摘要:

ABSTRACTA 0.71‐mm‐diameter punch mounted in the Instron Universal Testing Machine was used to measure hardness of 100 individual grains of 15 rices after cooking. A hardness distribution curve for each rice was obtained. The puncture forces of rices cooked at a fixed water:rice weight ratio of 2 were more variable than those for rices cooked in excess water for the optimum cooking time. High‐ and intermediate‐amylose rices cooked using a water:rice ratio of 2 were harder than corresponding rices cooked in excess water. For waxy and low‐amylose rices, the reverse was generally true. Pairs of rices with almost identical physicochemical properties but which differed in preference tests by consumers also differed in their hardness distributio

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00056.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTA tensile test was used to measure four mechanical properties of carrot tissue cooked under various time‐temperature conditions. A kinetic model describing the changes of these mechanical properties measured during cooking was developed. The histological properties of the rupture surfaces caused by the mechanical testing were investigated. The kinetic model was found capable of predicting the changes in the rupture mechanism of the cell walls. Determining the percentage of cell wall ruptures proved to be an accurate method to assess the textural state of carrot tissue during cooking as compared to the measurement of the mechanical propertie

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00057.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTPreliminary results using an oscillatory probe rheometer to follow sol to gel transformations of pasted starch gave illogical results. G″ appeared to increase instead of decrease, as would be expected for a gelling sol. The increase was dramatic at high temperatures. In many instances the viscosity loss values (η') were negative, which is physically impossible. Therefore, the equations used were examined for a source of error. It was found that no temperature correction was made for probe frequency in the test sample. Use of the temperature correction for probe frequency in the sample along with the equations provided with the instrument showed that the oscillatory probe rheometer effectively measured viscous and viscoelastic properties of starch gel systems throughout the sol to gel transformati

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00058.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTThe jaggedness of the force‐time relationship of capillary extrusion profiles of pasty foods was assessed by the power spectrum of the Fast Fourier Transform and the apparent fractal dimension of the curves. The same products were tested by a trained sensory panel for their smooth, soft, homogeneous and adhesive characteristics. The apparent fractal dimension, calculated through the dilation function of an image analysis system, gave a convenient measure of the overall capillary extrusion profile. It was hypothesized that this apparent fractal dimension represented the smoothness of the product which was correlated with the sensorial smooth character. The mean magnitude and the density of power spectra, determined by the Fourier analysis, were used to characterize the product consistency. Their shape was related directly to the smooth textural propert

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00059.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTEffects were studied of interactions between each of three hydrocolloids‐xanthan gum, guar gum and methylcellulose‐ and aspartame on sweetness intensity and sensory viscosity of low‐calorie peach nectars (60% fruit purée with no sucrose added). The flows of the nectars were characterized as near Newtonian without hydrocolloids, as Bingham plastic at lower hydrocolloids concentrations and as pseudoplastic at higher concentrations (Ostwald flow for guar and methylcellulose, and Herschel‐Bulkley for xanthan). Hydrocolloids concentrations were selected to cover viscosity range of commercial whole nectars: 0.10 and 0.20% xanthan or guar, and 0.15 and 0.30% methylcellulose. Aspartame concentrations tested were derived from the calculation of equisweet concentration as referred to a control nectar sample with sucrose (14°Brix) and of the upper and lower limen value: 0.216, 0.360 (equisweet), 0.502, and 0.644 g/L. Addition of either guar or methylcellulose did not alter the perceived sweetness in aspartame‐sweetened peach nectars. Xanthan addition, even at 0.10%, significantly lowered sweetness of samples sweetened with the highest aspartame concentration (0.644 g/L). Addition of aspartame did not modify the perceived viscosity in samples thickened with either xanthan or guar gums. At all methylcellulose concentrations tested, samples with the lowest aspartame concentration (0.216 g/L) were perceived as l

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00060.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTReduction of Chios mastiche hardness by additions of beeswax, lecithin or calcium stearate was studied by compression tests using an Instron machine. Beeswax and lecithin brought about a marked decrease of mastiche's resistance to compression while calcium stearate had the opposite effect. Esterification of the hard and brittle monomeric fraction of mastiche with ethanol caused a drastic modification of its texture yielding a plastic material. Its addition to mastiche at various percentages brought about a considerable decrease in the product's resistance to compression.

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00061.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTElectrorheology is an area of study that evaluates changes in flow properties upon the application of an electric field. Electrorheological fluids generally exhibit an increase in apparent viscosity and a greater yield stress over an unelectrified sample. The phenomenon requires an electric field, polar particles in suspension, and an insulating oil. Milk chocolate meets these criteria and displays unique behavior when exposed to an electric field. A concentric cylinder viscometer, fitted with special electrical attachments, was used for data collection. This system allowed for control of the applied dc voltage, fluid temperature, and shear rate while observing the resulting effects on the shear stress. Data analyses show that, at constant temperature, the shear stress increases as the voltage increases. Continued analyses depict that shear stress increases as temperature increases when subjected to a constant shear rate and voltage. These results establish milk chocolate as a bona fide electrorheological fluid. The chocolate industry may benefit from this research by gaining knowledge of a new technique to externally control the flow properties of milk chocolate, allowing the development of unique processes and products.

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00062.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

GENERAL PRINCIPLES: Gelation of Chicken Breast Muscle Actomyosin As Influenced by Weight Ratio of Actin to Myosin.S.F. Wang and D.M. SmithGENERAL PRINCIPLES: Wafer Batters: A Rheological Study.G. Oliver and S.S. Saki.GENERAL PRINCIPLES: Effects of Minerals and Apparent Phytase Activity in the Development of Hard‐to‐Cook State of Beans.O.L. Kilmer, P.A. Seib and R.C. Hoseney.GENERAL PRINCIPLES: Vioelastic Properties of Rice‐Flour Pastes and Their Relationship to Amylose Content and Rice Quality.K.R. Reddy, R. Subramanian, S.Z. Ali and K.R. Bhattacharya.GENERAL PRINCIPLES: Rheological Properties of Wheat Flour Doughs in Steady and Dynamic Shear:Effect of Water Content and Some Additives.S. Berland and B. Launay.GENERAL PRINCIPLES: Rheological Properties of Dough Made with Starch and Gluten from Several Cereal Sources.K.E. Petrofsky and R.C. Hoseney.GENERAL PRINCIPLES: Effects of Certain Breadmaking Oxidants and Reducing Agents on DoughGENERAL PRINCIPLES: Rheological Properties.W. Dong and R.C. Hoseney. P.P. Lewicki and W.E.I. Spiess.METHODOLOGY&INSTRUMENTATION: Firmness Measurement of Muskmelons by Acoustic Impulse Transmission.J. Sugiyama, K. Otobe, S. Hayashi and S. Usui.METHODOLOGY&INSTRUMENTATION: Changes in Mixograms Resulting from Variations in Shear Caused by Different Bowl Pin Sizes.Sizes. J.L. Hazelton and C.E. Walker.INSTRUMENTAL MEASUREMENTS: Changes in Sonic Resonance of ‘Delicious’ and ‘Golden Delicious’ Apples Undergoing Accelerated Ripening.Ripening. L.A. Liljedahl and J.A. Abbott.INSTRUMENTAL MEASUREMENTS: Damage Loss Cost Curves for Peach Impact Bruising.P.J. Vergano R.F. Testin, W.C. Newall, Jr.INSTRUMENTAL MEASUREMENTS: Correlation of Head Rice Yield to Selected Physical and Mechanical Properties of Rice Kernels.R. Lu and T.J. Siebenmorgen.bINSTRUMENTAL MEASUREMENTS: Rheological Properties of Raisins: Part 11. Effect of Water Activity.Lewicki and W. Wolf.INSTRUMENTAL MEASUREMENTS: Effect of Starter Cultures on Small Deformation Rheology of Stirred Yoghurt.H. Rohm and A. Kovac.INSTRUMENTAL MEASUREMENTS: Low and High Strain Macrobehavior of Grain Masses ‐ The Effect of Particle Eccentricity.M. Aloufi and J.C. SantamarinaINSTRUMENTAL MEASUREMENTS: Prediction of Dough Rheological Properties Using Neural Networks. R. RuanS. Almaer and J. Zhang.FACTORS AFFECTING TEXTURE: Thermal and Physical Properties of Tortilla Chips as a Function of Frying Time.R.G. Moreira, J. Palau, V.E. Sweat and X. Sun.FACTORS AFFECTING TEXTURE: Physicochemical Changes in Cassava Starch and Flour Associated With Fermentation: Effect on Textural Properties.F.A. Numfor, W.M. Walter, Jr and S.J. Schwartz.FACTORS AFFECTING TEXTURE: A Simulation Model to Determine the Allowable Depth for Apples Stored in Bulk.Y. Shahabasi, L.J. Segerlind and N.J. Carroll.FACTORS AFFECTING TEXTURE: Prediction of the Nonlinear Vicoelastic Properties of Gluten Doughs.C.F. Wang and J.L. Kokini.FACTORS AFFECTING TEXTURE: Measurement of Extensional Viscosity of Viscwlastic Liquid Foods.M. Padmanabhan.FACTORS AFFECTING TEXTURE: Modelling Deformation and Flow During Vapor‐Induced Puffing.H. G. Schwartzberg, J.P.C. Wu, A. Nussinovitch.FACTORS AFFECTING TEXTURE: Stress‐Strain Relation of Compressive Solka Floc Cakes.G.G. Chase and J. Arconti.FACTORS AFFECTING TEXTURE: Time Dependent Rheological Characterisation of Buttermilk at 5C.F. Bu

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00063.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY