UPLC-DAD/ESI-TOF-MS鉴定黑脉羊肚菌多酚化合物

以黑脉羊肚菌为原料,分离提取羊肚菌多酚(游离酚和结合酚),对提取物中酚类物质的含量及抗氧化活性进行研究,并采用超高效液相色谱-二极管阵列检测器/电喷雾飞行时间质谱对黑脉羊肚菌游离酚和结合酚的组分进行鉴定。结果表明,黑脉羊肚菌多酚主要为游离酚,且游离酚的DPPH自由基清除率、还原力及氧自由基吸收能力都显著强于结合酚(P0.05),而两者清除ABTS~+·能力相当。从黑脉羊肚菌多酚中鉴定出15种组分,分别是没食子酸、焦性没食子酸、原儿茶酸、对羟基苯甲酸、儿茶素、咖啡酸、绿原酸、荭草素、芦丁、金丝桃苷、白藜芦醇、木犀草素、槲皮素、肉桂酸、阿魏酸,游离酚提取物有15种组分,结合酚提取物有14种组分。     

黑脉羊肚菌多酚分级制备及其抗氧化活性

以黑脉羊肚菌为原料,采用不同极性溶剂提取多酚,分别得到乙酸乙酯相、甲醇相和水相多酚提取物,通过高效液相色谱分析其组分,测定其对1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除能力、2,2’-联氨-(3-乙基苯并噻唑啉-6-磺酸)二铵盐(2,2’-azinobis-(3-ethylbenzthiazoline-6-sulphonate),ABTS)自由基清除能力和抗氧化能力指数(oxygen radical absorbance capacity,ORAC)值,并探讨该多酚提取物含量与抗氧化相关性。结果表明,黑脉羊肚菌总酚含量为20.109 mg/g,其中水相组分多酚含量最高(14.478 mg/g),甲醇相次之(5.443 mg/g),乙酸乙酯相组分多酚含量最低(0.188 mg/g)。3种溶剂的多酚提取物组成中,荭草素含量均为最高。水相组分清除DPPH自由基能力最强,甲醇相组分清除ABTS~+·能力最强,乙酸乙酯相组分具有较高的ORAC值。多酚含量与DPPH自由基清除率、ORAC值具有显著相关性(P0.05)。     

不同产地尖顶羊肚菌多酚组成及抗氧化活性研究

为研究不同产地羊肚菌多酚的抗氧化活性及组成,以3 种不同产地（云南、西藏、新疆）尖顶羊肚菌为原料,提取羊肚菌游离酚和结合酚,测定其1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除能力、还原力、2,2’-联苯-二（3-乙基-苯并噻唑-6-磺酸）二铵盐（2,2’-azinobis-（3-ethylbenzthiazoline-6-sulphonate）,ABTS）自由基清除能力和抗氧化能力指数（oxygen radical absorbance capacity,ORAC）值,并通过高效液相色谱（high performance liquid chromatography,HPLC）分析其组分。结果表明,3 种尖顶羊肚菌平均总酚含量为5.958 mg GAE/g,游离酚约为结合酚的25 倍;云南尖顶羊肚菌游离酚、结合酚含量最高（（6.157±0.192）、（0.250±0.018） mg GAE/g）,西藏尖顶羊肚菌游离酚、结合酚含量最低（（4.928±0.045）、（0.188±0.026） mg GAE/g）。3 种尖顶羊肚菌多酚组分主要为酚酸和黄酮,组成较一致,但含量差异显著。体外抗氧化结果表明：3 种尖顶羊肚菌多酚均具有一定的抗氧化活性,其中对DPPH自由基的清除能力最强;西藏尖顶羊肚菌多酚的DPPH自由基清除能力和还原力最强;新疆尖顶羊肚菌多酚的ABTS＋·清除能力最强,ORAC值也最高。     

不同品种李子多酚组成及抗氧化活性

为研究不同品种李子果皮、果肉多酚组成及抗氧化活性,以9个不同品种的李子(芙蓉李、巫山李、玫瑰李、红布李、黑布李、西梅李、脆红李、江安李、青李)为原料,提取游离酚和结合酚,测定其1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除能力和抗氧化能力(oxygen radical absorbance capacity,ORAC)值,并通过高效液相色谱分析其多酚组成。结果显示:9种李子果皮总酚含量范围为111.52~775.88 mg GAE/100 g;果肉总酚含量范围为120.65~301.91 mg GAE/100 g,其中红布李果皮、果肉总酚含量均最高,西梅李总酚含量均最低。在多酚组成上,游离酚含量显著高于结合酚,且多酚组分主要为酚酸(原儿茶酸、绿原酸、咖啡酸)。体外抗氧化结果显示:9种李子果皮、果肉多酚均具有一定的抗氧化活性,DPPH自由基清除IC50值范围为4.38~46.46μg/m L,ORAC值范围为0.24~210.50μmol TE/g,其中巫山李果肉游离酚对DPPH自由基的清除能力最强,红布李果皮游离酚ORAC值最高。     

不同处理对糙米发芽后酚类含量及其抗氧化活性影响

为研究糙米发芽后不同处理方式对其中酚类物质及体外抗氧化活性的影响,在对同一稻谷品种的精米、糙米、发芽糙米3个样品中游离酚、结合酚及其1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除能力、亚铁还原能力（ferric ion reducing antioxidant power,FRAP）和氧化自由基吸收能力（oxygen radical absorbance capacity,ORAC）分析基础上,以常温25℃匀浆处理方式为对照分别考察热风干燥、真空干燥对样品中游离酚、结合酚及其DPPH自由基清除能力、FRAP和ORAC变化情况。结果表明,精米、糙米、发芽糙米中游离酚、结合酚及DPPH自由基清除能力、FRAP、ORAC均有显著性差异（P＜0.05）,其中经过热风干燥后的发芽糙米相较糙米的游离酚、结合酚增加了27.28、10.24 mg GAE/100 g DW,游离酚和结合酚的DPPH自由基清除能力、FRAP、ORAC也显著增加（P＜0.05）;而热风干燥、真空干燥组之间的游离酚、结合酚及其对应的DPPH自由基清除能力、FRAP、ORAC之间无显著性差异（P＞0.05）,但相较于常温25℃匀浆处理方式,热风干燥、真空干燥组中的游离酚、结合酚及其对应的DPPH 自由基清除能力、FRAP、ORAC 显著降低（P＜0.05）。     

薏米中多酚化合物的分离纯化及抗氧化活性分析

利用葡聚糖凝胶将薏米中两类多酚类物质进行分离纯化,从而得到6个不同的组分。采用Folin-Ciocalteu法测定该6个组分总酚含量,采用氧自由基吸收能力(oxygen radical absorbance capacity,ORAC)、过氧化氢自由基清除能力(peroxyl radical scavenging capacity,PSC)和细胞内抗氧化能力(cellular antioxidant activity assay,CAA)分析法测定所得6个组分抗氧化能力。在所得的6个组分中选择抗氧化活性最强的3个组分进行半制备,可制得4种薏米多酚纯化物,并测定其4种纯化物的抗氧化活性。结果发现,所分离的6个组分中,薏米中的多酚主要存在于组分2、组分3及组分5中,其总酚含量分别为(30.56±2.25)、(17.40±2.76)、(25.18±1.10)mg GAE/100 g薏米粉末,结合型酚类化合物占薏米总酚含量1/3以上。组分2、组分3及组分5薏米多酚的抗氧化能力较强。经过半制备液相得到的4种多酚纯化物质分别为N_1,N_5-双(对香豆酰)亚精胺、对香豆酸、阿魏酸及芦丁,其中N_1,N_5-双(对香豆酰)亚精胺为游离型多酚的主要物质,而阿魏酸为结合型多酚的主要物质,但在游离型多酚中也有少许存在。4种酚类化合物均具有强抗氧化活性,是薏米中多酚类物质发挥抗氧化作用的主要活性成分。     

纤维素酶水解处理提高燕麦全粉中总多酚含量与抗氧化活性

采用Folin-酚法和高效液相色谱法考察了纤维素酶水解处理对燕麦粉中总多酚及多酚组分含量的影响,并利用2,2’-联氮双-（3-乙基苯并噻唑啉-6-磺酸）二铵盐（2,2’-azinobis (3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt,ABTS）自由基、1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除能力、铁离子还原能力（ferric reducing antioxidant power,FRAP）和蛋白损伤修复等方法测定酶解前后提取液的体外抗氧化活性。结果表明：酶解处理以后可显著增加燕麦粉中总多酚含量,尤其是阿魏酸含量提高了11～24 倍;酶解处理后燕麦粉多酚提取物的ABTS＋·、DPPH自由基清除能力和FRAP值等体外抗氧化活性和蛋白氧化损伤修复能力得到显著增强。总体而言,纤维素酶水解处理能够有效提高燕麦粉中总多酚含量及其功能活性,主要原因可能是阿魏酸等酚酸物质含量的提高。     

老黑谷米中多酚化合物的提取及体外抗氧化活性研究

以老黑谷米面粉为原料,提取分离其中的可溶性多酚、游离多酚、酯化多酚、醚化多酚、键合多酚,利用比色法进行多酚和类黄酮含量测定,并采用DPPH自由基清除能力、铁离子还原/抗氧化能力测定(FRAP)、总抗氧化能力测定(TEAC)、还原能力测定(RP)和H2O2清除活性等5种不同的体外抗氧化测定体系进行抗氧化活性测定。结果表明:5种多酚中,可溶性多酚含量最高,酯化多酚含量次之,显著高于游离多酚、醚化多酚、键合多酚。多酚中类黄酮含量最高为键和多酚和可溶性多酚,显著高于其他3种多酚。5种多酚均有较高的体外抗氧化能力,键合多酚的DPPH自由基清除能力最高,可溶性多酚的H2O2清除能力、FRAP还原能力、RP还原能力和TEAC总抗氧化能力最高。本研究为老黑谷米的开发利用提供科学依据。     

萌发对燕麦多酚含量及抗氧化活性相关性的研究

为明确燕麦活性成分随发芽过程的变化，确定多酚存在形式对抗氧化活性的影响，以燕麦为原料，考察浸泡时间和温度对燕麦发芽效果的影响。浸泡时间为4 h和萌发温度为20℃时燕麦发芽率最高。随着发芽时间的延长，β-葡聚糖的含量逐渐减少，蛋白质呈现先下降后上升的趋势。发芽时长达到72 h时，β-葡聚糖和蛋白质的含量分别为1.98%和12.66%。萌发显著增加了燕麦中游离酚、结合酚和总酚的含量（P<0.05）。通过DPPH自由基清除能力、ABTS自由基清除能力和FRAP铁离子还原能力的测定，结果表明，游离酚和结合酚分别使抗氧化能力增加约4倍和2倍。进一步利用斯皮尔曼对酚类含量和抗氧化效果进行相关性分析，发现游离酚相关系数大于结合酚。研究为扩大萌发处理在食品领域的应用范围提供参考。     

广林9号桉叶多酚抗氧化活性研究

采用不同极性有机溶剂对广林9号桉叶提取物进行系统萃取分离,用福林-酚法测定各组分的总酚含量,以1,1-二苯基-2-三硝基苯肼(DPPH)、2,2＇-联氮-双-(3-乙基苯并噻唑啉-6-磺酸)(ABTS)、还原能力3种体外抗氧化活性方法测定了桉叶各组分的抗氧化活性。结果表明,不同萃取组分中,乙酸乙酯组分总酚含量最高,达到502.67mg/g;其对DPPH自由基和ABTS＋·的清除能力和还原能力也最强,优于阳性对照物茶多酚,其清除两种自由基的IC50分别为0.097mg/mL 和0.034mg/mL;通过总酚含量与抗氧化活性比较发现,其抗氧化活性与总酚含量成正相关,由此判断桉叶提取物的抗氧化活性成分主要为多酚类物质;桉叶粗提物中多酚含量达到30%以上,与茶叶粗提物中多酚含量相当,具有开发意义。     

Antioxidant Properties of Free,Soluble Ester and Insoluble‐Bound Phenolic Compounds in Different Barley Varieties and Corresponding Malts

Ten different barley cultivars and their corresponding malts were used to obtain different fractions. Phenolics extracted belonged to free, soluble esters and insoluble‐bound fractions. Total phenolic content (TPC) of the free fraction, as measured according to the Folin‐Ciocalteu method, ranged from 37.7 to 167.2 mg gallic acid equiv/kg of dried material (GAE/kg_dw) for barley and between 34.1 and 72.3 mg GAE/kg_dw for malt. The bound phenolic content ranged from 210.3 to 320.5 and between 81.1 and 234.9 mg GAE/kg_dw for barley and malt, respectively. The contribution of bound phenolics to the TPC was significantly higher than that of free and esterified fractions. Catechin and ferulic acid, quantified by high performance liquid chromatography with diode array detector (HPLC‐DAD), were the most abundant phenolics in the free and bound fractions, respectively. The p‐coumaric acid content was lower in hulless genotypes, as compared to hulled genotypes, showing that it is mainly concentrated in the hull. The antioxidant activities of the phenolic fractions were investigated using the radical scavenging assay (DPPH) and ferricyanide reducing power. The bound phenolics demonstrated a significantly higher antioxidant capacity compared to the free and esterified phenolics. During the malting process, a significant decrease of the bound phenolics was observed with a corresponding increase of the esterified fraction.     

溶剂提取对青稞中不同形态多酚组成及抗氧化活性的影响

为研究不同极性溶剂对青稞全谷物中不同形态酚类化合物含量、组成及抗氧化性的影响,建立适宜于青稞全谷物中多酚提取的方法。以4?个不同品种青稞为原料,比较4?种不同溶剂及酸法、碱法分别对青稞中游离酚和结合酚含量、组成与抗氧化活性的影响。结果表明,所有提取试剂中80%丙酮溶液提取的游离态总酚含量（139.79～235.96?mg/100?g）及总黄酮含量（9.88～15.52?mg/100?g）最高,酸法提取的青稞结合态总酚含量是碱法的1.9～3.1?倍,结合态黄酮含量是碱法的1.3～2.9?倍;80%丙酮溶液提取物中检测到8～18?种青稞游离酚类化合物,且酚类化合物含量显著高于其他溶剂,绿原酸、苯甲酸、儿茶素、槲皮素、芦丁是其主要的游离酚类化合物。与碱法相比,酸法能释放出更多的结合酚类化合物类型及含量,没食子酸、p-香豆酸、丁香酸、苯甲酸、藜芦酸、橙皮苷是其主要的结合酚类化合物;参试青稞80%丙酮溶液提取物显示出最高的1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除能力（852.56～1?484.18?μmol/100?g）,2,2’-联氮-双-（3-乙基苯并噻唑啉-6-磺酸）二铵盐（2,2’-azinobis-(3-ethylbenzthiazoline-6-sulphonate),ABTS）自由基清除能力（358.93～518.09?μmol/100?g）及铁离子还原能力（ferric ion reducing antioxidant power,FRAP）（1?250.55～2?041.16?μmol/100?g）。酸法水解参试青稞结合酚DPPH自由基清除能力、FRAP、ABTS＋?清除能力分别是碱法水解的7.6～10.3、1.2～1.8?倍和1.1～1.3?倍。因此,80%丙酮溶剂和酸法分别是青稞中游离酚与结合酚的适宜提取溶剂,且本研究表明青稞全谷物中富含丰富的酚类物质,是一种潜在的天然抗氧化剂来源。     

Bioaccessibility and antioxidant potential of millet grain phenolics as affected by simulated in vitro digestion and microbial fermentation

Dehulled and cooked grains of five millet varieties (kodo, finger, proso, foxtail and pearl) were subjected to in vitro enzymatic digestion and microbial fermentation under physiological conditions in order to determine the bioaccessibility of their phenolic compounds. Extracts recovered as supernatants from enzymatic digestion and microbial fermentation were employed for the determination of their total phenolic content (TPC) and total flavonoid content (TFC), as well as the scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH), peroxyl and hydroxyl radicals. Furthermore, trolox equivalent antioxidant capacity (TEAC), reducing power and ferrous ion chelating activity of the extracts so obtained were evaluated. The DPPH and hydroxyl radical scavenging activities were determined using electron paramagnetic resonance (EPR) spectroscopy. The peroxyl radical activity was measured using an oxygen radical absorbance capacity (ORAC) assay. The TPC ranged from 12.7 to 35.4 and 21.2 to 47.4 μmol ferulic acid equivalents per gram of grain, on a dry weight (dw) basis at the end of intestinal digestion and colonic fermentation, respectively. All five millet varieties exhibited effective antioxidant activity and the order of efficacy differed according to the assay employed. The present study thus demonstrated that phenolic compounds of processed millets were bioaccessible and colonic fermentation released the phenolics bound to the insoluble fibre in the grain.     

Evaluation of antioxidant activities and total phenolic contents of typical malting barley varieties

Fourteen typical malting barley varieties from China were evaluated for their DPPH radical, ABTS radical cation and superoxide anion radical scavenging activities, reducing power, metal chelating activities, and total phenolic contents (TPC). All barley samples exhibited significant antioxidant activities determined by different assays, and contained significant levels of phenolic compounds. Gan4 and Wupi1 barley exhibited the highest DPPH radical scavenging activity, ABTS radical cation scavenging activity and reducing power. Gan4 and Humai16 barley showed the highest TPC, whereas the highest superoxide anion radical scavenging activity and metal chelating activity were found in Huaimai19 and Ken3 barley, respectively. The Pearson correlation analysis revealed that the TPC showed strong correlations with DPPH radical scavenging activity, ABTS radical cation scavenging activity, and reducing power (P < 0.01), whereas its correlations with superoxide anion radical scavenging activity and metal chelating activity were poor (P > 0.05). Moreover, DPPH radical scavenging activity, ABTS radical cation scavenging activity and reducing power were well positively correlated with each other (P < 0.01). Principal component analysis (PCA) was applied to understand the interrelationships among the measured antioxidant activity evaluation indices, and to gain an overview of the similarities and differences among the 14 barley varieties.     

Phenolic content and antioxidant activity of eight representative sweet corn varieties grown in South China

In the present study, phenolic content and antioxidant capacities including cellular antioxidant activity of eight Chinese sweet corn varieties were investigated. The total phenolic content revealed significant varietal differences and phenolics existed mainly in free form. HPLC analysis showed that ferulic and p-coumaric acids were the dominating phenolics in sweet corn. The DPPH scavenging capacity, ferric reducing antioxidant power, and cellular antioxidant activity demonstrated distinct varietal differences, which were positively correlated with their phenolic content, although the orders of antioxidant activity of eight varieties determined by three different methods were not consistent. Sweet corn could be a better substitute for many commonly consumed vegetables in terms of phenolics and antioxidant activity.     

Phenolic composition and antioxidant activity of Rocha pear and other pear cultivars – A comparative study

The phenolic profile and the antioxidant activity of Rocha pear, a Portuguese pear cultivar, were determined and compared with the commercially available pear varieties Comice, Abate, General Leclerc and Passe Crassane. Phenolic composition of the methanolic extracts of these pears was determined by high performance liquid chromatography with diode array detection (HPLC-DAD), while antioxidant activities were evaluated using three complementary test systems: DPPH radical scavenging activity, ferric reducing power capacity and β-carotene/linoleic acid bleaching assay. When compared to the studied varieties, Rocha pear (peel and flesh) presented the highest content of total phenolics. Among them, chlorogenic, syringic, ferulic and coumaric acids, arbutin and (?)-epicatechin were detected as major components. In addition, among the tested varieties, Rocha pear presented the best antioxidant activities in the DPPH and ferric reducing power assays.     

Antioxidant potential of barley as affected by alkaline hydrolysis and release of insoluble-bound phenolics

Phenolic constituents of six barley varieties, namely Falcon, AC Metcalfe, Tyto, Tercel, Phoenix and Peregrine were separated into free, soluble conjugate and insoluble-bound fractions. Soluble conjugates and insoluble-bound phenolics were extracted into diethyl ether after consecutive alkaline hydrolysis for 4 h. Total phenolic content of each of the three fractions was determined by using Folin–Ciocalteau method. Total antioxidant capacity of the phenolic fractions was determined by trolox equivalent antioxidant capacity (TEAC) assay. The extracts were evaluated for their efficacy in scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. Oxygen radical scavenging capacity (ORAC_FL) of the extracts was determined using a fluorometric assay. Effectiveness of phenolic extracts in inhibiting oxidation of human LDL cholesterol and radical-induced supercoiled DNA breakage was also evaluated. The contribution of insoluble-bound phenolics toward total phenolic content was significantly (p < 0.05) higher than the soluble phenolics for all barley extracts tested. The ratio of soluble to insoluble phenolics ranged from 1:27 to 1:35. TEAC and ORAC values and DPPH radical scavenging capacity of the insoluble phenolic fraction were significantly (p < 0.05) higher than those of their insoluble counterparts. A similar trend was observed against inhibition of LDL cholesterol oxidation and radical-induced DNA breakage.