1、第三节 食品质地的仪器测定1.质构仪质构仪第三节 食品质地的仪器测定1.质构仪质构仪第三节 食品质地的仪器测定1.质构仪质构仪n 应用：面粉应用：面粉/面团、烘焙食品、面条、米饭、乳制品、休面团、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、凝胶闲食品、水产畜牧及其加工制品、蔬菜、包装材料、凝胶测试等。测试等。n 数据：硬度、酥脆性、胶着性、黏聚性、韧性、屈服点、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。度、凝胶强度等。n 测试标准：测试标
2、准：AACC（美国谷物化学协会）、（美国谷物化学协会）、AOAC（美国（美国与欧洲凝胶协会）、与欧洲凝胶协会）、BS（英国国家标准）、（英国国家标准）、ASTM（美国（美国材料试验协会）等。材料试验协会）等。质构仪l Back Extrusion反向挤出l Forward Extrusion 正向挤出l Bend 弯曲（折断）l Compression压缩l Stress relaxation应力松弛l Creep A B蠕变l Penetration穿透（插入）l Shear剪切l Stickiness test A B黏性lTension拉伸质构仪-TPA testTexture prof
3、ile analysis(TPA，质地剖面分析)is an objective method of sensory analysis pioneered in 1963 by Szczesniak,who defined the textural parameters first used in this method of analysis.Later in 1978 Bourne adapted the Instron to perform TPA by compressing standard-sized samples of food twice-二次压缩试验.SZCZESNIAK,A
4、.S.(1963).Classification of textural characteristics.J.Food Sci,28,385-389.BOURNE,M.C.(1978).Texture Profile Analysis.Food Technol.,32(7),62-66,72.l TPA is based on the recognition of texture as a multi-parameter attribute.For research purposes,a texture profile in terms of several parameters determ
5、ined on a small homogeneous sample may be desirable.l The test consists of compressing a bite-size piece of food two times in a reciprocating motion that imitates the action of the jaw and extracting from the resulting force-time curve a number of textural parameters that correlate well with sensory
6、 evaluation of those parametersSZCZESNIAK,A.将以上仪器测定值与感官侧定值进行相关性分析(如表3-12所示)，可得到，与各项目感官评价相关性最大的仪器测定项目(按最大相关性顺序取前3位)。Stringiness is the distance the product is extended during decompression before separating from the compression probe.质构仪-TPA testThey are the chracteristics most difficult to measure p
7、recisely,because mastication involves compressing,shearing,piercing,grinding,tearing and cutting,along with adequate lubrication by saliva at body temperatures.粉质仪得出的面团阻力曲线叫粉质曲线。Texture profile analysis(TPA，质地剖面分析)is an objective method of sensory analysis pioneered in 1963 by Szczesniak,who defined
8、 the textural parameters first used in this method of analysis.硬度、固着性和咀嚼口感与穿孔试验的最大应力有很高的相关关系；第三节 食品质地的仪器测定粉质仪得出的面团阻力曲线叫粉质曲线。其质地的各性质要求比较适中。(2)制定标准实施评价。Texture Measurements.第四节 食品质地评价仪器的选择第三节 食品质地的仪器测定而弹性感和固着性感觉只与穿孔试验的最大应力有很高相关；standard determination method 1They are the chracteristics most difficult
9、to measure precisely,because mastication involves compressing,shearing,piercing,grinding,tearing and cutting,along with adequate lubrication by saliva at body temperatures.,20,50,55-58.l The mechanical textural characteristics of foods that govern,to a large extent,the selection of a rheological pro
10、cedure,and instrument can be divided into the primary parameters of hardness,cohesiveness,springiness(elasticity),and adhesiveness,and into the secondary(or derived)parameters of fracturability(brittleness),chewiness and gumminess l SZCZESNIAK,A.S.(1966).Texture Measurements.Food Technol.,20,50,55-5
11、8.质构仪-TPA testlTPA test第三节 食品质地的仪器测定1.质构仪质构仪-参数参数Texture Profile Analysis.Food Technol.Texture Profile Analysis.Texture profile analysis(TPA，质地剖面分析)is an objective method of sensory analysis pioneered in 1963 by Szczesniak,who defined the textural parameters first used in this method of analysis.而弹性
12、感和固着性感觉只与穿孔试验的最大应力有很高相关；Gumminess is a characteristic of semisolid foods with a low degree of hardness and a high degree of cohesiveness.以牛肉饼(hamburger)为例说明仪器测定和感官评价的特点因此，在感官评审前要认真进行必要的说明和示范。In general,the smaller the deformation under a given load,the lower the cohesiveness and the greater the abil
13、ity to fracture of the product.第三节 食品质地的仪器测定They are the chracteristics most difficult to measure precisely,because mastication involves compressing,shearing,piercing,grinding,tearing and cutting,along with adequate lubrication by saliva at body temperatures.到下降到50020B.数据：硬度、酥脆性、胶着性、黏聚性、韧性、屈服点、纤维强度、
14、弹性、延展性、回复性、弹性、黏着性、咀嚼度、凝胶强度等。疏松感可用穿孔最大应力和切断强度值综合判断；the total force necessary to pull the compression plunger away from the sample.5 seconds divided by the Contact Area.对以下8个项目进行测定：The mechanical textural characteristics of foods that govern,to a large extent,the selection of a rheological procedure,a
15、nd instrument can be divided into the primary parameters of hardness,cohesiveness,springiness(elasticity),and adhesiveness,and into the secondary(or derived)parameters of fracturability(brittleness),chewiness and gumminess该方法称为对比得分法。Springiness(originally called elasticity)is related to the height t
16、hat the food recovers during the time that elapses between the end of the first bite and the start of the second bite.Springiness(originally called elasticity)is related to the height that the food recovers during the time that elapses between the end of the first bite and the start of the second bi
17、te.Hardness(硬度)lHardness is defined as the maximum peak force during the first compression cycle (first bite)and has often been substituted by the term firmness.l Brittleness,crunchiness,and crumbliness,which are a similar concept,can be measured as the ease with which the material fractures under a
18、n increasing compression loadl In general,the smaller the deformation under a given load,the lower the cohesiveness and the greater the ability to fracture of the product.Fracturability 酥脆性酥脆性，易碎性、脆性、脆度，易碎性、脆性、脆度(originally called brittleness)is defined as the force at the first significant break in
19、 the TPA curve.Adhesiveness黏着性，黏附性l Adhesiveness is defined as the negative force area for the first bite and represents the work required to overcome the attractive forces between the surface of a food and the surface of other materials with which the food comes into contactl i.e.the total force ne
20、cessary to pull the compression plunger away from the sample.For materials with a high adhesiveness and low cohesiveness,when tested,part of the sample is likely to adhere to the probe on the upward stroke.Springiness（恢复性，弹性，回弹）l Springiness(originally called elasticity)is related to the height that
21、 the food recovers during the time that elapses between the end of the first bite and the start of the second bite.Cohesiveness凝聚性，黏聚性lCohesiveness is defined as the ratio of the positive force area during the second compression to that during the first compression.l Cohesiveness may be measured as
22、the rate at which the material disintegrates under mechanical action.Tensile strength is a manifestation of cohesiveness.If adhesiveness is low compared with cohesiveness then the probe is likely to remain clean as the product has the ability to hold together.l Cohesiveness is usually tested in term
23、s of the secondary parameters chewiness and gumminess.Gumminess胶黏性、lGumminess is defined as the product of hardness cohesiveness.lGumminess is a characteristic of semisolid foods with a low degree of hardness and a high degree of cohesiveness.Chewiness（咀嚼性）l Chewiness is defined as the product of gu
24、mminess springiness(which equals hardness cohesiveness springiness)and is therefore influenced by the change of any one of these parameters.l Chewiness,tenderness and toughness are measured in terms of the energy required to masticate a solid food.They are the chracteristics most difficult to measur
25、e precisely,because mastication involves compressing,shearing,piercing,grinding,tearing and cutting,along with adequate lubrication by saliva at body temperatures.l It should be understood that the same product cannot exhibit both chewiness and gumminess,unless as a solid it becomes a semisolid duri
26、ng sensory mastication.Such a transition is practically never accomplished during instrumental TPA evaluation.l Thus,it is incorrect to quantify and report chewiness and gumminess in TPA of solid or semisolid products.l Chewiness should be reported for solids and gumminess for semisolids.而弹性感和固着性感觉只
27、与穿孔试验的最大应力有很高相关；They are the chracteristics most difficult to measure precisely,because mastication involves compressing,shearing,piercing,grinding,tearing and cutting,along with adequate lubrication by saliva at body temperatures.It should be understood that the same product cannot exhibit both che
28、winess and gumminess,unless as a solid it becomes a semisolid during sensory mastication.仪器测定和感官评价的特点食品物性仪器测定的开展第三节 食品质地的仪器测定将以上仪器测定值与感官侧定值进行相关性分析(如表3-12所示)，可得到，与各项目感官评价相关性最大的仪器测定项目(按最大相关性顺序取前3位)。淀粉粉力测定仪（RVA，rapid viscosity analyser）由调粉器和动力测定计组成。Back Extrusion反向挤出Texture profile analysis(TPA，质地剖面分析)
29、is an objective method of sensory analysis pioneered in 1963 by Szczesniak,who defined the textural parameters first used in this method of analysis.（1）感宫评价前首先使评审员理解和明确各项感官评价用语的定义(如表3-11所示)。Stickiness test A B黏性Compression压缩疏松感可用穿孔最大应力和切断强度值综合判断；主要用于各种粉质的品质鉴定，如面粉、玉米粉、绿豆粉等。Initial ModulusTensile stre
30、ngth is a manifestation of cohesiveness.,20,50,55-58.Initial ModulusInitial Modulus is not a parameter from the original Texture Profile Analysis work but instead has developed from looking more closely at the portion of the curve before fracture.食品物性仪器测定的开展Stringiness 筋性筋性Stringiness is the distanc
31、e the product is extended during decompression before separating from the compression probe.lIt is not a parameter from the original Texture Profile Analysis work but instead has developed from looking more closely at the adhesiveness portion of the curve.lAlthough this parameter is not built into t
32、he TPA macro and results files，the flexibility is available to include this parameter if you so desire.lThe units of this parameter would be in distance e.g.mm.Initial Modulusl Initial Modulus is derived as Initial Stress/Initial Strain.Units are in e.g.N/mm.The Initial Stress is calculated as the a
33、verage force of the points in the range 0.5 seconds to 1.5 seconds divided by the Contact Area.l Initial Strain is the strain calculated at the 1.5 second point of the curve.l The Initial Strain can only be calculated if STRAIN is available and hence PRODUCT HEIGHT can be derived.l Initial Modulus i
34、s not a parameter from the original Texture Profile Analysis work but instead has developed from looking more closely at the portion of the curve before fracture.第三节 食品质地的仪器测定2.流变仪流变仪?流变仪可以进行各种压缩、流变仪可以进行各种压缩、拉伸、插入、剪断等测定，拉伸、插入、剪断等测定，还可以完成几乎所有流变性还可以完成几乎所有流变性质的力学测定。质的力学测定。第三节 食品质地的仪器测定3.布拉班德粉质仪布拉班德粉质仪主
35、要用于各种粉质的品质鉴主要用于各种粉质的品质鉴定，如面粉、玉米粉、绿豆定，如面粉、玉米粉、绿豆粉等。粉等。第三节 食品质地的仪器测定3.布拉班德粉质仪布拉班德粉质仪由调粉器和动力测定计组成。测定原理是把小麦粉和水用调由调粉器和动力测定计组成。测定原理是把小麦粉和水用调粉器的搅拌臂揉成一定硬度的面团，并持续搅拌一段时间，粉器的搅拌臂揉成一定硬度的面团，并持续搅拌一段时间，并自动记录在揉面搅动过程中面团阻力的变化。并自动记录在揉面搅动过程中面团阻力的变化。1搅拌槽 2测力计 3轴承4连杆5缓冲器 6指示盘 7记录仪 8恒温水槽9循环管 10循环电机 11滴管第三节 食品质地的仪器测定3.布拉班德粉
36、质仪布拉班德粉质仪n 数据分析数据分析粉质仪得出的面团阻力曲线叫粉质仪得出的面团阻力曲线叫粉质曲线粉质曲线。第三节 食品质地的仪器测定3.布拉班德粉质仪布拉班德粉质仪n 数据分析数据分析第三节 食品质地的仪器测定3.布拉班德粉质仪布拉班德粉质仪n 数据分析数据分析吸水率吸水率(water absorption)：小麦粉形成硬度为：小麦粉形成硬度为500B.U.的面的面团所需要的加水量。强筋粉吸水率大，弱筋粉吸水率小。团所需要的加水量。强筋粉吸水率大，弱筋粉吸水率小。面团形成时间面团形成时间(dough development time)：从揉面开始达到：从揉面开始达到最高黏度的时间。最高黏度的
37、时间。面团稳定度面团稳定度Stab(stability)：阻力曲线中心线最初开始上升：阻力曲线中心线最初开始上升到到50020B.U.到下降到到下降到50020B.U.所需要的时间，越长说所需要的时间，越长说明面团加工稳定性越好。明面团加工稳定性越好。第三节 食品质地的仪器测定3.布拉班德粉质仪布拉班德粉质仪n 数据分析数据分析面团衰落度面团衰落度(weakness)：曲线从开始下降开始：曲线从开始下降开始12 min后的后的下降值，衰落度值越小，说明面团筋力越强。下降值，衰落度值越小，说明面团筋力越强。综合评价值综合评价值VV(valorimeter value)：用面团形成时间和衰：用面团
38、形成时间和衰落度综合评价的指标。落度综合评价的指标。第三节 食品质地的仪器测定standard determination method 1 uAACC 76-21.01 和 ICC 国际标准 No.162方法推荐标准方法1（STD1）进行测定4.淀粉粉力测定仪（淀粉粉力测定仪（RVA，rapid viscosity analyser）第三节 食品质地的仪器测定4.淀粉粉力测定仪（淀粉粉力测定仪（RVA，rapid viscosity analyser）测试结果：峰值黏度峰值黏度 谷值黏度谷值黏度 衰减值衰减值 最终黏度最终黏度 回生值回生值 峰值时间峰值时间 糊化温度糊化温度糊化特征曲线糊化
39、特征曲线,20,50,55-58.可以看出，与感官项目肉粒感、多筋性相关最大的仪器侧定方法为:刃状压头剪切时的切断功；第三节 食品质地的仪器测定粉质仪得出的面团阻力曲线叫粉质曲线。Springiness(originally called elasticity)is related to the height that the food recovers during the time that elapses between the end of the first bite and the start of the second bite.SZCZESNIAK,A.Texture prof
40、ile analysis(TPA，质地剖面分析)is an objective method of sensory analysis pioneered in 1963 by Szczesniak,who defined the textural parameters first used in this method of analysis.Adhesiveness黏着性，黏附性数据：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。第三节 食品质地的仪器测定Springiness(originally called elastic
41、ity)is related to the height that the food recovers during the time that elapses between the end of the first bite and the start of the second bite.咬断性可用硬度值和切断强度值综合判断；Texture Measurements.AACC 76-21.Stringiness 筋性Tensile strength is a manifestation of cohesiveness.（1）感宫评价前首先使评审员理解和明确各项感官评价用语的定义(如表3-
42、11所示)。Back Extrusion反向挤出肉饼的硬度感受可用咀嚼仪器侧定和水分测定的数值综合判定;Although this parameter is not built into the TPA macro and results files，the flexibility is available to include this parameter if you so desire.Texture profile analysis(TPA，质地剖面分析)is an objective method of sensory analysis pioneered in 1963 by Sz
43、czesniak,who defined the textural parameters first used in this method of analysis.Food Sci,28,385-389.第四节 食品质地评价仪器的选择1.仪器测定和感官评价的特点仪器测定和感官评价的特点食品物性仪器测定的开展l目的性要强感官评价科学分析l方法要科学首先要明确要评价的感官性质及其内涵-进行分析型评价-确定重要的感官性质然后用仪器进行各种可能的评价建立感官与仪器评价之间的相关关系确定仪器评价方法和指标替代感官评价时仪器测定的分析与选择l以牛肉饼(hamburger)为例说明l（1）感宫评价前首先使
44、评审员理解和明确各项感官评价用语的定义(如表3-11所示)。往往一些评审员在许多情况下，搞不清“硬”和“弹性”的定义，或将这两者混同。因此，在感官评审前要认真进行必要的说明和示范。(2)制定标准实施评价。l 感官评价的得分标准如图3-12所示。该方法称为对比得分法。即将2种以上的试样与对照食品(标准食品)相比较，把比较后感到的差异程度，以数值的形式打分评价。在选择标准食品时，注意要预先进行感官检查。其质地的各性质要求比较适中。每次品尝试验时，同时摆出一个标准食品和一个试样食品，由5名评审员按图3-12的各项目品评打分，本例对48种试样进行了试验。(3)仪器测定l对以下8个项目进行测定：水分，肉
45、粒平均直径，离液量(挤压流汤量)，应力松弛，切断试验，咬断剪压)试验(用U形或V形模头剪压试样)，咀嚼试验(即压缩破坏试验,测硬度、疏松度)，穿孔试验(测最大破坏应力)。standard determination method 1Texture profile analysis(TPA，质地剖面分析)is an objective method of sensory analysis pioneered in 1963 by Szczesniak,who defined the textural parameters first used in this method of analysis
46、.每次品尝试验时，同时摆出一个标准食品和一个试样食品，由5名评审员按图3-12的各项目品评打分，本例对48种试样进行了试验。AACC 76-21.Stress relaxation应力松弛Stringiness is the distance the product is extended during decompression before separating from the compression probe.Hardness is defined as the maximum peak force during the first compression cycle (first
47、bite)and has often been substituted by the term firmness.Food Sci,28,385-389.而弹性感和固着性感觉只与穿孔试验的最大应力有很高相关；It is not a parameter from the original Texture Profile Analysis work but instead has developed from looking more closely at the adhesiveness portion of the curve.Such a transition is practically
48、never accomplished during instrumental TPA evaluation.5 seconds to 1.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。In general,the smaller the deformation under a given load,the lower the cohesiveness and the greater the ability to fracture of the product.,20,50,55-58.第三节 食品质地的仪器测定It is n
49、ot a parameter from the original Texture Profile Analysis work but instead has developed from looking more closely at the adhesiveness portion of the curve.Later in 1978 Bourne adapted the Instron to perform TPA by compressing standard-sized samples of food twice-二次压缩试验.食品物性仪器测定的开展The Initial Stress
50、 is calculated as the average force of the points in the range 0.,20,50,55-58.1搅拌槽 2测力计 3轴承(4)相关性分析。l 将以上仪器测定值与感官侧定值进行相关性分析(如表3-12所示)，可得到，与各项目感官评价相关性最大的仪器测定项目(按最大相关性顺序取前3位)。l 可以看出，与感官项目肉粒感、多筋性相关最大的仪器侧定方法为:刃状压头剪切时的切断功；硬度、固着性和咀嚼口感与穿孔试验的最大应力有很高的相关关系；而油腻感仅与离液量有一定相关，与其它测定项目结果无关。(5)多元回归分析。l 进行多元回归分析找出代替感官
