超声波辅助提取光皮木瓜多糖及其体外抗氧化性研究

通过单因素以及正交试验研究超声波辅助提取光皮木瓜多糖的最佳工艺及其体外抗氧化性。结果表明：超声波辅助提取光皮木瓜多糖的最佳提取条件为料液比1:45(g/mL)、提取温度80℃、提取时间40min,超声波功率600W,在此条件下多糖的提取率为12.072%。光皮木瓜多糖对NO2、DPPH·以及·OH 清除作用明显,具有较好的还原力,表明光皮木瓜多糖有较好的抗氧化活性。     

响应面试验优化超声波提取光皮木瓜黄酮和多糖复合物

目的：促进光皮木瓜资源的综合利用。方法：采用Box-Behnken试验设计和响应面分析法,优化木瓜黄酮和多糖复合提取工艺。结果：超声波法提取光皮木瓜黄酮和多糖的工艺条件为超声波功率480W、提取时间35min、温度73℃、液料比为90:1(mL/g),黄酮和多糖总得率为15.62%,比热水浸提法总得率提高了21.46%。结论：超声波法提取光皮木瓜黄酮和多糖复合物得率较高。     

光皮木瓜中齐墩果酸的提取工艺研究

以光皮木瓜中的齐墩果酸提取率为考察指标,探讨乙醇体积分数、药材粒径、提取温度、料液比、提取时间、提取次数对回流提取的影响;通过正交试验得到最优提取工艺条件为:乙醇体积分数80%,料液比1:10(g/mL),提取温度70℃,提取时间2h,提取2次,粒度60目。在此工艺条件下,光皮木瓜中齐墩果酸提取率约为0.290%。     

从脐橙皮中提取可溶性多糖的工艺条件研究

目的：研究脐橙皮中水溶性多糖的提取条件,测定其多糖含量。方法：通过单因素试验和正交试验,研究料液比、温度、时间对多糖提取率的影响。结果：在此实验范围内料液比、时间和温度对脐橙皮多糖提取率的影响均达到了极显著水平,其影响程度顺序为：提取温度>提取时间>料液比,确定出脐橙皮多糖的最佳提取条件为：料液比1:40(W/V),提取时间3h,提取温度95℃。在最佳提取条件下,脐橙皮的多糖提取率为6.82%。     

木瓜叶多糖的提取及抗氧化活性研究

以木瓜叶为原料,用超声波辅助提取木瓜叶中的多糖,并对其抗氧化活性进行研究。通过单因素试验和正交试验确定最佳提取条件,试验表明:超声波频率90kHz、醇沉浓度95%、提取时间60min、料液比1:25(m/v)的条件下,木瓜叶中多糖得率最高,达到2.47%。抗氧化试验表明,木瓜叶多糖具有较强清除DPPH.和.OH自由基的能力,其IC50(半抑制浓度)分别为29、110μg/mL。     

基于Design-Expert 软件设计优化大蒜多糖提取工艺

主要研究大蒜多糖提取的4种影响因素及其交互作用对大蒜多糖提取率的影响,借助于Design-Expert软件设计,优化大蒜多糖提取工艺条件,以期为开发利用大蒜多糖提供参考。采用水煮醇沉法提取大蒜多糖,以苯酚-硫酸法检测其含量,分别考察浸提时间、料液比、浸提温度及浸提次数对大蒜多糖得率的影响。在单因素试验的基础上,利用Design-Expert软件进行四因素三水平Box-Behnken试验设计,建立了大蒜多糖提取率和各因素之间的数学模型。结果表明,提取温度、液料比、提取时间和提取次数的一次项,个别交互项及其二次项对大蒜多糖得率的影响显著,而液料比与提取时间,液料比与提取次数的交互项作用不明显。大蒜多糖提取最优条件最终确定为:提取温度81℃,液料比14∶1(m L/g),提取时间84 min,提取次数2次。     

光皮木瓜绿原酸的提取及抗菌活性测定

为提高木瓜的利用价值,首次利用甲醇研究光皮木瓜中绿原酸的最佳提取工艺,在单因素试验基础上,通过正交试验设计考察浸提溶剂体积分数、浸提温度、浸提料液比和浸提时间对绿原酸提取的影响,并初步考察绿原酸样品液对志贺氏痢疾杆菌及金黄色葡萄球菌的抗菌活性。结果表明从木瓜中提取绿原酸的最佳工艺条件为：以85% 甲醇溶液(85:15,V/V)浸提木瓜粉、浸提料液比1:30(g/mL)、浸提温度40℃、浸提时间14h。在该工艺条件下,绿原酸的最高产率可达到0.142%。绿原酸提取液对志贺氏痢疾杆菌和金黄色葡萄球菌具有明显的抗菌活性,表明民间所用的木瓜白酒浸泡液的主要药理活性成分可能为绿原酸。     

正交试验法提取四倍体板蓝根多糖的最佳工艺

优选四倍体板蓝根多糖提取的最佳工艺条件.用正交试验法设计最佳提取工艺条件,以提取物中多糖得率为测定指标,考察脱脂液、温度、料液比和醇沉比例四个因素对提取多糖的影响.最佳提取工艺条件为:脱脂液为乙醚,温度为100℃,料液比1∶20(g/mL),醇沉比例为80%,板蓝根根部多糖的提取率为3.08%.该方法可以适用于四倍体板蓝根多糖的提取.     

袖珍菇多糖提取的研究

以袖珍菇为原料进行多糖技术提取研究。通过单因素试验和正交试验,研究对袖珍菇热水提取的工艺条件中料液比、时间、温度、浸提次数、醇沉条件对袖珍菇多糖提取率的影响,从而得到最佳工艺条件组合:料液比:1∶40(mg/mL),浸提温度:80℃,浸提时间:2 h,醇沉时乙醇浓度:70%,醇沉时间:4 h,醇沉温度:25℃。     

响应面优化绿豆皮不溶性膳食纤维超声辅助提取工艺

以绿豆皮为原料,采用超声波辅助碱法提取绿豆皮不溶性膳食纤维,通过单因素实验来探讨提取时间、提取温度、超声功率、碱液浓度、液料比五个因素对不溶性膳食纤维提取率的影响,并通过响应面分析来优化工艺条件。结果表明:采用碱液浓度3.0 mol/L,液料比15:1 mL/g,温度52 ℃,在350 W超声波作用下提取148 min,不溶性膳食纤维提取率最大为66.28%±0.052%,此工艺可以有效地从绿豆皮中提取不溶性膳食纤维。     

褪黑素对小鼠抗氧化作用的影响

目的:研究小鼠在受到脂多糖(LPS)刺激时,褪黑素的抗氧化作用,并探讨其可能机制。方法:用脂多糖建立氧化应激模型,检测血清、小肠、肝脏和脾组织中的ROS含量,肝脏、脾组织中的谷胱甘肽过氧化物酶(GSH-PX)、超氧化物歧化酶(SOD)、丙二醛(MDA)的变化。结果:在LPS刺激后的4h和16h,褪黑素均能降低血清、小肠、肝脏、脾组织中的ROS含量,提升肝脏和脾组织中的GSH-PX、SOD活性,降低MDA含量。结论:褪黑素有助于增强氧化应激小鼠的抗氧化能力,降低组织中NO含量与NO合成酶活性,增加了SOD、GSH-PX等抗氧化酶的活性,保护机体免受氧化损伤。     

Determination of the variability of both hydrophilic and lipophilic toxins in endemic wild bivalves and carnivorous gastropods from the Southern part of Chile

The aim of this study was to analyse and determine the composition of paralytic shellfish poisoning (PSP) toxins and lipophilic toxins in the Region of Aysén, Chile, in wild endemic mussels (Mytilus chilensis, Venus antiqua, Aulacomya ater, Choromytilus chorus, Tagelus dombeii and Gari solida) and in two endemic carnivorous molluscs species (Concholepas concholepas and Argobuccinum ranelliforme). PSP-toxin contents were determined by using HPLC with fluorescence detection, while lipophilic toxins were determined by using LC-MS/MS. Mean concentrations for the total of PSP toxins were in the range 55–2505 μg saxitoxin-equivalent/100 g. The two most contaminated samples for PSP toxicity were bivalve Gari solida and carnivorous Argobuccinum ranelliforme with 2505 ± 101 and 1850 ± 137 μg saxitoxin-equivalent/100 g, respectively (p < 0.05). The lipophilic toxins identified were okadaic acid, dinophysistoxin-1 (DTX-1), azaspiracid-1 (AZA-1), pectenotoxin-2 (PTX-2) and yessotoxins (YTX). All analysed molluscs contained lipophilic toxins at levels ranging from 56 ± 4.8 to 156.1 ± 8.2 μg of okadaic acid-equivalent/kg shellfish together with YTX at levels ranging from 1.0 ± 0.1 to 18 ± 0.9 μg of YTX-equivalent/kg shellfish and AZA at levels ranging from 3.6 ± 0.2 to 31 ± 2.1 μg of AZA-equivalent/kg shellfish. Furthermore, different bivalves and gastropods differ in their capacity of retention of lipophilic toxins, as shown by the determination of their respective lipophilic toxins levels. In all the evaluated species, the presence of lipophilic toxins associated with biotransformation in molluscs and carnivorous gastropods was not identified, in contrast to the identification of PSP toxins, where the profiles identified in the different species are directly related to biotransformation processes. Thus, this study provides evidence that the concentration of toxins in the food intake of the evaluated species (Bivalvia and Gastropoda class) determines the degree of bioaccumulation and biotransformation they will thereafter exhibit.     

高效液相色谱法同时检测6种甜味剂

建立同时测定6种人工合成甜味剂阿斯巴甜、糖精钠、甜蜜素、安塞蜜、纽甜、甜聚糖甙的高效液相色谱分析方法。以Platicil ODS柱为分离柱,20mmol/L硫酸铵缓冲溶液(pH4.4)-乙腈为流动相,进行梯度洗脱。采用二极管阵列检测器进行检测,整个分离过程在30min内完成。6种甜味剂在0.4～120mg/L范围内其质量浓度与峰面积的线性关系良好,相关系数为0.99967～0.99998,在4.0～10.0mg/kg范围内,样品加标回收率为85%～107%;相对标准偏差小于3.2%。该方法简便、快速,净化效果较好,可用于食品中6种甜味剂的同时测定。     

气相色谱法检测饮料中二羰基化合物

建立同时在线检测丙酮醛和乙二醛的气相色谱方法。确定检测二羰基化合物的最佳条件为：以丁二酮为内标,以邻苯二胺为衍生化试剂,邻苯二胺的用量67 倍于二羰基化合物、衍生化时间10 min、萃取溶剂二氯甲烷、超声时间15 min、萃取2 次、柱箱初始温度40 ℃、程序升温5 ℃/min,色谱柱载气流量2.0 mL/min,分流比1∶1。丙酮醛和乙二醛的定量限（RSN≈10）分别为0.06 mg/L和0.08 mg/L,检出限（RSN≈ 3）分别为0.02 mg/L和0.03 mg/L,方法灵敏度高。     

对药剂敏感性不同的烟蚜体内几种关键性酶活性的比较分析

对吡虫啉和氧化乐果在三明地区和合肥地区烟蚜的毒力进行了测定,并对两地烟蚜的羧酸酯酶、乙酰胆碱酯酶和谷胱甘肽转移酶的活性进行了研究.结果表明吡虫啉对两地烟蚜的生物活性远高于氧化乐果,三明烟蚜对两种药剂的敏感性都比合肥烟蚜的低,三明烟蚜种群的毒力方程b值低,存在一定的异质性;两地烟蚜的羧酸酯酶、乙酰胆碱酯酶活性差异不显著,但三明地区烟蚜的谷胱甘肽转移酶活性显著高于合肥地区烟蚜.     

盐胁迫对芦荟几项生理生化指标的影响

以常规库拉索芦荟为对照 ,检测经不同浓度海水灌溉 3a的库拉索芦荟的几项生理生化指标的变化。结果表明 ,盐胁迫对芦荟全叶原汁的吸光度、pH值、相对密度、总固形物、水分含量和镁离子含量的影响较小 ,但对多糖和钙离子含量的影响较大。 2 5 %或 5 0 %海水灌溉的芦荟中多糖含量很高 ,增加了 2～ 3倍 ;低浓度海水灌溉下 ,芦荟中钙离子含量高于对照 (CK) ;而在高浓度海水灌溉下 ,芦荟中钙离子含量则低于CK。在盐胁迫下 ,芦荟体内积累一定量丙二醛 ,而脯氨酸含量则下降 ;过氧化物酶活力先在低盐条件下显著提高 ,随后则下降 ,与CK相当 ;过氧化氢酶活力随海水浓度的提高而迅速下降 ;超氧物歧化酶活力受盐浓度影响不大 ,基本上趋于稳定。     

Correlation of methylglyoxal with acrylamide formation in fructose/asparagine Maillard reaction model system

α-Dicarbonyl compounds were highly reactive intermediates formed in Maillard reaction (MR), and o-phenylenediamine (OPD) was widely used as a trapping agent for α-dicarbonyl compounds. Both aqueous fructose/asparagine (Fru/Asn) and fructose/asparagine/o-phenylenediamine (Fru/Asn/OPD) model systems were heated at 150 °C for up to 30 min. Methylglyoxal (MG) was the main α-dicarbonyl compounds formed in MR, which was chosen as a representative of α-dicarbonyl compound to investigate the influence on acrylamide (AA) formation. The concentrations of AA, MG and Asn were detected during MR by HPLC method. The results indicated that the formation of AA increased with the heating time, and nearly 75% of AA was formed through the participation of α-dicarbonyl compounds. The amounts of formation and consumption of MG increased with heating time, and from 12 min of reaction, the consumed amounts of MG accounted for 62.1–90.3% on the basis of total amounts of MG formed in MR, suggesting that most of the MG took part in further reactions. Meanwhile, Asn concentration decreased with heating time in both models. The formation of AA and consumption of Asn were highly correlated with MG. Indeed, as MG concentration in MG/Asn model system decreased during heating at 150 °C, the concentration of AA significantly increased. The coefficient of correlation between consumed amounts of MG and the formed amounts of AA was 0.931, demonstrating that MG plays a role in AA formation.     

Analysis of carbohydrates in seven edible fruits of Bangladesh

Dry matter, ash, lignin, starch and soluble and insoluble dietary fibre contents of the edible parts of seven fruits of Bangladesh were determined. Analysis of the low molecular weight carbohydrates showed that all the fiuits, except lukluki and hogplum, contained substantial amounts of these materials of which glucose and fiuctose were the main components. The main constituent of the polysaccharides in all the fruits was glucose. The dietary fibre contents of the dry fruits ranged from 29% to 79%. Lukluki has by far the best combination of low fiee sugars and high dietary fibre, and pineapple the worst.     

嘧菌酯处理对厚皮甜瓜POD和CAT活性的影响

以厚皮甜瓜(Cucumis melonL.)作为实验材料,研究嘧菌酯处理对厚皮甜瓜采后过氧化物酶和过氧化氢酶活性的影响,实验结果表明:甜瓜经50、100、200mg/L嘧菌酯浸泡处理后,其果实的过氧化物酶和过氧化氢酶活性均有所变动,其中,100mg/L嘧菌酯处理,两种酶的活性均处于稳定上升趋势,到第14天达到最高值,此后呈下降趋势,但到第21天时,酶活性仍高于对照。     

亚甲基蓝对单增李斯特菌菌膜的光动力杀伤作用

探讨单增李斯特菌（Listeria monocytogenes,LM）生物菌膜的生长特性及亚甲基蓝对LM生物菌膜光动力杀伤作用。通过结晶紫染色法判断与观察LM生物菌膜的形成并用酶标仪在595 nm波长处对其不同生长阶段的生物量进行测定,同时通过细菌平板菌落计数法研究亚甲基蓝对LM生物菌膜的光动力杀伤作用。结果表明：结晶紫染色法可用于定性判断与观察LM生物菌膜,且随着培养时间的延长,LM生物菌膜生物量不断增加,形成的网状结构越来越致密。当光敏剂质量浓度为10 μg/mL的亚甲基蓝在光功密度为200 mW/cm2 的可见光照射30 min时,即可使LM生物菌膜的失活率达到99.99%以上,其菌落数降低了4.08（lg（CFU/mL））。亚甲基蓝对LM生物菌膜的光动力灭活作用非常显著,其杀伤效果主要取决于光敏剂质量浓度和光照时间。