《食品质地仪器测定》PPT课件

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1、第三节食品质地的仪器测定第三节食品质地的仪器测定1.质构仪第三节食品质地的仪器测定1.质构仪第三节食品质地的仪器测定1.质构仪应用：面粉/面团、烘焙食品、面条、米饭、乳制品、休闲食品、水产畜牧及其加工制品、蔬菜、包装材料、凝胶测试等。数据：硬度、酥脆性、胶着性、黏聚性、韧性、屈服点、纤维强度、弹性、延展性、回复性、弹性、黏着性、咀嚼度、凝胶强度等。测试标准：AACC（美国谷物化学协会）、AOAC（美国与欧洲凝胶协会）、BS（英国国家标准）、ASTM（美国材料试验协会）等。质构仪BackExtrusion反向挤出Forwar

2、dExtrusion正向挤出Bend弯曲（折断）Compression压缩Stressrelaxation应力松弛CreepAB蠕变Penetration穿透（插入）Shear剪切StickinesstestAB黏性Tension拉伸质构仪-TPAtestTextureprofileanalysis(TPA，质地剖面分析)isanobjectivemethodofsensoryanalysispioneeredin1963bySzczesniak,whodefinedthetexturalparametersfirstus

3、edinthismethodofanalysis.Laterin1978BourneadaptedtheInstrontoperformTPAbycompressingstandard-sizedsamplesoffoodtwice-二次压缩试验.SZCZESNIAK,A.S.(1963).Classificationoftexturalcharacteristics.J.FoodSci,28,385-389.BOURNE,M.C.(1978).TextureProfileAnalysis.FoodTechnol.,32(

4、7),62-66,72.TPAisbasedontherecognitionoftextureasamulti-parameterattribute.Forresearchpurposes,atextureprofileintermsofseveralparametersdeterminedonasmallhomogeneoussamplemaybedesirable.Thetestconsistsofcompressingabite-sizepieceoffoodtwotimesinareciprocatingmotio

5、nthatimitatestheactionofthejawandextractingfromtheresultingforce-timecurveanumberoftexturalparametersthatcorrelatewellwithsensoryevaluationofthoseparametersThemechanicaltexturalcharacteristicsoffoodsthatgovern,toalargeextent,theselectionofarheologicalprocedure,and

6、instrumentcanbedividedintotheprimaryparametersofhardness,cohesiveness,springiness(elasticity),andadhesiveness,andintothesecondary(orderived)parametersoffracturability(brittleness),chewinessandgumminessSZCZESNIAK,A.S.(1966).TextureMeasurements.FoodTechnol.,20,50,55

7、-58.质构仪-TPAtestTPAtest第三节食品质地的仪器测定1.质构仪-参数Hardness(硬度)Hardnessisdefinedasthemaximumpeakforceduringthefirstcompressioncycle(firstbite)andhasoftenbeensubstitutedbythetermfirmness.Brittleness,crunchiness,andcrumbliness,whichareasimilarconcept,canbemeasuredastheeasewi

8、thwhichthematerialfracturesunderanincreasingcompressionloadIngeneral,thesmallerthedeformationunderagivenload,thelowerthecohesivenessandthegreatertheabil