石花菜醇提物提取工艺及抗氧化、抗菌活性研究

在单因素实验基础上,通过响应面法优化石花菜醇提物的提取工艺。将石花菜醇提物经石油醚、乙酸乙酯和正丁醇依次萃取,研究不同萃取相的抗氧化和抑菌活性。结果表明,石花菜醇提物的最佳提取工艺为:60%乙醇溶液、料液比1∶35、提取时间64 min、超声功率350 W、提取温度55 ℃。在此条件下,石花菜醇提物得率为0.0165 g/g,DPPH自由基清除率为58.29%(质量浓度2 mg/mL)。不同萃取相抗氧化和抗菌活性均具有浓度依赖性,其中乙酸乙酯相活性最强,清除DPPH自由基、ABTS+自由基和羟基自由基的IC50值分别为672.4,14.1,599.7 μg/mL。对金黄色葡萄球菌和副溶血性弧菌的最小抑菌浓度(MIC)分别为156.3,156.3 μg/mL,最小杀菌浓度(MBC)分别为625,312.5 μg/mL。     

油茶花醇提物的体外抗氧化活性研究

测定油茶花醇提物冻干粉的活性成分,并以DPPH自由基(DPPH·)清除率、羟自由基(·OH)清除率、亚铁离子(Fe2+)鳌和率和总还原力为指标研究体外抗氧化活性,并同维生素C和叔丁基对苯二酚(TBHQ)进行比较.结果 表明:油茶花醇提物含总黄酮(134.72±1.36) mg/g、总多酚(79.80±1.05) mg/...     

槐耳醇提物的抗氧化降血糖活性

采用分光光度计法对槐耳醇提物进行成分分析,采用四种方法对其抗氧化性进行评估,并探讨其对α-淀粉酶的抑制作用。结果表明:槐耳醇提物中多酚含量为103.62 mg PE/g FDW(Pyrogallol equivalent,PE;Freeze drying weight,FDW),黄酮含量为195.64 mg RE/g FDW(Rutin equivalent,RE),黄酮醇含量为1.50 mg RE/g FDW,黄烷醇含量为203.2 mg CE/g FDW(Catechin equivalent,CE),酚酸含量为43.79 mg PE/g FDW;通过铁离子还原抗氧化能力、清除ABTS+自由基能力、总还原力和总抗氧化力四种方法得出槐耳醇提物具有较强的抗氧化活性;槐耳醇提物抑制α-淀粉酶的IC50值为1.28 mg/mL,表明其具有高效的降血糖的能力。     

五种蜂花粉醇提物抗氧化能力的比较

比较五种蜂花粉醇提物的抗氧化能力。在最佳提取条件下提取蜂花粉中的抗氧化物质,并通过DDPH自由基(DPPH.)、羟基自由基(.OH)、超氧阴离子自由基(O2-.)、亚硝酸盐的清除效果以及还原力,研究其抗氧化活性。五种蜂花粉醇提物均表现出较强的抗氧化活性,但抗氧化能力均小于VC,除荷花蜂花粉外其他四种蜂花粉醇提物抗氧化能力均大于BHT,且抗氧化活性与醇提物质量浓度呈正相关。五种蜂花粉均是很好的天然抗氧化剂。     

猴头菇醇提物及其不同极性部位的体外抗氧化活性

以猴头菇为原材料,探究猴头菇醇提物及其不同极性萃取相的体外抗氧化活性。采用不同极性有机溶剂萃取猴头菇醇提物得到石油醚相、乙酸乙酯相、正丁醇相和水相4个不同极性部位萃取物。分别测定各极性部位总酚和总黄酮含量,并比较猴头菇醇提物及其各极性部位的体外抗氧化活性。结果表明:乙酸乙酯相的总酚和总黄酮含量最高,分别为16.52 mg/g和10.08 mg/g。猴头菇醇提物及其不同极性部位萃取物均具有一定的抗氧化活性,其中乙酸乙酯相的抗氧化活性相对较高,对DPPH·、·OH和ABTS⁺·的清除率分别可达到41.64%（2.5 mg/m L）、82.84%（2.5 mg/m L）和89.18%（0.5 mg/m L）。由此可见,猴头菇醇提物的乙酸乙酯相萃取组分具有较好的抗氧化活性,可作为主要活性部位进行后续单体分离研究。      

金银花醇提物的抗氧化及保肝作用

采用电子自旋共振(ESR)技术检测金银花不同浓度醇提物清除DPPH自由基的能力。利用DMN诱导大鼠肝损伤模型,评价金银花醇提物对大鼠血清中ALT、AST、ALP、ALB、γ-GT、TP,组织匀浆中MDA、GPX水平的影响,并结合病理学Azan染色,研究其对大鼠肝纤维化损伤的保护作用。研究结果:75%金银花醇提物清除DPPH自由基的能力最强,其IC50值为195.75μg/m L,并可抑制大鼠血清中ALT、AST、γ-GT、ALP的水平升高。与模型组相比既能使大鼠中ALB和TP的水平升高,又能降低肝组织中MDA、GPX含量。肝组织Azan染色显示金银花、利加隆治疗组肝细胞变性坏死较模型组明显降低,肝组织内结缔组织增生也明显减轻。     

脱脂油棕果肉醇提物体外抗氧化活性研究

本研究主要分析了脱脂嫩油棕果醇提物(YNE)及脱脂成熟油棕果醇提物(MNE)的体外抗氧化活性。结果表明,YNE清除DPPH.的能力显著高于MNE,但二者的清除能力均显著低于对照物Trolox、没食子酸和BHT。YNE与Fe2+的络合能力显著高于MNE及3种对照物,MNE与Fe2+的络合能力显著高于Trolox,但与没食子酸及BHT无显著差异。在多酚含量为0.6mg/mL以下,YNE清除ABTS+.的能力高于MNE,但当多酚含量在0.6mg/mL以上时二者无显著差异。MNE及YNE清除OH.的能力相当,均显著高于3种对照物。MNE对脂质过氧化的抑制能力显著高于YNE,但都显著低于3种对照物。     

蜜蜂巢脾醇提物的抗氧化活性研究

目的：研究蜜蜂巢脾不同浓度乙醇提取物的综合抗氧化能力。方法：制备蜜蜂巢脾的乙醇提取物;测定蜜蜂巢脾的总多酚和总黄酮含量;采用总抗氧化力、清除DPPH自由基、还原力、清除超氧阴离子自由基(O2－ ·)、清除羟自由基( ·OH)能力等指标,评价蜜蜂巢脾醇提物的综合抗氧化性能。结果：6种不同浓度乙醇提取物中50%醇提物的总多酚含量最多为(9.75±0.16)mg/g,95%醇提物中黄酮含量最多为(14.2±0.26)mg/g;抗氧化实验结果表明,6种不同浓度乙醇提取物均有较强的综合抗氧化能力,其综合抗氧化能力由大到小依次为：50%醇提物、75%醇提物＞25%醇提物、95%醇提物、水提物＞100%醇提物。结论：蜜蜂巢脾醇提物是一种优良的天然抗氧化剂。     

三种香辛料醇提物对三文鱼丸冻藏期间色泽和抗氧化稳定性的影响

研究了桂皮、大茴香和丁香三种香辛料醇提物对三文鱼丸冻藏期间色泽和抗氧化性的影响.实验结果表明:三种香辛料(桂皮、大茴香、丁香)醇提物对三文鱼丸冻藏期间的L?值和b?值无显著影响(p>0.05),桂皮醇提物显著提高了a?值(p<0.05),大茴香和丁香醇提物对a?值无显著影响(p>0.05).三种香辛料(桂皮、大茴香、丁...     

三种香辛料提取物的抗氧化活性研究

主要研究了丁香、桂皮和花椒三种香辛料的抗氧化活性.实验结果表明:三种香辛料提取物对DPPH自由基的清除效果较BHT好,三种香料提取物清除过氧化氢效果较好.     

香辛料提取物对生肉糜的抗氧化作用

研究了迷迭香、肉桂、丁香提取物对生肉糜的抗氧化效果,测定了生肉糜在贮藏期间色差、pH、硫代巴比妥酸反应物值(TBARS)、高铁肌红蛋白(metMb)的变化,并与BHA进行比较,结果表明香辛料提取物能显著抑制肉糜中脂肪的氧化,增加肉糜鲜红的色泽,与0.02%BHA效果相当.     

Antioxidant activity of spice extracts in a liposome system and in cooked pork patties and the possible mode of action

Three experiments were conducted to assess the antioxidant efficacy of spice extracts in cooked meat. In experiment 1, antioxidant activity of 13 common spice extracts was screened in a liposome system. Six of the extracts (clove, rosemary, cassia bark, liquorice, nutmeg, and round cardamom), identified to have the greatest total phenolic contents, were strongly inhibitory of TBARS formation. In experiment 2, 2,2-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, ferric-reducing power, and metal chelation of these six spice extracts were evaluated. Clove exhibited the greatest reducing power, and all had strong DPPH scavenging activity. In experiment 3, clove, rosemary, and cassia bark extracts were further tested for in situ antioxidant efficacy. Cooked pork patties containing these spice extracts had markedly reduced TBARS formation and off-flavour scores but a more stable red colour, during storage. The results demonstrated strong potential of spice extracts as natural antioxidants in cooked pork products.     

The in vitro antibacterial activity of dietary spice and medicinal herb extracts

The in vitro antibacterial activities of a total of 46 extracts from dietary spices and medicinal herbs were investigated by agar-well diffusion method against five foodborne bacteria (Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Salmonella anatum). Their total phenolic contents were also evaluated. Many herb and spice extracts contained high levels of phenolics and exhibited antibacterial activity against foodborne pathogens. Gram-positive bacteria were generally more sensitive to the tested extracts than Gram-negative ones. S. aureus was the most sensitive, while E. coli was the most resistant. There were highly positive relationships (R(2)=0.73-0.93) between antibacterial activities and phenolic content of the tested extracts against each bacterium. This suggested that the antibacterial activity of the tested extracts was closely associated with their phenolic constituents.     

石榴皮提取物的抗氧化作用研究

分别以水、甲醇、丙酮和乙酸乙酯为溶剂,对石榴皮中的多酚进行了提取,得到4种提取物。采用油脂过氧化值(POV)法和二苯三硝基苯肼(DPPH)自由基法研究了提取物的抗氧化活性。结果显示,4种提取物均具有抗油脂过氧化和清除DPPH自由基的能力,其抗氧化活性随添加量的增加而增加。4种提取物中,丙酮提取物的抗油脂过氧化作用最大,其次为水提取物和甲醇提取物,乙酸乙酯提取物的抗油脂过氧化作用最小。当丙酮提取物添加量为猪油质量的0.1%时,其抗油脂过氧化活性接近添加量为0.02%茶多酚或BHT。4种提取物对DPPH自由基的清除能力大小顺序依次为:水提取物、丙酮提取物、甲醇提取物和乙酸乙酯提取物。浓度为0.0175 mg/mL的水提取物对DPPH自由基的清除率高达85.2%,高于BHT,但略低于茶多酚。石榴皮多酚是一种有效的天然抗氧化剂。     

黑豆提取物抗氧化性的研究

以抗坏血酸为参照物,对黑豆提取物的抗氧化性进行研究,结果表明,黑豆提取物具有比较强的DPPH·自由基清除能力、超氧阴离子自由基清除能力、抗脂质体氧化能力以及还原能力。因此,黑豆提取物具有可以作为天然的抗氧化剂应用于食品开发的潜质。     

Antioxidant and antimicrobial activity of guarana seed extracts

The antioxidant and antibacterial activities of guarana (Paullinia cupana) seed extracts were determined. The seeds were extracted with water, methanol, 35% acetone and 60% ethanol at room (T_R) and at boiling (T_B) temperature of solvent.     

Antioxidant activity of mechanically separated pork extracts

Utilization of synthetic carnosine as a food additive is limited by both regulatory and economic hurdles. Therefore, the potential of producing carnosine-containing antioxidant extracts from an underutilized skeletal muscle source, mechanically separated pork (MSP), was investigated. Carnosine-containing MSP extracts were capable of inhibiting lipid oxidation both in vitro and in salted ground pork. Heating (60-80°C) the MSP extract removed iron and increased in vitro antioxidant activity. Isolation of a low molecular weight fraction of the MSP extract by ultrafiltration was effective at decreasing iron but did not substantially increase in vitro antioxidant activity. Freeze dried extracts (untreated, 80°C, ultrafiltration permeate) were capable of inhibiting both TBARS and lipid peroxide formation in ground, salted pork stored at -15°C. While MSP extracts were capable of inhibiting lipid oxidation both in vitro and in salted, ground pork, their antioxidant activity was low suggesting that their use as a food additive would be impractical.     

Antioxidant activity and total phenolics of edible mushroom extracts

Methanol and water crude extracts from Shiitake mushroom (Lentinus edodes) and straw mushroom (Volvariella volvacea) were investigated for their antioxidant capacity in three different assays, namely, the β-carotene and linoleic acid system, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, and inhibition of hemolysis of rat erythrocyte induced by peroxyl radicals. Among the four mushroom extracts, the water extract from L. edodes showed the most potent radical scavenging activity in each assay, showing 75.9% (at 20 mg/ml) in the β-carotene bleaching method, 55.4% in the DPPH radical scavenging method (at 6 mg/ml) and 94.9% of inhibition of erythrocyte hemolysis (at 5 mg/ml). Total phenolics in the water extracts were higher than that of the methanol ones. Positive correlations were found between total phenolic content in the mushroom extracts and their antioxidant activities. Edible mushrooms may have potential as natural antioxidants.     

排草提取物抗氧化和抑菌活性的研究

为了研究排草的抗氧化和抑菌活性,以水作为溶剂得到排草水提取物,分别采用DPPH法、ABTS法和还原力法测定其抗氧化活性。同时进行体外抑菌试验,测定排草水提取物对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌、苏云金芽孢杆菌、肠球菌等5种常见食源性污染菌的抑菌效果。结果表明:排草水提取物具有一定的抗氧化活性,对ABTS自由基的清除效果最好,EC50为22.71μg/mL。体外抑菌试验表明排草水提取物对肠球菌和苏云金芽孢杆菌有很好的抑菌效果,最低抑菌浓度为60mg/mL,抑菌强弱顺序为:肠球菌>苏云金芽孢杆菌>枯草芽孢杆菌>金黄色葡萄球菌>大肠杆菌。     

Antioxidant activity of ethanolic extracts of amaranth seeds

Antioxidant activity of ethanolic extracts obtained from two amaranth species was evaluated in a beta-carotene-linoleic acid model system. The addition of amaranth extracts in the range of 0.01-0.1% inhibited degradation of a beta-carotene in a model emulsion during incubation at 60 degrees C; 0.05% addition of amaranth seeds extract was proposed as practically applicable. The total content of phenolic compounds was estimated by the Folin-Ciocalteu method and ranged from 39.17 mg/100 g of Amaranthus caudatus to 56.22 mg/100 g of A. paniculatus seeds. Free phenolic acids contained in ethanolic extracts of amaranth seeds were purified and isolated by solid-phase extraction (SPE) and identified by reversed-phase high-performance liquid chromatography (RP-HPLC). The technique involved gave a good separation of the free phenolic acids in the amaranth seeds. Significant differences in phenolic acids profiles of both amaranth species were observed.