虎纹蛙肌肉挥发性成分和脂肪酸分析

对虎纹蛙肌肉中的挥发性成分和脂肪酸分别进行测定。采用顶空固相微萃取-气相色谱-质谱联用技术(HS-SPME-GC-MS)分析虎纹蛙肌肉中的挥发性成分。结果共鉴定出36种成分,其中醛类化合物有15种,且含量最高,占挥发性成分总量的68.76%;己醛、(Z)-4-庚烯醛、(E,Z)-2,4-癸二烯醛、(E,E)-2,4-癸二烯醛、1-辛烯-3-醇和2,3-戊二酮等可能对虎纹蛙肉的整体风味贡献较大;虎纹蛙肌肉脂肪酸主要由不饱和脂肪酸(UFA)组成,占脂肪酸总量的72.89%;在日常饮食中,虎纹蛙肉为n-3多不饱和脂肪酸(n-3 PUFA)较为丰富的食物资源;亚麻酸(C18:3 n-3,ALA)、二十碳五烯酸(C20:5 n-3,EPA)和二十二碳六烯酸(C22:6 n-3,DHA)为主要的n-3 PUFA。UFA为虎纹蛙肉的重要风味前体物质。     

混合菌株发酵南瓜汁及其香气分析

本文研究了混合菌株发酵南瓜汁的香气物质。采用固相微萃取技术(SPME)富集、气相色谱-嗅辨-质谱(GC-O-MS)分离检测手段,结合计算机检索技术对分离化合物进行鉴定,应用色谱峰面积归一法测定各成分的相对含量。实验结果表明:新鲜南瓜和南瓜汁中分别分鉴定出58和41个香气化学成分,南瓜汁和新鲜南瓜共有的挥发性成分有19种,南瓜中含量较高的挥发性物质为己醛、3-甲基丁醛、壬醛、戊醛、庚醛、环丁醇等物质。经过乳酸菌、酵母菌和二者混合发酵南瓜汁后挥发性成分分别鉴定出51、36和45种。通过乳酸菌和酵母菌混合发酵的南瓜汁的挥发性成分主要是乙醇、异戊醇、辛酸乙酯、1-庚醇、2,3-丁二酮和异丁醇。与乳酸菌和酵母菌单独发酵的南瓜汁相比,混合发酵后挥发性成分以醇类居多;相对含量较高的香气成分种类相似,而微量特征香气成分差异较为显著。     

酱香型白酒液液微萃取-毛细管色谱骨架成分与香气重组

应用液液微萃取（LLME）、气相-质谱联用仪（GC-MS）研究酱香型白酒骨架成分。液液微萃取定量48种香气物质,确定29种骨架成分。通过52种物质香气重组,得到的模拟酒香气较为丰满,且富有层次感,呈现酱香型白酒的背景香,但未出现典型酱香。缺失实验表明酱香型白酒骨架成分中香气贡献较大的主要是酯类和醇类物质,其中：己酸乙酯、乙酸乙酯、丁酸乙酯、1-丙醇、2-苯乙醇以及3-甲基丁醇是重要的香气物质;缺失与添加实验验证了三甲基吡嗪、糠醛、4-乙基愈创木酚和呋喃扭尔（furaneol）与酱香型白酒的典型酱香无关。     

不同茶树品种白牡丹茶香气成分的HS-SPME-GC-MS分析

该研究利用顶空固相微萃取-气相色谱-质谱联用技术,结合主成分分析、偏最小二乘法判别分析和层次聚类分析方法,对政和大白茶（ZD）、福鼎大毫茶（FD）、福建水仙（SX）和梅占（MZ）白牡丹茶的香气成分进行对比分析,旨在探明不同茶树品种白牡丹茶香气品质特征及其品质差异的物质基础。结果表明：不同品种白牡丹茶香气品质表现优异、各具特点,具体表现为ZD清香带花香,FD嫩香、毫香显,SX花香显,MZ花香浓且持久,香气得分大小排序为MZ>SX>FD>ZD>90分;4个品种白牡丹茶中检测出101个香气成分,其中ZD、FD、MZ和SX中分别鉴定出98、98、100和96个香气成分,均以醇类、碳氢类、酯类和酮类物质为主;基于所有香气成分的相对含量建立的PCA和PLS-DA模型,可将不同品种白牡丹茶进行有效区分,不同品种白牡丹茶的标志差异性呈香成分有13个（VIP>1、p<0.05）。综上,4个茶树品种白牡丹茶的香气品质特征明显不同、香气轮廓区别明显,筛选出的13个香气成分是其品质差异形成的重要组分。     

苦荞糊和苦荞茶挥发性香气成分分析

采用固相微萃取法（SPME）对苦荞茶和苦荞糊中的挥发性香气成分进行提取,并经气相色谱-质谱联用（GC-MS）技术定性分析。从苦荞茶和苦荞糊中分别检测出30种和41种挥发性香气成分,相同成分有15种,其中含量较高的是烃类、醛类和杂环类,三者在苦荞茶和苦荞糊中含量分别为24.56%、35.04%、18.42%和46.97%、21.22%、7.22%。研究表明,顶空固相微萃取具有快速简便、不使用溶剂和样品检测非破坏性等优点,结合气-质联用技术可以很好的分析苦荞产品中挥发性物质,并说明不同加工工艺制得的苦荞产品其挥发性物质存在一定差异。     

Quantitative determination and characterisation of the main odourants of Mencía monovarietal red wines

This study focus on the development of a headspace solid-phase microextraction (HS-SPME) method coupled to gas chromatography–ion trap mass spectrometry (GC–ITMS) to identify and quantify simultaneously 32 characteristic volatile compounds. A mixed level factorial 3 × 2³ design was performed to asses the influence of several factors and their interactions (extraction temperature, fibre coating, salt addition and sample volume) on the extraction efficiency. The evaluation of the design showed that temperature and fibre coating were the most significant variables. The method showed good linearity (r² > 0.990) and repeatability (RSD ? 16%) for all compounds, with detection limits ranging from 0.0024 μg/L for limonene to 238 μg/L for ethyl 3-hydroxybutyrate, in general below their odour threshold limits. Matrix effects were thoroughly studied. The method was after applied to the first aroma characterisation of the monovarietal young red wine Mencía from the Galician (NW Spain) designation of origin “Valdeorras DO”. To achieve the identification of the major would-be impact odourants, the odour activity value (OAV) was also calculated.     

Identification and characterisation of headspace volatiles of fish miso, a Japanese fish meat based fermented paste,with special emphasis on effect of fish species and meat washing

The present study investigated the suitability of four species of trash fishes for the production of fish miso, a Japanese fermented fish meat paste compared with soy and rice miso from the point of view of product aroma. The effect of washing fish meat on finished product was also evaluated. Headspace volatiles for different miso samples were analyzed by using solid phase microextraction (SPME) technique. A total of 107 volatile compounds have been identified, where 94 were common for all the miso samples. Considering the lower threshold perception and higher odour active values 2-methylbutanal, 3-methylbutanal, methional, isoamyl acetate, dimethyl disulfide, dimethyl trisulfide, 2,3-butanedione, 3-methylethyl butanoate, 3-methyl-1-butanol, ethyl hexanoate, 1-octen-3-ol, heptanol, heptanal and 2-undecanone were identified as key compounds for the miso products. Principal components analysis (PCA) and hierarchical cluster analysis (HCA) of headspace volatiles clearly elucidated the relationship amongst different miso samples based on fish species and effect of fresh water washing of meat on aroma of finished product.     

对虾头酶解液Maillard反应中挥发性成分变化及影响因素

以南美白对虾虾头为原料,经中性酶酶解再经美拉德反应后,应用固相微萃取技术,对原料、酶解液、美拉德反应液中的挥发性物质进行GC-MS分析和比较,并研究反应温度、时间、pH、添加牛磺酸等因素对美拉德反应液挥发性成分的影响。结果表明,原料经酶解再到Maillard反应是一个醇类、醛类、酮类、酯类等物质相对含量减少,吡嗪类等物质生成的过程,且温度升高、反应时间延长、pH值升高及半胱氨酸盐酸盐的添加均能促进此趋势。     

Simultaneous Determination of 10 Photoinitiators in Milk by Solid‐Phase Microextraction Coupled with Gas Chromatography/Mass Spectrometry

Photoinitiators (PIs) are widely used in food packaging materials, can migrate easily from packaging materials to food, and cause food contamination. It is essential to establish a method of determining PIs residues in food. A new method for simultaneously determining 10 kinds of PIs in milk has been established by using solid‐phase microextraction (SPME) combined with a simple method of protein precipitation as the pretreatment approach and gas chromatography/mass spectrometry as the detecting technique. The limits of detection for 10 PIs in different milks were between 0.05 and 1.4 μg/L (skimmed milk), between 0.07 and 2.2 μg/L (semi‐skimmed milk), between 0.11 and 4.4 μg/L (whole milk), respectively. The recoveries were from 71.5% to 133.5%, and the relative standard deviations were less than 15%. Twelve kinds of packed milk with different brands and fat contents were determined using this method.     

基于电子鼻、HS-GC-IMS和HS-SPME-GC-MS 对5种食用植物油挥发性风味成分分析

采用电子鼻、顶空气相色谱-离子迁移谱(HS-GC-IMS)和顶空固相微萃取-气相色谱-质谱联用(HS-SPME-GC-MS)法对5种食用植物油(花生油、大豆油、玉米油、油茶籽油、棕榈油)中挥发性成分进行分析,并采用相对气味活度法确定关键风味物质。结果表明:电子鼻检测发现花生油与油茶籽油气味轮廓相似,但花生油气味浓度大于油茶籽油,大豆油、玉米油和棕榈油整体气味差异相对较小且浓度较低; HS-GC-IMS共检出5种食用植物油56种化合物(其中定性24种),定性的共有风味化合物为戊醛(单体)、己醛(单体)、庚醛、1-戊醇(单体)、1-丙醇、2-丁酮(单体)、辛醛和丁醛(单体),并得到5种食用植物油差异图谱; HS-SPME-GC-MS鉴定出5种食用植物油86种化合物,共有关键风味化合物为己醛、壬醛和庚醛,花生油、大豆油和棕榈油特有关键风味化合物分别为吡嗪类化合物、(E,E)-2,4-庚二烯醛和6-甲基-5-庚烯-2-酮。