基于非靶向代谢组学分析不同地区羊肉代谢物的差异

为探究不同地区羊肉的代谢物差异,采用超高效液相色谱-四极杆飞行时间质谱技术,结合多元统计分析法和通路分析对青海茶卡、青海玉树、青海祁连、四川、内蒙古和宁夏共6个地区的特色羊肉进行非靶向代谢组学研究。结果显示,从青海3个地区羊肉中筛选出176个差异显著代谢物（VIP≥1,P<0.05）,主要包括氨基酸及其代谢物、苯和取代衍生物、有机酸及其衍生物、杂环化合物、核苷酸及其代谢物等,共注释到88条代谢通路,主要为组氨酸代谢、新陈代谢通路、D-谷氨酰胺和D-谷氨酸代谢通路、辅因子的生物合成和氨基酸的生物合成通路;从青海省内3地区和省外3地区当地特色羊肉中筛选出50种差异显著代谢物（VIP≥1,P<0.05,FC≥2或FC≤0.5）,主要包括氨基酸及其代谢物、甘油磷脂、脂肪酸、醇和胺类、苯和取代衍生物等,共注释到24条代谢通路,主要为新陈代谢通路、嘌呤代谢、酪氨酸代谢、铁死亡和花生四烯酸代谢通路。非靶向代谢组学可从整体水平上揭示不同地区羊肉的代谢差异,为不同地区特色羊肉的鉴别和品质评价提供方向。     

糙米和大米非靶向代谢组学分析

为分析全谷物糙米和大米的差异代谢产物及其代谢途径,采用液相色谱-串联质谱联用非靶向代谢组学技术,分析糙米碾磨前后的代谢物变化和主要参与代谢途径。通过单变量和主成分分析、偏最小二乘判别分析和聚类分析等多变量统计分析发现,在差异倍数不小于1.2或不大于0.833 3、P＜0.05、变量投影重要性值不小于1的条件下,正离子模式下检测到糙米和大米中显著变化的差异代谢物为460 种（其中上调300 种、下调160 种）,负离子模式下检测到糙米和大米中显著变化的差异代谢物为579 种（其中上调383 种、下调196 种）;正离子模式下主要参与代谢途径为2 条（苯丙氨酸、酪氨酸和色氨酸的生物合成、组氨酸代谢）,参与代谢物为4 种;负离子模式下主要参与代谢途径为5 条（甜菜碱生物合成、C5-支链二元酸代谢、嘌呤代谢、玉米素生物合成和碳代谢）,参与代谢物为10 种。结果发现,全谷物糙米与大米相比,差异代谢物上调为主,而且通过影响氨基酸代谢、碳代谢、嘌呤代谢、玉米素代谢和甜菜碱生物合成等代谢途径,调节米糠和胚中多种氨基酸、多酚、脂肪酸类物质含量,提升稻米的营养品质。本研究为全谷物糙米的营养评价提供理论依据,为以糙米为原料的相关加工技术和产品的开发提供基础。     

基于非靶向代谢组学的蓝莓酵素和沙棘酵素代谢产物特征比较

为了探索不同酵素之间代谢产物的差异性,本研究以自然发酵的蓝莓酵素和沙棘酵素为样品,使用超高效液相色谱-四级杆飞行时间质谱测定两种酵素样品中全部代谢物丰度,并对代谢物进行筛选和鉴定,利用代谢组学方法分析蓝莓酵素和沙棘酵素的代谢产物差异。结果表明,两种酵素样品中关键性代谢差异物为9种,通过KEGG数据库的比对分析可知富集代谢产物较多且显著性高的关键代谢通路有6条,主要体现在黄酮和黄酮醇的生物合成,泛酸和辅酶A的生物合成,酪氨酸代谢,丙氨酸、天冬氨酸和谷氨酸代谢,脯氨酸和精氨酸代谢,谷胱甘肽代谢。基于非靶向代谢组学分析,该文初步揭示了蓝莓和沙棘酵素代谢产物差异性,为水果酵素功能性的比较研究提供一定的理论基础和依据。     

基于非靶向代谢组学分析不同品种宁夏枸杞差异性代谢物

目的 通过非靶向代谢组学分析宁杞7号、宁杞9号、宁杞10号3个不同品种的宁夏枸杞的差异性代谢物。方法 采用超高效液相色谱-四极杆/静电场轨道阱高分辨质谱法建立非靶向代谢组学研究方法,通过主成分分析(principal component analysis, PCA)、偏最小二乘法分析(partial least-squares discrimination analysis,PLS-DA)模型、聚类分析等统计学方法对不同品种的宁夏枸杞进行差异分析。结果 宁杞7号、宁杞9号、宁杞10号3种宁夏枸杞品种中正、负模式下均存在的代谢物有393个,共鉴定出17种差异性代谢物[变量投影重要性(variable importance in project, VIP)>1],包括有机酸类及其衍生物3种、氨基酸类及其衍生物2种、黄酮类及黄酮醇类化合物7种、酚酸类2种、其他3种。结论 该研究确定了宁杞7号、宁杞9号、宁杞10号3种宁夏枸杞品种的差异代谢物,可以为不同宁夏枸杞品种的差异性分析提供新的研究思路,对优质宁夏枸杞种质资源的挖掘与选育提供重要参考。     

基于非靶向代谢组学分析不同包装方式预制烤鱼代谢物的差异

为探究不同包装预制烤鱼的代谢物差异,采用液相色谱-串联质谱技术,基于非靶向代谢组学方法分析比较托盒包装、真空包装和气调包装预制烤鱼的代谢物组成。结果表明,在二级质谱信息下,3种包装的预制烤鱼共鉴定出318种代谢物。依据正交偏最小二乘法判别分析模型的变量重要性投影值（variable importance projection value, VIP,VIP>1）和P<0.05,共筛选出47种差异代谢物,包括脂肪酸类10种,核苷酸类10种,氨基酸类9种,有机酸及衍生物类7种,苯及衍生物类3种,醇胺类2种,其他类6种。通过对47种差异代谢物相对含量的聚类热图分析,发现3种不同包装方式预制烤鱼的代谢物相对含量存在差异。其中,气调包装烤鱼的多种呈味氨基酸和单磷酸腺苷相对含量明显高于常规的真空和托盒包装。研究结果初步表明,气调包装对保持烤鱼鲜味有积极作用,将为烤鱼包装多样化发展提供方向。     

基于非靶向代谢组学的信阳毛尖茶加工过程非挥发物代谢轮廓分析

为了解信阳毛尖茶在加工过程中非挥发性代谢物的变化规律,以信阳群体种鲜叶为原料,采用非靶向代谢组学技术对信阳毛尖茶加工过程样品进行系统分析。结果显示,在信阳毛尖茶加工过程中共对比鉴定出1 000种非挥发性代谢物,多元统计分析表明信阳毛尖茶在杀青后其非挥发性代谢物发生显著变化;同时共筛选出53个差异化合物,其中氨基酸、儿茶素、黄酮糖苷、脂质、嘌呤核苷、有机酸等化合物的转化是形成信阳毛尖茶风味和品质的关键;尤其是一些酰化黄酮糖苷、溶血磷脂酰类、嘌呤核苷类化合物在杀青后相对含量显著提升;京都基因与基因组百科全书代谢通路富集分析结果显示,差异化合物在嘌呤代谢,甘油磷脂代谢,苯丙氨酸代谢,氨酰基-tRNA生物合成,苯丙氨酸、酪氨酸和色氨酸生物合成和甘氨酸、丝氨酸和苏氨酸代谢这些代谢通路中显著富集（P<0.05）。本研究进一步挖掘了影响信阳毛尖茶风味和品质的主要非挥发性代谢物,为揭示信阳毛尖茶风味和品质形成机制提供依据和参考。     

基于非靶向代谢组学分析酿酒酵母甲酸胁迫的响应和耐受性机制

采用液相色谱-质谱联用(liquid chromatography-mass spectrometry,LC-MC)的非靶向代谢组学,探究酿酒酵母(Saccharomyces cerevisiae)响应甲酸胁迫的代谢机制.主成分分析和正交偏最小二乘判别分析等多元统计结果表明,甲酸处理后酿酒酵母中发生显著变化(P＜0.0...     

嗜酸乳杆菌发酵枣汁的非靶向代谢组学研究

以嗜酸乳杆菌（Lactobacillus acidophilus）发酵枣汁为研究对象,采用气相色谱-质谱（GC-MS）非靶向代谢组学分析技术对不同发酵阶段的枣汁中差异代谢物进行鉴定,并对结果进行多元统计分析。结果表明,未发酵、发酵0 h、18 h、22 h的代谢产物之间存在差异,基于正交偏最小二乘法-判别分析（O-PLS-DA）结果发现,共有29种代谢物被鉴定为差异代谢物。根据影响值筛选出12条代谢通路具有重要作用,其中关键代谢物为L-组氨酸、去甲缬氨酸、尿素、次黄嘌呤、褪黑素、烟酰胺。经嗜酸乳杆菌发酵后的红枣发酵汁的酯类物质和醛类物质增加,生物活性物质的含量增加,该研究为发酵枣汁中风味物质的调控、营养物质的形成提供一定的理论指导。     

基于非靶向代谢组学分析老面酵头传代发酵过程中的代谢差异

以老面酵头为研究对象,采用基于超高效液相色谱-四极杆飞行时间质谱（UHPLC-QTOF-MS）的非靶向代谢组学分析技术对老面酵头传代发酵过程的差异代谢物进行鉴定分析,并研究老面酵头传代发酵过程中的风味特征代谢物的相对含量变化和关键代谢通路。结果表明,传代发酵1代、2代和4代的代谢产物存在差异,共鉴定出54种差异代谢物,主要的差异代谢物种类为氨基酸及肽类、有机酸类和糖类。共检索到15条与差异代谢物相关性高的关键代谢通路和14种主要参与的差异代谢物,其中关键代谢物为D-麦芽糖、鞘氨醇、L-谷氨酸、纤维二糖、鞘磷脂、甘油磷酸胆碱。该研究从代谢组学角度初步揭示了老面酵头传代发酵过程的代谢产物差异性以及特征化合物,为进一步对老面酵头发酵过程中的风味调控机制提供理论依据。     

基于非靶向代谢组学评价传统发酵对客家酸芥菜酚类化合物组成的影响

芥菜的酚类物质组成及乳酸发酵对其影响仍未完全探明.该文采用高效液相色谱串联质谱的非靶向代谢组学,结合主成分分析、相关性分析和偏最小二乘判别分析等,对广西传统客家酸芥菜(客家擦菜)的原料和成品进行了酚类物质组成分析与对比.结果表明,新鲜芥菜和客家擦菜共初步定性检出136种酚类物质,其中119种(包括25种多酚类物质、34...     

Technical note: Nontargeted detection of adulterated plant proteins in raw milk by UPLC-quadrupole time-of-flight mass spectrometric proteomics combined with chemometrics

We built and validated a chemometric model to detect possible milk adulteration with plant proteins. Specifically, we extracted proteins in raw milk, treated with tryptic digestion, and obtained peptide fingerprints by UPLC-quadrupole time-of-flight-mass spectrometry with proteomics to differentiate authentic milks from their counterparts adulterated with nonmilk proteins. This approach is able to detect soybean and pea powder-adulterated milks at as low as 1% (wt/wt). Additionally, we obtained the characteristic peptide sequences for milk authentication by principal component analysis. The prediction accuracies for milk authentication by partial least-squares-discriminant analysis were greater than 95%. These results indicated that peptide fingerprints with the chemometric analysis could be successfully applied for milk quality control.     

不同等级烘青绿茶生化成分及抗氧化能力的研究

：目的 研究3个不同等级烘青绿茶的生化成分、感官品质及抗氧化活性。方法 使用分光光度计测定3种茶样中总黄酮、茶多酚、氨基酸和咖啡碱的含量,利用清除二苯代苦味酰基自由基（1,1-dipheny-2-picryhydrazyl free radical, DPPH）法测定了其抗氧化活性,并进行感官评价。结果 3个等级绿茶总黄酮、茶多酚、氨基酸和咖啡碱含量差异显著（P＜0.05）,茶多酚随着茶样等级的降低而升高,咖啡碱的含量则相反,而氨基酸和黄酮是波动变化;不同等级绿茶的半抑制浓度（half maximal inhibitory concentration, IC50）差异显著（P＜0.05）,且IC50随着等级的降低而下降;感官评价得分随着等级的降低而降低;3种茶的抗氧化活性与其茶多酚含量成极显著正相关P＜0.01）,与咖啡碱的含量和感官审评得分呈极显著负相关（P＜0.01）。结论 3个等级的炒青绿茶抗氧化性随着等级的降低而升高,且与其主要生化成分呈显著相关。     

3种不同等级遵义红茶香气成分差异分析

目的 探究遵义红的主要香气成分, 对比分析不同等级遵义红茶的香气成分差异。方法 采用固相微萃取-气相色谱-质谱技术对不同等级遵义红茶的香气成分进行测定并对其香气成分差异进行分析。结 果 本研究共检测出遵义红茶中54种香气成分, 其中遵义红茶的香气成分主要以醇类、酯类和烃类为主, 有少量的酮类、醛类、酚类以及酸类;醇类挥发性香气物质多呈花果香, 酯类化合物多呈现水果清香, 部分烃类或酮类如δ-杜松萜烯、茉莉酮等具有木本或花香的香气特性。不同等级遵义红茶中含量水平具有显著差异的香气成分有三种不同等级遵义红茶中大部分香气组分含量水平具有显著差异,如: 香叶醇、反式-橙花叔醇、橙花叔醇、棕榈酸甲酯、左旋-β-蒎烯、δ-杜松萜烯、茉莉酮、3-羟基-L-络氨酸等40多种香气成分香叶醇、反式-橙花叔醇、橙花叔醇、棕榈酸甲酯、(Z)-己酸-3-己烯酯、δ-杜松萜烯、β-愈创木烯、3-蒈烯、茉莉酮、2,4-而叔丁基苯酚、2,6-氨基庚二酸、反式-2-己烯基己酸等香气成分;结合热图分析结果,得出遵义红茶香气成分的相对含量大致分布为尊品>精品>特级。。结论 本研究明确了不同等级遵义红茶香气成分组成与差异, 为优化遵义红茶品质提供理论基础。     

基于非靶向代谢组学比较不同发酵方式红茶滋味物质差异

目的 基于非靶向代谢组学,明确恒温发酵和变温发酵红茶的滋味物质差异。方法 采用超高效液相色谱-四极杆-静电场轨道阱高分辨质谱法（ultra performance liquid chromatography-quadrupole-electrostatic orbitrap high-resolution mass spectrometer,U PLC-Q-Orbitrap-MS）对华蓥山不同发酵方式红茶的非挥发性化合物进行了非靶向筛查,采用Compound Discoverer 3.1和Chemspider软件对化合物进行鉴定,并结合多元统计学软件筛选特征差异化合物。结果 通过UHPLC-Q-Orbitrap-MS检测到358种非挥发性化合物,通过正交偏最小二乘-重要变量投影（orthogonal partial least square-variable import project,OPLS-VIP）结合非参数检验,获得了具有标志性差异的成分91种（VIP＞1.0,P＜0.05）;变温发酵红茶有66种物质相对含量显著 高于恒温发酵红茶,有25种物质相对含量显著低于恒温发酵红茶。结论 该研究确定了恒温发酵和变温发酵红茶的差异滋味物质,为四川华蓥山红茶滋味品质的调控和加工工艺的改善提供了参考依据。     

Beer metabolomics: molecular details of the brewing process and the differential effects of late and dry hopping on yeast purine metabolism

The flavour of beer is complex, based upon changes at the molecular level in the key raw materials, notably grain, hops and yeast, as well as during the process stages that comprise malting and brewing. As analytical techniques evolve in their sophistication and sensitivity, there are opportunities to delve ever more deeply into the fate of small molecules in brewing. To this end, ¹H nuclear magnetic resonance (NMR) metabolomics was used to follow the progression of 76 metabolites in four different late or dry hopped beers (brewed in triplicate) at five time points throughout the brewing process. The majority of the metabolites identified, including sugars, amino acids and nucleotides, significantly decreased in concentration from the start of the boil to post‐secondary fermentation, whereas energy‐related and fatty acid associated metabolites significantly increased in concentration as wort nutrients were consumed by the yeast. Adenine was significantly higher in the dry hopped brews than in the late hopped brews after both primary (p = 2.1 × 10^?6) and secondary (p = 2.7 × 10^?9) fermentation, while 2′‐deoxyadenosine (after primary, p = 1.1 × 10^?2, after secondary, p = 3.2 × 10^?5) and adenosine (after primary, p = 2.6 × 10^?8; after secondary, p = 3.1 × 10^?7)were significantly lower in the dry hopped beers at these time points. These results give molecular insight into the brewing process and the differential effects of hopping methods on yeast purine metabolism. Copyright © 2016 The Institute of Brewing & Distilling     

不同温度条件下分子蒸馏姜黄精油收率及其成分的GC-MS分析

超临界萃取的姜黄油在分子蒸馏温度为80、100、120、140℃的条件下进行分离获得姜黄精油,将姜黄精油分别进行GC-MS成分及相对含量的分析,不同温度条件下获得的姜黄精油成分及其相对含量基本一致。随着分子蒸馏温度升高,姜黄精油收率也随之升高,100℃以上时收率差异很小,温度越高颜色也越深。综合考虑姜黄精油的收率、外观性状、成分及其含量,分子蒸馏温度选择以100℃为佳。     

Complementary hepatic metabolomics and proteomics reveal the adaptive mechanisms of dairy cows to the transition period

The transition period from late pregnancy to early lactation is a vital time of the lifecycle of dairy cows due to the marked metabolic challenges. Besides, the liver is the pivot point of metabolism in cattle. Nevertheless, the hepatic physiological molecular adaptation during the transition period has not been elucidated, especially from the metabolomics and proteomics view. Therefore, the present study aims to investigate the hepatic metabolic alterations in transition cows by using integrative metabolomics and proteomics methods. Gas chromatography quadrupole-time-of-flight mass spectrometry-based metabolomics and data-independent acquisition-based quantitative proteomics methods were used to analyze liver tissues collected from 8 healthy multiparous Holstein dairy cows 21 d before and after calving. In total, 44 metabolites and 250 proteins were identified as differentially expressed from 233 metabolites and 3,539 proteins detected from the liver biopsies during the transition period. Complementary functional analysis of different metabolites and proteins indicated the upregulated gluconeogenesis, tricarboxylic acid cycles, AA degradation, fatty acid oxidation, AMP-activated protein kinase signaling pathway, peroxisome proliferator-activated receptor signaling pathway, and ribosome proteins in postpartum dairy cows. In terms of the metabolites and proteins, glucose-6-phosphate, fructose-6-phosphate, carnitine palmitoyltransferase 1A, and phosphoenolpyruvate carboxykinase played a significant role in these pathways. The upregulated oxidative status may be accompanied by the pathways mentioned above. In addition, the upregulated glucagon and insulin signaling pathways also indicated the significant requirement for glucose in postpartum dairy cows. These outcomes, from the view of global metabolites and proteins, may present a better comprehension of the biology of the transition period, which can be helpful in further developing nutritional regulation strategies targeting the liver to help cows overcome this metabolically challenging time.     

Untargeted metabolomics to explore the oxidation processes during shelf life of pork patties treated with guarana seed extracts

The changes of metabolites in pork patties with different antioxidants added (control without antioxidants, 200 mg kg⁻¹ butylated hydroxytoluene (BHT) and 250 mg kg⁻¹ guarana seed extracts (GSEs)) under modified atmosphere (80% O₂ and 20% CO₂) for 18 days of refrigerated storage were evaluated. Untargeted metabolomic approach based on UHPLC-ESI-QTOF-MS analysis was applied. GSE phytochemical profile revealed a wide variety of compounds (caffeine, glycerol 1-propanoate, amino acids, alkaloids and glycerophospholipids), together with antioxidants (tyrosols, procyanidins and flavonoids). Important differences in BHT and GSE patties metabolomic profiles were found during storage. Most of the differences could be attributed to glycerophospholipids and fatty acyls, along with specific compounds derived from lipid oxidation (i.e. 2-hexenal, 4-hydroxy-2-hexenal and 2,4-heptadienal) and protein degradation (spermine). Therefore, the approach used highlighted a modulation of lipid oxidative processes, together with strict correlation between metabolic profiles and factors associated with meat quality, highlighting GSE effect on active compounds delaying oxidative phenomena.