes and have to be taken into account in food intake studies. The authors studied the food intake suppression associated with rancidity occurring during the storage of diets based on casein or heated or lyophilised lupin protein concentrates, and with or without ascorbic acid supplementation in five groups of 10 weanling Wistar rats for 21 or 26 days. After 15 days of storage, the unsaturated fatty acids were oxidised in heated lupin-protein-based diet without ascorbic acid. Compared to casein, food intake was decreased slightly during the first 10, 16 or 20 days for, respectively, heated lupin protein diet without ascorbic acid, heated lupin protein diet with ascorbic acid, and lyophilised lupin protein diet with or without ascorbic acid. After these periods, food intake decreased strongly. Body weight gain variations did not exactly follow food intake variations. The storage at 20°C could induce first an accumulation of free radicals, which were not detectable in measurement of fatty acids but perceived by rats, and then a fast oxidation of unsaturated fatty acids that increased rancid smell, modified nutritional quality and caused a dramatic decrease of rat food intake. Supplementing ascorbic acid into the diet could diminish the formation of free radicals at the beginning of storage, and consequently could delay food intake decrease. © 1997 SCI.     

膳食中n-3多不饱和脂肪酸对2型糖尿病患者血糖和胰岛素敏感性的影响

2型糖尿病是世界上最常见的慢性疾病之一。膳食中的n-3多不饱和脂肪酸可能会减少亚洲人的2型糖尿病风险, 中国2型糖尿病患者血浆磷脂n-3不饱和脂肪酸与胰岛素敏感性呈正相关。而欧美的前瞻性研究均发现, 鱼类的摄入和n-3多不饱和脂肪酸的摄入会增加2型糖尿病的发病风险, 在西方白种人群中进行的n-3多不饱和脂肪酸干预的随机对照试验也并未发现n-3多不饱和脂肪酸能够改善患者胰岛素抵抗水平或血糖水平, n-3多不饱和脂肪酸甚至可轻微地降低患者胰岛素的敏感性。本文综述了目前n-3多不饱和脂肪酸摄入量与2型糖尿病风险之间的关系。     

Identification of odour‐active compounds in muscle of brown trout (Salmo trutta) as affected by dietary lipid sources

The effect of fatty acid composition on odour‐active compounds in brown trout (Salmo trutta) muscle was evaluated. The fillets were obtained from three groups of fish fed experimental diets containing either fish oil (FO), soybean oil (SO) or linseed oil (LO). Muscle fatty acid composition was shown to be influenced by diet. Thirty‐one odorous compounds were detected by gas chromatography/olfactometry (frequency‐of‐detection method). Most of these compounds were formed by the oxidation of unsaturated fatty acids. Independently of diet, (E)‐2‐pentenal, (E)‐2‐pentenol and (E)‐2‐hexenol contribute strongly to the odour of brown trout. (E,Z)‐2,4‐Heptadienal was detected with high frequency in fish fed diets containing high levels of n‐3 PUFAs (FO and LO groups). Hexanal, (E)‐2‐hexenal and 2‐nonanol seem to contribute most to the odour of fish fed diets containing vegetable oils. Many odorous compounds were derived from the oxidation of mono‐ and di‐unsaturated fatty acids, which could be promoted by high levels of PUFAs. © 2002 Society of Chemical Industry     

Lipid Modification Strategies in the Production of Nutritionally Functional Fats and Oils

Rapid improvements in the understanding of the nutritional requirements of both infants and adults has led to new developments in the modification of fats and oils. Specific targets include the improvement in growth and development of infants, treatment of disease in adults, and disease prevention. Efforts have been focussed on the production of structured lipids using medium-chain acids and long-chain polyunsaturated fatty acids (PUFAs), as well as the concentration of long-chain PUFAs from new and existing sources. Short- and medium-chain fatty acids are metabolized differently than long-chain fatty acids and have been used as a source of rapid energy for preterm infants and patients with fat malabsorption-related diseases. Long-chain PUFAs, specifically docosahexaenoic acid and arachidonic acid, are important both in the growth and development of infants, while n-3 PUFAs have been associated with reduced risk of cardiovascular disease in adults. Based on the requirements for individual fat components by different segments of the population, including infants, adults, and patients, ideal fats can be formulated to meet their needs. By using specific novel fat sources and lipid modification techniques, the concentrations of medium-chain, long-chain saturated, and long-chain polyunsaturated fatty acids as well as cholesterol can be varied to meet the individual needs of each of these groups. While genetic modification of oilseeds and other novel sources of specific lipid components are still being developed, chemical and lipase-catalyzed interesterification reactions have moved to the forefront of lipid modification technology. Fractionation of fats and oils to provide fractions with different nutritional properties has potential, but little work has been performed on the nutritional applications of this method. The choice of suitable lipid modification technologies will depend on the target lipid structure, production costs, and consumer demand. A combination of some or all of the present lipid modification techniques may be required for this purpose.     

不饱和脂肪酸自动氧化形成反式脂肪酸机理研究进展

食用油热加工过程中由其不饱和脂肪酸异构化产生的反式脂肪酸 (TFAs) 对人体健康存在风险,有效控制TFAs的形成,对提升食品安全水平具有重要意义。以前研究者们重点关注的是油脂不完全氢化形成TFAs机理研究,而无需催化剂条件下油脂中不饱和脂肪酸热致异构化机理和氢化机理完全不同。而近年来油脂热处理过程中关注最多的顺反异构主要集中在C=C上的异构现象,因此,本文将着重总结不饱和脂肪酸自动氧化形成反式脂肪酸机理,旨在为为高脂食品中反式脂肪酸形成抑制作用研究提供理论基础和科学依据。     

梭鱼脂肪及脂肪酸成分分析和评价

为了解梭鱼的应用价值,对江苏沿海滩涂池塘养殖梭鱼（均质量（445.8±26.9）g）6 种组织（鱼头、鱼皮、背肌、腹肌、肝脏、腹脂）的脂肪分布、性质、脂肪酸组成进行分析和评价。索氏提取法测定组织中脂肪含量,滴定法测定脂肪的碘值和酸价,气相色谱-质谱法分析脂肪酸的组成。结果表明：梭鱼体内各组织脂肪分布差异显著（P＜0.05）,其中背肌和腹肌中脂肪含量分别为3.66%、10.16%;各组织脂肪的不饱和程度较高,碘值为90～106 g/100 g;各组织脂肪酸价较高,介于4～9 mg KOH/g之间;梭鱼脂肪中C22∶6n 3和C20∶5n 3含量丰富,品质好;鱼头、背肌、腹肌中饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸构成比例约为1∶1.5∶（0.7～0.8）,n-3/n-6多不饱和脂肪酸比值在0.7～0.8之间,组成合理;肝脏和腹脂中脂肪含量丰富,其中含有大量的n-3和n-6多不饱和脂肪酸,因此梭鱼的内脏也具有较好的可利用前景。     

内源性n-3多不饱和脂肪酸对下丘脑神经干细胞来源外泌体miRNA的调节

目的：通过培养fat-1转基因小鼠下丘脑神经干细胞获取外泌体并提取总RNA进行高通量测序,研究内源性n-3多不饱和脂肪酸（n-3 polyunsaturated fatty acids,n-3 PUFAs）对丘脑神经干细胞来源外泌体miRNA的调节作用,探究n-3 PUFAs抑制下丘脑炎症及肥胖的作用机制。方法：分别培养fat-1转基因小鼠与野生型C57BL/6小鼠下丘脑神经干细胞,从细胞培养上清液中收集外泌体并提取总RNA,经高通量测序后利用生物信息学技术对差异表达的miRNA进行分析及靶基因预测,对靶基因进行基因组百科全书（Kyoto encyclopedia of genes and genomes,KEGG）富集分析后,利用实时荧光定量聚合酶链式反应（quantitative real-time polymerase chain reaction,qPCR）进行相对表达量的测定。结果：与野生型C57BL/6小鼠相比,fat-1转基因小鼠下丘脑神经干细胞来源的外泌体miRNA具有特异表达谱,且具有显著差异表达的miRNA靶基因处于下丘脑炎症、脂肪酸代谢等通路中关键位置。经qPCR验证,差异表达的miRNA关键靶基因表达均受到调控。结论：内源性n-3 PUFAs水平的增加可以调节下丘脑神经干细胞外泌体中miRNA的表达,进而调控炎症反应与脂质代谢相关基因的表达,从而发挥抑制下丘脑炎症、抵抗肥胖的作用。