沪浙地区不同泌乳期母乳脂肪酸组成及分布研究

研究了我国沪浙地区不同泌乳期(0～1,1～3,3～6和6～12月)母乳总脂肪酸、甘油三酯sn-2位脂肪酸和磷脂脂肪酸组成及分布。结果显示,随着泌乳期的延长,母乳脂肪中的中链饱和脂肪酸(MCSFA)、C_(12:0)和C_(14:0)含量逐渐升高,多不饱和脂肪酸(PUFA)、C_(18:2n-6)(LA)和C_(18:3n-3)(ALA)含量先升高后下降,C_(20:4n-6)(ARA)和C_(22:6n-3)(DHA)含量先显著下降而后趋于稳定,而饱和脂肪酸(SFA)、C_(16:0)和C_(18:0)含量几乎没有变化。母乳脂肪酸在甘油三酯结构中的位置分布具有独特性:MCSFA、SFA、C_(12:0)、C_(16:0)、ARA和DHA主要结合在sn-2位上,而MUFA、C_(18:1n-9)、PUFA、LA和ALA主要分布在sn-1,3位上,且这种独特的位置分布几乎不随泌乳期的变化而变化。母乳磷脂脂肪酸中的ARA和DHA含量尽管在不同泌乳期之间有所差异,但均显著高于其在母乳总脂肪酸中的含量。研究结果为我国婴儿配方乳粉的脂质母乳化特别是结构母乳化提供了重要的数据支撑。     

牦牛肾脂氧化初期脂肪酸动态变化研究

以牦牛肾周脂为研究对象,研究了其在15±1℃下储藏期脂肪酸的动态变化。结果表明:牦牛肾脂肪氧化初期发生于储藏期第0～25d(15±1℃),在此期间,饱和脂肪酸(SFA)含量由49.68%提高至55.96%,多不饱和脂肪酸(PUFA)含量和单不饱和脂肪酸(MUFA)分别由10.73%和37.85%下降至6.95%和28.22%。第0～20d,n-6/n-3PUFA的比率低于4,但在第25d达到4.46,并且MUFA/SFA较PUFA/SFA下降幅度高11.24%。此外,除共轭亚油酸(CLA)和油酸(LA)外,功能性脂肪酸(ARA,EPA,DHA)在10d后下降显著(p<0.05)。     

泌乳期母乳脂肪酸变化及其多不饱和脂肪酸影响因素

采用气相色谱-质谱联用技术测定不同泌乳期母乳中脂肪酸的动态变化,并分析乳母血型、生育年龄、孕周、孕前身体质量指数（body mass index,BMI）、分娩方式和婴儿性别、胎次对成熟母乳中与婴儿生长发育直接相关的重要多不饱和脂肪酸（polyunsaturated fatty acid,PUFA）,亚油酸（linoleic acid,LA）、α-亚麻酸（α-linolenic acid,ALA）、花生四烯酸（arachidonic acid,AA）,二十碳五烯酸（eicosapentaenoic acid,EPA）、二十二碳六烯酸（docosahexaenoic acid,DHA）相对含量的影响。结果显示,饱和脂肪酸（saturated fatty acid,SFA）含量在初乳和成熟乳间差异显著（P＜0.05）,单不饱和脂肪酸（monounsaturated fatty acid,MUFA）含量随着泌乳期的延长逐渐降低,但差异不显著（P＞0.05）,PUFA含量在各泌乳期无显著差异（P＞0.05）,AA、DHA含量随着泌乳期的延长逐渐降低,在初乳、过渡乳中含量差异均不显著（P＞0.05）,但均显著高于成熟乳中含量（P＜0.05）;母乳中LA含量与婴儿性别有关,ALA含量与乳母孕前BMI有关,母乳中AA、EPA含量与乳母血型有关,DHA含量与乳母孕前BMI、乳母血型有关,均具有统计学意义（P＜0.05）。     

n-6/n-3多不饱和脂肪酸比例对HepG2细胞脂代谢的影响

本文研究了不同比例n-6/n-3多不饱和脂肪酸对HepG2细胞影响,通过体外培养细胞60μM不同比例LA/ALA培养24 h,通过反转录PCR研究不同比例LA/ALA对HepG2细胞SREBP-1、FAS、HMG-CR、LDLr和Apo B蛋白等脂代谢相关基因及蛋白表达量的影响。结果表明在组1(LA)、组2(10:1 LA/ALA)、组3(5:1 LA/ALA)、组4(1:1 LA/ALA)、组5(1:5 LA/ALA)、组6(1:10LA/ALA)和组7(ALA)7组比例中,1:1 LA/ALA比例处理细胞效果最佳,此比例脂肪酸通过下调HepG2细胞SREBP-1和FAS基因的表达来降低细胞TG的含量;下调HMG-CR基因的表达,上调LDLr基因的表达来降低细胞TC和LDL-C含量;通过上调SR-B1基因表达增加胆固醇逆转运,从而实现对HepG2脂代谢的有效调控。此多不饱和脂肪酸体外营养评价模型,为n-6/n-3多不饱和脂肪酸最佳营养比例推荐及食用植物油中多不饱和脂肪酸比例营养评估提供理论依据。     

3种淡水鱼油脂肪酸的含量分析

运用气相色谱质谱联用方法,分析了鲢鱼、罗非鱼和草鱼3种淡水鱼脂肪的脂肪酸组成。淡水鱼脂肪经氯仿/甲醇(体积比=2∶1)提取后,用三氟化硼甲醇溶液衍生,衍生物用气相色谱质谱法分析。结果显示,3种淡水鱼脂肪多不饱和脂脂酸(PUFA)含量为29.26%～41.49%,主要有亚油酸(C18∶2)、亚麻酸(C18∶3)、花生四烯酸(C20∶4)、二十二碳五烯酸(C20∶5,EPA)和二十二碳六烯酸(C22∶6,DHA);单不饱和脂肪酸(MUFA)的含量为26.46%～39.60%,主要有棕榈油酸(C16∶1)和油酸(C18∶1);饱和脂肪酸(SFA)的含量为23.35%～37.05%,主要有肉豆蔻酸(C14∶0)、棕榈酸(C16∶0)和硬脂酸(C18∶0)。3种淡水鱼脂肪SFA∶MUFA∶PUFA的比值,鲢鱼为0.56∶0.84∶1;罗非鱼为1.07∶1.35∶1;草鱼为1.02∶0.72∶1。鲢鱼、罗非鱼和草鱼脂肪的n-6/n-3脂肪酸比值分别为1.16,2.46和1.98。3种淡水鱼脂肪具有较高的营养和开发价值。     

草鱼脆化过程中腹内脂肪酸组成变化

以不同脆化期的草鱼腹内脂肪为原料,采用气相-色谱质谱(GC-MS)联用技术,研究草鱼脆化过程中腹内脂肪酸组成变化。结果显示,不同脆化期的草鱼腹内脂肪中共检出19种脂肪酸,其中饱和脂肪酸(saturated fatty acid,SFA)7种,单不饱和脂肪酸(monounsaturated fatty acid,MUFA)2种,多不饱和脂肪酸(polyunsaturated fatty acid,PUFA)10种。随着脆化时间的延长,MUFA含量显著增加,PUFA、n-6 PUFA含量显著减少(p0.05)。整个脆化过程中,SFA∶MUFA∶PUFA的比值近似于1∶2∶1,以普通草鱼最为接近。而n-3 PUFA在脆化20 d时开始减少(p0.05),始终低于普通草鱼。n-6/n-3 PUFA的比值为3.36%±0.04%~4.10%±0.04%,脆化20 d时最高。研究表明,虽然脆化改变了腹内脂肪酸的组成,但脆肉鲩腹内脂肪仍具有较好的开发价值。     

α-亚麻酸体内转化为二十碳五烯酸和二十二碳六烯酸的研究进展

水产品是二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)等n-3长链多不饱和脂肪酸(n-3LCPUFA)的主要膳食来源。我国广大内陆地区居民膳食中水产品消费量很低,EPA和DHA的摄入量远低于推荐量。α-亚麻酸(ALA)是我国居民膳食中最主要的n-3多不饱和脂肪酸(n-3PUFA),其在体内可以转化为n-3 LCPUFA。近来的研究表明,ALA转化能力受ALA摄入状况及人群生理差异影响,其中新生儿的内源转化效率较低,而育龄期妇女和鱼类低消费人群的转化效率较高,提示膳食ALA对改善这些人群的脂肪酸营养状况有着重要的意义。通过对相关方面的研究进行综述,以期更加客观、全面地认识α-亚麻酸的作用。     

新时期国民膳食脂质摄入推荐的几点建议（网络首发、推荐阅读）

随着社会经济水平的快速提高,我国居民膳食结构发生了明显的改变。膳食脂质是膳食结构的重要组成部分,其推荐摄入量对改善居民膳食结构,实现新时期健康中国建设目标的都有着重要影响。对中国居民膳食脂质参考摄入量的修订提出几点建议。（1）我国18岁及以上居民的膳食脂肪供能比可接受范围上限（U-AMDR）是30%E,低于欧盟和北美国家的35%E。有学者建议提高我国成年人膳食脂肪供能比的U-AMDR,但仍缺乏足够的证据,暂不宜做修改。然而,考虑到老年人需要高能量和营养密度膳食的特点,应考虑提高老年人膳食脂肪的U-AMDR。（2）一些研究表明n-6/n-3多不饱和脂肪酸比值（n-6/n-3PUFA）与多种慢性非传染性疾病发生风险密切相关。我国居民膳食中n-6/n-3PUFA比值的平均值达到8.6,在某些人群中甚至更高。因此,建议将膳食中n-6/n-3PUFA比值的推荐值纳入新版膳食脂质参考摄入量推荐中。（3）尽管开展了大量研究,但膳食胆固醇摄入量与心血管疾病等多项慢性疾病发生结局之间的关系仍不明确。我国城市居民平均每日胆固醇摄入量为264.0 mg,农村居民为168.8 mg,处于正常范围。基于目前的研究证据,仍无法针对一般成年人群制订膳食胆固醇摄入限量。对于心脑血管疾病等慢性疾病的患者,建议参考相应疾病指南中膳食胆固醇摄入量的推荐。     

不同类型膳食脂肪酸对肥胖小鼠肝脏及其血液中脂肪酸组成和代谢相关基因影响

目的探讨不同类型膳食脂肪酸对肥胖小鼠肝脏及其血液中脂肪酸组成及代谢相关基因的影响。方法 8周龄雄性C57BL/6小鼠随机分为7组,即对照组(喂基础饲料)、长链饱和脂肪酸(LCSFA)组(喂猪油高脂饲料)、中链饱和脂肪酸(MCSFA)组(喂椰子油高脂饲料)、n-3多不饱和脂肪酸(n-3 PUFA)组(喂亚麻籽油高脂饲料)、n-6多不饱和脂肪酸(n-6 PUFA)组(喂大豆油高脂饲料)、单不饱和脂肪酸(MUFA)组(喂橄榄油高脂饲料)和反式脂肪酸(TFA)组(喂8%氢化大豆油高脂饲料),每组10只,共干预16周,所有种类饲料总能量均相同,基础饲料脂肪供能比为10%,各高脂饲料脂肪供能比均为45%,喂养周期结束后,禁食12 h,麻醉后立刻解剖取出肝脏。采用气相色谱法分析肝脏及其血液中脂肪酸组成的变化,实时荧光定量聚合酶链式反应(PCR)检测肝脏脂肪酸代谢相关基因的表达,肝脏脂质沉积采用油红O染色法检测。结果与对照组比较,LCSFA组、MCSFA组、n-6 PUFA组、MUFA组和TFA组小鼠肝脏中均出现明显的脂质沉积,n-3 PUFA组小鼠肝脏未出现明显的脂质沉积。与对照组比较,LCSFA组小鼠肝脏及血液中总n-6 PUFA和总PUFA含量升高; n-3 PUFA组小鼠肝脏及血液中总n-3 PUFA和总PUFA含量增加,但总MUFA含量减少; n-6 PUFA组小鼠肝脏及血液中总n-6PUFA、总n-3 PUFA和总PUFA含量升高,但总饱和脂肪酸(SFA)和总MUFA含量降低; MUFA组小鼠肝脏及血液中总SFA含量减少; TFA组小鼠肝脏及血液中C18∶1 n-9t(TFA)含量升高;以上差异均有统计学意义(P0. 05)。LCSFA组和MCSFA组小鼠肝脏脂肪酸代谢基因固醇调节元件结合蛋白1(SREBP-1c) mRNA水平高于对照组和n-6 PUFA组,差异均有统计学意义(P0. 05)。结论小鼠肝脏及其血液中脂肪酸构成与其对应的膳食脂肪酸模式一致。不同类型脂肪酸高脂饲料可通过对相关基因的表达影响肥胖状态下肝脏的脂质代谢及脂质沉积。     

不同处理后的四川白兔肌内脂肪酸组成在冷藏过程中的变化

研究了用4种不同的处理方式(微波、烘烤、蒸煮、和超声波辅助腌制)对四川白兔的后腿肌(hind leg muscle,HL)进行处理后再用2种不同包装方式进行包装(非真空和真空包装),分析样品在冷藏过程中肌内总脂肪含量及脂肪酸组成的变化。结果表明,四川白兔肌内脂肪主要含20种脂肪酸,多数为不饱和脂肪酸。在0~12 d的冷藏过程中,4种方式处理后的四川白兔肌内脂肪含量显著下降(P0.05)。相对其他处理方式来说,微波处理对不饱和脂肪酸(UFA)尤其是多不饱和脂肪酸(PUFA)的影响较小,而蒸煮对PUFA破坏作用最大。随冷藏时间的延长,饱和脂肪酸(saturated fatty acid,SFA)的含量升高显著(P0.05),UFA、PUFA含量与P/S(PUFA/SFA)、n-6/n-3(n-6系列PUFA/n-3系列PUFA)的比值显著降低(P0.05),而单不饱和脂肪酸(MUFA)含量变化不显著。从脂肪氧化角度来看,处理后兔肉中丙二醛(MDA)的沉积量在0~10 d冷藏期间内不断升高,且耐贮性不断降低。真空包装的样品在饱和脂肪酸(saturated fatty acid,SFA)上升与UFA下降的趋势方面有减缓作用,同时将TBA值维持在较低的水平,延缓了加工肉品的腐败变质。     

Influence of ouabain of electrolyte and water transport in the rabbit ileum and colon in vitro and in vivo

We studied the influence of the Na⁺-K⁺ pump inhibitor ouabain on water and electrolyte transport in the rabbit distal ileum and proximal colon in vitro and in vivo. Under in vitro conditions, ouabain markedly reduced the absorption of water, sodium, chloride and bicarbonate, and reduced potassium secretion in both the ileum and the colon. In vivo results were similar but less marked than those obtained in vitro, with significant differences only at the level of the distal ileum.     

Determination of nitrite and nitrate in some horticultural and meat products and in samples of soil

This study of quantitative determination of nitrite and nitrate contents is based on spectrophotometric measurement of the red colour formed when sulphanilic acid is diazotised by the nitrite to be determined and coupled to 1-naphthylamine-7-sulphonic acid (Cleve's acid 1-7). Nitrate is first reduced to nitrite in a cadmium reducing column. Good results have been obtained with some horticultural and meat products and samples of soil.     

Differences in content and composition of free lipids and carotenoids in flour of spring and winter wheat cultivated in Poland

The work presents the content and composition of free lipids and carotenoids in spring and winter classes of wheat flour. It discusses genetical and physiological aspects of their synthesis and accumulation in wheat kernels and also indicates how methodological differences explain differences in results presented in the literature. It has been reported that spring wheat flours are richer in free lipids, especially in the non-polar fraction. The content of glycolipids ranged from 134 to 215 mg/100 g flour and was more stable within the winter wheat class. The percentages of the two main fractions, namely DGDG and MGDG, were similar in both wheat classes and reached ca. 77%. Phospholipids constituted the smallest fraction of the flour free lipids in both wheat classes; however, spring wheat flours were richer in these compounds, which is likely associated with a greater content of spherosomes in the endosperm of this wheat class. The free lipids of spring wheat flour contained more oleic and slightly less linoleic and linolenic acids. Spring wheat flour was also richer in carotenoids, although there were varieties in both classes that deviated from this. The main carotenoid was lutein, whose total percentage in the form of different isomers ranged from 71.3% to 83.3% and was slightly lower for spring wheat flour. Lutein, in the form of a trans-isomer, constituted about 62% and 70% of all carotenoids in spring and winter wheat flours, respectively.     

Influence of ouabain of electrolyte and water transport in the rabbit ileum and colon in vitro and in vivo.

We studied the influence of the Na(+)-K+ pump inhibitor ouabain on water and electrolyte transport in the rabbit distal ileum and proximal colon in vitro and in vivo. Under in vitro conditions, ouabain markedly reduced the absorption of water, sodium, chloride and bicarbonate, and reduced potassium secretion in both the ileum and the colon. In vivo results were similar but less marked than those obtained in vitro, with significant differences only at the level of the distal ileum.     

2018年深圳市售蔬菜和鸡蛋中氟虫腈及其代谢物的检测分析

目的 建立超高效液相色谱-串联质谱法同时测定蔬菜和鸡蛋中氟虫腈及其代谢物(氟甲腈、氟虫腈砜和氟虫腈亚砜), 并对深圳市售的蔬菜和鸡蛋中氟虫腈及其代谢物残留状况进行抽样检测。方法 采用QuEChERS前处理方法, 以C18色谱柱为分离柱, 以乙腈和10 mmol甲酸+6 mmol甲酸铵水溶液为流动相进行梯度洗脱, 用超高效液相色谱-串联质谱(ultra performance liquid chromatography-mass spectrometry/mass spectrometry, UPLC-MS/MS), 电喷雾电离(electrospray ionization, ESI), 多反应监测(multiple reaction monitoring, MRM)模式检测, 外标法同时定量测定氟虫腈及其代谢物。结果 方法的线性范围为0.1~2.0 μg/L, 线性相关系数均大于0.9994, 检出限0.0005 mg/kg, 定量限0.001 mg/kg; 蔬菜中3个水平的平均加标回收率88.0%~101.2%, 相对标准偏差(relative standard deviation, RSD)均小于8.5%; 鸡蛋中3个水平的平均加标回收率86.1%~104.8%, 相对标准偏差(RSD)均小于9.2%。结论 该方法具有操作简单、干扰少、快速、准确可靠等特点, 可适用于蔬菜鸡蛋中氟虫腈及其代谢物的检测。     

生物技术在制浆造纸中的应用与研究进展

介绍了生物技术在制浆造纸工业的应用与研究进展，包括生物制浆、生物漂白、生物脱墨及造纸过程中的生物技术等。     

Characterization of limestones and their effects in vitro and in vivo in dairy cattle

Capacities of limestones of differing particle size to neutralize acid in vitro and to modify pH and utilization of feedstuffs in vivo were compared. Acid neutralization during pH-stat titrations was faster for fine than for coarse limestone, and mixed microbial cultures were more resistant to pH change when they contained fine calcium carbonate. Diets containing 25:75 corn silage to concentrates and .95% calcium from either coarse or fine limestone were fed to rumen-fistulated heifers. Total ruminal volatile fatty acid concentrations were higher for the fine limestone treatment. Ruminal volumes, dry matter disappearance, and ruminal fluid pH and dilution rate did not differ between fine and coarse limestone treatments. Ruminal fluid volume, osmolality, ratios of acetate to propionate, and concentrations of total volatile fatty acids were unaffected in rumen-fistulated Holstein cows fed 60:40 corn silage to concentrates and either .5% calcium (control) or 1.0% calcium from either coarse or fine limestone. Ruminal pH increased .07 to .10 units with limestone supplementation. Ruminal fluid dilution and particulate turnover rates were slower for the coarse limestone than the control treatment. Differences between coarse and fine limestones in vitro were observed under some conditions in vivo, but they were not consistent.     

开封市畜禽沙门菌污染状况及血清学鉴定分析

了解开封市畜禽肉中沙门菌的污染状况及血清学分布,为沙门菌引起的食源性疾病的防控提供依据。方法 依据GB 4789.4—2010《中华人民共和国国家标准食品卫生微生物学检验方法》和2011年国家食源性疾病监测网监测方案,定期对开封市畜禽养殖场和屠宰场进行随机采样监测。结果 在691份样品中,沙门菌检出率为35.9%(248/691);分离出沙门菌253株,有17个血清型。结论 开封市生鸡肉和生猪肉不同程度受到沙门菌的污染,以生鸡肉污染最严重。应加强禽畜类养殖、屠宰加工等过程的卫生监管,减少食源性疾病的发生。     

Periparturient changes in secretion and mammary uptake of insulin and in concentrations of insulin and insulin-like growth factors in milk of dairy cows

Mammary uptake of insulin from blood was quantified near parturition in nine dairy cows, some of which were milked prepartum to induce prepartum lactogenesis. Milk samples were immunoassayed for concentrations of insulin, insulin-like growth factor I, and insulin-like growth factor II. Cows milked prepartum, but in which prepartum lactogenesis did not occur (denoted as unsuccessful group), had higher arterial concentrations and greater mammary uptake of insulin during several days immediately preceding parturition than did those with prepartum lactogenesis. Although mammary uptake of insulin was measurable before parturition, estimated uptake on postpartum d 4 through 6 was negligible. Colostrum and milk contained very substantial quantities of insulin, insulin-like growth factor I, and insulin-like growth factor II. Cows in which prepartum lactogenesis was induced (denoted as successful group) had lower concentrations of both forms of insulin-like growth factor in prepartum samples of milk. Cows of the successful group also had a decreasing prepartum profile of milk insulin, but the unsuccessful group had an increasing trend until parturition. Milk concentrations of insulin and both forms of insulin-like growth factor declined rapidly after parturition and completion of lactogenesis.     

Advantages and limitations of in vitro and in vivo methods of iron and zinc bioavailability evaluation in the assessment of biofortification program effectiveness

ABSTRACT

Biofortification aims to improve the micronutrient concentration of staple food crops through the best practices of breeding and modern biotechnology. However, increased zinc and iron concentrations in food crops may not always translate into proportional increases in absorbed zinc (Zn) and iron (Fe). Therefore, assessing iron and zinc bioavailability in biofortified crops is imperative to evaluate the efficacy of breeding programs. This review aimed to investigate the advantages and limitations of in vitro and in vivo methods of iron and zinc bioavailability evaluation in the assessment of biofortification program effectiveness. In vitro, animal and isotopic human studies have shown high iron and zinc bioavailability in biofortified staple food crops. Human studies provide direct knowledge regarding the effectiveness of biofortification, however, human studies are time consuming and are more expensive than in vitro and animal studies. Moreover, in vitro studies may be a useful preliminary screening method to identify promising plant cultivars, however, these studies cannot provide data that are directly applicable to humans. None of these methods provides complete information regarding mineral bioavailability, thus, a combination of these methods should be the most appropriate strategy to investigate the effectiveness of zinc and iron biofortification programs.