缓释载体微孔淀粉的研制

微孔淀粉是一种优良的缓释栽体。采用α-淀粉酶水解玉米淀粉制备微孔淀粉,最佳条件为：反应时间为12h、反应温度为55℃、所加酶量为100u/g干淀粉、反应pH为6.0。     

药物载体淀粉微球的可控降解及释药行为研究

模拟人体胃肠环境,对淀粉微球的降解性能进行了研究,使其在人体中的可控降解成为可能;借助FT-IR对微球降解后的结构进行了表征,粒度分析仪跟踪微球降解过程中的粒度变化;以亚甲基蓝为药物模型,考察了淀粉微球的载药及释药行为。结果表明：可以控制微球在3h内基本不降解,12h内缓慢降解;微球载药率约20％,包封率可达90％;微球在0-2.5h释药迅速,释药量31％,2.5-12h均匀释放,释药量40％,12-24h平衡缓释,释药量10％。     

Blood and Milk Lipid Responses Induced by Growth Hormone Administration in Lactating Cows

Nine multiparous Holstein cows (average 5.8 yr, 63 to 132 days postpartum) were in a 28-day single reversal experiment in the Beltsville open circuit respiration chambers with two 14-day injection periods (placebo versus bovine growth hormone, 51.5 IU/day). With growth hormone treatment, milk fat percentage increased 25 to 29%, milk fat yield increased 41%, and cows averaged ?13.7 Mcal/day energy balance. There were small increases of triglycerides and 1,2-diglycerides, core lipids, and small decreases of cholesterol and phospholipids, the membrane lipids. Fat from growth hormone treatment had 6% less short (6:0, 8:0, 10:0) and medium (12:0, 14:0, 14:1, 15:0, 16:0) chain fatty acids and 6% more long chain 18:1 fatty acids. Plasma of cows treated with growth hormone had an increase of concentrations of free fatty acids, but no shifts were apparent among other lipid classes. Analysis of total plasma fatty acids did not show any net changes, but within individual plasma lipid classes, 18:1 increased and 18:2 decreased. Overall changes of blood and milk lipids are consistent with the concept that adipose tissue reserves were mobilized in response to hormone treatment and that these mobilized lipids were the major carbon source for the 41% increase of milk fat secretion. Increases of de novo synthesis of short and medium chain fatty acids also occurred but much less. Cows treated with growth hormone were in negative energy balance, and the mechanism may differ when cows are in positive energy balance.     

载体油对槲皮素纳米乳液理化稳定性和生物利用度的影响

研究载体油种类和体积分数对纳米乳液稳定性和槲皮素生物利用度的影响.以中链甘油三酯(medium-chain triglyceride,MCT)和长链甘油三酯(long-chain triglyceride,LCT)为油相,梨小豆蛋白为乳化剂制备槲皮素负载型纳米乳液.通过光散射粒径分析、Zeta电位、物理稳定性、游离脂肪...     

半胱胺对仔猪增重及有关激素的影响

１２０头４５日龄的杜长大仔猪分成２组,每组３个重复,每个重复２０头。试验组喂以半胱胺８０ｍｇ／ｋｇＢＷ,每周１次,试验时间４０ｄ。结果表明,试验组增重提高１２．５９％（Ｐ〈０．０５）,料重比下降７．６７％（Ｐ〈０．０５）。和对照组比较,试验组生长抑素（ＳＳ）下降５６．４５％（Ｐ〈０．０５）,而生长激素（ＧＨ）,Ｔ３、Ｔ４分别上升１３６．９５％,２６．５３％,１７．７１％（Ｐ〈０．０５）。     

Effects of In Vivo Administration of Growth Hormone on Milk Production and In Vitro Hepatic Metabolism in Dairy Cattle

Bovine growth hormone (50 IU/d) or placebo injections were administered for 11 consecutive d to Holstein cows (four per treatment) in midlactation. Growth hormone injections increased milk yield, efficiency of milk production, and concentrations of growth hormone and free fatty acids in plasma. Concentrations of β-hydroxybutyrate and acetoacetate in whole blood and glucose in plasma were not affected by treatment. Liver biopsies were taken from both groups of cows 8 d prior to and on the last day of injection. Liver slices were used for in vitro incubations with carbon-14-labeled propionate, alanine, butyrate, and palmitate. Rates of substrate metabolism before and after placebo treatment were similar. Compared with pretreatment, however, liver slices from cows receiving growth hormone had significantly higher rates of propionare conversion to both glucose and carbon dioxide. There was also a nonsignificant increase in rate of alanine conversion to glucose and carbon dioxide. Growth hormone treatment did not change in vitro production of ketones or carbon dioxide from butyrate or palminate. Results indicate that growth hormone increases hepatic capacity for propionate metabolism and supports the concept that growth hormone partitions fatty acids for preferential use by mammary tissue.     

酶解和酸解处理对杨梅汁键合态香气释放的影响

采用Amberlite XAD-2树脂吸附洗脱分离得到杨梅汁键合态香气物质,在不同的酶解和酸解条件下处理键合态组分,基于固相微萃取-气相色谱-质谱联用(SPME-GC-MS)技术对水解得到的键合态香气物质进行鉴定.结果显示,用果胶酶、β-葡萄糖苷酶2种酶水解,共检出22种键合态物质,包括顺-3-壬烯-1-醇、β-石竹烯...     

酶解中草药对母猪泌乳性能和激素水平的影响

研究酶解中草药对母猪泌乳性能和激素水平的影响.结果表明:酶解中草药组的21日龄仔猪平均个体重、平均日增重及母猪产乳量显著高于未酶解中草药组和对照组(P<0.05).另外,酶解中草药组母猪初乳中PRL水平显著高于未酶解中草药组和对照组(P<0.05);酶解中草药组的母猪初乳、21 d的母乳中GH水平有高于未酶解中草药组和对照组趋势.未酶解中草药组与对照组相比仔猪平均日增重、母猪产奶量及母乳中PRL和GH水平差异均不显著(P>0.05).     

转生长激素基因鲤鱼的雌激素样作用研究

目的研究转生长激素基因鲤鱼是否具有类雌激素样作用。方法用啮齿动物子宫试验方法,选用19日龄未成年雌性SD大鼠,分为6个组:溶剂对照组玉米油5ml/(kgBW·d),亲本鲤鱼对照组3g/(kgBW·d),转生长激素基因鲤鱼组3g/(kgBW·d),E2(17β-雌二醇)经口低剂量组1μg/(kgBW·d),E2经口高剂量组3μg/(kgBW·d),E2经皮组3μg/(kgBW·d)。所有剂量组连续给予受试物3d(从19日龄到21日龄)。实验结束称量子宫湿重和干重,对子宫、卵巢和阴道做组织病理学检查,并测量子宫内膜上皮细胞高度。结果与溶剂对照组比较,E2经口低剂量组和转生长激素基因鲤鱼组及亲本鲤鱼对照组的子宫重量差异无统计学意义,E2经口高剂量组和E2经皮组与溶剂对照组比较差异有统计学意义(P0.05)。结论转生长激素基因鲤鱼经口摄入未见雌激素样作用。     

L-苹果酸对大鼠转运蛋白及抗氧化酶基因表达的影响

对12月龄SD大鼠给予L-苹果酸30d后,采用含有SYBR Green I的Real Time RT-PCR法,对肝脏和心脏线粒体苹果酸天冬氨酸穿梭中的两种转运蛋白(天冬氨酸谷氨酸转运蛋白(AGC)与α-酮戊二酸苹果酸转运蛋白(OMC))以及两种抗氧化酶(过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px))的基因表达进行检测,以研究L-苹果酸增强线粒体抗氧化作用的分子生物学机制。结果表明:苹果酸组中大鼠心肌细胞AGC、OMC、CAT、GSH-Px的mRNA表达量分别是空白对照组的1.25、1.39、1.12、1.01倍。苹果酸组中大鼠肝脏细胞AGC、OMC、CAT、GSH-Px的mRNA表达量分别是空白对照组的1.33、1.02、1.25、0.94倍。由此推测,L-苹果酸可能通过促进苹果酸天冬氨酸穿梭蛋白以及抗氧化酶的基因表达,实现提高线粒体的抗氧化作用。     

淀粉基胃漂浮控释载体的制备及其控释特性

通过在淀粉分子中引入羧甲基基团,制备了淀粉基胃漂浮控释系统载体材料。系统考察了不同羧甲基取代度对淀粉基胃漂浮控释系统载体结构和性能的影响规律。结果显示,随着取代度的提高,羧甲基淀粉的结晶程度降低,溶胀性能先增大后降低,当取代度为0.08时,其溶胀性能比原淀粉提高了10倍。在此基础上,选择维生素B1作为模型功能活性物质,羧甲基淀粉作为胃漂浮控释系统载体材料,制备了胃靶向漂浮控释系统,并考察了其对维生素B1在体外模拟胃液中的释放性能。结果表明,羧甲基淀粉胃漂浮控释系统具有良好的漂浮性能和控缓释性能。以取代度为0.08的羧甲基淀粉为载体,所制得的淀粉基胃漂浮控释系统起漂时间小于2 min,持续漂浮时间可达8 h。体外释放动力学研究显示,此羧甲基淀粉胃漂浮控释系统可使维生素B1释放时间延长至6 h,释放行为符合零级动力学。     

防粘纸离型性能研究

本研究通过比较以3种不同有机硅树脂为防粘剂的防粘纸离型性能,从中优选出水性有机硅树脂作为后续混合正交实验的防粘剂,重点探讨了底涂主剂类型、底涂压光条件、防粘层涂布量和防粘层配比对防粘纸离型性能的影响.结果表明,以不同配比水性有机硅树脂为防粘剂制备的防粘纸,剥离强度范围为0.3 ～ 1.9N/15mm;在探讨的4个影响因素中,防粘层配比对离型性能的影响最大.     

羧甲基壳聚糖与阿霉素联合对Hela 细胞的抑制作用研究

目的：探讨羧甲基壳聚糖与阿霉素联合应用对人宫颈癌Hela 细胞增殖的影响。方法：采用四甲基偶氮唑蓝(MTT)比色法测定单独和合用羧甲基壳聚糖与阿霉素对癌细胞的生长抑制作用,应用金氏公式进行联合用药分析。结果：羧甲基壳聚糖和阿霉素均可有效的抑制癌细胞生长,且同时给药对癌细胞可产生单纯相加至增强的协同杀伤效果。序贯给药法中先给阿霉素后给羧甲基壳聚糖结果为协同作用,先给羧甲基壳聚糖后给阿霉素为拮抗作用。结论：羧甲基壳聚糖与阿霉素同时联合用药可产生协同作用,序贯联合用药产生单向协同作用。     

Effect of Ultra-Violet B on Release of Volatiles in Tea Leaf

Many volatiles in fresh tea leaf are in the forms bound with glycosides and they are released by action of ß–primeverosidase and ß-glucosidase during tea processing. Effect of ultra-violet B on release of volatiles in fresh tea leaves of two tea cultivars, “Maoxie” and “Anhui-9,” were investigated. Types of volatile and their concentration increased when ultra-violet B was applied at 3.0 μmol m^?2 s^?1 for 2 h and then decreased as the irradiation was extended to 6 h. The relation of expression of ß–primeverosidase and ß-glucosidase genes to the release of volatiles were also discussed.     

动物性食品中环境激素对人体的影响及其防治

文中分别介绍了环境激素的定义、激素与环境激素间的关系,以及动物性食品中所包含的环境激素种类,通过分析动物性食品中环境激素的污染途径及其对人体的影响,提出了控制措施以增强人们对其危害的重视,并减少环境激素对人体损害,有利于控制环境激素在动物性食品中的含量。     

甲状腺素对HepG2细胞氧化损伤的保护作用

研究甲状腺激素(T3)对人肝癌细胞(HepG2)氧化损伤的保护作用。体外建立HepG2细胞H2O2氧化损伤模型,添加不同浓度T3进行保护,测定T3对细胞ROS、存活率、抗氧化酶及相关基因的影响。10-9、10-7、10-5mol/L的T3预处理24 h可分别有效降低50、100、200μmol/L H2O2处理细胞的ROS水平,提高细胞存活率(p0.05)。但10-5mol/L的T3反而会增加50μmol/L H2O2处理细胞的ROS水平,降低存活率(p0.05)。适量T3可显著降低H2O2氧化损伤的HepG2细胞MDA含量(p0.05),显著提高T-AOC、GSH-Px以及SOD活性(p0.05)。但过量T3会增加细胞MDA水平,降低酶活。基因表达也有类似趋势,T3预处理使损伤细胞内PI3K、Nrf2的表达显著提高(p0.05),且与T3作用剂量相关。可见T3对H2O2氧化损伤的HepG2细胞的氧化还原状态具有明显的改善作用,其抗氧化保护功能与提高抗氧化酶的活性及细胞内抗氧化相关基因的表达有关,且T3作用效果与其剂量及细胞损伤水平相关。     

冲泡条件对玫瑰茄花青素及总黄酮溶出量的影响

为提高玫瑰茄活性成分的有效利用率,以玫瑰茄干花萼为原料,研究不同冲泡条件对其茶汤中花青素及总黄酮溶出的影响。分别以花青素和总黄酮溶出量为指标,结合单因素和正交试验,优化玫瑰茄花茶冲泡的工艺条件。结果显示,在冲泡时间30 min、冲泡温度70℃、茶水比1∶50(g/mL)时,玫瑰茄花茶中花青素的溶出量最高,可达7.94 mg/g;在冲泡时间为40 min、冲泡温度为80℃、茶水比为1∶50(g/mL)时玫瑰茄花茶中总黄酮溶出效果最佳,溶出量可达58.77 mg/g。     

肌原纤维蛋白转谷氨酰胺酶交联程度对鱼糜凝胶及其风味释放影响的研究进展

转谷氨酰胺酶可以催化肌原纤维蛋白发生交联反应。随着交联程度的增加,鱼糜凝胶从弹黏体变为弹脆体,风味也随之改变。风味物质的扩散、释放与凝胶网络的交联程度密切相关,因此深入了解交联程度与食品品质的关系及风味物质在凝胶网络中的扩散行为显得尤为重要。本文总结转谷氨酰胺酶催化肌原纤维蛋白的交联机理,归纳了国内外对肌原纤维蛋白交联程郭彩霞度的测定方法与影响因素,探讨交联程度对鱼糜蛋白的凝胶特性与风味释放的影响,并对今后的研究方向提出思考与展望。