摘要:

ABSTRACTImpact transmission wave measurement technique was applied for nondestructive ripeness evaluation of Golden apples. Three types of texture properties referred to as firmness parameters, viscoelastic parameters and rupture parameter were measured from destructive penetration tests to represent apple ripeness. Curve‐fitted model functions of transmission velocity and time span were established to evaluate the texture properties with the correlation coefficients between 0.791 and 0.957. The transmission wave parameters were used to discriminate six groups of the apples for their ripeness. A discrimination accuracy of 86.7% was obtained. It was concluded that the transmission wave may be used as a nondestructive means for reliable estimation and discrimination of apple ripenes

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00064.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTFreezing was used to induce controlled damage to apple and potato parenchyma. As the tissue freezes ice crystals form extra‐ or intracellularly, pushing the cells apart or rupturing cell walls producing large voids within the tissue. Mechanical tests (wedge penetration, tensile and compression) on specimens frozen to a certain temperature at a controlled rate and thawed show that the changes in the mechanical behaviour of the material are directly related to the degree of cell damage. As the tissue freezes, the fastest rate of tissue damage occurs between ‐3C and ‐10C. In this range there is a marked decrease in stiffness and an increase in the deformation required to cause failure. In apples, slow freezing leads to the intercellular spaces expanding, increasing their aspect ratio and hence, the anisotropy of the tissue. The increasing number of voids increases crack‐stopping and ductility; more energy is dissipated in flow elevating the fracture toughness. Toughness then decreases with further damage. This effect can be mimicked with brittle paper: fracture toughness of tracing paper initially increases with increasing number of holes punched randoml

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00065.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTThe role of granule size and size distribution, measured by laser diffraction, in affecting the flow behavior and yield stress of cowpea starch dispersions (2.6% w/w) heated for various time intervals at 67, 70, 75 and 80C was studied. Flow data on the dispersions at 20C were fitted to the power law flow equation. The standard deviation of the granules described the transition of flow behavior from shear thickening (dilatant) in the early stages of gelatinization to shear thinning (pseudoplastic) in the latter stages. It was an important variable for also correlating the critical shear rate, λ˙c, for the onset of shear thickening in starch dispersions. The granules swelled to a maximum of about 3.5 X raw starch granule mean diameter and a granule mass fraction of 65%. The consistency index of the dispersions increased with granule mean diamete

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00066.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTThe rheological behaviour of two different loquat juices was studied. Juices containing pectins and pulp exhibited non‐Newtonian with yield stress behavior. Juices from which pectins and pulp were removed exhibited Newtonian behavior. The Bingham model described the relationship between shear stress and shear rate for the first type of juice and the Newtonian model described the second type. The effect of temperature on the Bingham plastic viscosity and the Newtonian viscosity was described by Arrhenius equation. The effect of soluble solids contents was described by power‐law and exponential expressions. Finally, two equations that described the combined effect of temperature and concentration were develo

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00067.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTAlkaline corn was cooked for 20, 55 or 80 min, and the nixtamal was ground into masas with medium or coarse particle size distributions. Water was added to each corn masas in order to obtain the same adhesiveness. Rheological properties of these masas were evaluated with the squeezing flow viscometry technique with lubrication at crosshead speeds of 0.05, 0.2 and 0.5 cm/min, respectively. From the data collected, stress‐strain and biaxial elongational viscosityradial extension rate curves were obtained. All the fresh corn masas gave the same stress and elongational viscosity at any given specific strain and radial extension rate, respectively, regardless of the cooking time and degree of grinding. The elongational viscosity could be useful to predict fresh corn masa behavior during molding and cutting steps in the tortilla‐making proc

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00068.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTThe effect of four composition factors on fat destabilisation, melting resistance and sensory characteristics were studied in hardened ice creams by the means of principal components analysis (PCA). For all the proteins, PCA revealed a pronounced contrast between ‘coldness’ and ‘creaminess’ in ice cream. The third sensory descriptor ‘length in mouth’ was either correlated with ‘creaminess’ for skim milk powder (SMP) and whey protein concentrate (WPC) series, or with ‘coldness’ in the case of the skim milk replacer (SMR) series. In each calculation, the butteroil was not correlated with ‘creaminess.’ In the case of SMP ice cream the descriptor ‘creaminess’ was strongly correlated with a small initial droplet size and with a high fraction of fat destabilised: the initial droplet size was itself associated with a high ratio emulsifier to butteroil. For both SMR and WPC ice cream, creaminess was not correlated to the extent of fat d

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00069.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTLight microscopy during tensile tests was used to examine the effect of postrigor sarcomere length (SL) on mechanical and structural characteristics of raw and heat‐denatured (1 h at 80C) muscle fibres of porcinelongissimus lumborumand the structural deformation mechanisms of such fibres inducing mechanical differences. The effect of the collagenous network associated with single coldshortened muscle fibres on maximum stress was analysed. Muscle bundles developed rigor at 2C (cold‐shortened = CS), at22C (control = C), and at

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00070.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.tb00071.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

GENERAL PRINCIPLES: The Role of Covalent Cross‐Linking in the Texturizing of Muscle Protein Sols.H.G. Lee and T.C. Lanier.GENERAL PRINCIPLES: Modelling of Starch Gelatinization Kinetics of Bread Crumb during Baking.B. Zanoni, C. Peri and D. Brun.GENERAL PRINCIPLES: Structural Changes of Starch during Cooking of Durum Wheat Pasta.Pasta. C. Cunin, S. Handschin, P. Walther.GENERAL PRINCIPLES: Gluten Viscoelasticity Is Not Lipid‐Mediated. A Rheological and Molecular Flexibility Study on Lipid and Non‐Prolamin Protein Depleted Glutens.J. Hargreaves, Y. Popineau,GENERAL PRINCIPLES: Rheologid Characteristics and Gelation Mechanism of Tofu (Soybean Curd).K. Kohyama, Y. Sano and E. Doi.GENERAL PRINCIPLES: Surface Shear Viscosity and Protein Surfactant Interactions in Mixed Protein Films Adsorbed at the Oil‐Water InterfaceJ. Chen and E. Dickinson.GENERAL PRINCIPLES: Rheological Analysis of Anion‐Induced Matrix Transformations in Thermally Induced Whey Protein Isolate Gels.E.L. Bowland, E.A. Foegeding and D.D. Hamann.GENERAL PRINCIPLES: The Dynamic Rheological Properties of Glutens and Gluten Sub‐Fractions from Wheats of Good and Poor Bread Making Quality.B.S. Khatkar, A.E. Bell and J.D. Schofield.GENERAL PRINCIPLES: Wheat Flour Compound that Produces Sticky Dough: Isolation and Identification.W.Z. Chen and R.C. Hoseney.METHODOLOGY AND INSTRUMENTATION: Performance of an Instrument Designed for, and Evaluation of Methods to Assess, Peach Fruit Impact Bruise SusceptibilityN.O. Maness, G.H. Brusewitz, D. Chrz and G.G. Taylor.METHODOLOGY AND INSTRUMENTATION: Viity Measurement of Potato Starch Paste with the Rapid Visco Analyzer.N.U. Haase, T. Mintus and D. Weipert.METHODOLOGY AND INSTRUMENTATION: Application of Cone Penetrometry to Texture Measurement in Biscuits (in French).A. Goullieux, K. Allaf and J.‐M. Bouvier.METHODOLOGY AND INSTRUMENTATION: Studies on Oat Gum: Composition, Molecular Weight Estimation and Rheological Properties.N.L. Dawkins and I.A. Nnanna.METHODOLOGY AND INSTRUMENTATION: Rheological Properties of Cocoyam Starch Paste and Gel.K. Shiraishi

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1996.tb00072.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY