海地瓜血管紧张素转换酶抑制肽体外评价

目的:运用优化改进后的血管紧张素转化酶(ACE)抑制剂体外筛选方法,对海地瓜多肽进行初筛,找出ACE抑制活性最强的海地瓜多肽用于下一步研究。方法:对文献报道的ACE抑制剂体外筛选方法稍作改进,并将改进后的方法应用于海地瓜ACE抑制肽初筛。结果:ACE抑制剂筛选反应体系中加入抑制剂时,分解产物马尿酸峰面积下降,ACE活性明显受到抑制;改进后的ACE抑制剂筛选方法精密度、稳定性、重复性均符合要求;海地瓜多肽ACE抑制活性初筛结果显示,海地瓜多肽4的ACE抑制活性最强,可用于下一步分离纯化。结论:通过ACE抑制剂体外筛选方法,已初步筛选得到具有较强活性的海地瓜ACE抑制肽。     

核桃蛋白源血管紧张素转化酶抑制剂的分离纯化

从核桃蛋白源的胃蛋白酶水解物中分离纯化出具有高体外血管紧张素转化酶(ACE)抑制活性的抑制剂。利用超滤、凝胶色谱、高效液相色谱等方法进行分离纯化,以体外ACE抑制活性为检测指标,并用N端氨基酸测序鉴定其结构为酪氨酸-谷氨酸-脯氨酸(Tyr-Glu-Pro,YEP),对筛选出的抑制剂进行体外模拟消化稳定性研究。结果表明,胃蛋白酶酶解液通过纯化所得ACE抑制剂的IC50值为0.32μg/mL,该ACE抑制剂在经过体外模拟消化后仍保持良好的ACE抑制活性。     

豆豉功能性的研究

本文对不同品种豆豉的抗氧化、α-葡萄糖苷酶抑制和血管紧张素转换酶(ACE)抑制效果进行了比较,并对埃及曲霉纯种发酵曲中ACE抑制剂与ACE和肠胃蛋白酶预混合保温后的抑制活性进行分析,结果表明豆豉曲提取液具有较好的抗氧化和α-葡萄糖苷酶抑制效果;与ACE预混合保温后ACE抑制活性变化不大,而被不同的肠胃蛋白酶消化后抑制活性均有较大的提高,为前药型抑制剂。     

三斑海马蛋白肽ACE抑制活性的研究

本文通过三斑海马酶解液的制备、ACE抑制活性肽的分离和体外消化模型的建立研究了三斑海马蛋白肽的ACE抑制活性。利用碱性蛋白酶制备得到具有ACE抑制活性的三斑海马酶解液,经葡聚糖凝胶层析分离纯化后,得到具有较高ACE抑制活性的组分(其IC50为0.91 mg/m L);通过对该组分的氨基酸组成和体外消化模型分析,发现该组分中疏水性氨基酸的含量为50.48%,消化酶作用后,显著提高ACE抑制活性,经判断,该组分中的蛋白肽为前体型抑制剂。      

血管紧张素转化酶抑制剂产生菌的筛选及发酵条件优化

以大豆分离蛋白为基质,以血管紧张素转化酶（ACE）抑制活性和多肽含量为评价指标,筛选高产ACE抑制剂的菌株,并以 ACE和蛋白水解度（DH）为考察指标对其产ACE抑制剂的发酵条件进行单因素优化。 通过微生物发酵法筛选出一株具有高ACE抑制 活性的枯草芽孢杆菌（Bacillus subtilis）BS90。 经单因素试验确定最优发酵条件为：采用液态发酵,大豆蛋白含量5%,初始pH值9.0,培 养温度35 ℃,培养时间40 h。 在此发酵条件下,DH和ACE抑制活性分别达到89.1%和81.8%,较优化前分别提高69.5%、13.4%。 为后续 ACE抑制肽的分离制备奠定了基础。     

海洋生物来源血管紧张素转换酶抑制肽的研究进展

血管紧张素转化酶(angiotensin converting enzyme,ACE)抑制剂通过抑制ACE活性能够降低血压。目前人工合成ACE抑制药物已开发并应用到降血压的治疗中,但会带来多种副作用。食源性ACE抑制肽与合成抑制剂相比因其副作用小、安全性高等特点,成为ACE抑制肽研究的热点。由于独特的生活环境与巨大的存在数量,海洋生物具有与陆地生物截然不同的化学结构及丰富的生物活性成分。海洋生物来源ACE抑制肽的研究为食源性ACE抑制肽的筛选提供了基础。本文结合海洋生物来源ACE抑制肽的作用机制及制备流程,对鱼类、软体动物、虾类、藻类及海绵、海蜇、粗刺参等不同生物来源的ACE抑制肽制备工艺进行了综述,并对海洋生物的综合开发利用进行了概括。     

南瓜籽蛋白源血管紧张素转化酶抑制肽的制备及其降血压活性

食源性降血压肽在调节机体血压过程中发挥着一定的积极作用。本实验采用碱性蛋白酶水解南瓜籽蛋白,水解物经膜分离获得血管紧张素转化酶（angiotensin converting enzyme,ACE）抑制肽,通过质谱鉴定其结构,并采用抑制动力学和分子对接方法研究ACE抑制肽的活性机制;此外,通过ACE抑制活性实验、自发性高血压大鼠（spontaneously hypertensive rats,SHRs）模型等评价南瓜籽蛋白水解物、膜分离组分以及南瓜籽肽的降血压活性。结果表明,低于1 kDa南瓜籽蛋白水解物组分ACE抑制活性较好,1 mg/mL下ACE抑制率为46.22%,100 mg/kg mb 剂量下灌胃SHRs 6 h后收缩压可以降低21.42 mm Hg;鉴定出9 个ACE抑制肽（LLV、LVF、LTPL、SVLF、LLPQ、MLPL、LLPGF、VLLPE和RFPLL）,其中RFPLL、LLPGF、MLPL和LVF具有较好的ACE抑制活性,半抑制浓度均低于1 mmol/L;RFPLL和LVF具有较好的降血压活性,30 mg/kg mb剂量下灌胃6 h后SHRs的收缩压降低量分别为37.0 mm Hg和22.2 mm Hg,SHRs的舒张压降低量分别为17.0 mm Hg和11.2 mm Hg;RFPLL、LLPGF、MLPL和LVF可以很好地对接ACE的活性中心,RFPLL是ACE混合型抑制剂,MLPL对ACE的抑制模式可能是竞争型抑制,LLPGF、LVF可能是ACE的非竞争型抑制剂。综上,低于1 kDa南瓜籽蛋白水解物是一种良好的降血压功能食品原料,其中RFPLL和LVF可用于降血压功能食品或者药品的开发原料。     

酱油对血管紧张素转换酶抑制作用的研究

考察了若干酱油样品的血管紧张素转换酶(ACE)抑制活性,发现所试样品均表现出ACE抑制活性,其IC50值范围为0.7405～3.0265mg/mL。样品的ACE抑制活性与其蛋白质降解程度、多肽含量及颜色值无明显相关性,应为多种活性物质综合作用的结果。对我国酱油产品中ACE抑制剂的结构表征可为潜在降血压功能性食品的研发提供指导。     

酪蛋白源降血压肽稳定性及其抑制作用机理的研究

酪蛋白源降血压肽经体外胃肠道蛋白酶消化后,其ACE抑制活性仍能保持原来活性的94%.降血压肽与ACE作用前后,其ACE抑制活性和肽谱基本保持不变,证实了酶解乳蛋白源降血压肽是真正的抑制剂类型,不受ACE作用.采用抑制酶解动力学方法,初步探讨降血压肽的抑制作用机理,根据lineweaver-Burk方程,确定酶解酪蛋白源降血压肽是非竞争性抑制类型.     

血管紧张素转化酶抑制剂体外活性检测方法的改进及应用

通过测定不同缓冲体系、氯离子浓度、酶底物比等对血管紧张素转化酶（ACE）活力测定反应体系的影响，建立了适用于食源性ACE抑制剂体外活性检测的分析方法，并分析了该方法的可靠性。测定方法条件为：浓度为200mmol／LNaCl的Tris—HCl缓冲体系．反应温度37℃，检测342nm波长下吸光值在7min内的连续变化；用已知的ACE抑制剂Captopril对方法进行检验。并将其应用于乳蛋白质不同酶水解产物ACE抑制活性的测定。     

The effects of modified atmosphere gas composition on microbiological criteria, color and oxidation values of minced beef meat

This paper reports the effects of modified atmosphere gas compositions with different concentrations of CO(2)/O(2)/N(2) on color properties (L*, a* and b* values), oxidation stability (TBARS value) and microbiological properties of minced beef meat stored at +4 °C. Sampling was carried out on the 1st, 3rd, 5th, 7th, 9th, 11th and 14th day of storage. The gas mixtures used were as follows: (i) %30O(2) + %70CO(2) (MAP1), (ii) %50O(2) + %50CO(2) (MAP2), (iii) %70O(2) + %30CO(2) (MAP3), (iv) %50O(2) + %30CO(2) + %20N(2) (MAP4), and (v) %30O(2) + %30CO(2) + %40N(2) (MAP5). Control samples (AP) were packaged under atmospheric air. Pseudomonas, lactic acid bacteria, Brochothrix thermosphacta, and Enterobacteriaceae members were monitored. Among these five modified atmosphere gas compositions, the best preservation for minced beef meat was in MAP4 gas combination maintaining acceptable color together with oxidation stability and acceptable microbial loads until the end of storage period of fourteen days.     

顶空-固相微萃取两种传统面酱挥发性成分的气相色谱-质谱联用分析

采用顶空固相微萃取和气-质联用(GC-MS)技术,对2种传统面酱(M1和M2)中的挥发性成分进行提取、分析。从M1中鉴定出53种挥发性化合物,占色谱流出峰总面积的77.408%,包括醛类6种,酯类5种,酸类14种,烃类2种,醇类2种,杂环类化合物12种,酮类2种,其他化合物10种。从M2中鉴定出48种挥发性化合物,占色谱流出峰总面积的64.455%,包括醛类6种,酯类8种,酸类6种,烃类4种,醇类5种,杂环类化合物9种,酮类4种,其他化合物6种。     

中国大鲵肌内脂肪酸组成及其抗氧化研究

分析中国大鲵肌内脂肪酸的组成,并研究肌内脂肪酸抗氧化,提供肌内脂肪酸开发利用的基础理论。通过气相色谱/质谱联用技术分析肌内脂肪酸的组成;通过Schaal烘箱法(63±1℃)研究肌内脂肪酸的抗氧化特性。GC-MS分析结果表明:肌内脂肪主要含13种脂肪酸,其含量由高到低依次为,C18∶124.2%,C16∶015.4%,C16∶113.7%,C18∶28.2%,C20∶56.7%,C18∶34.5%,C22∶64.3%,C14∶13.0%,C18∶02.8%,C22∶52.6%,C20∶42.2%,C17∶02.0%,C17∶11.9%。饱和脂肪酸(SFA)为20.2%,不饱和脂肪酸(UFA)达71.3%。单不饱和脂肪酸(MUFA)为42.8%,多不饱和脂肪酸(PUFA)为28.5%,具有保健功能性作用的ω-6型PUFA为13.0%,ω-3型PUFA为15.5%。ω-6型与ω-3型PUFA比为0.8。Schaal烘箱法研究结果表明:抗氧化剂二丁基对甲苯酚(BHT)、没食子酸丙酯(PG)、特丁基对苯二酚(TBHQ)对肌内脂肪酸有明显的抗氧化作用,其中特丁基对苯二酚抗氧化效果较佳。中国大鲵肌内脂肪富含ω-3和ω-6型...     

第一过渡金属对槲皮素的化学改性及抗氧化活性

通过对槲皮素的化学改性,合成了槲皮素的第一过渡系生命元素的配合物,并对槲皮素配合物的溶解性、总抗氧化能力、清除O2·自由基和DPPH·自由基的活性进行了比较研究.研究结果表明,槲皮素配合物的在水中的溶解性优于槲皮素;槲皮素配合物的总抗氧化能力强弱为:槲皮素＜槲皮素铁(Ⅱ)＜槲皮素铬(Ⅱ)＜槲皮素镍(Ⅱ)＜槲皮素钴(Ⅱ)＜槲皮素锰(Ⅱ)＜槲皮素铜(Ⅱ)＜槲皮素锌(Ⅱ);清除O2自由基的能力为:槲皮素＜槲皮素铁(Ⅱ)＜槲皮素铬(Ⅱ)＜槲皮素镍(Ⅱ)＜槲皮素锰(Ⅱ)＜槲皮素铜(Ⅱ)＜槲皮素钴(Ⅱ)＜槲皮素锌(Ⅱ);清除DPPH·自由基的能力为:槲皮素＜槲皮素铁(Ⅱ)＜槲皮素镍(Ⅱ)＜槲皮素铬(Ⅱ)＜槲皮素铜(Ⅱ)＜槲皮素钴(Ⅱ)＜槲皮素锰(Ⅱ)＜槲皮素锌(Ⅱ).槲皮素经化学改性的产物比槲皮素有更好的生物活性.     

正山小种红茶挥发性成分分析

采用顶空固相微萃取结合气相色谱-质谱联用对不同价位的正山小种红茶的挥发性成分进行了分析。结果表明,不同价位正山小种红茶主要挥发性成分都包括醇类、醛类、碳氢类、酯类、酚类、酮类、酸类、含氮类以及杂氧类化合物,但各类化合物在不同红茶中的相对含量存在差异。红茶A（高价位）中苯乙醇（11.05%）,苯甲醇（7.88%）,香叶醇（5.75%）,苯甲醛（5.33%）,水杨酸甲酯（3.74%）和（E,E）-3,5-辛二烯-2-酮（3.42%）等成分相对含量较高。红茶B（中等价位）中香叶醇（7.4%）,愈创木酚（5.83%）,苯酚（4.21%）,2-吡咯甲醛（3.63%）,萘（3.53%）和水杨酸甲酯（3.51%）等成分相对含量较高。红茶C（低价位）中香叶醇（7.98%）,苯乙醇（7.32%）,苯甲醛（7.13%）,苯甲醇（3.33%）,水杨酸甲酯（3.24%）,糠醛（2.52%）等成分相对含量较高。      

Development of hydrogel patch for controlled release of alpha-hydroxy acid contained in tamarind fruit pulp extract

Synopsis The aim of this study was to develop hydrogel patch using crosslinked chitosan-starch as polymeric matrix for controlling the release of the natural alpha-hydroxy acid (AHA) contained in the extract of tamarind's fruit pulp. The chitosan (MW 100 000) was blended with corn, tapioca or rice starch in various ratios and then crosslinked with glutaraldehyde. The physical characteristics, mechanical resistance, bio-adhesion property and surface morphology of the prepared hydrogel patches with and without the extract were investigated. The release patterns of the hydrogel patches containing the extract were investigated by measuring the amount of tartaric acid, a major AHA present in the tamarind's fruit pulp extract, accumulated in the receptor medium of the vertical diffusion cell at various time intervals over a period of 6 h. The results indicated that the formulations of chitosan : corn starch 4.5 : 0.5 with glutaraldehyde 0.02% w/w (C(4.5)C(0.5)G(0.02)) or 0.04% w/w (C(4.5)C(0.5)G(0.04)), chitosan : tapioca starch 4.5 : 0.5 with glutaraldehyde 0.04% w/w (C(4.5)T(0.5)G(0.04)) or 0.05% w/w (C(4.5)T(0.5)G(0.05)), and chitosan : rice starch 4.5 : 0.5 with glutaraldehyde 0.04% w/w (C(4.5)R(0.5)G(0.04)) and chitosan : rice starch 4.0 : 1.0 with glutaraldehyde 0.03% w/w (C(4.0)R(1.0)G(0.03)) provided the flexible and elastic patches with good bio-adhesive property. The tensile strength values ranged from 5 to15 N mm(-2) and the elasticity ranged from 30 to 60%. The addition of the extract in these formulations significantly increased the tensile strength values of the obtained patches. The patch of C(4.0)R(1.0)G(0.03) formulation containing the extract showed relatively highest porosity, corresponding to its highest amount (12.02 +/- 0.33 mg) and rate (0.452 +/- 0.012 mg mm(-2) min(-1/2)) of tartaric acid released. The amounts of tartaric acid released from the developed hydrogel patches were proportional to a square root of time (Higuchi's model), particularly the release from C(4.0)R(1.0)G(0.03) (R(2), 0.9978 +/- 0.0020) and C(4.5)R(0.5)G(0.04) (R(2), 0.9961 +/- 0.0024) patches.     

Antioxidative and anti-inflammatory protection of oleanolic acid and ursolic acid in PC12 cells

PC12 cells were used to examine the in vitro antioxidative and anti-inflammatory effects of oleanolic acid (OA) and ursolic acid (UA). PC12 cells were pretreated with OA or UA at 20 and 40 microM and followed by exposure of hydrogen peroxide (H(2)O(2)) or 1-methyl-4-phenylpyridinium ion (MPP(+)) to induce cell injury. Results showed that H(2)O(2)- or MPP(+)-treatment significantly decreased cell viability and increased lactate dehydrogenase (LDH) release (P < 0.05). The pretreatment from OA or UA significantly and concentration-dependently reduced subsequent H(2)O(2)- or MPP(+)-induced cell death and LDH release (P < 0.05). Either H(2)O(2)- or MPP(+)-treatment significantly increased malonyldialdehyde (MDA) formation, decreased glutathione (GSH) content, and diminished glutathione peroxidase (GPX), catalase, and superoxide dismutase (SOD) activities (P < 0.05). The pretreatment from OA or UA significantly retained GSH, and reversed H(2)O(2)- and MPP(+)-induced impairment in catalase and SOD activities (P < 0.05), and decreased MDA formation (P < 0.05). Either H(2)O(2)- or MPP(+)-treatment significantly elevated interleukin-6 (IL-6) and tumor necrosis factor (TNF)-alpha levels (P < 0.05). The pretreatments from OA or UA significantly attenuated subsequent H(2)O(2)- or MPP(+)-induced release of IL-6 and TNF-alpha (P < 0.05). Based on the observed antioxidative and anti-inflammatory activities from OA and UA, these 2 compounds were potent agents against neurodegenerative disorder.     

Photostabilization of ascorbic acid with citric acid, tartaric acid and boric acid in cream formulations

This study involves the evaluation of the effect of certain stabilizers, that is, citric acid (CT), tartaric acid (TA) and boric acid (BA) on the degradation of ascorbic acid (AH(2) ) in oil-in-water cream formulations exposed to the UV light and stored in the dark. The apparent first-order rate constants (0.34-0.95 × 10(-3) min(-1) in light, 0.38-1.24 × 10(-2) day(-1) in dark) for the degradation reactions in the presence of the stabilizers have been determined. These rate constants have been used to derive the second-order rate constants (0.26-1.45 × 10(-2) M(-1) min(-1) in light, 3.75-8.50 × 10(-3) M(-1) day(-1) in dark) for the interaction of AH(2) and the individual stabilizers. These stabilizers are effective in causing the inhibition of the rate of degradation of AH(2) both in the light and in the dark. The inhibitory effect of the stabilizers is in the order of CT > TA > BA. The rate of degradation of AH(2) in the presence of these stabilizers in the light is about 120 times higher than that in the dark. This could be explained on the basis of the deactivation of AH(2) -excited triplet state by CT and TA and by the inhibition of AH(2) degradation through complex formation with BA. AH(2) leads to the formation of dehydroascorbic acid (A) by chemical and photooxidation in cream formulations.     

基于OAV和GC-O-MS法鉴定香椿中的关键香气成分

采用固相微萃取（Solid-Phase Microextraction,SPME）与溶剂辅助风味蒸发（Solvent-Assisted Flavor Evaporative,SAFE）法结合香气活性值（Odor Activity Value,OAV）和气相色谱-嗅闻-质谱联用技术（Gas Chromatography-Olfactory-Mass Spectrometry,GC-O-MS）分析鉴定新鲜香椿中关键香气成分。结果显示,采用两种萃取方法共鉴定出90种挥发性化合物,主要包括含硫类12种,醛类11种,萜烯类34种,酮类2种,醇类4种,酯类4种,酚类1种,酸类1种,烷烃类15种,环烷烃类4种,其他类2种。经OAV值计算,共确定出(E,E)/(E,Z)/(Z,Z)-二丙烯基二硫醚、反-2-巯基-3,4-二甲基-2,3-二氢噻吩、2-甲基环硫乙烷、己醛、3-甲基-正丁醛、反-2-己烯醛、反-2-辛烯醛等9种香气成分;经GC-O-MS分析,共鉴定出(E,E)/(E,Z)/(Z,Z)-二丙烯基二硫醚、2-甲基环硫乙烷、反-2-巯基-3,4-二甲基-2,3-二氢噻吩、己醛、反-2-己烯醛等7种香气活性物质。综合OAV和GC-O-MS分析,最终确认(E,E)/(E,Z)/(Z,Z)-二丙烯基二硫醚、反-2-巯基-3,4-二甲基-2,3-二氢噻吩、2-甲基环硫乙烷、己醛、反-2-己烯醛为新鲜香椿的关键香气成分。     

1-L-亮氨酸-1-脱氧-D-果糖和1-L-异亮氨酸-1-脱氧-D-果糖的热裂解分析

采用热重-差热法对1-L-亮氨酸-1-脱氧-D-果糖（Ⅰ）和1-L-异亮氨酸-1-脱氧-D-果糖（Ⅱ）的热失重和热裂解温度进行了研究,通过在线裂解GC-MS联用技术分别对（Ⅰ）和（Ⅱ）在350℃、450℃、550℃、650℃、750℃和850℃条件下的裂解产物进行了鉴定。研究结果表明2种Amadori化合物的的热失重曲线相似,（Ⅰ）的裂解温度为144.67℃,（Ⅱ）的裂解温度为164.26℃,600℃时（Ⅰ）和（Ⅱ）失重约80%;二者裂解产物主要为吡嗪类、吡啶类、吡咯类、喹啉类和呋喃类等杂环化合物,芳香族化合物以及醛类和酮类,其中以吡嗪类为主;裂解产物的数量随着裂解温度的升高而增多,（Ⅰ）的裂解产物数量与（Ⅱ）的裂解产物数量相当。对（Ⅰ）和（Ⅱ）的主要裂解产物形成途径进行了初步探讨,可为研究其在卷烟燃烧过程中的转化行为提供参考。