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Chapter10Chapter10Chapter10Chapter10食品的气味化学OdorchemistryoffoodOdorchemistryoffoodOdorchemistryoffoodOdorchemistryoffoodwww.docin.com/dengyuekewww.docin.com/dengyuekewww.docin.com/dengyuekewww.docin.com/dengyueke好文档尽在阿灯精品屋�Anodorodorodorodororodourodourodourodouristheobjectofperceptionofthesenseofolfaction.Odorsarealsocalledsmellssmellssmellssmells.Thetermstenchstenchstenchstench恶臭,,,,orpongpongpongpong难闻的气味isusedtodescribeanunpleasantodor.Thetermfragrancefragrancefragrancefragranceoraromaaromaaromaaromaisusedprimarilybythefoodandcosmeticindustrytodescribeapleasantodor,andissometimesusedtorefertoperfumes.ODORS�Therearethousandsofodors,andtheTherearethousandsofodors,andtheTherearethousandsofodors,andtheTherearethousandsofodors,andthesensitivityofthesmellorganisabout10000sensitivityofthesmellorganisabout10000sensitivityofthesmellorganisabout10000sensitivityofthesmellorganisabout10000timesgreaterthanthatofthetasteorgan.timesgreaterthanthatofthetasteorgan.timesgreaterthanthatofthetasteorgan.timesgreaterthanthatofthetasteorgan.�TheoutstandingfeatureofolfactionTheoutstandingfeatureofolfactionTheoutstandingfeatureofolfactionTheoutstandingfeatureofolfaction嗅觉ofofofofchemicalsubstancesascomparedtotasteischemicalsubstancesascomparedtotasteischemicalsubstancesascomparedtotasteischemicalsubstancesascomparedtotasteisitsextremesensitivitytolowconcentrationsitsextremesensitivitytolowconcentrationsitsextremesensitivitytolowconcentrationsitsextremesensitivitytolowconcentrationsofchemicalsubstancesanditsabilitytoofchemicalsubstancesanditsabilitytoofchemicalsubstancesanditsabilitytoofchemicalsubstancesanditsabilitytodifferentiateamongthemdifferentiateamongthemdifferentiateamongthemdifferentiateamongthemTheoryofolfactionTheoryofolfactionTheoryofolfactionTheoryofolfactionhowolfactionwork?howolfactionwork?howolfactionwork?howolfactionwork?�Asdiscoveredby[LindaB.Buck]and[RichardAxel](whowereawardedthe[NobelPrize]in2004),mammalsgenerallyhaveabout1000genesforodorreceptors.一、嗅觉生理学MitralMitralMitralMitralcellcellcellcellOlfactorybulbOlfactorybulbOlfactorybulbOlfactorybulb�Eacholfactoryreceptorneuroninthenoseexpressesonlyonefunctionalodorreceptor.�Theaxonsfromallthethousandsofcellsexpressingthesameodorreceptorconvergeintheolfactorybulb.Mitralcells僧帽细胞intheolfactorybulbsendtheinformationabouttheindividualfeaturestootherpartsoftheolfactorysysteminthebrain,whichputstogetherthefeaturesintoarepresentationoftheodor.Sincemostodormoleculeshavemanyindividualfeatures,thecombinationoffeaturesgivestheolfactorysystemabroadrangeofodorsthatitcandetect.2004年度诺贝尔生理学或医学奖获奖者、美国科学家理查德·阿克塞尔和琳达·巴克，通过自己开拓性的工作找到了解开这一谜底的钥匙，清楚地阐明了人类嗅觉系统的工作方式。�人的大脑中约有2000个“嗅小球”，数量是气味受体细胞种类的2倍。�“嗅小球”也非常的“专业化”，携带相同受体的气味受体细胞会将神经信号传递到相应的“嗅小球”中，也就是说，来自具有相同受体的细胞的信息会在相同的“嗅小球”中集中。�人体约有1000个基因用来编码气味受体细胞膜上的不同气味受体，这占人体基因总数的约3％�人的嗅觉系统具有高度“专业化”的特征。比如，每个气味受体细胞仅表达出一种气味受体基因，气味受体细胞的种类与气味受体完全相同。�气味受体细胞会将神经信号传递至大脑嗅球中被称为“嗅小球”的微小结构。�每个气味受体细胞会对有限的几种相关分子作出反应。绝大多数气味都是由多...