摘要:

ABSTRACTA new method to study texture perception is described. Miniaturized load cells were placed in the oral cavity to record the time course of the bite force. The bites were made, during psychophysical tests on hardness comparison, into products (silicone elastomers) exhibiting simple rheological behaviour. The silicone samples were placed on either side of the load cell. The control measurements proved that the recordings under these conditions were stable and reproducible. An analysis of the time course of the curves revealed differences in perception strategy between the subjects. The use of load cells together with standardized products allows a better understanding of the relationship between the rheological measurements of a product and the motor activity of the chewing apparatus when the texture of a solid food product is perceived.

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1993.tb00048.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTThe effect of formulation factors on Casson yield values measured at low shear rates (0.08 ≤γ≤ 1.01s‐1) (σ01) and at medium shear rates (2.58 ≤γ≤ 387.30s‐1) (σ02) was analyzed in previously sheared strawberry and peach jams. Twenty three samples of each fruit jam were prepared according to a second order composite rotatable design. Composition ranges were: fruit content, 25–55%; soluble solids content, 60–70° Brix; added pectin in strawberry jams, 0.3–0.7% and in peach jams, 0.1–0.5%. Variation of σ01values in strawberry jams depended mainly on the interactions between fruit and soluble solids and between fruit and pectin, while in peach jams, it depended on fruit‐soluble solids and soluble solids‐pectin interactions. Patterns of change of σ02values with composition were similar to those observed for σ01in both strawberry and peach jams. Predictive power of σ01and σ02values for estimation of fruit content was low, but taken in conjunction with soluble solids content and total pectin values, 79.5% of the variability of fruit content in strawberry jams and 91.1% of same

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1993.tb00049.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTRheological properties of bread dough having different levels of added gluten (0, 2.5, 5.0 and 7.5%) were measured. The dough was forced through a slit die attached to a cylindrical container. The material functions of interest included steady shear viscosity, first normal stress coefficient in steady shear flow derived from hole pressure measurements and planar extensional viscosity as estimated from entrance pressure drop measurements. These rheological properties were correlated to the loaf volume of the baked bread. Results indicate that the first normal stress coefficient and planar extensional viscosity were affected by the gluten content of the dough and correlated well with the loaf volume. The entrance pressure drop increased with increasing apparent shear rate but entrance correction was found to decrease with apparent shear rate. Water had a greater effect on the rheological properties than gluten content. The Trouton ratio was rather large and ranged between 850 to 2000 at a strain rate of 1s‐1and decreased with increasing extension rate for most case

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1993.tb00050.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTThe effects of droplet size and emulsifier type on the rheology of whey protein isolate (WPI) gels containing emulsion droplets was studied. Gels were prepared by dispersing droplets of corn oil (20 wt%, d32= 0.7 – 4 μm) in a 10 wt% WPI solution (pH 7.0, 50 mM NaCl), and heating at 90C for 15 min. Gel strength was determined by measuring the stress of gels at 20% compression using an Instron Universal Testing Machine. Droplets stabilized by WPI increased the gel strength, those stabilized by non‐ionic surfactants (Tween 20 and Triton X‐100) decreased it slightly, and those stabilized by SDS decreased it drastically. Gel strength increased as the droplet size decreased for droplets stabilized by WPI, but was relatively insensitive to the size of droplets stabilized by the small molecule surfactants. These observations may be explained in terms of the interactions between the emulsifiers and the protein network. Droplets coated with emulsifiers which can be incorporated into the protein network reinforce the structure and so increase gel strength, whereas droplets coated with emulsifiers which cannot be incorporated into the protein network disrupt the three dimensional structure of the gel and decrease its st

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1993.tb00051.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTThe compressive mechanical properties of fruit and vegetable parenchyma are related to the morphology of the material such as size, shape and orientation of cells and intercellular spaces, and cellular adhesion. Uni‐axial compression tests on geometrical specimens of apple and potato flesh have shown that apple parenchyma is mechanically very anisotropic whereas potato shows no such behaviour. Apple flesh is highly orientated in the cortex into radially elongated cells and intercellular spaces. If the flesh is compressed along the rows of cells (radial) it generally fractures by a collapse of single layer of cells at right angles to the force. If the flesh is compressed at right angles to the rows of cells (tangential) it fails in shear. It is stiffer radially but tougher tangentially requiring greater deformation to fail. There is no orientation of such morphological structures in potato and hence the compressive properties are not dependent on the direction. It always fails in shear. Mature late season apples tend to be stiffer and tougher than early apples as they have smaller cells and thicker cell walls. Early season apples become mealy quickly and cracking occurs by cell separation due to the early breakdown of pectins in the weak intercellular lamellae. This makes them mechanically much weaker than late season apples where cell adhesion is strong and cracking occurs by cell rupture, a process requiring greater force and energ

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1993.tb00052.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTRheological properties of low‐moisture part‐skim Mozarella cheese were evaluated as a function of storage time, test temperature, and deformation rate by uniaxial extension in a horizontal plane. Proteolysis of Mozzarella cheese caused marked decreases in the tensile strength and the deformability modulus, but not in the fracture strain. As the temperature increased from 10 to 40C, the fracture strain increased more than five‐fold. The strength and the deformability modulus decreased about 60 and 85%, respectively, as the cheese temperature increased from 10 to 30C. The fracture strain of the cheese did not exhibit a clear trend with the deformation rate in the range of 50–500 mm/min. However, its strength and deformability modulus increased with the increasing deformati

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1993.tb00053.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTThe time dependent rheological behaviour of 4 commercial stirred yoghurts was evaluated at constant shear rate within the range 18 to 280 s‐1.The viscosity decreased greatly to an equilibrium value after 600 s of shearing. A simple model based on a structural approach was used. A rheological test was designed and carried out at a constant shear rate of 111 s‐1and a temperature of 10C. Three types of stirred yoghurt processed in the laboratory under standard conditions were compared with the 4 commercial brands. Two parameters of the model were highly significant for comparing the different stirred yoghurts. These were the rate constant of the structural decay and the consistency index at equilibr

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1993.tb00054.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

GENERAL PRINCIPLES: Preparation and Functional Properties of Rapeseed Protein Products.E.H. Mansour, J. Perédi and E. DworschákGENERAL PRINCIPLES: Determination of the Molecular Mass of Polygalacturonic Acid.Gy. Mady, B. Lakatos, J.J. Kever and N.V.D. YakonovaGENERAL PRINCIPLES: Crystallization Kinetics of Emulsified Triglycerides.S. Özilgen, C. Simoneau, J.B. German, M.J. McCarthy and D.S. ReidGENERAL PRINCIPLES: The Role of Phytase and Lignin in Decorticated Dry Bean (Phaseolus vulgaris) Hardening During Storage.M.M. Mafuleka, D.N. Ott, G.L. Hosfield and M.A. UebersaxGENERAL PRINCIPLES: Effect of Flour Quality Characteristics on Puff Pastry Baking Performance.R.L. HayBASIC PRINCIPLES: Effects of pH On Gelaion and Emulsification of a β‐Lactoglobulin Concentrate.P. Reikin, T. Liu and B. LaunayMETHODOLOGY AND INSTRUMENTATION: Analysis of the Helical Screw Rheometer for Fluid Food.M.S. Tamura, J.M. Henderson, R.L. Powell and C.F. ShoemakerMETHODOLOGY AND INSTRUMENTATION: Stress Relaxation Test Conditions for Meat Products to Measure Viscoelasticity.G.S. Mittal, M. Zhang and S. BarbutMETHODOLOGY AND INSTRUMENTATION: Impact Damage on Rough Rice.A.D. Sharma, O.R. Kunze and N.N. SarkerMETHODOLOGY AND INSTRUMENTATION: Frequency Factor—Activation Energy Compensation Relations for Viscosity of Fruit Juices.M. Ozilgen and L. BayindirliMETHODOLOGY AND INSTRUMENTATION: Dynamic Measurement of Starch Granule Swelling During Gelatinization.G.R. Ziegler, D.B. Thompson and J. CasasnovasMETHODOLOGY AND INSTRUMENTATION: Development of Two Instrumental Methods for Corn Masa Texture Evaluation.B. Ramirez‐Wong, V.E. Sweat, P.I. Torres and L.W. RooneyINSTRUMENTAL MEASUREMENTS: Rheology of Bengal Gram (Cicer arientinum) Flour Suspensions.S. Bhattacharya, K.K. Bhat and K.G. RaghuveerINSTRUMENTAL MEASUREMENTS: Residence Time Distribution of Food Suspensions Containing Large Particles When Flowing in Tubular Systems.K. Palmieri, D. Cacace, G. Dipollina, G. Dall'Anglio and P. MasiSENSORY ASSESSMENT: Understanding Mouthfeel Attributes: A Multidimensional Scaling Aproach.M. Bertino and H.T. LawlessSENSORY ASSESSMENT: Effect of Homogenization and Fat Content on Oral Perception of Low and High Viscosity Model Creams.N.J. Richardson, D.A. Booth and N.L. StanleySENSORY ASSESSMENT: Discrimination of Texture and Appearance in Cheddar Cheese Using Consumer Free‐Choice Profiling.F.R. Jack, J.R. Piggott and A. PatersonSENSORY ASSESSMENT: Influence of Oat Gum, Guar Gum and Carboxymethyl Cellulose on the Perception of Sweetness and Flavour.Y. Mälkki, R.‐L. Heiniö and K. AutioFACTORS AFFECTING TEXTURE: Physical, Chemical, and Dry‐Milling Properties of Corn of Varying Density and Breakage Susceptibility.A.J. Peplinski, M.R. Paulsen and A BouzaherFACTORS AFFECTING TEXTURE: Frozen Dought: Rheological Changes and Yeast Viability.K. Autio and E. SindaFACTORS AFFECTING TEXTURE: Modified Atmosphere Storage of Peaches and Nectarines to Reduce Storage Disorders.S. LurieFACTORS AFFECTING TEXTURE: Peach Firmness During Storage as Affected by Three Irrigation Schedules.X. Zhang, G.H. Brusewitz, S.M. Huslig and M.W. SmithFACTORS AFFECTING TEXTURE: Effect of Hot Processing on the Properties of Restructured Beef with Alginate/Calcium Binders.M.A. Al‐Joher and A.D. ClarkeFACTORS AFFECTING TEXTURE: Cohesion and Hardness of Extrusion‐Cooked Mechanically‐ and Hand‐Deboned Poultry Meat with Soy Protein Isolate and Kappa‐Carrageenan.A.S. Ba‐Jaber, J.N. Sofos, G.R. Schmidt and J.A. MagaFACTORS AFFECTING TEXTURE: Effect of Squid Liver Extract on Proteins and Texture of Cooked Squid Mantle.I. Kolodziejska, J. Pacana and Z.E. SikorskiFACTORS AFFECTING TEXTURE: Bacterial Cellulose. IV. Application to Processed Foods.A. Okiyama, M. Motoki and S. YamanakaFACTORS AFFECTING TEXTURE: Physical and Chemical Evaluation of Peanut Butter During Storage.N.M. El‐SHimiFACTORS AFFECTING TEXTURE: Effect of Emulsifiers on the Properties of Pasta Products.E. Kovács, É Vámos‐Kardos, M. Kiss‐Laszlavik and E. PallagiFACTORS AFFECTING TEXTURE: Biochemical, Rheological, Cooking Quality and Acceptability of Defatted Soy‐Supplemented Whole Durum Meal Noodles.S.A. TahaFACTORS AFFECTING TEXTURE: Physical Properties of Wheat Flour Extrudates Produced with Shortening and Starch Plus Several Baking Ingredients.G.H. Ryu and C.E. WalkerFACTORS AFFECTING TEXTURE: Analytical Model for Plastic Impact of Fruit on Thin Plate.S. Gan‐Mor and A. MizrachFACTORS AFFECTING TEXTURE: Gel‐Strength in Restructured Potato Products Affects Oil Uptake During Deep‐Fat Frying.E.J. Pinthus, P. Weinberg and I.S. SaguyFACTORS AFFECTING TEXTURE: Texturization of Sweetened Mango Pulp: Optimization Using Response Surface Methodology.C. Mouquet, J‐C Dumas and S. GuilbertFACTORS AFFECTING TEXTURE: Effect of Dextrans of Differing Molecular Weights on the Rheology of Wheat Flour Doughs and the Quality Characteristics of Pan and Arabic Breads.A.S. Ross, G.J. McMaster, J.D. Tomlinson and N.W.H. CheethamFACTORS AFFECTING TEXTURE: Changes in Rheological Properties of Hydroxypropyl Potato Starch Pastes during Freeze–Thaw Treatments. III. Effects of Cooking Conditions and Concentration of the Starch Paste.H.R. Kim, P. Muhrbeck and A.‐C. EliassonFACTORS AFFECTING TEXTURE: Functional Properties of the Starchy Flour Extracted from Cassava on Fermentation with a Mixed Culture Inoculum.S.N. Moorthy, M. George and G. PadmajaFACTORS AFFECTING TEXTURE: Effect of Sorghum Flour Addition on the Characteristics of Wheat Flour Tortillas.P.I. Torres, B. Ramirez‐Wong, S.O. Serna‐Saldivar and L.W. RooneyFACTORS AFFECTING TEXTURE: Effects of Cooking Water Composition on Stickiness and Cooking Loss of Spaghetti.L.J. Malcolmson and R.R. MatsuoFACTORS AFFECTING TEXTURE: Effects of Emulsifiers and Hydrocolloids on Whole Wheat Bread Quality: A Re

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1993.tb00055.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY