摘要:

ABSTRACTFlow and viscoelastic properties of three thickened systems are presented: aqueous solutions of locust bean gum, of xanthan and a dispersion of a crosslinked waxy corn starch. Creep measurements allow investigations at very low shear rates. The existence of a yield stress is discussed. Flow was observed at low shear rates, but the starch paste exhibited pseudo‐yield stress behaviour. Dynamic measurements were performed and the relationships between flow curves and mechanical spectra are discusse

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb01321.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTCylindrical samples of cheese and frankfurters were subjected to a 50% uniaxial compression between flat plates and artificial molars, mounted on a Texture Analyser, operating at two speeds, with and without lubrication. At both speeds and with both types of probe the maximum force was less for the lubricated probes than the unlubricated probes. In all cases the maximum force recorded at the higher speed was greater than at the lower speed and greater when plates were used than when teeth were used. Through observations made during the testing and from photographs taken, it was concluded that the frictional effect of the cusps on the molar teeth was greater than the effect of lubrication. Observations made when samples were compressed between molar teeth in the mouths of panellists confirmed the conclusion that compression of foods in the mouth follows the nonlubricated pattern despite the lubrication provided by saliva.

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb01322.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTTemperature cycling significantly reduced the solid fat content, peak force and firmness. The fats with the highest level of palmitic acid were the most stable in the β' polymorphic form. Those with the lower palmitic acid content changed to the β polymorphic form on isothermal storage as well as temperature cycling. In spite of these polymorphic changes, no dramatic change in other physical characteristics occurre

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb01323.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTIn many fruits and vegetables, it is desired to replace destructive firmness measurement methods by nondestructive ones. The inevitable question is to what degree do two firmness measurement methods agree? The present article proposes a new approach for method comparison in firmness tests of fruits, by optimal translation of the readings taken on the scale of one test, to the scale of another test and vice versa. The proposed scale translation mode is based on minimizing the sum of squares of the differences between the absolute values of the Fast Fourier Transform (FFT) series, derived from the readings of the compared measurement methods. The line taken is illustrated by a comparative study on a large sample of Red Delicious apples, assessing the performance of a nondestructive fruit firmness sensor versus the conventional destructive test which measures the applied piercing force on the fruit by a penetrometer.

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb01324.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTA small impact pendulum was developed to measure the shatter resistance of seed pods. While clamped by their stems, the pods are hit by the rigid pendulum; the rupture energy is derived from the measured angles of swing. The consistency of the pendulum was confirmed by tests on a sample of fine spring wire. The pendulum was then used in a series of trials on 13 rapeseed varieties and rupture energy results were compared with earlier bending moment and bending energy results obtained from tests using a quasi‐static cantilever arrangement. Rupture energy values were much less variable than bending energy. However, the ranking of varieties by all three strength measures was generally simila

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb01325.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThe 37 sensory characteristics of commercially canned peaches were measured using Quantitative Descriptive Analysis. Some mechanical parameters of the fruit were also measured by using both empirical and fundamental instrumental tests. Principal Component Analysis was employed to study the intra‐ and interrelationships of the sensory and the mechanical characteristics of the canned peaches. The results indicated that most of the characteristics were grouped in four main clusters. These clusters defined two perceptual axes corresponding to the first two principal components which described 76% of the variation. The first component described the viscoelasticity and the second the pleasantness of the sensory characteristics. It was also shown that the mechanical parameters of the fruits were good predictors of the whole range of their textural characteristic

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb01326.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTFlow observed in the Bostwick consistometer was evaluated as a gravity current; the balance of forces yields the Bostwick measurement as a function of the geometry of the apparatus and fluid properties. Experimental measurements for Newtonian and power law fluids are compared to theoretical predictions. Although the theory can be used to evaluate values for power law parameters, the best results are obtained by predicting the ratio of apparent viscosity to density to the –0.2 power. The agreement between theory and experiment for homogeneous fluids is within 2%. Values of Bostwick measurement versus (η/ρ)−0.2for tomato suspensions fall along the same curve as the homogeneous f

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb01327.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThe puncture properties (firmness, toughness) of tomato skin and its influence on the overall puncture properties of mature‐green fruit during ambient temperature (22C) ripening or chilled (5C) storage were estimated from the difference between whole fruit puncture force‐deformation behaviour and that measured with the skin removed. Although the firmness of the skin of nonchilled fruit did not change significantly (p>0.05) over 28 days of ripening, its contribution to overall puncture firmness increased from about 25 to 70%. Both skin toughness and its contribution to overall puncture toughness doubled within the first week of ripening of nonchilled fruit. The firmness of chilled fruit skin decreased (p>0.05) only after 16 days of storage, but its contribution to overall puncture firmness remained constant at 25–30%. Both the toughness of the skin of chilled fruit and its contribution to overall puncture toughness remained constant during storage. Possible artifacts in the measurement of puncture properties of chilled fruit are discussed. The results are consistent with a toughening of tomato skin during early stages of ripening of nonchilled fruit that somewhat compensates for a rapid reduction in pericarp tissue integrity, and with an increase in firmness or rigidity of tomato skin and underlying tissue(s) during chilled storage of

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb01328.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb01329.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

General Principles:Modeling of Bean Hardening Kinetics During Storage.J. M. Del Valle, J. M. Aquilera andA.I.HohlbergGeneral Principles:A Rheological Model for Sodium Caseinate (Ftesearch Note). J.FichtaliGeneral Principles:Viscoelastic Properties of Myofibrillar Protein‐Polysaccharide Composite Gels.Y. L. Xiong and S. P. BlanchardGeneral Principles:Rheological Changes During Gelation of High‐Methoxyl Pectin/Fructose Dispersions: Effect of Temperature and Aging.M. A. Rao,J. P.van BurenGeneral Principles:Water Binding Capacity and Macrostructure of Apple Tissue Particles (in German).R. Kabbert. K. Herrmuth and H. KunzekMethodology and Instrumentation:A Simple Antibody‐Based Test for Dough Strength. I. Development of Method and Choice of Antibodies.J. H. SkerrittInstrumental Measurements:Failure Deformation and Stress Relaxation of Heated Egg White Gels. Y. L.Instrumental Measurements:Relationship Between Texture and Some Objective Indices in Frozen Blocks of Argentine Hake (Meduccius hubbsi) Fillets.D. H. Giannini, A. S. CiarloSensory Assessment:Sensory Evaluation of the Texture of Hard and Semi‐Hard Cheeses. A Col‐ laborative Study(in French). P. LavanchySensory Assessment:Panelist Texture Preferences Affect Sensory Evaluation of Green Bean Cultivars (Phaseolus vulgaris L.).R. F. Baron and M. P. PenfieldSensory Assessment:Stability of Frozen Starch Pastes; Effect of Freezing, Storage and Xanthan Gum Addition.C. Ferrero.M. N.Martino and N. E. ZaritzkySensory Assessment:Rheological Properties of Dried Squid Mantle; Change on Softening.M. KuginoSensory Assessment:Firmness Retention in Pickled Peppers as Affected by Calcium Chloride, Acetic Acid and Pasteurization.H. P. Fleming, R. L. Thompson and R. F. McFeetersSensory Assessment:Effect of Various Thermal Pre‐Treatments on the Texture of Frozen Cher‐ ries (Prunus avium L.). Related Enzyme Activities.J. Al

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1994.tb01330.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY