8种猕猴桃抗氧化活性评价及基于HPLC与FT-IR指纹分析的品种区分

为探明不同品种猕猴桃的体外抗氧化活性差异,并对不同猕猴桃品种进行有效区分,采用高效液相色谱法(HPLC)、傅里叶变换红外光谱法(FT-IR)对猕猴桃进行指纹分析,分析测定了脐红、金艳等8个品种猕猴桃的体外抗氧化能力、多酚组成及FT-IR光谱,并对其进行了方差分析、主成分分析(PCA)及系统聚类分析(CA)。结果表明:华优的抗坏血酸及总酚含量比其他品种高约2倍,其体外抗氧化活性显著强于其他品种。对抗氧化指标、酚类含量及FT-IR数据的主成分分析中前两个主成分累积解释率分别达到63.49%、55.91%、84.96%。三种聚类分析均可将不同品种猕猴桃进行较好区分,尤其对金艳、华优、海沃德区分效果最好。基于FT-IR数据的品种区分效果优于基于抗氧化指标、酚类含量的区分,同植物学分类最为一致。基于抗氧化指标的聚类分析对脐红、晚红、徐香的区分效果欠佳。     

现代仪器分析技术在黄酒分析研究中的应用

介绍了光谱、色谱等分析法中几种现代仪器分析技术的基本原理及其在黄酒分析研究中的应用,总结了目前黄酒研究中常用的分析方法。     

Phenolic Composition,Essential Oil,and Antioxidant Activity in the Aerial Part of Artemisia Herba-Alba from Several Provenances: A Comparative Study

This study characterized the phenolic, aroma compositions, and antioxidant capacities of four Artemisia herba alba accessions collected from north and center regions in Tunisia in order to select valuable origin with optimal bioactive compounds production. The total polyphenol and flavonoid contents varied between accessions with maxima contents observed in center regions. Kaempherol, apigenin, naringenin, p-coumaric, trans-cinnamic, and caffeic acids were the most abundant compounds with percentage varying depending on the considered accession. Significant changes on essential oil yields (0.4–1.2%) were found between accessions and three different oil chemotypes were distinguished: camphor, fenchol/α-thujone, and α-thujone/camphor. Cluster analysis of volatile and phenolic compositions grouped the accessions on different groups. Antioxidant activities of extracts were found to be higher than essential oils for the four provenances. The results suggested that the center regions have high potential for selecting varieties rich on essential oil, antioxidant phenolic acids, and flavonoids.     

Bioactive and Antioxidant Activity from Citrus bergamia Risso (Bergamot) Juice Collected in Different Areas of Reggio Calabria Province,Italy

The chemical composition and antioxidant activity of juice extracted from seven samples of bergamot (Citrus bergamia Risso) collected in different areas of Reggio Calabria Province were investigated. The ascorbic acid, total polyphenol, and flavonoid contents were determined. Total flavonoids and polyphenols were analyzed by ultraviolet spectra, while flavanone content was analyzed by high-performance liquid chromatography. The antioxidant activity of the fractions was assessed using three representative assays: 2,2′-azinobis(3-ethylbenzothiazoline 6-sulfonic acid), 1,1-Diphenyl-2-picryl-hydrazyl radical quenching and β-carotene bleaching test. The main flavanones were naringin, neohesperedin, and neoeriocitrin, and their average content 242.4 ± 1.8, 183.0 ± 0.6, and 247.0 ± 1.4 mg mL^–1, respectively. The results showed that bergamot juice possessed a good quality and a valuable source of health promoting constituents. In fact it contained eriocitrin, naringin, neoeriocitrin, and neohesperedin, which may contribute differentially to the antioxidant capacity.     

高效液相色谱法测定8 个彩色马铃薯品种中花青素种类和含量

采用高效液相色谱法,以表皮和薯肉为研究对象,定量分析8 个彩色马铃薯品种块茎中花青素的种类和含量。研究发现,彩色马铃薯块茎中最多含有6 种花青素,即飞燕草色素、矢车菊色素、矮牵牛色素、天竺葵色素、芍药色素和锦葵色素。紫色马铃薯块茎中主要花青素为矮牵牛色素、芍药色素和锦葵色素,红色马铃薯块茎中主要花青素是天竺葵色素和芍药色素。飞燕草色素和芍药色素广泛存在于彩色马铃薯（紫色和红色）块茎的表皮中,而红色马铃薯块茎中未检测到锦葵色素。品种之间差异显著（P＜0.05）,其中紫云1号的总花青素含量最高。块茎表皮的花青素含量约是薯肉的6～176 倍,且大部分品种的表皮花青素种类比薯肉多。彩色马铃薯块茎的表皮富含丰富的花青素,是天然色素和抗氧化剂的重要来源。     

羟基酪醇酶促聚合产物的表征及其抗氧化和热稳定性

利用漆酶对羟基酪醇（hydroxytyrosol,HT）进行酶促氧化聚合,运用紫外-可见分光光度计、傅里叶红外光谱、凝胶色谱和液相色谱-质谱联用对聚合产物进行表征。结果表明,形成的聚合物呈现多分散性（D=2.1）,主要生成了三聚体、四聚体、六聚体化合物。同时,以VC和2,6-二叔丁基-4-甲基苯酚（dibutyl hydroxy toluene,BHT）为阳性对照,分别通过清除1,1-二苯基-2-三硝基苯肼自由基和热重-傅里叶变换红外光谱（thermogravimetry-Fourier transform infrared spectroscopy,TG-FTIR）联用的方法对其进行抗氧化性及热稳定性评价。结果表明,HT聚合物较HT和BHT具有更强的抗氧化性,分别约是其2.28?倍和5.7?倍,接近于VC（约是其72%）。基于热重微分曲线峰值温度（315.1?℃）和残余质量所占百分比（66.09%）结果可知,HT聚合物的热稳定性较VC（228.1?℃）、BHT（236.2?℃）和HT（314.9?℃）更强,且FTIR结果表明,HT聚合物及其他受试化合物均是以羟基断裂开始,脱氢形成醌式结构或脱水碳碳双键。这些数据可为HT的深加工利用提供理论和实践基础。     

基于中红外漫反射光谱技术测定精米中直链淀粉含量的研究

研究了基于傅里叶中红外漫反射光谱(DR-FTIR)技术结合偏最小二乘法(PLS)、主成分分析法(PCR)、经典最小二乘法(CLS)、逐步多元线性回归法(SMLR)快速测定精米中直链淀粉含量。实验选取了161个精米样品作为研究对象,通过光谱预处理,异常值剔除,波谱区间选择对模型进行了优化。结果表明:采用PLS建模,通过多元散射校正,向后区间偏最小二乘法预处理后,所构建的模型效果最优。此时,建模区间为3 800~3 500、3 100~3 000、2 900~2 400、2 300~1 300、1 000~900 cm~(-1),模型相关系数R为0.995 6,校正均方差为0.291,预测均方差为1.23;同时,实验另选了34种精米样品对模型进行了准确性验证。结果显示验证集样品的红外预测值与真实值高度相关,线性拟合方程为Y=0.994X+0.068,相关系数R为0.994 9,说明实验所开发的直链淀粉DR-FTIR模型是有效的,预测结果准确度好,模型稳定性高。     

芡实谷蛋白的结构及热力学性质研究

采用Osborne分级法制备芡实谷蛋白,并采用还原与非还原聚丙烯酰胺凝胶电泳(SDS-PAGE)、示差扫描量热仪(DSC)和傅里叶红外光谱(FT-IR)分别对芡实谷蛋白亚基分子量、热学性质以及二级结构作初步研究。结果表明:芡实谷蛋白主要含有6个亚基,大部分高分子量的多肽链以分子间或分子内二硫键连接;在等电点(p H=5.0)时,芡实谷蛋白的变性温度和变性焓最高;在p H=9.0溶液中变性温度和变性焓最低;随着盐浓度的升高,芡实谷蛋白的变性温度显著升高,而变性焓变化不显著,表明有更高热稳定性的结构出现;芡实谷蛋白中主要为有序结构,二级结构中β折叠所占比例最高,比例为31.16%。研究表明芡实谷蛋白含丰富的二硫键,有较强的热稳定性,结构较稳定,可为后续研究芡实谷蛋白的功能特性以及应用提供理论依据。     

糙米多酚3 种纯化方法的比较

分别用液液萃取、大孔树脂、固相萃取法纯化糙米多酚粗提物,对纯化物的多酚回收率和抗氧化性进行研究,并通过高效液相色谱分析3 种纯化方法总酚酸和其中9 种酚酸的回收率,3 种纯化方法多酚回收率分别为20.51%、53.45%、87.87%,总酚酸回收率分别为56.84%、67.35%、68.99%,多酚纯度由粗提物的19.23%分别提高到40.72%、46.84%和78.71%。多酚含量与1,1-二苯基-2-苦肼基自由基清除能力、铁还原能力极显著相关（P＜0.01）。除品种因素外,纯化方法是导致提取物中非酚酸多酚物质回收率差异大,进而引起多酚含量差异显著的另一重要原因;纯化方法对酚酸回收率有显著影响,应依据纯化目标物回收率来进行纯化方法的筛选,而非以传统的总多酚或总酚酸回收率判断具体某种酚酸的最适纯化方法。     

Usage pattern and exposure assessment of food colours in different age groups of consumers in the State of Uttar Pradesh,India

The present study aims to investigate the nature and levels of colours in food items and to undertake risk assessment vis-à-vis intake among different age groups of consumers in the State of Uttar Pradesh, India. A total of 478 edible foodstuffs were analysed, and of six permitted colours, Sunset Yellow FCF (SSYFCF) and Tartrazine were most popular, and two non-permitted colours, namely Metanil Yellow and Rhodamine B, were encountered. The study showed a marked improvement in the trend of use of non-permitted colours over previous surveys, with 90% foods now resorting to approved food colours. However, 59% of foods employing permitted colours exceeded the maximum allowable limit, with average quantities crossing the threshold of 100 mg kg^?1 in most food commodities. The intake of SSYFCF exceeded the acceptable daily intake (ADI) for children and adolescents by 88% and 39%, respectively, and was statistically significant when analysed by error bars and distribution curves. In adults, SSYFCF saturated 59% of the ADI. For Carmoisine, Tartrazine and Ponceau 4R, saturation of ADI ranged from 27.4% to 90.3% in children and adolescents and from 10.8% to 47.6% in adult subjects. These results indicate that children and adolescents are more vulnerable to higher intakes of food colours compared with the adult population. Allowing a uniform level of all colours in foods under Indian rules, notwithstanding wide variations of 250-fold in their allocated ADIs, could be one reason for the higher intake and hence only technological need-based levels of individual colours are desired to be prescribed.     

Comparison of extraction solvents and conditions for herbicide residues in milled rice with liquid chromatography-diode array detection analysis (LC-DAD)

Different extraction procedures and clean-up methods were compared in order to develop a sample preparation procedure for the multi-residue analysis of six post-emergence herbicides (metsulfuron methyl, bensulfuron methyl, pyrazosulfuron ethyl, bentazone, bispyribac sodium and cyhalofop butyl) in rice grains followed by liquid chromatography-diode array detection (LC-DAD). Optimum results were obtained dispersing milled rice grain in water, followed by the addition of 1% acetic acid in acetonitrile, MgSO₄ and sodium acetate as a modification of the quick, easy, cheap, effective, rugged and safe (QuEChERS) method but no primary and secondary amine (PSA) sorbent was added due to the acidic nature of the herbicides. The method was further expanded to other post-emergence herbicides (quinclorac, clomazone and propanil). Except for quinclorac, which cannot be analysed with this method, the recoveries of the other eight herbicides were in the range 73–111%, with relative standard deviations lower than 12%. Limits of detection (LODs) ranged from 0.03 to 0.08 mg kg^?1. A single analyst can extract twelve samples in 4 h. The method presented here allows the simultaneous residue determination of the most common post-emergence herbicides employed in cultivating rice. It is simple, rapid, sensitive, and can be applied routinely to polished rice grain herbicide residue analysis.     

HPLC analysis and safety assessment of coumarin in foods

Coumarin is a component of natural flavourings including cassia, which is widely used in foods and pastries. The toxicity of coumarin has raised some concerns and food safety authorities have set a maximum limit of 2 mg/kg for foods and beverages in general, and a maximum level of 10 mg/l for alcoholic beverages. An efficient method for routine analysis of coumarin is liquid chromatography with diode array detection. The optimal sample preparation for foods containing cinnamon was investigated and found to be cold extraction of 15 g sample with 50 mL of methanol (80%, v/v) for 30 min using magnetic stirring.     

Phytochemical Content,Antioxidant Properties,and Phenolic Profile of Tunisian Raisin Varieties (Vitis Vinifera L.)

Four raisin (Vitis vinifera L.) varieties, Chriha, Razeki, Assli, and Meski, were evaluated for total phenolic content, total o-diphenol content, total flavonoid content, total condensed tannin, total carotenoid content, and total anthocyanin content. Antioxidant potential was assessed by three assays: 2,2-Diphenyl-1-Picrylhydrazyl and 2,2’-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid radical scavenging capacity and ferric reducing power. Individual phenolic profiles were determined by high-performance liquid chromatography. The results revealed that the four raisin varieties had considerable phenolic content and antioxidant activity. Chriha had the highest total phenolic content (534.2 mg/g dry weight) while Meski had high total condensed tannin (208.6 mg CEQ/g dry weight), TAC (137 mg/100 g dry weight), total o-diphenol content (115.8 mg/g dry weight), total flavonoid content (93 mg CEQ/g dry weight), and total carotenoid content (33 mg/100 g dry weight). There were significant differences in phenolic content among the four varieties (p < 0.05). Meski had the highest 2,2-Diphenyl-1-Picrylhydrazyl scavenging capacity, while Chriha had adequate reducing power and 2,2’-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid scavenging capacity. The individual phenolic compounds (2.96–6.54 mg/g dry weight) were variety-dependent.     

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（highperformance 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。     

凝胶渗透色谱-液相色谱法测定辣椒及其制品中对位红和苏丹红

建立了一种凝胶渗透色谱-高效液相色谱同时检测辣椒及其制品中对位红和五种苏丹红的方法。样品经环己烷-乙酸乙酯(体积比为1:1)提取,凝胶渗透色谱(GPC)净化,采用Diamond柱(250mm×4.6mmi.d.,5μm)分离,以乙腈:水(体积比为95:5)为流动相,流速1.0ml/min;用紫外检测器检测,检测波长500nm。对位红和苏丹红0.01～10.0mg/L时线性关系良好,加标回收率为90%～102%,相对标准偏差为1.6%～5.2%,六种染料的检出限均为0.01mg/kg。     

Polyphenolic Composition and Antioxidant Activity of Galician Monovarietal Wines from Native and Experimental Non-Native White Grape Varieties

Galicia region (Northwestern Spain) wine production is mainly focused to high-quality white wines. The polyphenolic composition and the antioxidant activity have been determined to characterize the wines obtained from white grape varieties (Albariño, Branco Lexitimo, Caiño blanco, Godello, Loureiro, Torrontes, and Treixadura) grown in Galician protected production areas, and the wines elaborated with non-native varieties experimentally grown in Galicia (Chardonnay, Gewürztraminer, Pinot blanc, Pinot gris, Riesling, and Sauvignon blanc). Since Albariños are the varietal wines with the highest production and commercialization extension, we have studied their polyphenolic composition as a function of the production subarea. Three vintage years (2010, 2011, and 2012) have been considered to account for climate variability. Liquid chromatography with diode array and mass spectrometry detection was used to obtain the phenolic profiles. Wines from native grapes could be fully discriminated by their phenolic composition, with only Albariño being partially confused with other varietal wines. Albariño wines produced in O Rosal and Ribera do Ulla could be clearly differentiated, whereas Condado do Tea and Val do Salnés wines were partially confused. The polyphenolic profile was enough to differentiate the wines obtained from non-native grapes. The total polyphenols content and the antioxidant activity of white wines elaborated in Galicia were comparable, although significant differences were found among varieties.     

高效液相色谱法测定粽子中的黄酮类化合物及其迁移规律

建立天然包装材料箬叶及粽米中荭草苷、异荭草苷、牡荆苷、异牡荆苷、对香豆酸5 种黄酮类化合物的高效液相色谱的分析方法。通过测定一次蒸煮、二次蒸煮、不同保存条件等因素对箬叶及粽米中黄酮类化合物含量变化的影响,阐明了不同条件下箬叶中黄酮类化合物在粽子中的迁移规律。结果表明：一次蒸煮后,荭草苷、异荭草苷、牡荆苷、异牡荆苷、对香豆酸5 种黄酮化合物从箬叶迁移到粽米的迁移率为7.41%～45.18%;二次蒸煮时,在120 min内箬叶中5 种黄酮类化合物的迁移率为18.07%～65.94%,特别是在前30 min中,箬叶中黄酮类化合物降低明显,分别占120 min总减少量的51.61%～72.48%,并且二次蒸煮的迁移率大于一次蒸煮。在30 d的保存时间内,箬叶中黄酮类化合物在前15 d减少明显,占总减少量的68.60%～85.50%（除异牡荆苷为0外）;第15天后迁出缓慢;30 d内总迁移率分别为25.90%～64.84%（除异牡荆苷为0外）。随着二次蒸煮时间与保存时间的变化,荭草苷与异荭草苷较迁移缓慢。新鲜保存的方式最有利于异牡荆苷在粽子中迁移,速冻保存最有利于荭草苷、异荭草苷、牡荆苷、对香豆酸的迁移。异牡荆苷在真空保存和速冻保存时短时间内不发生迁移。     

Modification of rice protein with glutaminase for improved structural and sensory properties

Rice protein is highly nutritive and hypoallergenic but certain physicochemical properties restrict its applications in beverages. This study aimed to tackle this issue by modifying rice endosperm protein with glutaminase via deamidation. Glutaminase treatment facilitated an increase in deamidation degree and mean particle size of rice protein and a continuing decrease in turbidity with time. Favourable changes induced in sensory properties included: improved suspendability (increased by 81.25%), lumpiness (decreased by 84.78%), grittiness (decreased by 72.34%) and overall taste liking (improved by 12.24%). Visual observations of rice protein dispersions and turbidity measurements further confirmed the improved suspendability in water. Fourier transform infrared spectroscopy analysis revealed that the action of glutaminase did not remarkably change the protein structure, but slightly reduced α-helical conformation whilst increased β-sheet and β-turn structures. Glutaminase could be useful for deamidation modification of products with high content of glutamine residues (like rice protein), through inducing the breakdown of some intermolecular and intramolecular bonds including hydrophobic interactions and hydrogen bonding without serious cleavage of the peptide bonds, allowing protein rearrangements to more flexible or extended forms. As a result of protein unfolding with more hydrophobic clusters exposed, certain physicochemical properties of rice protein were improved.     

Natural Bamboo (Neosinocalamus affinis Keng) Fiber Identification Using FT-IR and 2D-IR Correlation Spectroscopy

The objective of this study as to identify natural bamboo (Neosinocalamus affinis Keng) fiber through Fourier transform infrared spectroscopy (FT-IR), second derivative IR spectra, and two-dimensional infrared correlation spectroscopy (2D-IR). Textile plant fibers, including natural bamboo, jute, and flax fibers, were collected, and isolated by hydrogen peroxide and glacial acetic acid becoming single fibers to avoid uncontrolled influence. All the chemically treated plant fibers showed generally similar IR spectral profiles. However, different numbers of peaks in the range of 1,300–1,200/cm and the variation in peak intensity at around 1,059/cm were observed for bamboo fiber differentiation. A few differences in their second derivative IR spectra between bamboo fiber and the other plant fibers also provided information for differentiation. Furthermore, the characteristic features of bamboo fiber were presented in 2D-IR correlation synchronous spectra in the range of 800–1,200/cm and 1,425–1,750/cm, which were obviously distinguished from other investigated fibers. In addition, the results showed that the distinction between bamboo fiber and bamboo pulp fiber could be easily carried out using FT-IR and 2D-IR spectroscopy because of their different chemical compositions and crystal lattice types of cellulose (I, II). Therefore, it is demonstrated that FT-IR combined with 2D-IR correlation spectroscopy can become a new approach for natural bamboo fiber identification.     

反相高效液相色谱法检测鱼肉中的ATP关联物

建立同时测定鱼肉组织中6种ATP关联物的高效液相色谱方法。采用反相高效液相色谱分离模式,使用Sepax Bio-C18(250mm×4.6mm,5μm,200A。)色谱柱,以60mmol/L磷酸二氢钾、60mmol/L磷酸氢二钾组成的缓冲液(pH6.68)为流动相等比洗脱,流速0.6mL/min;紫外检测波长为254nm,带宽为16nm。6种组分在20min内基线分离,平均加标回收率在98.3%～104.1%之间,线性范围为1～400mg/L,检出限在15～40μg/L之间。该方法简便、准确,易于移植。