摘要:

ABSTRACTThe effect of storage temperature on rheological behaviour of four varieties of baby foods was studied. After 24‐month storage at 15C and 25C, the constant A in Weltman model increased significantly for the vegetables, meat and fish samples, and decreased significantly for the fruit samples. After 24‐month storage at 5C and 15C there were no significant changes in flow behavior index, consistency index and yield stress of the Herschel‐Bulkley model for the vegetables, meat, fish and fruit samples. Increase in storage temperature decreased the consistency index and yield stress of the fruit sa

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00081.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTA new methodology for modelling the thixotropy of inelastic fluids is described and its application demonstrated. In order to validate the model, data from two measurement protocols are compared and shown to give coherent results. The structural kinetics approach uses a reduced structural variable, λ, which has values between zero, when the structure is totally broken down, and one, when the structure is complete. The new approach is applied to the thixotropy of a solution of iota carrageenan, a well known food hydrocolloid. Solutions were sheared before testing in order to eliminate their viscoelasticity. The measurement protocols used were: (1) stress jumps from above and below each shear stress tested, and (2) triangular ramp‐up/ramp down stress profiles, often called hysteresis loops. The first series of measurements was used to determine the equilibrium structure and kinetics of structural build‐up and breakdown at each shear stress. This data completely determines the parameters in the thixotropic model and allows prediction of the samples response to any stress/time profile. Without using any additional parameters, this model was then used to predict the shape of the hysteresis loops in the second series of measurements. The agreement between the predictions and measurements was very good, provided that the experimental data was first corrected for the efects of inertia and the finite gap‐width of the rhe

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00082.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTCherries of three varieties were compressed between two plates in the loadingunloading test to determine the energy dissipated during the test. After compression, the bruise volume of the deformed fruit was determined. Bruise resistance coefficient (BRC) and bruise sensitivity (BS) were evaluated in a similar way as for apples. It is shown that, contrary to the results for apples, the BRC and BS values depend on the compression ratio in a more complicated way for cherries than for apples. The principal differences in bruise sensitivity were observed for different cherry varieties. These differences cannot be explained by the macroscopic mechanical properties of the fruits only.

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00083.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTDifferential scanning calorimetric (DSC) data on 10% (w/w) corn starch dispersion showed one endothermic peak and on soybean protein (SP) isolate dispersions two peaks attributed to 7S and 11S globulins. In corn starch‐SP isolate mixtures, thermal transitions appear to occur independently of one another. Dynamic rheological data over 0.63–62.9 rad s‐1revealed weak gel‐like behavior of both 10% corn starch and SP isolate dispersions with magnitudes of storage modulus (G′) being significantly higher than those of loss modulus (G″) and both exhibiting slight frequency‐dependence; G′ of corn starch dispersion was higher than that of SP isolate and in mixed dispersions its magnitude decreased with increase in proportion of protein. The Maxwell model described creep‐compliance data on dispersions high in corn starch, while the Burgers model described dispersions high in SP isolate. Plots of protein/starch ratio versus G′ and instantaneous elastic modulus showed similar trends in phase separ

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00084.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTAt 10% solids content, magnitudes of G′ and G″ of soybean 7S dispersion were substantially lower than those of corn starch dispersion, while those of soybean 11S dispersion were much higher than those of starch. Profiles of G′ at 30 Hz as a function of starch concentration of starch + 7S and starch + 11S gels were asymmetrical reflecting phase separation due to thermodynamic incompatibility. However, the starch concentration corresponding to the critical point below which no phase separation occurs for the starch + 7S dispersion was about 7% and for the starch + 11S dispersion it was about 3%. At equal starch fractions, values of G′ at 30 rad s‐1of corn starch + 7S dispersions were nearly equal to those of only corn starch. In contrast, at starch concentrations between 6–8%, G′ values of the corn starch + 11S dispersions were much higher than those of only starch and a minimum value occurred at a starch concentration of about 5%. Based on frequency dependence of G′ values, heated corn starch + 7S dispersions may be classified as weak gels, while heated corn starch + 11S dispersions may be classifi

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00085.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTThis study examined the effect of differences in chewing efficiency on selected panellists' perceptions of the stickiness and flavour of cooked pasta. Chewing efficiency was measured by the degree of breakdown of an almond, and weight loss of chewing gum after predetermined numbers of chews. Pasta was cooked for various lengths of time in tomato juice to provide a series of samples varying in texture and flavour. The attributes considered in this study were clearly understood and detected in all of the samples by all the subjects. Nevertheless the subjects differed in the time intensity representations of their perceptions of these attributes. Differences in the efficiencies with which subjects break down food in the mouth may account for the abilities of subjects to distinguish between samples in terms of texture and flavour.

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00086.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTBased on laser diffraction, pulp particles>900 μm were detected in tomato concentrates; particles greater than 100–200 μm were found in serum from a concentrate. Creep‐compliance and dynamic rheological data showed that viscoelastic properties of 21 °Brix tomato concentrates using a 0.84 mm finisher screen were higher than those from a 0.69 mm screen. Both types of viscoelastic properties were sensitive to increase in concentration in that they increased with increase in Brix of the concentrates. Magnitudes of instantaneous modulus (G0= 1/J0) of the tomato concentrates were of the same order of magnitude as the storage modulus (G') at 1 r

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00087.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00088.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

GENERAL PRINCIPLES: Rheology and Microstructure of β‐Lactoglobulin/Sodium Polypectate Gels.E.E. Ndi, B.G. Swanson, G.V. Barbosa‐Canovas and L.O. LuedeckeGENERAL PRINCIPLES: A Theoretical Analysis of Stress Concentrations in Gels Containing Spherical Fillers.Y.C. Gao, J. Lelievre and J. Tang.METHODOLOGY AND INSTRUMENTATION: Packing Line Bruise Evaluation for ‘Walla Walla’ Summer Sweet Onions.R.W. Bajema and G.M. Hyde.bMETHODOLOGY AND INSTRUMENTATION: A Dynamic Sensor for Cherry Firmness.F.L. Younce and D.C. Davis.METHODOLOGY AND INSTRUMENTATION: Nondestructive Dynamic ForceAIefonnation Measurement of Kiwifruit Firmness (Actinidia deliciosa).J.A. Abbott and D.R. Massie.METHODOLOGY AND INSTRUMENTATION: Investigation of Gelation Phenomena of Some Polysaccharides by Ultrasonic Spectroscopy.Spectroscopy. M. Audebrand, J.L Doublier, D. Durand and J.R. Emergy.METHODOLOGY AND INSTRUMENTATION: Modelling Steady and Transient Rheologicsl Properties.C.F. Chan Man Fong, G. Turcotte and D. De KeeMETHODOLOGY AND INSTRUMENTATION: Rheology of Cooked Debranned Maize Hour Suspensions.S. Bhattacharya and S. Bhattacharya.METHODOLOGY AND INSTRUMENTATION: Rheological Models for Xanthan Gum.(Research Note) Z. Xuewu, L. Xin, G. Dexiang, Z. Wei, X. Tong and M. Yonghong.METHODOLOGY AND INSTRUMENTATION: Rheological Behaviour of Sloe (Prunus Spinosu) Fruit Juices.A. Jbarz, A. Garvin and J. Costa.METHODOLOGY AND INSTRUMENTATION: Yield Stress and Relative Viscosity of Tomato Concentrates: Effect of Total Solids and Finisher Screen Size.B. Yoo Pangbae‐Dong, Seochu‐Gu, Seoul, So. Korea) and M.A. Rao.METHODOLOGY AND INSTRUMENTATION: Viscoelastic Properties of Butter.A. Shukla and S.S.H. Rizvi.SENSORY MEASUREMENTS: Consumer Acceptability of Beef Steak Tenderness in the Home and RestaurantM.F. Miller L.C. Hoover, K.D. Cook, A.L. Guerra, K.L. Huffman, H.C. Brittin and L.M. Huffman.FACTORS AFFECTING TEXTURE: Postmortem Changes in the Mechanical Properties and Ultrastructure of the Longissimus in Two Porcine Breeds.G. Minelli, J. C ulioli, X. Vignon and G. Monin.FACTORS AFFECTING TEXTURE: Pork Quality Audit: A Review of the Factors Influencing Pork Quality.J.E. Cannon, J.B. Morgan, J. Heavner, F.K. McKeith, G.C. Smith and D.L. Meeker.FACTORS AFFECTING TEXTURE: Initial Postmortem Porcine Muscle pH Effect on Heat‐Induced Gelation Properties.Properties. Y.H. Lan, J.E. Novakofski, R.H. McCusker, M.S. Brewer, T.R. Carr and F.K. McKeith.FACTORS AFFECTING TEXTURE: Effect of Homogenization Pressure on Consistency of Tomato Jiuce.Jiuce. B.R. Thakur, R.K. Singh and A.K. Handa.FACTORS AFFECTING TEXTURE: Influence of Blanching Treatments on the Texture and Color of Some Processed Vegetables and Fruits.Z. Lin and E. Schyvens.FACTORS AFFECTING TEXTURE: Effect of Freezing Rate on the Rheological Behaviour of Systems Based on Starch and Lipid Phase.A.S. Navarro, M.N. Martino and N.E. Zaritzky.FACTORS AFFECTING TEXTURE: Changes in Texture and Cell Wall Polysaccharides of Olive Fruit during “Spanish Green Olive ProcessingA. Jimknez, R. Guillbn, C. Sanchez, J. Fernhndez‐ Bola&and A. Heredia.FACTORS AFFECTING TEXTURE: Liquid Drainage and Firmness in Full‐Fat, Low Fat and Fat‐Free Cottage Cheese.M. Rosenberg, Z. Wang, G. Sulzer.FACTORS AFFECTING TEXTURE: Mechanical Properties of Gellan Gels in Relation to Divalent Cations.J. Tang, M.A. Tung and Y. Zeng.FACTORS AFFECTING TEXTURE: Softening Rates of Fermented Cucumber Tissue: Effects of pH, Calcium and Temperature.R.F. McFeeters, M.B. Balbuena and H.P. Fleming.FACTORS AFFECTING TEXTURE: Freeze‐Thaw Stability of Prefermented Frozen lean Wheat Doughs: Effect of Flour Quality and Fermentation Time.J. Rashen, H

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00089.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY