电子鼻在调理牦牛肉新鲜度识别中的应用

利用电子鼻技术对调理牦牛肉在冷藏过程中,不同贮藏时间下的挥发性气味进行了识别,采用主成分分析法(PCA)及判别因子分析(DFA)对所获得的响应信号进行分析,并将分析结果与理化检测数据进行比对。实验结果发现,随着贮藏时间的延长和新鲜度的下降,肉类原料的气味发生变化,电子鼻技术能有效的区分样品之间的差异,通过与理化检测数据的比对发现电子鼻对调理牦牛肉新鲜度的识别较准确。     

冷藏时间对馒头品质的影响

为探究冷藏(4℃)时间对馒头品质的影响,通过X射线衍射、差示扫描量热法(differential scanning calorimetry,DSC)、傅里叶红外光谱(fourier transform infrared spectrometer,FTIR)、扫描电镜(scanning electron microscope,SEM)、质构仪、pH计、感官评分等方法,从微观和宏观的角度上研究馒头淀粉粒晶体、蛋白质二级结构、微观结构、质构和感官,分析冷藏时间对馒头品质的影响。结果表明:随着馒头冻藏时间的增加,馒头的pH值呈现先降低后升高,12 h的馒头pH值显著低于0 h的馒头;冷藏12 h的馒头淀粉在2θ靠近17°和20°出现强的衍射峰,淀粉已经从无序状态向有序状态转变;随着冷藏时间的增加,熔化晶体所需的热焓值显著性增加,结晶含量也在增加;面筋蛋白二级结构中β-转角和无规则卷曲的相对含量呈现上升的趋势,α-螺旋、β-折叠呈现下降的趋势,蛋白二级结构稳定性逐渐下降;通过SEM发现,随着冷藏时间的增加,部分或全部淀粉颗粒裸露部在面筋网络外面。冷藏12 h,馒头的硬度、咀嚼性比0 h分别从2 386 g增加到17 201.367 g,咀嚼性从1 563.996增加到了4 197.586;冷藏12 h对馒头的老化有显著影响。     

两种贮藏温度对鲤鱼肉感官品质影响的差异性分析

以淡水鲤鱼为研究对象,研究两种贮藏温度对鲤鱼肉感官品质的影响。采用色差、电子鼻与质构并结合感官评定分析,探讨鲤鱼肉在冰温贮藏（-2℃）与冷藏（4℃）的两种贮藏温度条件下感官品质变化的差异。结果表明:-2℃下鲤鱼的感官分值明显优于4℃,前者在贮藏12 d时感官评分仍保持在18分以上,新鲜度良好,后者则在第8 d后迅速降至13分,失去其食用与商业价值;两组贮藏温度下的鱼肉颜色与贮藏时间显著相关,其中-2℃的鱼肉样品颜色变化更为缓慢;电子鼻分析结果得出,Linear Discriminant Analysis（LDA）分析较Principal Component Analysis（PCA）分析能更好反映冰温和冷藏条件下鲤鱼肉挥发性物质的变化情况;冰温和冷藏条件下样品的弹性指标与贮藏天数均显著相关（p<0.05）,说明贮藏时间对鱼肉的弹性影响较大。综合来看,-2℃贮藏的鱼肉在感官品质,色泽与挥发性成分的变化上优于4℃,在鱼肉硬度与弹性变化上,-2℃的样品变化更为平缓;在粘聚性,胶着度与咀嚼度方面,-2℃与4℃的差别较小。      

不同压力处理大米制得米饭冷藏期间风味变化的电子鼻分析

采用电子鼻测定了不同压力处理大米制得米饭冷藏期间的挥发性成分,探讨电子鼻用于检测米饭风味成分、区分不同冷藏时间米饭的可行性及超高压处理对米饭冷藏期间风味变化情况的影响。大米在温度40℃、米水比(w/w)为1∶2的条件下浸泡40min,并在15℃下分别经200、400、600MPa处理10min,以未经超高压处理的大米作为对照组,将其蒸煮15min制成米饭,保鲜膜密封后置于4℃下贮藏,冷藏期间每天采用PEN3电子鼻对米饭进行测定。采用主成分分析法(PCA)、传感器贡献率分析法(LA)、线性判别式分析法(LDA)分析了米饭冷藏期间的挥发性成分,并建立了特征雷达图。结果表明:压力对米饭冷藏期间甲烷、硫化物、乙醇、芳香类及有机硫化物的产生有较大影响,贮藏期间200MPa米饭甲烷、硫化物、乙醇的产生量最高,600MPa米饭硫化物、芳香类及有机硫化物的产生量最低;W5S、W1W是识别米饭挥发性成分的主要传感器;电子鼻对米饭的挥发性物质反应比较灵敏,可用于米饭挥发性物质的无损检测;PCA分析可区分不同贮藏天数的对照或600MPa米饭,LDA分析可区分不同贮藏天数的400MPa或600MPa米饭。      

电子鼻及其在肉品感官评定中的应用

电子鼻是一种新颖的模拟人的嗅觉来分析、识别和检测复杂嗅味和挥发性成分的仪器,它可以在几小时,几天甚至数月的时间内连续地、实时地监测特定位置的气味状况.因而,在食品检测行业的应用越来越广泛.本文主要介绍电子鼻在国内外肉品感官检测领域的应用与发展前景.     

基于电子鼻的葡萄酒感官评价模型的构建

利用PEN3电子鼻检测10种不同菌株酿造的葡萄酒及1瓶商业葡萄酒样的香气,并通过电子鼻WinMuster及SPSS 19.0软件进行模式识别分析,评价基于不同模式识别分析方法电子鼻对不同菌株葡萄酒的区分效果;建立葡萄酒感官评价的综合主成分评价模型,并用该模型对这11种葡萄酒进行感官评价,进一步通过传统的专业品尝员对葡萄酒感官评价方法检测所建综合主成分模型的评价效果。结果表明,基于主成分分析与线性判别分析,电子鼻可以更好地区分不同菌株酿造的葡萄酒样;另外所建模型对葡萄酒的感官评价结果与传统感官评价方法具有较好的一致性,为进行更客观的葡萄酒感官评价提供了新的途径及一定的参考。     

低温冷藏对烟草粉螟亲代和子代适合度的影响

为明确低温冷藏对烟草粉螟亲代和子代适合度的影响,根据年龄-龄期两性生命表理论,对5℃冷藏160d后的烟草粉螟5龄幼虫亲代生殖适合度及其子代发育历期、存活率、繁殖率和种群参数进行研究。结果表明,低温冷藏160d后烟草粉螟F₀代的蛹期显著长于对照,雌雄成虫寿命、平均繁殖力和产卵时间均显著低于对照;但在F₁代中,除了低温处理的平均繁殖力（148.29粒）显著高于对照（113.93粒）外,其他参数均无显著差异。研究表明,低温冷藏显著降低烟草粉螟亲代的适合度,对子代的适合度则无显著影响。     

Sensory analysis of lipstick

Sensory analysis of lipstick product by trained panellists started with recruiting female panels who are lipstick users, in good health condition and willing to be a part of sensory members. This group of people was further scrutinized with duo-trio method using commercial lipstick samples that are commonly used among them. About 40% of the 15 panels recruited were unable to differentiate the lipstick samples they usually use better than chance. The balance of nine panels that were corrected at least with 65% across all trials in panels screening process was formed a working group to develop sensory languages as a means of describing product similarities and differences and a scoring system. Five sessions with each session took about 90 min were carried out using 10 types of lipsticks with different waxes mixture ratio in the formulation together with six commercial lipsticks that are the most common to the panels. First session was focus on listing out the panels' perception towards the characteristic of the lipstick samples after normal application on their lips. Second session was focus on the refining and categorizing the responses gathered from the first session and translated into sensory attributes with its definition. Third session was focus on the scoring system. Fourth and fifth sessions were repetition of the third session to ensure consistency. In a collective effort of the panels, sensory attributes developed for lipstick were Spreadability, Off flavour, Hardness, Smoothness, Moist, Not messy, Glossy and Greasy. Analysis of variance was able to provide ample evidence on gauging the panel performance. A proper panels selecting and training was able to produce a reliable and sensitive trained panel for evaluating the product based on the procedures being trained.     

Delayed harvest and cold storage period influence ethylene production,fruit firmness and quality of ‘Cripps Pink’ apple

The effects of harvest date and cold storage period on ethylene production, fruit firmness and quality of ‘Cripps Pink’ apple were investigated. Fruit were harvested from Perth Hills and Donnybrook (Western Australia) at commercial maturity (CM), 2, 4 and 6 weeks after CM prior to 0, 45, 90 and 135 days cold storage in 2003 and 2004. Delayed harvest significantly increased ethylene production, CIE values a* and C* at both locations in 2 years. Delayed harvest and extended cold storage period increased the internal ethylene production and reduced fruit firmness, soluble solids concentration: titratable acidity (SSC:TA) ratio and reduced CIE values L*, b*, h° during both years and locations. Fruit harvested 2 weeks after CM can be cold‐stored for 90 days with acceptable fruit quality. If the fruit is intended to be sold fresh immediately in local markets, the harvest can be delayed up to 6 weeks after CM to harness substantially improved fruit colour with acceptable fruit quality.     

希森6号马铃薯预炸薯条在冻藏过程中品质变化研究

该研究对希森6号马铃薯预炸薯条在储藏过程中品质的稳定性、受欢迎程度以及营养品质变化进行研究。以质构剖面分析、色差分析、电子鼻气味测试以及感官评定中的三点检验法评价薯条在冻藏过程中品质的稳定性;以感官评定中的喜好度分析评价希森6号薯条与市售薯条的受欢迎程度;以干物质含量、还原糖含量、淀粉含量、蛋白质含量评价其营养品质。在-18℃冻藏条件下,预炸薯条在整个冻藏周期内硬度均维持在900 g左右;凝聚性、咀嚼性、回复性均先上升后下降,4周后趋稳;其中,咀嚼性从287上升至387后再下降至210,之后维持在200～250之间,回复性从0.12上升至0.25再下降至0.11,之后维持在0.1附近;弹性先维持在0.75左右,第2周～第4周有一个显著的下降过程,第4周以后维持在0.60附近;黏着性第1周～第6周有一个持续的下降过程,从-6.25下降至-31.04,第6周后维持在-30附近。薯条的L*值在第1周～第6周呈下降趋势,从78下降至63,第6周后基本趋于稳定,a*值和b*值则呈轻微波动变化,整体变化不显著。冻藏180 d后复炸的薯条与鲜炸薯条在0.2到0.001风险水平之间均未检测出存在显著性差异;与市售冷冻薯条相比在0.05风险水平感官差别存在,感官品质评价认为希森6号马铃薯预炸薯条样品优于市售冷冻薯条的人数占70.8%。希森6号预炸薯条干物质含量比市售薯条高36.9%,淀粉含量高32.8%,干物质中蛋白含量则与市售薯条相当。希森6号马铃薯在冻藏过程中品质基本稳定,受欢迎程度显著高于市售速冻薯条产品,且具有较好的营养品质。     

不同酒花对葡萄酒感官品质的影响

为研究酒花对葡萄酒品质的影响,分别添加6个品种酒花（法格、哈拉道、捷克萨滋、卡斯卡特、西楚、西姆科）和4个梯度剂量（0.5 g/L、0.8 g/L、1.0 g/L和1.3 g/L）进行葡萄酒发酵,评价葡萄酒气味、滋味、色泽和口感等感官指标,并结合电子鼻对实验结果进行分析。感官评价结果表明,0.5 g/L西楚酒花葡萄酒气味（92.5分）与0.5 g/L西姆科酒花葡萄酒滋味和口感感官评分较高（86.0分和87.9分）,0.8 g/L法格葡萄酒的色泽呈红宝石色,颜色最清澈透明（90分）。电子鼻检测结果表明,空白对照和捷克萨滋、西姆科和哈拉道、法格和卡斯卡特两两相似度高;西楚与其他5种酒花葡萄酒及空白对照差异较大。实验结果对酒花酿造葡萄酒的工业化生产提供一定的参考。