基于高通量定量蛋白组学技术的全脂牛乳和脱脂牛乳蛋白组差异分析研究

蛋白质是牛乳中重要的营养成分,然而关于脱脂处理对牛乳蛋白含量的影响尚不清楚。本文采用串联质谱标签（Tandem Mass Tags,TMT）标记定量蛋白组学方法,对全脂牛乳和脱脂牛乳中全蛋白组进行分析,探究脱脂对牛乳蛋白的影响。全脂和脱脂牛乳中共鉴定出1352个蛋白,筛选出199个差异表达蛋白。与全脂牛乳相比,脱脂后有67个蛋白上调,132个蛋白下调。牛乳主要活性蛋白中,κ-酪蛋白在脱脂后相对含量降低,而β-乳球蛋白和乳铁蛋白在脱脂后相对含量升高,α-乳白蛋白、αs1-酪蛋白、αs2-酪蛋白、β-酪蛋白、牛血清蛋白及乳过氧化物酶相对含量则无显著性差异。乳脂肪球膜蛋白中嗜乳脂蛋白和乳凝集素在脱脂后相对含量降低。脱脂对牛乳中骨架蛋白、代谢相关蛋白等也有影响,改变了牛乳品质及营养价值。通过对全脂和脱脂牛乳中蛋白质分析,明确了脱脂对牛乳蛋白的影响,可以为婴幼儿乳品开发及消费者购买不同脂肪含量的牛奶提供参考。     

巴氏灭菌与超高温灭菌对全脂牛乳挥发性风味物质的影响

采用顶空固相微萃取分别对原料全脂牛乳、巴氏灭菌全脂牛乳和超高温灭菌全脂牛乳的挥发性成分进行萃取,经气相色谱-质谱联用仪分析。结果显示,原料全脂牛乳中共鉴定出12种挥发性物质,主要包括酸类和烷烃类;巴氏灭菌全脂牛乳中共鉴定出17种挥发性物质,主要包括酸类、酯类、酮类和烷烃类;超高温灭菌全脂牛乳中共鉴定出17种挥发性物质,主要包括酸类、酮类和烷烃类。经数据统计分析,3种牛乳样品的挥发性组分呈现明显差异。     

牛乳含量对发酵豆乳风味成分的影响

探讨引起发酵豆乳异味的主要风味成分,采用顶空固相微萃取与气相色谱-质谱联用检测分析技术,结合感官评价对不同牛乳含量的发酵豆乳的挥发性风味成分进行分析。不同基质发酵乳共检测出44种风味成分,其中有19种共有风味成分。随着基质牛乳添加量的增加,发酵豆乳的可接受性亦逐渐提高,且发酵豆乳中醇、醛和呋喃类化合物呈下降趋势,表明发酵豆乳的异味可能主要来自于醇、醛和呋喃类。同时对随着基质牛乳添加量增加而下降的21种风味物质,结合呈味特征、阈值、相对含量以及变化趋势,并与发酵豆乳感官评价进行分析比较,对发酵豆乳异味贡献较大的成分主要为1-辛烯-3-醇、正己醇、2-庚烯醛和2,4-癸二烯醛。     

基于2 种培养基生长的植物乳杆菌发酵草鱼的关键风味比较

探讨以不同培养基生长的植物乳杆菌发酵草鱼,分析在各发酵阶段挥发性物质的变化与差异,为发酵草鱼的特征性风味物质的研究提供参考。运用电子鼻和顶空固相微萃取-气相色谱-质谱联用仪对挥发性物质进行检测和分析,结合感觉阈值,通过相对气味活度值确定草鱼发酵的关键风味成分。结果显示：电子鼻能灵敏地检测到草鱼发酵过程中气味的变化,线性判别式分析能够区分各个样品间的差异。气相色谱-质谱在MRS肉汤和质量分数12%脱脂牛乳培养基发酵草鱼鱼肉中分别检测出90 种和70 种挥发性成分,主要为烃类、醇类、醛类、酮类、酯类、酸类及其他化合物。2 种培养基发酵草鱼鱼肉中共有的关键风味化合物主要有D-柠檬烯、1-辛烯-3-醇、庚醛、辛醛、癸醛和3-羟基-2-丁酮;MRS肉汤培养基中发酵草鱼鱼肉的关键风味化合物主要有E-2-壬烯醛和2,3-丁二酮;质量分数12%脱脂牛乳培养基中发酵草鱼鱼肉的关键风味化合物主要有己醛、壬醛和丁酸乙酯。     

基于全二维气相色谱质谱法对全脂乳粉在不同水合工艺下挥发性成分的分析

为了优化全脂乳粉水合工艺,探究低温水合对复原乳风味影响,本研究采用顶空固相微萃取（Headspace solid phase microextraction, HS-SPME）结合全二维气相色谱质谱法（Comprehensive two-dimensional gas chromatography-mass spectrometry,GC-GC-MS）考察全脂乳粉单段水合（55℃水合30 min）和两段水合（55℃水合30 min后4℃水合4、8、12 h）工艺条件下复原乳主要挥发性化合物相对含量,并利用ROAV法和主成分分析法分析挥发性物质对复原乳的风味贡献。结果表明：四组复原乳样品共鉴定出醇、醚、呋喃等9大类挥发性物质共68种,十二醇、正己醛、正辛醛、壬醛、反-2-辛烯醛、癸醛、反式-2-壬醛为四组复原乳共有的特征风味物质,醛类化合物对复原乳特征风味的贡献大于其他挥发性化合物;通过主成分分析,将单段水合复原乳与两段水合复原乳进行了良好区分,增加工序4℃水合工艺有利于降低1-辛烯-3-醇、十二醇、反式-2-癸烯醛造成的异味,其中4℃水合8 h最有利于提升复原乳有益风味,为最佳水合工艺...     

香蕉牛乳保藏过程中挥发性风味物质的变化分析

采用顶空固相微萃取(Head Space-Solid Phase Microextraction,HS-SPME)结合气相色谱-质谱联用(Gas Chromatography-Mass Spectrometry,GC-MS)技术对香蕉牛乳中的挥发性风味物质进行提取、检测和定量分析,并对主要风味物质进行含量跟踪分析和主成分分析(Principal Component Analysis,PCA)。结果表明:对香蕉牛乳风味贡献较大的风味物质有43种,均为醛、酮、醇、酯、醚、烃和萜烯类化合物,其中含量较高的化合物为乙酸异戊酯、乙酸-2-甲基丁酯、丁酸异戊酯、丁酸乙酯、乙酸叶醇酯、乙酸己酯和丁酸酐;随着保藏时间的延长,该7种主要风味物质的含量也发生相应的变化;利用主成分分析法提取出3个主成分及4种对香蕉牛乳风味影响较大的物质,能代替其风味物质信息的93.567%。     

纳米膜包装真姬菇贮藏期间挥发性风味成分变化分析

研究纳米膜包装真姬菇在采后贮藏过程中挥发性风味物质的变化规律。选用一种新型聚丙烯纳米膜（0.05 mm）为包装材料,在4 ℃进行12 d的真姬菇贮藏实验,采用顶空固相微萃取和气相色谱-质谱联用技术对真姬菇的挥发性成分进行分析检测,并采用相对气味活度值法和主成分分析（principal component analysis,PCA）法,确定真姬菇的特征风味物质。通过对真姬菇挥发性成分的动态监测可知,贮藏期间共鉴定出66 种挥发性物质,包括醛类23 种、醇类22 种、酮类10 种、酯类3 种、羧酸类4 种及呋喃类4 种。真姬菇挥发性物质总含量呈现先降低后升高的趋势,在贮藏前期（0 d）含量为98 927 μg/kg,贮藏中期（6 d）含量为28 079 μg/kg,贮藏后期（12 d）含量为89 021 μg/kg。相对气味活度值分析表明：正辛醛、1-辛烯-3-酮、1-辛烯-3-醇为真姬菇的特征风味物质,2-戊基呋喃对真姬菇的风味具有重要的修饰作用;反-2-辛烯醛是影响新鲜真姬菇风味形成的关键物质;反,反-2,4-壬二烯醛、3-辛酮是真姬菇风味劣化后的关键物质。PCA表明醛类和醇类对风味的影响最大。根据挥发性成分的变化规律可以有效区分不同贮藏时期的真姬菇样品,可为实现真姬菇品质的快速检测、风味鉴定以及货架期的预测提供一定的理论依据。     

四川浅发酵香肠加工进程中挥发性风味物质测定及其主成分分析

采用固相微萃取-气相色谱-质谱联用技术（SPME-GC-MS）,结合相对气味活度值（ROAV）、主成分分析（PCA）,对四川省一种浅发酵香肠在加工过程中挥发性风味物质的变化进行了分析。结果表明：香肠从鲜肉（0 d）至后发酵期（12 d）合计6个加工阶段共鉴定出超过6个类别共51种挥发性成分,其中醛类化合物对风味的影响最大,其次为醇类和酯类;采用ROAV法分析得到18种关键挥发性风味成分（ROAV≥1）,3 d前香肠中关键呈香物质种类及贡献程度都随加工时间延长而迅速增加;结合主成分分析法对这18种特征风味物质进一步进行分析,结果显示,6~12 d风味无明显变化,且主要以(E)-2-壬烯醛、(E)-2-癸烯醛为特征风味物质;风干发酵后期（6~12 d）挥发性风味物质种类和含量以及主体风味趋于稳定,而对补充产品风味的丰满度更有利。     

熏制即食罗非鱼片加工过程中的挥发性成分分析

为研究熏制即食罗非鱼片在不同加工阶段产品风味变化,采用同时蒸馏萃取结合GC-MS分析了新鲜鱼肉、熏制鱼肉、熏制腌制鱼肉以及添加调味油的熏制腌制鱼肉的挥发性物质,最终新鲜罗非鱼检测出17种挥发性成分,熏制罗非鱼和熏制腌制罗非鱼分别检测出35种和45种挥发性成分,而添加调味油的产品检测出53种挥发性成分。结果表明熏制过程赋予了鱼肉较多的以愈创木酚、4-甲基愈创木酚、4-已基愈创木酚、苯酚为代表的酚类物质,另外还有醛酮类物质以及一定的酸类物质,使鱼肉呈现出特有的烟熏风味,腌制过程对改变产品的风味作用不明显,添加香辛料油后产品增加了酯类物质、酚类物质和不饱和烯烃类物质,这些成分虽然在挥发性成分中含量较低,但是对改变产品的风味作用明显。     

脂肪含量对巴氏杀菌乳和酸乳品质的影响

根据全脂和脱脂乳的成分和感官特性,对其品质进行分析比较。用离心法脱去全脂乳的脂肪,对全脂和脱脂杀菌乳和酸乳的脂肪含量、蛋白质含量、酸度、风味物质和感官进行比较。结果表明,脱脂乳的脂肪含量降到0.5%以下;全脂乳和脱脂乳的蛋白质含量、酸度和pH差异不显著(p0.05)。气质联用仪测定风味物质结果表明,和全脂乳相比,脱脂乳的风味物质种类和数量差异较显著。巴氏杀菌乳中丙酮、乙醇、2,3-丁二酮含量,全脂乳分别是脱脂乳的12.6,21.6和13.3倍。全脂酸乳中的丙酮、辛酸、2,3-丁二酮、2-乙基-1-己醇和己酸含量,分别是脱脂酸乳的17.1,13.1,11.7,23.0和20.7倍。     

The effect of vitamin concentrates on the flavor of pasteurized fluid milk

Fluid milk consumption in the United States continues to decline. As a result, the level of dietary vitamin D provided by fluid milk in the United States diet has also declined. Undesirable flavor(s)/off flavor(s) in fluid milk can negatively affect milk consumption and consumer product acceptability. The objectives of this study were to identify aroma-active compounds in vitamin concentrates used to fortify fluid milk, and to determine the influence of vitamin A and D fortification on the flavor of milk. The aroma profiles of 14 commercial vitamin concentrates (vitamins A and D), in both oil-soluble and water-dispersible forms, were evaluated by sensory and instrumental volatile compound analyses. Orthonasal thresholds were determined for 8 key aroma-active compounds in skim and whole milk. Six representative vitamin concentrates were selected to fortify skim and 2% fat pasteurized milks (vitamin A at 1,500–3,000 IU/qt, vitamin D at 200–1,200 IU/qt, vitamin A and D at 1,000/200–6,000/1,200 IU/qt). Pasteurized milks were evaluated by sensory and instrumental volatile compound analyses and by consumers. Fat content, vitamin content, and fat globule particle size were also determined. The entire experiment was done in duplicate. Water-dispersible vitamin concentrates had overall higher aroma intensities and more detected aroma-active compounds than oil-soluble vitamin concentrates. Trained panelists and consumers were able to detect flavor differences between skim milks fortified with water-dispersible vitamin A or vitamin A and D, and unfortified skim milks. Consumers were unable to detect flavor differences in oil-soluble fortified milks, but trained panelists documented a faint carrot flavor in oil-soluble fortified skim milks at higher vitamin A concentrations (3,000–6,000 IU). No differences were detected in skim milks fortified with vitamin D, and no differences were detected in any 2% milk. These results demonstrate that vitamin concentrates may contribute to off flavor(s) in fluid milk, especially in skim milk fortified with water-dispersible vitamin concentrates.     

燕麦乳挥发性风味物质的SPME-GC-MS解析及原料关联性研究

燕麦乳作为新兴植物代乳近年来在国内外获得快速发展,燕麦乳的风味是影响产品接受度的重要因素。本文基于燕麦原料品种的差异,利用固相微萃取(SPME)-气相色谱-质谱联用(GC-MS)技术对燕麦乳挥发性风味物质进行解析,并从中筛选出适宜的燕麦原料。结果表明：燕麦原料与其加工制品(燕麦乳)的挥发性风味化合物的种类和含量存在显著差异,燕麦原料分析出14种挥发性风味化合物,经热烫、酶解、杀菌等加工处理后的燕麦乳中检测出30种化合物。结合各化合物的香气活度值(OAV)并进行主成分分析,发现己醛、2-戊基呋喃、正辛醛、壬醛、1-辛烯-3-醇、苯甲醛等挥发性物质对燕麦乳风味的贡献值较大。4种燕麦原料中ZBY01制得的燕麦乳感官评分最高、风味最佳,从其风味化合物组成上看,己醛、1-辛烯-3-醇、2-戊基呋喃等的含量较低,且可检出庚醛、壬醇等特殊香气成分。另通过对燕麦乳感官品质的总体评价,本研究初步筛选出适宜加工纯天然燕麦乳的适宜原料—ZBY01。     

Flavor and flavor chemistry differences among milks processed by high-temperature,short-time pasteurization or ultra-pasteurization

Typical high-temperature, short-time (HTST) pasteurization encompasses a lower heat treatment and shorter refrigerated shelf life compared with ultra-pasteurization (UP) achieved by direct steam injection (DSI-UP) or indirect heat (IND-UP). A greater understanding of the effect of different heat treatments on flavor and flavor chemistry of milk is required to characterize, understand, and identify the sources of flavors. The objective of this study was to determine the differences in the flavor and volatile compound profiles of milk subjected to HTST, DSI-UP, or IND-UP using sensory and instrumental techniques. Raw skim and raw standardized 2% fat milks (50 L each) were processed in triplicate and pasteurized at 78°C for 15 s (HTST) or 140°C for 2.3 s by DSI-UP or IND-UP. Milks were cooled and stored at 4°C, then analyzed at d 0, 3, 7, and 14. Sensory attributes were determined using a trained panel, and aroma active compounds were evaluated by solid-phase micro-extraction or stir bar sorptive extraction followed by gas chromatography-mass spectrometry, gas chromatography-olfactometry, and gas chromatography-triple quad mass spectrometry. The UP milks had distinct cooked and sulfur flavors compared with HTST milks. The HTST milks had less diversity in aroma active compounds compared with UP milks. Flavor intensity of all milks decreased by d 14 of storage. Aroma active compound profiles were affected by heat treatment and storage time in both skim and 2% milk. High-impact aroma active compounds were hydrogen sulfide, dimethyl trisulfide, and methional in DSI-UP and 2 and 3-methylbutanal, furfural, 2-heptanone, 2-acetyl-1-pyrroline, 2-aminoacetophenone, benzaldehyde, and dimethyl sulfide in IND-UP. These results provide a foundation knowledge of the effect of heat treatments on flavor development and differences in sensory quality of UP milks.     

基于顶空气相色谱-离子迁移谱技术分析花生烘烤后挥发性风味物质的变化

目的 建立基于顶空气相色谱-离子迁移谱（Headspace-gas chromatography-ion mobility spectrometry, HS-GC-IMS）技术分析花生烘烤后挥发性风味物质变化的方法。方法 对吉林四粒红和琼花1号两种花生品种进行去皮处理,采用HS-GC-IMS分别对其带种皮和不带种皮时烘烤的挥发性成分进行研究。结果 采用GC×IMS Library Search V2.2.1分析软件,利用内置NIST数据库和IMS数据库对样品中挥发性风味物质进行定性分析,并结合Reporter插件、Gallery Plot插件、Dynamic PCA插件采用实验室观察分析器（laboratory analytical viewer, LAV）对其建立标准曲线后进行定量分析,检出化合物共42种,主要为醛类、醇类、脂类、酮类等。带皮烘烤的花生主要挥发性成分为乙酸乙酯、异丙醇、2-甲基丁醇和正辛醛等,去皮烘烤主要挥发性成分为戊醛、2-甲基丁醛、糠醛和异戊醛等。发现经过烘烤后的林四粒红和琼花1号两种样品均有着更多的挥发性物质,吉林四粒红在烘烤后的挥发性成分比琼花1号多,尤其是去皮烘烤的样品中1-辛烯-3-醇、E-2-庚烯醛、2-庚酮、2-己烯-1-醇、戊醇、戊醛、己醇等物质的相对含量远高于琼花一号;结论 此方法结论 GC-IMS 可实现花生油挥发性风味物质的简便、快捷、灵敏、科学测定,该研究结果可为花生工业化生产提供理论指导。     

基于顶空气相离子迁移谱比较3 种加工方式对番鸭肉挥发性风味物质的影响

为研究煮制、微波熟制和烤制对番鸭肉挥发性风味物质的影响，采用电子鼻和顶空气相离子迁移谱（headspace-gas chromatography-ion mobility spectrometry，HS-GC-IMS）技术对番鸭肉的挥发性风味物质进行分析。结果表明，电子鼻可以实现对不同加工方式番鸭肉的香气轮廓进行快速区分。HS-GC-IMS共检测出54?种挥发性化合物，其中醛类18?种、醇类16 种、酮类11?种、酯类5 种、呋喃类3?种、烯类1 种，且醛类物质的相对含量高于其他种类。经相对气味活度值分析得到3 种加工方式共有的10 种关键风味物质，分别为癸醛、壬醛、辛醛、庚醛、戊醛、己醛、1-辛烯-3-酮、3-辛酮、1-辛烯-3-醇、2-乙基呋喃。对这些关键风味物质进行主成分分析，发现不同加工方式能获得较好区分，各处理组的关键风味物质具有一定的差异。本研究通过对不同加工方式下番鸭肉挥发性风味物质进行检测分析，为今后番鸭资源的精深加工提供一定理论依据。     

Characterization of Headspace Volatile Flavor Compounds Formed During Kefir Production: APplication of Solid Phase MicroextractioN

Headspace volatile flavor compounds of kefir were monitored using headspace solid phase microextraction (HS-SPME) method during fermentation of milk with kefir starter culture. Among all flavor compounds, forty volatile compounds were initially detected using gas chromatography coupled to time-of-flight mass spectrometer (GC-TOFMS). Consequently, eight volatile flavor compounds, namely ethanol, ethyl acetate, ethyl butyrate, 2-butanone, acetone, 3-hydroxy-2-butanone (acetoin), 2,3-butanedione (diacetyl) and acetaldehyde were considered as the representative of the alcohol, ketone, ester and aldehyde compounds in kefir. Moreover, in term of quantitative analysis, more than 97% of total flavor compounds composed of the proposed volatile flavor compounds. The results indicated that the concentration of 2-butanone released into headspace of kefir was found to be stable during fermentation. The release content of other volatile flavor compounds increased throughout the fermentation process. However, the headspace concentration of acetoin significantly (P < 0.05) decreased between pH 5.2 and 4.6.     

新鲜乳扇贮存期间关键香气组分变化分析

为探究新鲜乳扇贮存过程中香气组成及香气成分变化,利用固相微萃取-气相色谱-质谱联用法、气相色谱-嗅觉测量技术以及描述性感官评价,对乳扇贮存过程中挥发性风味组分变化情况进行分析。乳扇贮存过程中共鉴定得到70 种挥发性风味化合物,对其中能够嗅闻得到的19 种特征风味化合物进行定量并进一步计算其气味活性值（odor activity values,OAV）,得到OAV大于1的16 种关键香气组分。将乳扇的感官性质、关键香气组分以及贮存时间进行偏最小二乘分析,结果显示,乳扇的贮存期可分为3 个阶段：第1阶段为乳扇贮存的第1天,此时乳扇感官品质最高,这与乙酸乙酯、己酸乙酯等酯类组分的含量较高有关;第2阶段为乳扇贮存的第4、7天,乳扇感官品质温和,具有酒香特征,这可能与丁酸乙酯的含量有关;第3阶段为乳扇贮存的第11、15天,乳扇的感官品质最差,仅有δ-癸内酯的含量未随贮存时间的变化而降低,其余酯类和内酯类组分的含量均随着贮存时间的延长而降低。