PHENOLIC ANTIOXIDANTS DETERMINATION IN FOOD ITEMS USING REVERSED-PHASE HPLC

The determination of synthetic phenolic antioxidants （SPAs） including propyl gallate （PG）, tertiary butyl hydroquinone （TI3HQ）, butylated hydroxyanisole （BHA） and butylated hydroxytoluene （BHT） in food items is reported using high performance liquid chromatography （HPLC）. A Cls column is used as the stationary phase, acetonltrile and water：Acetic acid （1%） is used as the mobile phase of gradient elution and the UV detec- tor is set at 280 nm. Under the above conditions, four antioxidents is completely separated within 8 rain. The limit of detection, linear range, and reproducibility of HPLC are evaluated. Isolation parameters of SPAs from different types of food items （cooking oil, margarine and butter, and cheese） are optimized. SPAs are extracted from food items through extraction with methanol/acetonitrile （1 ： 1, in volume）, vortex, ultrasonic treatment and precipitation in a freezer （2 h）. For cooking oil margarine, butter and cheese at 50 and 200 rag/L, recoveries of SPAs are 93.3%0--108.3% （PG）, 85.3~^--108.3~~ （TBHQ）, 96.7~^--101.2~/6 （BHA）, and 73.9^-- 94.6% （BHT）. The method is applied to the determination of SPAs in 38 food items （16 cooking oils, 8 mar- garine, 6 butter and 6 cheese samples）. The levels of SPAs in positive samples are all below the legal limits of China.

Phenolic Antioxidants in Cypriot Wines as a Tool for Their Varietal Discrimination： Preliminary Results

A total of 56 wines from different vintages and wine-growing regions of Cyprus were used to analyze six biologically interesting phenolic antioxidants （gallic acid, catechin, vanillic acid, epicatechin, coumaric and feroulic acid） by high performance liquid chromatography. The study includes red and white Cypriot authentic wines from local and imported varieties that were produced under the same vinification conditions at a Model Winery. Results extracted after the chemometric analysis of the measured concentrations show a strong relationship of the phenolic antioxidative capacity with the variety of the wines and gallic acid followed by vanillic acid found in the highest concentrations of the other antioxidants studied. Comparing the concentrations found with bibliographic data for wines from other countries, it was found that, the concentration levels of vanillic and ferulic acid were significantly higher for Cypriot wines.

Quantification of phenolic compounds and antioxidant capacity of an underutilized Indian fruit:Rayan[Manilkara hexandra(Roxb.)Dubard]

The fruit of Manilkara hexandra(Roxb.)Dubard is one of the most underutilized fruits of India and in Gujarat state.It is popularly known as‘Rayan’.The fruit and seed of Rayan were analysed for their total phenolic and flavonoid content,phenolic compounds and total antioxidant capacity with six different assay methods.The results indicated that the methanolic extract of Rayan fruit being a good source of phenolic(811.3 mg GAE/100 g fw)and flavonoid(485.56 mg RE/100 g fw)content.Also,eleven known phenolic compounds were tentatively identified for the first time from the fruit and seed of Rayan.The LC–MS/MS analysis of fruit revealed the presence of major phenolic compounds such as gallic acid,quercetin and kaempferol,while quercetin,gallic acid and vanillic acid in seed.The presence of quercetin suggests health benefits.The fruit of Rayan was also proved to be a better source of antioxidants as measured by FRAP,RPA,DPPHRSA,ABTSRSA and HRSA except NORSA in comparison with that of seed.The current study explains that M.hexandra is a relatively good source of antioxidants such as phenols and flavonoids for diet.

A systematic study on mycochemical profiles, antioxidant, and anti-inflammatory activities of 30 varieties of Jew’s ear(Auricularia auricula-judae)

The health-promoting properties and chemical profiles of 30 Jew’s ear mushroom varieties were investigated. The antioxidant properties were determined by ferric reducing antioxidant power(FRAP), 1,1-diphenyl-2-picrylhydrazyl(DPPH) free radical scavenging, 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) free radical scavenging, and metal chelating ability(MCA) assays, while phenolic profiles were determined by total phenol content(TPC) and total flavonoid content(TFC) colorimetric assays. Total carbohydrate, β-glucan, and melanin contents were determined by colorimetric methods. 5’-Nucleotides, vitamin D_(2), ergosterol, and ergothioneine contents were determined by high performance liquid chromatography(HPLC). Anti-inflammation activities of Jew’s ear were evaluated by the colorimetric protease inhibitory method. The results showed that Jew’s ear mushrooms possessed substantial phenolics and antioxidant properties. All the Jew’s ear varieties contain high amount of total carbohydrate, β-glucan, reducing sugar, melanin, pectin, vitamin D2, ergosterol, and ergothioneine. The current findings could provide scientific information for breeders to nurture desired varieties and for food industry to develop new health promoting products.

Phytochemical constituents,antioxidant and antibacterial activities of methanolic extract of Ardisia elliptica

Objective:To investigate the antioxidant,antibacterial,and chemical ingredients of Ardisia elliptica(A.elliptica) methanolic extracts.Methods:The plant was extracted using methanol.Antibacterial and antioxidant activities were evaluated.Results:The results showed that both fruit and leaf extract of A.elliptica have significant antibacterial activities against Gram-positive and Gram-negative bacteria.Fruit extracts showed higher content of phenolic(71 ± 0.03 GAE/mg extract dry weight),in comparison to the leaf extracts(37 ± 0.05 GAE/mg extract dry weight).Flavonoid content,and Fe2+chelating activity of fruit extracts were higher than leaf extract.The percentage radical inhibition of fruit extract is found to be higher(70%) than that of leaf extract(60%).LCMS results indicated that the major compounds in the fruit extract were Gingerol,Aspidin,Kampherol,and Stercuresin,while the leaf extract contained Gingerol,Aspidin,Triangularin,and Salicyl acyl glucuronide.Furthermore,the results of GCMS indicated that fruit extract contained these major compounds:Vitamin E Tocopherol,5-hepylresornicol,2-Nonylmalonic acid,5-pentadecylresornicol,and Stigmasta-7-22-dien-3-ol.However,leaf extract of A.elliptica contained these major compounds:Alpha Amyrenol,4,4,6,6a,6b,8,8a,9,10,11,12,12 a,14,14 a,14 b octadehydro-2H-picen-3-one,and Lonasterol,4-t-Butyl-2-[4-nitrophenyl] phenol.Conclusions:The results provide evidence that fruit and leaf of A.elliptica extracts might indeed be used as a potential source of effective natural antimicrobial and antioxidant agents in pharmaceutical and food industries.

Simple phenols in tropical woods determined by UHPLC-PDA and their antioxidant capacities: an experimental design for Randall extraction using environmentally friendly solvents

A comprehensive experimental design was developed to determine suitable conditions(volume, percentage of solvent, extraction temperature) for the ethanol extraction of phenolic compounds from ten tropical woody plants. Wenge, angelim vermelho, zebrano, merbau,tigerwood, angelim pedra, jatoba, angelim amargoso,massaranduba, and doussie woods were used in experiments. The effects of three independent variables and their interactions on the yields of cinnamic and benzoic acid derivates were analyzed using UHPLC-PDA. The most significant parameters were found to be solvent percentage,extraction volume, and extraction temperature. Optimal conditions for the extraction of phenolic compound contents were an 80℃ extraction temperature, a 30 mL extraction volume, and the use of pure water as the extraction solvent. The tested species of woods contained mainly cinnamic acid derivates. Water extracts after hydrolysis contained greater amounts of cinnamic acid derivates than those extracts from non-hydrolyzed material.The total phenolics content was highest in water extracts of tigerwood, wenge and merbau;however, the extract of merbau wood was a stronger radical scavenger in ABTS?áassays: 34.11 ± 0.02 mM Trolox equivalents per g of dry extract. The main compounds possessing antioxidant activity in the extracts of vermelho wood assessed by UHPLC analysis were hydroxycinnamic acids.

百香果皮分级萃取物中多酚轮廓分析及其抗氧化活性物质筛选

为探究不同溶剂对百香果皮多酚的萃取效率,寻找其中抗氧化活性贡献大的特征多酚。选用石油醚、乙酸乙酯和正丁醇分级萃取百香果皮乙醇粗提物,采用分光光度法分别测定其总酚总黄酮含量,借助超高效液相色谱串联质谱解析各分级萃取物中酚类化合物,并结合非靶向代谢组学技术筛选差异代谢物并定量。选用DPPH自由基清除、ABTS^(+)自由基清除和Fe^(2+)还原法分析各分级萃取物体外抗氧化活性差异,通过皮尔逊相关性分析探寻百香果皮中抗氧化活性酚类标志物。结果表明:各萃取物总酚和总黄酮含量差异显著(P<0.05),由大到小依次为乙酸乙酯部位(EE)>正丁醇部位(BE)>乙醇粗提物(CE)>水部位(WE)>石油醚部位(PE)。从CE和各分级萃取物中共鉴定出33个酚类化合物,CE、EE和BE酚类化合物种类和数量较多。主成分分析(PCA)区分了各萃取物的代谢物,正交偏最小二乘法判别分析(OPLS-DA)对羟基苯甲酸、原儿茶酸、异槲皮苷和异荭草苷为差异物。EE中对羟基苯甲酸(653.44μg/g)、异槲皮苷(2420.64μg/g)和异荭草苷(113.23μg/g)含量最高,CE中原儿茶酸(152.40μg/g)含量最高。百香果皮各分级萃取物体外抗氧化活性差异显著,EE体外抗氧化能力最强,是优质的抗氧化剂开发部位。相关性分析结果显示,总酚和总黄酮是百香果皮抗氧化活性物质基础,异荭草苷和异槲皮苷是其中的抗氧化活性酚类标志物。研究结果为建立百香果皮相关抗氧化产品质量控制标准及精准开发利用百香果皮酚类化合物资源提供了基础数据。

不同品种梨果实酚类物质和抗氧化性能分析

以我国北方11个主栽梨品种黄冠、绿宝石、雪梨、鸭梨、丰水、南水、圆黄、黄金、华山、五九香和早酥的果实为试材,分别测定了果皮、果心和果肉中可溶性酚的含量,并对酚类物质进行了高效液相色谱(high performance liquid chromatography,HPLC)分析。通过分别测定果皮、果肉、果心的乙醇提取液对DPPH自由基和羟自由基的清除能力,对其所含酚类物质的抗氧化性能进行了评价。结果表明:1)梨果心酚类物质含量高于果皮,果肉最低;2)在果心和果皮中均检测出熊果苷、没食子酸、儿茶素、绿原酸、咖啡酸、表儿茶素、香豆酸和芦丁8种酚类物质,而在果肉中检测出熊果苷、没食子酸、绿原酸、表儿茶素和芦丁5种物质;3)熊果苷、绿原酸和表儿茶素都为果肉和果皮的主要酚类物质,果肉中绿原酸的含量高于熊果苷,果皮则反之,果心所含酚类物质以绿原酸和熊果苷为主,且绿原酸的含量高于熊果苷;4)果皮、果肉、果心不同部位的酚类物质的含量与1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除能力和羟自由基清除能力间均分别呈显著正相关关系,表明酚类物质与自由基清除能力的关系密切。

超微粉碎对香菇多酚组成及抗氧化活性的影响

将鲜香菇分为伞、柄后进行适当干燥,利用超微粉碎得到不同粒径的香菇伞粉和香菇柄粉,比较气流超微粉碎和纳米超微粉碎与普通粉碎处理在香菇伞粉和柄粉多酚溶出率、组成及抗氧化活性之间的差异。结果表明:与普通粉碎相比,超微粉碎可以使香菇伞粉总酚溶出率提高13%;通过高效液相色谱(high performance liquid chromatography,HPLC)检测分析,香菇多酚类物质主要为没食子酸、儿茶素、咖啡酸、芦丁、阿魏酸和槲皮素,其中游离酚以没食子酸和儿茶素为主,结合酚以没食子酸、儿茶素和槲皮素为主。抗氧化能力评价中,气流超微粉碎能明显改善香菇多酚的还原力、2,2’-联氨-双-(3-乙基-苯并噻唑啉-6-磺酸)二氨盐(2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid),ABTS)自由基清除力和总氧自由基吸收能力(oxygen radical absorbance capacity,ORAC);纳米超微粉碎能够提高柄粉多酚的1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除力。超微粉碎能够提高香菇多酚的溶出率及抗氧化活性,可以作为以香菇为原料开发功能性食品的一种前处理加工手段。

低温真空膨化与自然干制对红枣抗氧化活性的影响

目的:研究低温真空膨化和自然干制对红枣抗氧化成分及活性的影响,为生产加工优质枣产品和低温真空膨化技术在红枣加工方面应用提供科学依据。方法:以矮化密植枣树所得枣果为材料,采用Folin-Ciocalteu与NaNO2-Al(NO3)3法测定总酚、总黄酮含量;通过DPPH自由基清除率、ABTS+?清除能力、总还原力和抗亚油酸过氧化能力等指标表征枣果抗氧化能力;采用高效液相色谱法对酚类化合物进行定性定量分析。结果:红枣经膨化后总酚含量显著增加,而总黄酮未发生明显变化,自然干制使总酚、总黄酮含量显著降低。膨化枣DPPH自由基清除能力和总还原力显著优于鲜枣和自然干制枣,自然干制处理使红枣ABTS+?清除能力和β-胡萝卜-亚油酸抗氧化活性显著低于膨化枣与鲜枣。膨化枣中总酚、总黄酮和抗氧化能力显著高于自然干制枣。干制处理使枣果中酚类化合物组成发生明显变化,膨化枣中没食子酸、对羟基苯甲酸、咖啡酸、对香豆酸、阿魏酸、芦丁、肉桂酸和槲皮素的含量最高。相关性研究表明鲜枣与干制枣中抗氧化活性与总酚、总黄酮显著相关。结论:低温真空膨化枣含有丰富的酚类化合物与最高抗氧化能力,且加工时间短,口感酥脆香甜。综上所述,低温真空膨化技术可作为一种可用于规模化干制枣的现代化加工技术。

油炸薯条中酚类抗氧化剂的高效液相色谱法测定

采用反相高效液相色谱法测定油炸薯条中PG、TBHQ、BHA、4HR、BHT、2246。其中PG、TBHQ用50％甲醇（体积分数1％的冰醋酸）作流动相，BHA、4HR、BHT、2246用80％的甲醇作流动相，检测波长为280nm，用纯甲醇提取样品中的PG、TBHQ；用甲醇：二氯甲烷=9：1（v／V）提取BHA、4HR、BHT、2246。相关系数在0.9983-0.9996之间，检出限为1.0-2.0μg／g，标准偏差在0.21%－5.30％之间，平均回收率均在85％以上。

油炸小食品中酚类抗氧剂的高效液相色谱法测定

采用反相高效液相色谱法测定油炸小食品中BHA、4HR、BHT、2,2-2甲基双(4-甲基6-叔丁基苯酚) (2246)的含量。采用V(甲醇):V(二氯甲烷)=9:1作提取剂,ODS-2HYPERSIL(250mm×4.6mm,5μm)色谱柱,体积分数80%的甲醇作流动相进行分离。结果表明:浓度在2.0～40μg/mL,4种物质均呈线性关系,相关系数为0.998 3～0.999 1,标准偏差为1.14%～5.90%,平均回收率均在80%以上,检出限2μg/g。因此,该方法可用于油炸食品中酚类抗氧剂的测定。

凝胶渗透色谱-高效液相色谱法测定食品中酚类抗氧化剂

本文采用凝胶渗透色谱对食品进行脱油脂前处理,高效液相色谱仪(DAD检测器)对酚类抗氧化剂进行定性定量分析。该方法在实际样品检测中加标回收率在86.3%-105.3%间,相对标准偏差小于9.6%,最低检测限为1μg/mL。与国家标准方法相比,该方法可同时检测4种酚类抗氧化剂,具有较高的准确性与灵敏度,适用于食品中PG、TBHQ、BHA与BHT的检测。

用液相色谱法测定2,6-二叔丁基苯酚与丙烯酸甲酯反应的混合物

合成塑料、橡胶制品用抗氧剂1010的中间产物系2,6-二叔丁基苯酚与丙烯酸甲酯的反应混合物。用高效液相色谱法(HPLC)测定了该混合物的组成,分离出9个特征吸收峰。其主要产物β-(3,5-二叔丁基-4-羟基苯基)丙酸甲酯的含量>92％。用正反两相色谱和两种不同的检测器进行了定性分析,以面积外标法和内标法进行定量。各组分的相对误差为-0.82％—3.78％,相对偏差为0.86％—2.32％。本测定方法灵敏、准确,可满足科研和工业生产的定量分析要求。

绞股蓝中6种多酚化合物的HPLC检测及其醇提液的抗氧化活性

采用高效液相色谱法分析野生(5叶、7叶和9叶3种生态类型)和人工种植(7叶)绞股蓝的叶及茎中6种多酚化合物的含量,并测定样品醇提液的总多酚含量及抗氧化活性。结果表明:色谱条件为色谱柱poroshell120 PFP(4.6 mm×100 mm,2.7μm),流动相1%甲酸(A)和乙腈(B),检测波长254 nm和350 nm,在此条件下绞股蓝样品中6种多酚单体可在35 min内得到较好分离,且重复性好(相对标准偏差(relative standard deviation,RSD)≤4.6%)、精密度高(RSD≤2.68%)、稳定性好(RSD≤2.45%)、加标回收结果准确可靠(平均回收率84%~99%,RSD≤4.02%)。6种多酚单体在不同的绞股蓝样品中含量差异较大,但均呈现出芦丁含量最高,对羟基苯甲酸含量最低。绞股蓝样品醇提液中总多酚及抗氧化活性在不同样品间差异较大,在野生绞股蓝(7叶)叶中最高(分别为75、39.65、70.48 mg/g),在其茎中最低(分别为2.81、2.1、3.7 mg/g)。总体而言,绞股蓝的叶中总多酚含量高于茎中,醇提液的抗氧化活性也强于茎。

酿造啤酒大麦发芽前后多酚组分变化及抗氧化活性

以8种酿造啤酒大麦及麦芽为原料,分别提取游离酚和结合酚,分析多酚组分变化,并测定其抗氧化活性。结果显示,啤酒大麦发芽前后多酚含量及组分均有显著变化,大麦发芽后总酚含量普遍高于发芽前,其中,Hindmarsh发芽后总酚增加率最高;阿魏酸、荭草素含量在发芽过程中显著增加(P<0.05)。Hindmarsh游离没食子酸、香草醛与阿魏酸增加率最高;Metcalf结合阿魏酸与荭草素增加率最高。体外抗氧化结果表明,相比发芽前,麦芽多酚清除1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基能力及氧自由基吸收能力普遍增强,其中,Scope麦芽游离酚清除DPPH自由基能力最强,Baudin麦芽结合酚的氧自由基吸收能力最好。

不同成熟度杨梅酚酸的超声-微波协同优化提取及其抗氧化性对比

本研究采用超声-微波协同提取的方法对杨梅果实中游离酚酸的提取工艺进行优化,并与单一的微波辅助提取和超声辅助提取进行比较。采用优化后的工艺提取不同成熟度杨梅果实酚酸,利用高效液相色谱法分析了8种主要酚酸的分布及含量,同时还对不同成熟度杨梅酚酸提取物的抗氧化性进行了比较。以单因素试验为基础,根据Box-Behnken中心组合设计原理,选取乙醇体积分数、料液比、超声-微波结合方式进行响应面分析,得到酚酸提取工艺的最佳条件为:乙醇体积分数60%、料液比1∶23(m/V)、协同处理方式为先微波30 s后超声15 min,酚酸得率可达36.21μg/g。杨梅果实中主要的游离酚酸种类为没食子酸、原儿茶酸和对羟基苯甲酸,但不同成熟度杨梅酚酸的分布和含量不同,其中以五分熟杨梅酚酸含量最高,可达45.50μg/g。抗氧化活性研究结果表明,五分熟杨梅的酚酸提取物具有更强的1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除能力、羟自由基清除能力和还原能力,总酚酸含量与DPPH自由基清除能力、还原能力呈极显著正相关(P<0.01)。通过优化提取工艺明确了不同成熟度杨梅酚酸的组成和抗氧化性质,本实验结果可以为杨梅酚酸的综合利用开发提供科学依据。

红肉与白肉火龙果酚酸组成及其抗氧化活性

为研究火龙果果皮、果肉中的酚酸组成及抗氧化活性,以红肉火龙果和白肉火龙果为研究对象,采用高效液相色谱法(HPLC)测定其游离型酚酸(FPA)、可溶共价结合型酚酸(HPA)和束缚型酚酸(BPA)组分与含量,并测定其体外抗氧化活性,包括DPPH清除能力、还原能力和羟自由基抑制能力。结果表明:两种火龙果中酚酸含量顺序为:红肉果肉>白肉果肉>白肉果皮>红肉果皮。火龙果果肉中酚酸主要以HPA形式存在,果皮中酚酸的主要存在形式为BPA。没食子酸是红肉火龙果中的主要酚酸(1700.70μg/g干重);原儿茶酸是白肉火龙果中主要酚酸(1877.50μg/g干重)。红肉果皮的BPA对DPPH自由基清除能力最强(2206.37 mg/L),红肉果肉的HPA还原能力最强(A_(700)=0.82),白肉果皮的HPA对羟自由基抑制能力最强(77.50 U/mL)。酚酸含量与抗氧化活性的相关性分析表明:DPPH自由基清除能力和还原能力与酚酸的含量呈极显著(P<0.01)正相关,羟自由基抑制能力与酚酸含量无显著相关性。

火麻籽油中酚类化合物的检测及抗氧化活性研究

建立了利用高效液相色谱同时检测火麻籽油中10种酚类物质的方法,10种单体酚检出限为0.05~0.12μg/m L,线性相关系数为0.997 0~0.999 8,回收率为85%~108%。检测了8份不同产地火麻籽油的总酚、总黄酮含量及体外抗氧化活性指标(DPPH、FRAP、ABTS+·)。总酚含量为1.20~17.35mg对香豆酸/100g,总黄酮含量为7.61~51.72mg柚皮苷/100g。DPPH清除能力为9.03~19.71mmol TE/100g,FRAP还原能力为13.12~30.09mmol TE/100g,ABTS+·清除能力为29.40~358.37mmol TE/100g。相关性分析表明,总酚含量与DPPH、ABTS+·清除能力和FRAP还原能力呈显著正相关;总黄酮含量与DPPH清除能力、FRAP的还原能力呈显著正相关。

不同品种荔枝果皮酚类物质组成及其抗氧化活性比较

为比较不同品种荔枝果皮酚类物质含量、组成及其抗氧化活性差异,用80%甲醇分别提取6个品种荔枝果皮中的酚类物质,测定其总酚和总黄酮含量。采用铁离子还原能力(FRAP)和自由基离子清除能力(ABTS)等方法评价其抗氧化活性。通过高效液相色谱(HPLC)鉴定不同的单体酚并分析其在不同品种荔枝果皮之间的差异。结果表明,不同品种荔枝果皮的酚类物质含量为28.69~68.48 mg/g,不同品种荔枝果皮的酚类物质含量和抗氧化能力存在显著的差异(P<0.05)。酚类物质的含量、FRAP和ABTS抗氧化活性能力均以‘荔枝王’为最高,分别为68.48 mg/g、546.31μmol/g和511.25μmol/g。液相色谱结果鉴定出‘糯米糍’中的8种单体酚,而含量相对较高的是A型原花青素三聚体和原花青素A2。研究结果可为荔枝加工废弃物荔枝果皮的开发利用提供理论依据。