溶剂萃取-中心切割多维色谱-质谱法测定烟草主要中性香味成分

采用溶剂萃取-中心切割多维气相色谱-质谱技术(MDGC/MS)建立了一种烟草主要中性香味成分的分析方法.0.5 g烟样经5 mL乙醚萃取和2 mL 5％H2SO4酸洗,静置过夜后萃取液用多维气相色谱-质谱分析;以甲基丁子香酚为内标,对茄酮、β-大马酮、香叶基丙酮、β-紫罗兰酮、巨豆三烯酮和二氢猕猴桃内酯等中性香味成分进行了定性定量测定,并与同时蒸馏萃取(SDE)-气质联用(GC/MS)法进行比较.结果表明:各待测组分检出限在0.02～0.18μg/mL之间,回收率为80.0％～ 123.4％,日内相对标准偏差≤7.5％.该方法快速、简便、准确,适用于烟草中性香味成分的批量测试.     

中压制备色谱法分离黑果枸杞中2个矮牵牛素花色苷及其对胰脂肪酶的抑制活性

为了快速制备较高纯度的黑果枸杞花色苷,黑果枸杞花色苷粗提物首先用大孔树脂-中压制备色谱进行纯化,再用凝胶树脂-中压制备色谱分离获得2个花色苷单体,采用超高效液相色谱-串联质谱(ultra-high performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)、核磁共振氢谱(¹H nuclear magnetic resonance,¹H NMR)对其结构进行鉴定,并对纯化物的胰脂肪酶抑制活性进行评价。结果表明：用D101大孔树脂-中压制备色谱对黑果枸杞花色苷进行纯化,所得纯化物中P1、P2的相对含量分别为18.22%和30.77%,继续采用Sephadex LH-20联合中压制备色谱分离纯化可得到相对含量分别为84.16%和81.48%的两个黑果枸杞花色苷组分P1和P2,经UPLC-MS/MS和¹H NMR鉴定,2个花色苷化合物分别为矮牵牛素-3-O-芸香糖(反式-对香豆酰基)-葡萄糖苷-5-O-葡萄糖苷和矮牵牛素-3-O-芸香糖(反式-对香...     

基于静态顶空-GC/MS的加热卷烟用滤嘴载香颗粒评价研究

[目的]建立一种基于静态顶空-GC/MS的加热卷烟用滤嘴载香颗粒评价方法.[方法]采用静态顶空-GC/MS考察不同温度下4种载香颗粒中12种香味成分的释放行为,通过CH2Cl2萃取和GC/MS分析添加4种载香颗粒的加热卷烟主流烟气中香味成分释放量验证静态顶空-GC/MS评价结果.[结果]载香颗粒在加热卷烟实际抽吸降温段...     

咖啡油香气成分的初步分析

采用水蒸气蒸馏法和柱色谱法对咖啡油样品进行预处理,然后,用GC/MS联用仪对咖啡油中的挥发性香气成分进行分离、鉴定。     

黑枸杞中花青苷的定性分析及主要花青苷的抗氧化活性研究

以黑枸杞为实验材料,采用超高效液相-三重四级杆质谱仪(UPLC-MS/MS),对黑枸杞中花青苷进行定性分析。结果表明,黑枸杞中花青苷共5种分别为矮牵牛素-3-[芸香糖-(对-香豆酰葡萄糖)]-5-葡萄糖苷、矮牵牛素-3-(咖啡酰芸香糖)-5-葡萄糖苷、矮牵牛素-3-(对-香豆酰芸香糖苷)、飞燕草素-3-(对-香豆酰芸香糖)-5-葡萄糖苷和锦葵素-3-[鼠李糖-(对-香豆酰葡萄糖苷)]-5-葡萄糖苷。AB-8大孔树脂、聚酰胺和葡聚糖凝胶联用对黑枸杞花青苷主要成分进行分离纯化,矮牵牛素-3-[芸香糖-(对-香豆酰葡萄糖)]-5-葡萄糖苷和矮牵牛素-3-(对-香豆酰芸香糖苷)纯化后含量可达98%,并采用福林酚试剂法和清除DPPH自由基评价其抗氧化活性。可得黑枸杞中主要抗氧化成分为花青苷类化合物,且抗氧化活性与花青苷含量成正相关,相同苷元的酰基花青苷,其活性高于非酰基花青苷。     

高压静电场处理对番茄果实脂肪酸变化的影响

以番茄果实为试验材料,贮藏前用-200、+200 k V/m的高压静电场预处理2 h,在(13±1)℃试验冷库中贮藏24 d,并定期测定果实的脂肪氧化酶活性以及果实不同脂肪酸组成成分以及其含量的变化。结果表明:2种静电场(200 k V/m或-200 k V/m)对番茄果实预处理2 h可显著抑制果实脂肪氧化酶(LOX)活性及果实不饱和脂肪酸的氧化,延缓番茄果实的衰老进程,保持果实的新鲜度,从而解释了高压静电场预处理有利于果实保鲜的机制。     

烟用香精的极性偶合柱系统分析

为提高烟用香精分析结果的可靠性,针对在单柱气相色谱/质谱(GC/MS)上分离峰效果不佳或色谱图中有明显重叠峰的烟用香精,作者采用极性偶合柱系统GC/MS进行了定性分析,并优化分析条件,与单柱GC/MS分析结果进行比较。最后,比较了不同分析结果所得化学成分和品吸结果之间的对应关系。结果表明,极性偶合柱系统GC/MS比单柱GC/MS具有更强的分离能力,可定性的组分明显多于一维GC/MS,并且更符合该香精的评吸结果。这种分析方法有利于更全面地认识香精的化学成分,更准确地认识香精的组成与功能之间的关系。为增强加香配方研究的科学性、提高调香工作的效率提供有力的支持。     

种植海拔对烤烟中性挥发性香气物质及燃吸品质的影响

为选择适宜的烤烟种植条件,于湘西北200～1000 m范围内的不同海拔高度进行了烤烟云烟87盆栽对比试验,采用GC及GC/MS法测定了不同海拔高度盆栽初烤烟叶C3F的中性挥发性香气物质含量,并进行了卷烟评吸.结果表明:①中性挥发性香气物质总量、巨豆三烯酮A、巨豆三烯酮C、大马酮、二氢大马酮、3-羟基大马酮、苯甲醛、苯乙醛、苯乙醇及二氢猕猴桃内酯的含量均与湘西北海拔呈显著正相关(P＜0.05),而3-氧化紫罗兰酮、香叶基丙酮及降茄二酮的含量均与湘西北海拔呈显著的负相关(P＜0.05),巨豆三烯酮总量及茄酮的含量分别与湘西北海拔呈极显著正相关与极显著负相关(P＜0.01),而巨豆三烯酮B、巨豆三烯酮D及6-甲基-5-庚烯-2-酮的含量与种植海拔相关性不显著;②随着湘西北烤烟种植海拔的升高,C3F烟叶烟气的香气量增大,刺激性降低.提高湘西北种植海拔有利于提高烟叶的燃吸品质.     

烟梗的超临界CO_2流体萃取工艺及萃取物在电子烟中的应用

为开发新型电子烟烟液提取手段并实现烟梗的资源化利用,以超临界CO2流体萃取(SFE)工艺萃取烟梗末的香味物质,采用GC/MS法对萃取物的成分进行分析,并进行了电子烟加香效果评价。结果表明:1最佳萃取工艺条件为:萃取温度120℃,萃取流量5 L/min,萃取时间30 min,萃取压力20 MPa;此条件下烟梗末萃取物的产率为9.9%。2烟梗末样品萃取物经GC/MS分析共鉴定出32种主要成分,其中质量分数较高的2,3-二氢-3,5-二羟基-6-甲基-4H-吡喃-4-酮(DDMP)对电子烟烟气表现出的烘烤香和烟草本香具有重要贡献。3该法所制备的烟梗末萃取物为电子烟烟气赋予了甜的、烘烤的烟草香味,为特征风格电子烟产品的开发提供了潜在的应用价值。     

中式混合型卷烟白肋烟两次加里料和烘焙技术研究

以常规成分和香味成分分析为基础,对白肋烟两次加里料和烘焙技术进行研究。结果表明,将里料分两次施加,然后再经烘焙处理,和常规对照相比,白肋烟的总糖、还原糖、烟碱和氮的含量略有下降;在GC/MS定性定量的21种香味成分中,白肋烟中的重要香味成分,如巨豆三烯酮(3个异构体)、茄酮、二氢猕猴桃内酯、3-羟基-β-二氢大马酮、吲哚和乙酰基吡咯等香味成分增加;感官品质显著提高,特别是烟香气增强、杂气和刺激性减轻、余味改善。     

Reducing the coumarin content of tonka bean extracts using supercritical CO2

By supercritical fluid CO₂ extraction of tonka beans a lipophilic top phase and a crystalline base phase were obtained. These were analysed by gas chromatography-mass spectrometry (GC/MS) and high-performance liquid chromatography (HPLC) and compared with an ethanolic extract of the same batch of tonka beans. It was shown that the three samples differed considerably in their composition and that the bulk of the main compound coumarin was present in the base phase of the CO₂ extraction.     

HPLC analysis of tonka bean extracts

Based on the results of GC-MS analysis, an HPLC procedure was developed for the determination of coumarin, dihydrocoumarin, melilotic acid (o-dihyd-rocoumaric acid), methyl melilotate, ethyl melilotate, 5-hydroxymethylfurfural ando-coumaric acid which are characteristic compounds of tonka beans. The presence of melilotic acid and ethyl melilotate in tonka beans has not been reported previously. Following HPLC analysis of tonka bean extracts produced in the laboratory and one sample of commercially available tonka bean absolute, evidence was provided that solvents used for production are decisive for the kind and amount of the compounds detected.     

Determining degree of roasting in cocoa beans by artificial neural network (ANN)‐based electronic nose system and gas chromatography/mass spectrometry (GC/MS)

BACKGROUND

Roasting is a critical step in chocolate processing, where moisture content is decreased and unique flavors and texture are developed. The determination of the degree of roasting in cocoa beans is important to ensure the quality of chocolate. Determining the degree of roasting relies on human specialists or sophisticated chemical analyses that are inaccessible to small manufacturers and farmers. In this study, an electronic nose system was constructed consisting of an array of gas sensors and used to detect volatiles emanating from cocoa beans roasted for 0, 20, 30 and 40 min. The several signals were used to train a three‐layer artificial neural network (ANN). Headspace samples were also analyzed by gas chromatography/mass spectrometry (GC/MS), with 23 select volatiles used to train a separate ANN.

RESULTS

Both ANNs were used to predict the degree of roasting of cocoa beans. The electronic nose had a prediction accuracy of 94.4% using signals from sensors TGS 813, 826, 822, 830, 830, 2620, 2602 and 2610. In comparison, the GC/MS predicted the degree of roasting with an accuracy of 95.8%.

CONCLUSION

The electronic nose system is able to predict the extent of roasting, as well as a more sophisticated approach using GC/MS. © 2018 Society of Chemical Industry     

高压静电场对油菜种子萌发影响的研究

就高压静电场预处理对提高油菜种子活力机制作了初步探讨。实验证明,静电场大小和作用时间,对种子的发芽率、发芽后生长等会产生抑制作用;不同强度的静电场对种子的影响效果有所差异;同强度的静电场作用时间不同其效果也有所不同;即种子只有在一定剂量的静电场作用下才能起到促进的效果。     

Simple preprocessing method for multi-determination of 235 pesticide residues in cooked ingredients of foods by GC/MS and LC/MS/MS

A simple preprocessing method was developed for multiresidue determination of pesticides in processed agricultural products. Residues were extracted from homogenized samples with acetonitrile in a glass centrifuge tube, followed by salting-out and partitioning with n-hexane. Co-extractives were removed by means of mini-column clean up. Analysis was performed by GC/MS and LC/MS/MS. The prepared sample solutions were examined for matrix effects. Matrix effects had both positive and negative effects on quantitative value. Calibration was achieved by preparing matrix-matched calibration standards to counteract the matrix effects. Of the 235 pesticides spiked at 0.05 or 0.10 microg/g (Method GC), 0.025 or 0.05 microg/g (Method LC) into 8 foods (garlic paste, diced green sweet pepper, green peas paste, celery paste, sweet potato paste, dried adzuki beans, boiled bamboo shoots, tomato paste), recoveries of 214 pesticides were between 50 and 100% and the coefficient of variation was below 20%. This method is useful as a multi-residue analysis method for screening of pesticides in foods.     

不同萃取工艺香草兰萃取物成分研究

本文利用95％乙醇和超临界CO2流体分别萃取香草兰豆荚，对萃取物的香气成分GC／MS分析，并用NIST107LIB、NIST21LIB数据库检索，分别鉴定出28种和31种化合物；用高效液相色谱测定萃取物中香兰素的含量。结果表明，两种萃取方法得到的香气物质其化学组成有较大差别。     

GC/MS法分析水解植物蛋白衍生肉香风味的化学成分

水解植物蛋白添加半胱氨酸盐酸盐和木糖,经过热反应制得肉香风味剂,通过GC/MS法对制得的风味剂进行分析,共鉴定出40种化合物.其中具有肉类特征风味的成分主要是含氮杂环化合物和含硫化合物,而一般性风味成分主要是醛、酮、醇以及呋喃类化合物.     

Sensory evaluation and flavour analysis of soymilk produced from lipoxygenase‐free soya beans after modified processes and pulsed light treatment

Conventional static pulsed light (PL) treatment completely inactivated lipoxygenase (LOX) in whole soya beans to prevent off‐flavours produced by LOX. However, the produced soymilk had inadequate values for total solid content. The fully soaked treatment (FST) and shaking treatment (SHT) were best in terms of increasing total solid content of soymilk from 3.7% for control soymilk to 4.6% and 4.3%, respectively; therefore, these treatments were chosen for soymilk sensory evaluation. No significant statistical differences in sensory evaluation scores existed between the control and soymilk produced from FST. The SHT for 130 s had higher overall liking (4.8) and flavour (4.6) scores compared with the control (4.1 and 3.9, respectively). Flavour analysis (purge and trap GC‐MS) of the soymilk revealed that the ethanol peak area was the biggest difference between the treatments. This study demonstrated soya beans treated with PL have no negative sensory effect in general. Producing lipoxygenase‐free soya bean is an important achievement to enhance soyfood products because lipoxygenase catalyses lipid oxidation, which takes place when lipoxygenase is released during soy milling.