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Methoxyl methyl ether isoamylene quercetin, a quercetin derivative, protects rat aorta endothelial cells against oxidation and apoptosis
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作者 刘秀梅 刘晓岩 王银叶 《Journal of Chinese Pharmaceutical Sciences》 CAS CSCD 2013年第4期355-360,共6页
Methoxyl methyl ether isoamylene quercetin (MIAQ) is one of the newly synthesized quercetin derivatives. The present study investigated the effect of MIAQ on rat aorta endothelial cells (RAECs) injured by hydrogen... Methoxyl methyl ether isoamylene quercetin (MIAQ) is one of the newly synthesized quercetin derivatives. The present study investigated the effect of MIAQ on rat aorta endothelial cells (RAECs) injured by hydrogen peroxide (H2O2), as well as the potential mechanisms. We observed that MIAQ at 2.5-10μmol/L significantly enhanced the viability of injured RAECs, and the effect was more potent than quercetin and ct-tocopherol. However, M1AQ at the same concentration failed to show anti-oxidant activity in a cell-free system. In H2O2-injured endothelial cells treated with MIAQ (5-10μmol/L), the level of nitric oxide (NO) and malondialdehyde was decreased, and the activities of superoxide dismutase and glutathione peroxidase was enhanced. In addition, RAECs treated with MIAQ (2.5-10 μmol/L) exhibited significant inhibiting apoptosis. In conclusion, MIAQ had protective effect on RAECs, possibly through increasing NO production and antioxidases activities, as well as inhibiting apoptosis. These findings suggest that MIAQ is possibly beneficial in the prevention of atherosclerosis and other diseases related to endothelial injury. 展开更多
关键词 methoxyl methyl ether isoamylene quercetin Rat aorta endothelial cells Nitric oxide ANTI-OXIDATION ANTI-APOPTOSIS
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Debrominated and methoxylated polybrominated diphenyl ether metabolites in rainbow trout(Oncorhynchus mykiss) after exposure to decabromodiphenyl ether 被引量:4
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作者 Chenglian Feng,Yiping Xu,Yue He,Qian Luo,Jinmiao Zha,Zijian Wang State Key Laboratory of Environmental Aquatic Chemistry,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China. 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2010年第9期1425-1434,共10页
Decabromodiphenyl ether (BDE209) is the primary component in a commonly used flame retardant. Previous studies had proved that BDE209 itself was not toxic, while its metabolites including debrominated diphenyl ethe... Decabromodiphenyl ether (BDE209) is the primary component in a commonly used flame retardant. Previous studies had proved that BDE209 itself was not toxic, while its metabolites including debrominated diphenyl ethers (De-BDEs) and methoxylated brominated diphenyl ethers (MeO-BDEs) posed a potential threat to organisms. Many studies had indicated that BDE209 could metabolize quickly in mammals, but lacking in the basic data about the metabolism of BDE209 in fish. In the present study, two replicate treatment groups of rainbow trout (Oncorhynchus rnykiss) were exposed to BDE209 via a single intraperitoneal injection approximately 100 and 500 ng/g, respectively. Muscle, liver and blood samples were collected to analyze the specific metabolites on day 1 and day 28 post injection. The highest concentration of BDE209 was detected in muscle tissues, from 796.1 ng/g wet weight (day 1) to 687.1 ng/g wet weight (day 28) in high dose group, suggesting that BDE209 could accumulate slightly in muscle tissues. However, BDE209 was not detected in the blood for all treatments. Most congeners of De-BDEs were found in muscle and liver tissues, with the highest concentration in the liver. The main De-BDEs were nona-, octa-, hepta- and penta-De-BDEs. A total of seven MeO-BDE metabolites were observed among different fish tissues. Blood had the highest contribution of the MeO-BDE metabolites. Each MeO-BDE congener increased over the 28 days. These results in contrast to other studies suggested possible species-specific differences in metabolic abilities. 展开更多
关键词 decabromodiphenyl ether (BDE209) methoxylated brominated diphenyl ethers (MeO-BDEs) debrominated diphenyl ethers (De-BDEs) rainbow trout
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Influence of Mobile Phase Composition on the Enantioseparation of Methoxyl Flavanones with Self-prepared CDMPC Column and Chiral Recognition Mechanism 被引量:1
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作者 Bao Hai SHAO Xiu Zhu XU +2 位作者 Jian De LU Li ZOU Xiao Yun FU 《Chinese Chemical Letters》 SCIE CAS CSCD 2003年第4期401-403,共3页
The influence of different alcohol modifiers in mobile phase on the chiral separation of 4-methoxyl flavanone, 5-methoxyl flavanone and 6-methoxyl flavanone on cellulose tris (3, 5-dimethylphenylcarbamate) (CDMPC) col... The influence of different alcohol modifiers in mobile phase on the chiral separation of 4-methoxyl flavanone, 5-methoxyl flavanone and 6-methoxyl flavanone on cellulose tris (3, 5-dimethylphenylcarbamate) (CDMPC) column was studied and the chiral recognition mechanism was discussed. Using hexane-tert-butanol (1.31 mol L-1) as the mobile phase, those three methoxyl flavanones were excellently separated on CDMPC chiral column. 展开更多
关键词 Cellulose tris (3 5-dimethylphenylcarbamate) methoxyl flavanone chiral stationary phase enantioseparation.
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Syntheses, Crystal Structures and Properties of Two Metal-organic Complexes Based on 5-(4-Pyridyl)-methoxyl Isophthalic Acid 被引量:1
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作者 陶兆林 覃玲 郑和根 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2013年第7期1067-1075,共9页
Two new metal-organic frameworks, [Co3L2(NO2)2(H2O)2],, (1) and{[Ni(L)(H2O)5] (H2O)2.DMF}, (2, H2L = 5-(4-pyridyl)-methoxyl isophthalic acid), have been synthesized by the hydrothermal method and chara... Two new metal-organic frameworks, [Co3L2(NO2)2(H2O)2],, (1) and{[Ni(L)(H2O)5] (H2O)2.DMF}, (2, H2L = 5-(4-pyridyl)-methoxyl isophthalic acid), have been synthesized by the hydrothermal method and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis (TGA) and X-ray crystallography. Compound 1 crystallizes in the monoclinic system with space group P2/c and adopts a slightly distorted octahedral configuration. In compound 1, the 2D bilayered structures are linked by O-H...O and O-H...N hydrogen bonds to form a 3D framework. Compound 2 crystallizes in the monoclinic system with space group P2/n, and the central nickel atoms are octa-coordinated with five O atoms from coordinated water molecules and one N atom from one H2L ligand. The abundant O-H…O hydrogen bonds and π…π interactions link the molecules into a 3D framework. In addition, compounds 1 and 2 exhibit strong ultraviolet absorption in the solid state at room temperature. 展开更多
关键词 5-(4-pyridyl)-methoxyl isophthalic acid 2D bilayered structure hydrogen bond π…π stacking
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Antioxidant Activity of Methoxylated Flavonoids in Oils in Deep Frying Processes
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作者 Onesmus Maina Wanjau Symon Maina Mahungu Josphat Clement Matasyoh 《Food and Nutrition Sciences》 2018年第11期1273-1284,共12页
Methoxylated flavonoids isolated from cold acetone leaf wash of Polygonum senegalense;5-hydroxy-7-methoxyflavanone 1 and 5-hydroxy-6,7-dimethoxy-flavanone 3, were tested for their ability to enhance thermal stability ... Methoxylated flavonoids isolated from cold acetone leaf wash of Polygonum senegalense;5-hydroxy-7-methoxyflavanone 1 and 5-hydroxy-6,7-dimethoxy-flavanone 3, were tested for their ability to enhance thermal stability of vegetable oils. Determination of the peroxide value (P.V.) and the p-Anisidine value (p-A.V.) was done according to the standard methods of analysis. The compounds were tested for in vitro cytotoxicity against a mammalian cell-line, Chinese Hamster Ovarian (CHO) using the 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazoliumbromide (MTT)-assay. Studies on changes in peroxide and p-Anisidine values for the oils heated to temperatures between 180°C and 200°C recorded better stability enhancement at 100 ppm concentration with these flavonoids than the commercial antioxidant, butylated hydroxytoluene (BHT). The plant-based flavonoids had no significant cytotoxic effect against the CHO cell-line and may serve as alternative antioxidants to synthetic ones which have previously raised great concern over the health of consumers. 展开更多
关键词 POLYGONUM senegalense Antioxidant Activity methoxylated FLAVONOIDS Veg-etable OILS CYTOTOXIC Effect
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Advances in Enantioselective Construction of Trifluoromethoxylated Stereogenic Carbon Centers 被引量:2
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作者 Xiaohuan Jiang Pingping Tang 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2020年第1期101-102,共2页
In recent years,the trifluoromethoxy(OCF3)functional group has received extensive attention in phar-maceuticals,agrochemicals and material sciences.However,the methods for the enantioselective syn-thesis of trifluorom... In recent years,the trifluoromethoxy(OCF3)functional group has received extensive attention in phar-maceuticals,agrochemicals and material sciences.However,the methods for the enantioselective syn-thesis of trifluoromethoxylated stereogenic carbon centers are rare owing to the nature of easy decom-position of OCF3 anion and limited OCF3 reagent.And the asymmetric trifluoromethoxylation will be a hot research topic in near future due to the unique biological properties of a single isomer.This article mainly focuses on the recent advances in the enantioselectiveconstruction of trifluoromethoxylated stereogenic carbon centers. 展开更多
关键词 methoxyl REAGENT CENTERS
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STUDIES ON ZEOLITE-CATALYZED ALKOXY LATION OF TERPENES(Ⅲ)——METHOXYLATION OF α-PINENE AND β-PINENE
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作者 周萍 蒋文真 +2 位作者 郭衍萍 陈欣权 萧树德 《Chinese Science Bulletin》 SCIE EI CAS 1989年第2期125-129,共5页
We have reported H-Mordenite-catalyzed alkoxylation of camphene and tricyclene with C<sub>1</sub>--C<sub>4</sub> alcohols, and discussed the relationship of the structure to the odor of a serie... We have reported H-Mordenite-catalyzed alkoxylation of camphene and tricyclene with C<sub>1</sub>--C<sub>4</sub> alcohols, and discussed the relationship of the structure to the odor of a series of major products. Alkoxylation of α-pinene (3) and β-pinene (5), which are catalyzed by strongly acidic cation exchange resin, boron-trifluoride ether- 展开更多
关键词 Α-PINENE Β-PINENE methoxylATION ME α-terpinyl ETHER ME bornyl ether.
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Methoxylation and Direct Hydrogenative Coupling of Chloronitrobenzenes in Continuous Flow
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作者 Songjie Shi Li Wan +2 位作者 Xiaoning Sun Jiawei Zhang Kai Guo 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2017年第4期410-414,共5页
A novel continuous flow method for the methoxylation of chloronitrobenzenes was developed. The reaction went smoothly and high yields were achieved under the optimized conditions. Furthermore, up to 76% yield of azoxy... A novel continuous flow method for the methoxylation of chloronitrobenzenes was developed. The reaction went smoothly and high yields were achieved under the optimized conditions. Furthermore, up to 76% yield of azoxybenzenes were obtained from the corresponding nitrobenzenes in the presence of NaOH in continuous flow. Compared to batch conditions, the reaction time was significantly shortened, and the chemical waste was reduced obviously. 展开更多
关键词 methoxylATION AZOXYBENZENES chloronitrobenzenes continuous flow sodium methoxide
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Encapsulation of quercetin in pea protein-high methoxyl pectin nanocomplexes:Formation,stability,antioxidant capacity and in vitro release profile
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作者 Jiatong Li Xiaoge Zhang +3 位作者 Ru Zhao Yingcong Lu Ce Wang Cuina Wang 《Food Bioscience》 SCIE 2022年第4期493-500,共8页
Quercetin(Que)is a popular polyphenol with various activities.However,its application was limited due to its poor water solubility,stability,and low bioavailability.In this study,pea protein isolate(PPI)and high metho... Quercetin(Que)is a popular polyphenol with various activities.However,its application was limited due to its poor water solubility,stability,and low bioavailability.In this study,pea protein isolate(PPI)and high methoxyl pectin(HMP)complexes were fabricated to encapsulate and protect Que.Soluble PPI-HMP complexes at pH 5 and pH 6 were selected based on phase diagram of the two biopolymers during acidification.Fluorescence quenching experiments indicated that complex at pH 5 showed higher binding affinity towards Que than that at pH 6.Complexes at pH 5 displayed considerably higher encapsulation efficiency and loading ability with Que than those at pH 6.XRD results indicated that Que may be transformed from crystalloid to amorphous state after encapsulation.Photochemical and thermal stabilities of Que were improved by complexing with PPI-HMP nanocomplexes at both pH values.Encapsulation improved the 2,2-diphenyl-1-picrylhydrazyl(DPPH)and 2,2′-azinobis(2-ethylbenzothiazoline-6-sulfonate)(ABTS)free radical scavenging ability of Que and complex at pH 6 had higher antioxidative ability.The in vitro release study showed that Que displayed initial burst release followed by sustained release in simulated intestinal fluid and higher percentage of Que was released in complex at pH 6 than at pH 5.Data obtained may provide useful information for fabricating pea protein based effective delivery system for Que. 展开更多
关键词 Pea protein High methoxyl pectin QUERCETIN
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基于三氟(甲基/甲氧基)苯的新型电致变色的材料
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作者 杨留阳 沈双来 莫代泽 《广州化工》 2026年第1期64-69,94,共7页
近年来,三氟甲基(-CF3)和三氟甲氧基(-OCF3)基团因其独特的性质,在药物领域得到了广泛应用。但截至目前,它们在电致变色领域的应用仍十分有限。在本研究中,以3,4-乙烯二氧噻吩(EDOT)为末端单元,三氟甲基/三氟甲氧基苯单元为核心单元,通... 近年来,三氟甲基(-CF3)和三氟甲氧基(-OCF3)基团因其独特的性质,在药物领域得到了广泛应用。但截至目前,它们在电致变色领域的应用仍十分有限。在本研究中,以3,4-乙烯二氧噻吩(EDOT)为末端单元,三氟甲基/三氟甲氧基苯单元为核心单元,通过Stille偶联反应合成了四种不同的三氟甲基化/三氟甲氧基化单体。随后,采用电化学聚合法成功制备了P(TFOB-2,5-EDOT)和P(TFB-2,5-EDOT)两种聚合物薄膜。利用电化学技术和光谱电化学方法测试了单体及相应聚合物的电化学活性和电致变色性能。结果表明,P(TFB-2,5-EDOT)聚合物具有优异的着色效率(168.1 cm^(2)·C^(-1))、高光学对比度(37.1%)以及良好的光学稳定性和记忆效应。 展开更多
关键词 电致变色 三氟甲基/三氟甲氧基 EDOT 电化学聚合
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Voltammetric Behavior of Sodium 7-Methoxyl-4'-hydroxylisoflavone-3'-sulfonate and Its Application
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作者 张尊听 董社英 +2 位作者 郑建斌 张宏芳 高鸿 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2004年第9期920-924,共5页
Voltammetric behavior of sodium 7-methoxyl-4'-hydroxylisoflavone-3'-sulfonate (SMHS) in the aqueous solu-tion from pH 1 to 5 was studied by linear sweep voltammetry, cyclic voltammetry and normal pulse voltamm... Voltammetric behavior of sodium 7-methoxyl-4'-hydroxylisoflavone-3'-sulfonate (SMHS) in the aqueous solu-tion from pH 1 to 5 was studied by linear sweep voltammetry, cyclic voltammetry and normal pulse voltammetry. Experimental results showed that in 0.2 molL-1 sodium citrate-hydrochloric acid buffer solution (pH=4.65), SMHS caused only one reduction wave at -1.34 V (vs. saturated calomel electrode, SCE), which was an irreversi-ble adsorptive wave of SMHS protonized involving one electron and one proton. The peak current of SMHS on lin-ear sweep voltammogram was proportional to its concentration in the range of 8.0×10-6—8.0×10-5 molL-1 (r=0.995), and the detection limit was 5.0×10-6 mol昄-1. The method was applied to determination of SMHS in syn-thetic samples. In addition, its scavenging effect on superoxide anion radical was studied by the auto-oxidation of pyrogallol in HCl-tris buffer solution (pH=8.2) in order to explain its peculiar biological effects. The experimental results proved that SMHS has antioxidant quality, and it is an efficient free radical scavenger of superoxide anion radical. 展开更多
关键词 voltammetric behavior reduction sodium 7-methoxyl-4'-hydroxylisoflavone-3'-sulfonate superox-ide anion radical
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糖分子聚合度和种类对低酯酰胺果胶凝胶性能的影响
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作者 赵玮 毕金峰 +1 位作者 马有川 易建勇 《中国食品学报》 北大核心 2025年第1期61-71,共11页
果胶凝胶广泛应用于食品中,而许多凝胶食品均含有糖。前期研究表明,糖分子的聚合度和种类对果胶凝胶性能有显著影响,然而缺乏系统研究。本研究以常用的低酯酰胺果胶为对象,采用质构、流变、低场核磁、电镜观察等方法探讨果胶质量浓度为0... 果胶凝胶广泛应用于食品中,而许多凝胶食品均含有糖。前期研究表明,糖分子的聚合度和种类对果胶凝胶性能有显著影响,然而缺乏系统研究。本研究以常用的低酯酰胺果胶为对象,采用质构、流变、低场核磁、电镜观察等方法探讨果胶质量浓度为0.8~1.2 g/L、pH 2.5~5.5和钙离子浓度(R值为0.8~1.2)条件下,添加10%的不同种类和聚合度的糖分子对果胶凝胶成胶过程、凝胶强度、水分状态以及微观结构的影响,同时探讨不同聚合度和种类糖分子改变凝胶行为的可能机制。结果表明,添加不同种类糖在一定程度上可增加果胶凝胶强度,且随着糖聚合度的增加,其凝胶强度相应增加;在果胶质量浓度为0.8~1.2 g/L时,含有10%聚葡萄糖的果胶凝胶强度均显著高于其它种类糖,为未添加糖组的1.53~2.08倍。在不同R值(Ca^(2+)浓度)下,添加聚葡萄糖样品的凝胶强度也远高于添加其它种类糖的凝胶强度,当pH值为3.5时,添加葡萄糖的样品凝胶强度最大,为1.06 g/N,是未添加糖的1.28倍。本研究明确了8种糖分子对果胶凝胶性能的影响,为相关凝胶食品的制备提供了理论参考。 展开更多
关键词 低酯酰胺果胶 聚合度 凝胶 质构
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金属离子诱导低甲氧基果胶凝胶机制与应用研究进展
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作者 王凤昭 吕健 +1 位作者 谢晋 毕金峰 《中国食品学报》 北大核心 2025年第3期464-473,共10页
果胶因良好的凝胶性能而被广泛应用于食品中,其中低甲氧基果胶(LMP)在金属离子存在条件下即可形成凝胶,无需糖/糖醇类等共溶质,这对于开发低热量食品,制备药物递送体系等意义重大。本文综述金属离子诱导LMP凝胶的形成机制、影响因素以... 果胶因良好的凝胶性能而被广泛应用于食品中,其中低甲氧基果胶(LMP)在金属离子存在条件下即可形成凝胶,无需糖/糖醇类等共溶质,这对于开发低热量食品,制备药物递送体系等意义重大。本文综述金属离子诱导LMP凝胶的形成机制、影响因素以及在食品和医药领域的应用进展,以期为调控凝胶特性及拓宽LMP的应用范围提供理论参考。 展开更多
关键词 低甲氧基果胶 金属离子 蛋盒模型 静电相互作用 应用
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Two new C-glucoside oxanthrones from Rumex gmelini 被引量:1
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作者 Zhen Yue Wang Hai Peng Zhao +2 位作者 Yue Ming Zuo Zong Quan Wang Xian Ming Tang 《Chinese Chemical Letters》 SCIE CAS CSCD 2009年第7期839-841,共3页
Two new C-glucoside oxanthrones, 6-methoxyl-10-hydroxyaloin A (1) and 6-methoxyl-10-hydroxyaloin B (2), were isolated from the roots of Rumex gmelini Turcz. Their structures were elucidated on the basis of spectro... Two new C-glucoside oxanthrones, 6-methoxyl-10-hydroxyaloin A (1) and 6-methoxyl-10-hydroxyaloin B (2), were isolated from the roots of Rumex gmelini Turcz. Their structures were elucidated on the basis of spectroscopic techniques and chemical means C 2009 Zhen Yue Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All fights reserved. 展开更多
关键词 Rumex gmelini Turcz. C-glucosidc oxanthrones 6-methoxyl-10-hydroxyaloin A 6-methoxyl-10-hydroxyaloin B
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低甲氧基果胶的胶凝机理及防止预凝胶形成的措施 被引量:23
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作者 徐伟 马力 +3 位作者 袁永俊 熊华 朱秀灵 焦云鹏 《食品与发酵工业》 CAS CSCD 北大核心 2004年第3期90-93,共4页
对低甲氧基果胶的胶凝机理及影响胶凝的主要因素———pH值、可溶性固形物含量、钙离子浓度进行了探讨 ,并针对低甲氧基果胶应用中产生的降低产品质量的预凝胶问题进行了讨论 ,为分析低甲氧基果胶应用中的问题提供了依据 ,并提出了一些... 对低甲氧基果胶的胶凝机理及影响胶凝的主要因素———pH值、可溶性固形物含量、钙离子浓度进行了探讨 ,并针对低甲氧基果胶应用中产生的降低产品质量的预凝胶问题进行了讨论 ,为分析低甲氧基果胶应用中的问题提供了依据 ,并提出了一些防止预凝胶形成的措施。 展开更多
关键词 低甲氧基果胶 胶凝机理 预凝胶 预防措施 PH值 可溶性固形物含量
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海藻酸钠高甲氧基果胶复合体系凝胶特性的研究 被引量:11
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作者 周爱梅 郝淑贤 +3 位作者 刘欣 曾庆孝 李立虹 林洁 《华南农业大学学报》 CAS CSCD 北大核心 2003年第4期75-78,共4页
研究了海藻酸钠 高甲氧基果胶复合体系的凝胶特性及pH值、凝胶温度和时间对其凝胶特性的影响.结果表明:海藻酸钠和高甲氧基果胶具有协同作用,且体系的凝胶强度、持水性、凝固点和融点与两种胶的质量比、胶体总质量分数、pH值、凝胶温度... 研究了海藻酸钠 高甲氧基果胶复合体系的凝胶特性及pH值、凝胶温度和时间对其凝胶特性的影响.结果表明:海藻酸钠和高甲氧基果胶具有协同作用,且体系的凝胶强度、持水性、凝固点和融点与两种胶的质量比、胶体总质量分数、pH值、凝胶温度和时间密切相关.随海藻酸钠/果胶质量比增加,体系凝胶强度和凝胶融点增加,并在取得最大值后又下降,而持水性与凝固温度则变化不大;在pH3 0~3 5,体系可形成性能较好的凝胶,而当pH>4 20时,不能凝胶,pH还对凝胶融点有影响,而对凝固点影响不大;随凝胶温度升高,体系凝胶强度显著下降,凝胶融点也下降;在15℃凝胶6h,体系即可形成稳定的凝胶体. 展开更多
关键词 海藻酸钠 高甲氧基果胶 凝胶特性 PH值 温度 食品工业 凝胶剂
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甲基苯基氯硅烷和苯基三氯硅烷混合物的GC-MS分析 被引量:11
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作者 蒋可志 蒋剑雄 +3 位作者 来国桥 邬继荣 倪勇 邱化玉 《分析测试学报》 CAS CSCD 北大核心 2006年第3期106-108,共3页
使用GC-MS分析热缩合法生产的氯硅烷粗单体时,发现甲基苯基二氯硅烷和苯基三氯硅烷在HP-5毛细管柱上难以得到有效的分离。采用过量甲醇对粗产品氯硅烷进行甲氧基化后,甲基苯基二氯硅烷和苯基三氯硅烷相应的甲氧基化产物在色谱柱上能得... 使用GC-MS分析热缩合法生产的氯硅烷粗单体时,发现甲基苯基二氯硅烷和苯基三氯硅烷在HP-5毛细管柱上难以得到有效的分离。采用过量甲醇对粗产品氯硅烷进行甲氧基化后,甲基苯基二氯硅烷和苯基三氯硅烷相应的甲氧基化产物在色谱柱上能得到有效的分离,可为其色谱分析提供依据。 展开更多
关键词 甲基苯基二氯硅烷 苯基三氯硅烷 气相色谱-质谱 甲氧基化
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核桃壳木质素的^1H—NMR分析 被引量:16
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作者 郑志锋 邹局春 +2 位作者 陈浪 张宏健 凌敏 《西北林学院学报》 CSCD 北大核心 2007年第2期131-133,共3页
在核桃壳磨木木质素(MW L)提取纯化的基础上,对纯化的核桃壳磨木木质素进行了C、H、O及OCH3含量的测定,并利用1H-NMR对核桃壳木质素基本化学结构进行研究。结果表明:(1)核桃壳木质素的C、H、O含量分别为67.15%、5.73%和27.12%,甲氧基含... 在核桃壳磨木木质素(MW L)提取纯化的基础上,对纯化的核桃壳磨木木质素进行了C、H、O及OCH3含量的测定,并利用1H-NMR对核桃壳木质素基本化学结构进行研究。结果表明:(1)核桃壳木质素的C、H、O含量分别为67.15%、5.73%和27.12%,甲氧基含量为18.19%;(2)核桃壳木质素C9经验式为C9H9.22O1.99(OCH3)1.05,其C9单元结构的相对分子量为181.61;(3)核桃壳木质素属GS型木质素,其中G型木质素占多数,为80.68%;(4)核桃壳木质素中酚羟基(OHph)和脂肪族羟基(OHaliph)分别占总羟基数的32.21%和67.79%;(5)核桃壳木质素中存在较多的-βO-4、-β5和β-β结构。 展开更多
关键词 核桃壳 木质素 元素分析 甲氧基 ^1H—NMR
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正交试验优化向日葵盘果胶的提取和基本分析 被引量:14
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作者 王琨 华霄 +3 位作者 杨瑞金 康佳琪 张文斌 赵伟 《食品科学》 EI CAS CSCD 北大核心 2013年第14期1-5,共5页
研究向日葵盘果胶(SFHP)的提取工艺。通过单因素试验,比较酸化水、0.75%六偏磷酸钠、0.5%乙二胺四乙酸二钠、0.5%草酸-草酸铵、0.5%草酸和0.5%草酸铵6种提取剂的提取效果,确定较优的提取剂种类。选择pH值、提取温度、提取时间和提取固... 研究向日葵盘果胶(SFHP)的提取工艺。通过单因素试验,比较酸化水、0.75%六偏磷酸钠、0.5%乙二胺四乙酸二钠、0.5%草酸-草酸铵、0.5%草酸和0.5%草酸铵6种提取剂的提取效果,确定较优的提取剂种类。选择pH值、提取温度、提取时间和提取固液比为主要工艺参数,通过正交试验,确定较优的提取参数组合:pH3.50、提取时间45min、提取温度85℃、固液比1:30(g/mL)。在此条件下,向日葵盘果胶得率为20.9%(以半乳糖醛酸计)。采用高效尺寸排阻色谱-多角度激光散射检测器(HPSEC-MALLS)和高效阴离子交换色谱-脉冲安培检测器(HPAEC-PAD)测定了向日葵盘果胶的分子质量和单糖组成。结果表明,向日葵盘果胶的分子质量高于柑橘果胶,半乳糖醛酸为最主要单糖成分,占单糖总量的82.1%,鼠李糖为次要成分,仅占单糖总量的9.1%。 展开更多
关键词 向日葵盘 低甲氧基果胶 分子质量 单糖组成
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低酯果胶的流变学性能研究 被引量:28
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作者 汪海波 徐群英 汪芳安 《农业工程学报》 EI CAS CSCD 北大核心 2006年第11期223-227,共5页
以商品低酯果胶为研究对象。以AR-500型动态流变仪为主要设备,考察低酯果胶溶液的流变学基本特性,以及温度、剪切速率、体系pH值、金属离子、糖等因素对其流体性能的影响。结果表明,低酯果胶溶液是典型的剪切稀化型非牛顿流体,果胶... 以商品低酯果胶为研究对象。以AR-500型动态流变仪为主要设备,考察低酯果胶溶液的流变学基本特性,以及温度、剪切速率、体系pH值、金属离子、糖等因素对其流体性能的影响。结果表明,低酯果胶溶液是典型的剪切稀化型非牛顿流体,果胶浓度越高,溶液剪切稀化现象越严重。同时其溶液流体行为受温度、剪切速率、pH值等因素的影响。体系温度和pH值的升高均可导致溶液黏度降低;剪切速率的影响与果胶浓度有关,在低浓度条件下(0.3%),低速率时(0~200s^-1)剪切稀化现象越严重,高速率(400~700s^-1)时转变为胀塑性流体;在高浓度(1%、2%)条件下,随着剪切速率增高,溶液流体逐渐趋向于理想状态的牛顿流体。金属二价离子对低酯果胶溶液有显著的增稠效应,其增稠效果与离子浓度呈正相关。 展开更多
关键词 低酯果胶 流变学性能 温度 剪切速率 PH值 金属离子
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