基于LC-MS的紫娟烘青绿茶加工过程中花青素变化规律研究

优化建立了紫娟烘青绿茶中花青素的酸性乙醇提取方法和14种花青素组分的高效液相色谱-质谱联用技术(HPLC-MS)分析方法,并进一步对烘青绿茶加工过程中花青素组分的变化进行了定量分析。结果显示:在紫娟烘青绿茶中,共检测到9种花青素成分:飞燕草-3-O-半乳糖苷、矢车菊素-3-O-半乳糖苷、天竺葵-3-O-葡萄糖苷、矢车菊素、天竺葵素、飞燕草素、芍药素、飞燕草-3-O-(6-香豆酰)-半乳糖苷、矢车菊素-3-O-(6-香豆酰)-半乳糖苷,其中飞燕草类花青素和矢车菊类花青素为紫娟花青素的主要成分。紫娟鲜叶中花青素总量为4.64 mg·g~(-1),经摊放、杀青、揉捻、毛火干燥、足火干燥处理的茶样中花青素总量呈下降趋势,含量分别为4.83、3.74、3.70、2.83、1.82 mg·g~(-1)。高温处理是导致花青素下降的最主要因素,其中矢车菊素-3-O-半乳糖苷、飞燕草-3-O-(6-香豆酰)-半乳糖苷、矢车菊素-3-O-(6-香豆酰)-半乳糖苷的下降最为明显。     

超声波和微波对柑橘杂交种果皮中酚类物质浸提及其抗氧化能力的影响

以柑橘杂交品种葡萄柚、茂谷橘橙果皮为材料,研究超声波和微波对柑橘果皮提取物中酚类物质及其抗氧化活性的影响。结果表明:葡萄柚果皮中含有丰富的柚皮苷、芦丁、橙皮素等酚类物质,茂谷橘橙果皮中含有丰富的槲皮素、川陈皮素、橙皮素等酚类物质。葡萄柚果皮提取液的抗氧化活性高于茂谷橘橙。葡萄柚果皮超声波提取液中酚类物质的含量和抗氧化活性高于微波提取液。柑橘果皮提取物中酚类物质的含量与其DPPH自由基和羟自由基清除能力呈正相关。此结果说明超声波提取法可提高葡萄柚果皮中酚类物质的提取率和提取液抗氧化能力。     

甜叶菊总黄酮提取条件、成分与抗氧化活性研究

为探究甘肃酒泉产甜叶菊中总黄酮提取条件、成分与其抗氧化活性间的关系。采用乙醇超声水浴提取法,探讨提取时间、温度、料液比、功率等因素对总黄酮提取条件的影响;用HPLC柠檬酸-甲醇流动相梯度洗脱法测定甜叶菊中芦丁、圣草枸杞苷、山奈素、槲皮素、橙皮苷的含量;用FRPD和DPPH法评价甜叶菊茎叶中总黄酮提取物与抗氧化活性之间的关系。结果:通过正交试验,得出乙醇超声水浴的最佳提取条件:80%乙醇、提取功率450 W、料液比1∶20、提取时间150 min、温度85℃、提取3次,总黄酮提取率最高可达到0.88%;HPLC法检测甜叶菊茎叶中5种黄酮成分,以芦丁的含量(701.42μg/g)为最高,槲皮素含量(451.55μg/g)居其次,橙皮苷含量(297.54μg/g)与山奈素含量(241.21μg/g)较少,圣草枸杞苷含量(57.44μg/g)极微;用FRPD和DPPH法评价甜叶菊茎叶总黄酮提取物抗氧化活性,其抗氧化活性高达10.02 mg/g DW,黄酮含量与抗氧化活性二者呈较显著的正相关性(R=0.769～0.792)。这为甜叶菊中黄酮类物质的提取与进一步开发利用提供基础性研究资料。     

桃金娘果实提取物抗氧化活性研究

以去除种子后的桃金娘果实为试验材料,分别采用等体积的水与体积分数80%甲醇进行提取,测定2种提取物的总酚与总黄酮含量,并对2种提取物的DPPH自由基与ABTS自由基清除能力以及总抗氧化能力进行评价。结果表明,桃金娘果实的2种提取物均具有不同程度的多酚含量与抗氧化活性,体积分数80%甲醇提取物的总酚与总黄酮含量、DPPH与ABTS自由基清除能力以及总抗氧化能力均显著高于水提取物。研究结果表明,桃金娘果实多酚物质具有良好的抗氧化活性。     

“紫娟”晒青绿茶色素的HPLC-ESI-MS分离鉴定及其稳定性研究

研究"紫娟"晒青绿茶主要呈色成分及其稳定性。采用酸性甲醇-水和水分别提取"紫娟"晒青绿茶色素,利用HPLC-ESI-MS/MS方法对其主要色素进行了分离鉴定。结果显示,"紫娟"晒青绿茶含有14种花色素苷、24种黄酮、8种酚类以及3种生物碱。主要的花色苷类物质为天竺葵素-3-葡萄糖苷或天竺葵素-3-半乳糖苷、天竺葵素-3-(6-香豆酰基)-葡萄糖苷、飞燕草素-3-葡萄糖苷、飞燕草素-3-芸香糖苷、飞燕草素-3-O-(6-香豆酰基)-葡萄糖苷、Prodelphinidin B-2(or 4)3′-O-gallate、Procyanidin B-2(or 4)3′-O-gallate、Petunidin-3-glc-4-vinylphenol和Malvidin-3-glc-4-vinylepicatechin等。酸性甲醇-水提取的"紫娟"晒青绿茶红色素水溶性好,颜色随pH值变化而变化。酸性条件下该色素对光、低温有很好的稳定性,耐氧化性与耐还原性较强。Cu2+、Fe3+使色素稳定性变差。明确了"紫娟"晒青绿茶呈现紫色的主要物质基础。     

黔引迷迭香主要酚类成分分析及抗氧化活性比较

采用高效液相色谱法（HPLC）对 4 种黔引迷迭香的多酚成分进行定性和定量分析,并利用 DPPH、ABTS自由基清除能力和铁离子还原能力（FRAP）3 种方法评价多酚成分的抗氧化能力。结果显示 4 种材料均富含类黄酮、酚酸和二萜酚等多酚类化合物,总酚含量介于 4 345.5~5 673.0 mg/100 g 。其中槲皮素、迷迭香酸、阿魏酸、绿原酸和鼠尾草酸是迷迭香最主要的酚类物质。黔引迷迭香 4 号的抗氧化活性最高,利用 DPPH、ABTS 和 FRAP等 3 种方法检测的结果依次为 184.4、290.0、155.6 μmol/g。相关性分析表明,总酚与总抗氧化活性能力显著相关,迷迭香酸对总抗氧化活性能力贡献最大,其次为鼠尾草酸、槲皮素和水杨酸。本研究对于了解黔引迷迭香抗氧化活性成分,以及资源的进一步开发利用具有重要指导意义。     

烘青绿茶苦涩味及其滋味贡献物质分析

对烘青绿茶苦涩味量化分析及其主要滋味贡献物质进行探讨。以不同嫩度烘青绿茶为原料,采用量化感官分析方法及化学分析手段分析了茶汤滋味分属性（包括苦味、涩味、鲜味和醇味等）和滋味化学成分含量,并建立了两者之间的相关性。研究结果表明,随着烘青绿茶嫩度的下降,其茶汤苦味、涩味和鲜爽味强度呈下降趋势,整体滋味品质也显著下降。通过分析茶叶滋味化学成分含量及其滋味Dot值,发现烘青绿茶苦味的主要贡献物质是EGCG和咖啡碱;而涩味的主要贡献物是儿茶素和黄酮苷,其中儿茶素以EGCG为主,包括EGC和ECG,黄酮苷以槲皮素-3-O-芸香糖苷（Que-rut）和槲皮素-3-O-半乳糖苷（Que-gala）为主,包括杨梅素-3-O-半乳糖苷（Myr-gala）、槲皮素-3-O-葡萄糖苷（Que-glu）、牡荆素-2"-O-鼠李糖苷（Vit-rha）、山柰酚-3-O-半乳糖苷（Kae-gala）、山柰酚-3-O-芸香糖苷（Kae-rut）、山柰酚-3-O-葡萄糖苷（Kae-glu）等。Dot值分析表明氨基酸对烘青绿茶鲜爽味没有显著贡献。本研究初步明确了烘青绿茶苦涩味的主要贡献物质,为茶叶品质提升和滋味化学研究提供理论基础。     

长白山珍稀药材山兰的体外抗氧化活性研究

探索山兰丙酮层、正丁醇层、甲醇层提取物的体外抗氧化活性,为珍稀药材山兰的开发利用提供理论依据。以山兰为原料,用95%乙醇提取,依次用丙酮、正丁醇和甲醇萃取,测定其体外抗氧化活性(总抗氧化能力、DPPH清除率、ABTS清除率和铁离子还原能力)。结果表明,山兰正丁醇层提取物的抗氧化活性优于丙酮层和甲醇层提取物的抗氧化活性,接近于Vc的表现,值得深入开发。     

锡兰橄榄主要营养成分与酚酸类组成分析评价

采用国标方法分别对锡兰橄榄中主要营养成分(蛋白质及氨基酸、脂肪及脂肪酸、水分、碳水化合物及矿物质元素)的组成和含量进行了测定,并利用HPLC-MS对抗氧化活性较高的70%乙醇提取物中的特征性成分进行了分析。结果表明:锡兰橄榄中的主要营养成分为碳水化合物和粗脂肪;其常量与微量元素含量较为丰富,以Mg和Ca含量相对较高。富含人体必需氨基酸,氨基酸组成合理均衡;主要含有不饱和脂肪酸,其中亚油酸和亚麻酸含量相对较高。通过HPLC-MS从70%乙醇提取物中得到19种酚类物质,其中10种酚类物质被鉴定出来。说明锡兰橄榄具有较好的食用价值和保健作用,可以作为补充人体营养物质的理想食品来源。     

椰子种皮油提取物的抗氧化活性研究

测定椰子种皮油提取物中的总酚含量,对羟基自由基、DPPH（1,1-二苯基-2-三硝基苯肼）自由基、ABTS（2,2连氮-双-（3-乙基苯并噻咪唑-6-磺酸）自由基清除能力和总抗氧化能力等抗氧化活性指标。结果表明,椰子种皮油提取物中含有较高的总酚含量（68 mg/g）,提取物浓度为0.1 mg/mL时对羟基自由基的清除率为56.89％,对DPPH自由基的清除率为71.0％,对ABTS自由基的清除率为96.4％,表明椰子种皮油提取物具有很好的抗氧化活性。     

地胆头化学成分及其生理活性的研究

研究地胆头提取液中总多酚和类黄酮含量及其生理活性。测定了不同地胆头提取液的总多酚含量、类黄酮含量及其清除DPPH自由基的能力,并比较了不同料液比的地胆头提取液对血管紧张素转化酶(ACE)的抑制率。结果表明:不同提取剂提取的地胆头总多酚和类黄酮含量不同,其中,丙酮提取液中总多酚和类黄酮含量分别为12.27 mg/g、7.50 mg/g,均高于乙醇、甲醇、水提取液中的总多酚和类黄酮含量;地胆头丙酮、甲醇、乙醇提取液对DPPH自由基的清除率分别为94.60%、93.41%、90.87%,均高于人工合成氧化剂BHT(89.15%)和地胆头水提取液(62.75%);地胆头提取液对ACE的抑制效果随着料液比的增加而越明显,其中,1∶10的料液比下,乙醇地胆头提取液对ACE抑制率达到96.67%。通过本研究得出,在地胆头乙醇、甲醇、水、丙酮4种提取液中,丙酮提取液的总多酚和类黄酮含量最高,且其抗氧化性效果最佳,乙醇地胆头提取液的抗高血压能力最强。地胆头提取液具有明显的抗氧化性和抗高血压等生理活性,在功能食品及中草药领域里具有良好的开发应用前景。     

Antioxidant Compounds Recovery from Juçara Residue by Thermal Assisted Extraction

This study aimed to recover bioactive compounds by solid-liquid extraction from the agro-industrial residue obtained during juçara fruits processing into pulp. A preliminary study using different solvents (methanol, ethanol and water) indicated ethanol in aqueous solution as the best solvent for antioxidants recovery. Then, a Box-Behnken design was applied considering as independent variables the solvent composition (30–70% ethanol in water), temperature (30–70 °C) and time (30–60 min), in order to evaluate the effects of these factors on antioxidant activity in juçara extract. Results showed that the extracts with higher antioxidant activity were obtained using 30% ethanol at 70 °C for 60 min; measurements included ABTS and DPPH assays, determination of total phenolic content and total monomeric anthocyanins. Furthermore, the effect of pH in antioxidants recovery was evaluated. For this purpose, the 30% ethanol solution was acidified to pH 1 and 2 with HCl. Principal component analysis showed the formation of three distinct groups: one characterized by high bioactive compounds content (pH 1.0), another with superior antioxidant activity (pH 5.75, non-acidified), and finally the group at pH 2 presenting the worst concentrations in the evaluated responses. HPLC analysis showed the presence of cyanidin-3-O-rutinoside and cyanidin-3-O-glucoside in the extracts. Therefore, the conventional solid-liquid extraction using renewable solvent can be successfully applied to recover bioactive compounds from juçara residue, which can be used by different food industries.     

云南普洱茶不同溶剂提取物抗氧化活性研究

以芦丁与Vc为对照,测定云南普洱茶不同溶剂提取物清除DPPH自由基、羟自由基、超氧阴离子自由基、亚硝酸盐的能力及其还原力.结果表明:普洱茶不同溶剂提取物的抗氧化活性与其浓度成正相关,对DPPH自由基、羟自由基与超氧阴离子有较强的清除作用,对亚硝酸盐的清除作用不明显,具有一定的还原力.其中,乙醇沉析物、正丁醇提取物、乙醇提取物、乙醇溶解物对DPPH.自由基清除效果较好,相同浓度下优于芦丁;水提取物、乙醇沉析物及乙酸乙酯提取物对羟自由基清除效果较好,但效果不如Vc;乙酸乙酯提取物对超氧阴离子自由基和亚硝酸盐的清除作用较好,还原力也很强.     

刺五加叶不同部位抗氧化活性的研究

目的研究刺五加叶不同部位在不同浓度下的体外抗氧化活性。方法采用清除ABTS+自由基、DPPH自由基评价法和测定还原性法,利用紫外分光光度计法测定刺五加叶的总提液、10%、30%和50%大孔吸附树脂醇洗脱部位在不同浓度下的抗氧化能力。结果刺五加叶不同部位抗氧化活性的强弱顺序为:30%部位>10%部位>总提液>50%部位,随着各部位浓度的增加,抗氧化能力增强。ABTS+自由基和DPPH自由基模型中,在浓度为0.64mg/mL时,30%的部位对ABTS+DPPH自由基模最大清除率分别达到99.541%、95.331%,与同浓度VC的清除率接近,其次浓度0.64mg/mL的10%部位的最大清除率分别达到96.324%、88.033%。在还原性法测定中30%部位在浓度为0.64mg/mL时,吸光度为2.269,与VC较接近,同浓度时10%部位的吸光度为2.155,次于30%部位。结论刺五加叶抗氧化能力较好,各种评定方法结合分析,其30%部位最好,可以开发为抗氧化剂,为进一步研究和开发刺五加叶提供了科学依据。     

食用菌的抗氧化活性及竹荪抗氧化物质提取工艺的优化

对26种食用菌子实体干品水提液和醇提液分别进行总还原能力、羟自由基、超氧阴离子自由基和DPPH自由基的清除能力测定。结果表明:26种食用菌子实体干品2种提取液均具有不同程度的还原能力及羟自由基、超氧自由基、DPPH自由基清除能力。且总体来说,水提液抗氧化性要强于醇提液抗氧化性。采用模糊综合评价法比较评价26种子实体干品的抗氧化性,其中以竹荪水提液和醇提液的抗氧化活性最高。在单因素实验的基础上,用L9(34)正交设计法,研究乙醇浓度(A)、回流温度(B)、料液比(C)和提取时间(D)等4个因素,以DPPH自由基清除率为评价指标优化长裙竹荪中抗氧化物质的提取条件。结果表明,影响提取物抗氧化效果的主因素为回流温度。最佳的提取工艺为:乙醇浓度90%,回流温度90℃,料液比1/35,回流时间2.5h。     

Free radical scavenging activity of selected medicinal plants of Eastern Botswana

Water and methanol extracts from roots of Ozoroa paniculosa (Anarcardiaceae); seeds of Colophospermum mopane (Caesalpiniaceae) and Cucumis metuliferus (Cucurbitaceae) ripe fruits were assessed for in vitro antioxidant activity. Free radical scavenging activity was measured spectrophotometrically as maximum fading power of DPPH at 525 nm. Water and methanol extracts of Ozoroa paniculosa exhibited higher scavenging potency than extracts of either Colophospermum mopane or Cucumis metuliferus at all tested concentrations. None of the extracts from Cucumis metuliferus exhibited any recognizable free radical scavenging activity. Above 50 microg mL(-1) both water and methanol extracts of Ozoroa paniculosa exhibited 91% scavenging activity similar to the control compounds L-ascorbic acid (91%) and (-) epicatechin (92%). Between 50-100 microg mL(-1), water and methanol extracts of Colophospermum mopane exhibited scavenging potency of < or = 70%. However, above 100 microg mL(-1), both water and methanolic extracts of C. mopane exhibited scavenging activity > 70%. Chloroform extracts of all the tested plants showed poor scavenging activity (< 30%). The order of scavenging potency for the tested samples was as follows: L-ascorbic acid > or = epicatechin > O. paniculosa (methanolic extract) > O. paniculosa (water extract) > O. paniculosa (ethylacetate extract) > C. mopane (methanolic extract) > C. mopane (water extract) > all extracts of C. metuliferus. These findings lend credence to the use of these plants as anti-inflammatory and antioxidant agents in folk medicine.     

成熟芒果果皮甲醇提取液的抗氧化能力研究

对成熟芒果台农、红6、金煌3个品种的果皮甲醇提取液的抗氧化能力进行研究,并分析讨论3种提取液的DPPH清除能力和总还原能力。结果表明,3种提取液的DPPH清除能力和总还原能力与溶液浓度均呈量效关系。成熟台农果皮的DPPH清除能力和总还原能力最高,其总酚含量也是最高,而金煌的各项测试指标均最低。进一步的实验表明,3种提取液的DPPH清除能力和总还原能力存在相协关系,两者在一定程度上都依赖于溶液中总酚的含量。     

Total Phenolic Levels,In Vitro Antioxidant Properties,and Fatty Acid Profile of Two Microalgae,Tetraselmis marina Strain IMA043 and Naviculoid Diatom Strain IMA053, Isolated from the North Adriatic Sea

This work studied the potential biotechnological applications of a naviculoid diatom (IMA053) and a green microalga (Tetraselmis marina IMA043) isolated from the North Adriatic Sea. Water, methanol, and dichloromethane (DCM) extracts were prepared from microalgae biomass and evaluated for total phenolic content (TPC) and in vitro antioxidant properties. Biomass was profiled for fatty acid methyl esters (FAME) composition. The DCM extracts had the highest levels of total phenolics, with values of 40.58 and 86.14 mg GAE/g dry weight (DW in IMA053 and IMA043, respectively). The DCM extracts had a higher radical scavenging activity (RSA) than the water and methanol ones, especially those from IMA043, with RSAs of 99.65% toward 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt (ABTS) at 10 mg/mL, and of 103.43% against 2,2-diphenyl-1-picrylhydrazyl (DPPH) at 5 mg/mL. The DCM extract of IMA053 displayed relevant copper chelating properties (67.48% at 10 mg/mL), while the highest iron chelating activity was observed in the water extract of the same species (92.05% at 10 mg/mL). Both strains presented a high proportion of saturated (SFA) and monounsaturated (MUFA) fatty acids. The results suggested that these microalgae could be further explored as sources of natural antioxidants for the pharmaceutical and food industry and as feedstock for biofuel production.     

Antiradical properties of sorghum (Sorghum bicolor L. Moench) flour extracts

Epidemiological studies support the belief that whole grains are protective against several chronic diseases. The health benefits of whole grains are attributed in part to their unique phytochemical composition. Major phytochemicals in grains include various classes of phenolic compounds, flavonoids and coumarin derivatives, etc. Phenolic compounds present in grains possess antioxidant properties that are associated with the health benefits of grains and grain products. Sorghum is one of the main staple cereal grains in hot dry tropics and ranks fifth among cereal crops in the world. Although sorghum is rich in phenolics and tannins which are proven anticancer and cardioprotective constituents, human consumption of sorghum is limited. To our knowledge, there is limited literature on the profile of antioxidant phytochemicals in the local white variety of sorghum. Hence, the objective of this study was to investigate the antioxidant property of white sorghum flour extracts in vitro and also to identify the fractions responsible for the antioxidant activity. In the present study, we analyzed the antioxidative properties of various extracts (water, 60% methanol, 60% ethanol, and 60% t-butanol) of white sorghum flour employing the 1,1-diphenyl-2-picrylhydrazyl (DPPH) model system. Phenolics, antiradical and antioxidant activities were also examined in chromatographic sub-fractions of the soxhlet methanolic extract. Our results indicated that the various extracts exhibited significant antioxidant activity that did not correlate with the phenolic content. Further, two sub-fractions eluted with methanol and acetone/methanol were found to possess strong antioxidant activity in two assay systems. Our results suggest that a diet rich in sorghum may be useful in combating diseases in which free radical production plays a key role.