bluuebunny/crossref_metadata_2025 huggingface dataset:
POSSIBLE RELATIONSHIPS BETWEEN SHEAR, TENSILE, AND ADHESION PROPERTIES OF MEAT AND MEAT STRUCTURE
Authors: BOUTON P. E. , HARRIS P. V. , SHORTHOSE W. R.
Published: February 2007

Contributions to the structural strength of meat samples by the myofibrillar and connective tissue components were altered by varying the myofibrillar contraction state, muscle type and the cooking temperature. Shear, tensile and adhesion measurements were used to evaluate quantitatively changes in the properties of the samples. Detailed examination of shear and tensile force‐deformation curves suggested that the initial effect of shear, compression or tensile force was to produce a yield in the myofibrillar structure. After the initial yield, the applied force was probably resisted mainly by the connective tissue structure. Adhesion and tensile values showed changes which indicated a probable rearrangement of the collagen fibers in the connective tissue network as it adjusted to accommodate changes in the myofibrillar contraction state.
VISCOSITY CHARACTERIZATION OF UNMODIFIED CASSAVA STARCH PASTE
Authors: ODIGBOH E. U. , MOHSENIN N. N.
Published: February 2007

Unmodified cassava starch paste was characterized on the basis of its paste viscosity as affected by drying, cooking, and paste temperatures at different paste concentrations The paste exhibited plastic fluid flow with high hot‐paste peak viscosity. The temperature of the peak viscosity decreased with increasing concentration. Drying temperature had statistically significant effects on the paste viscosity; the higher the temperature at which the starch was dried, the lower was the paste viscosity over the levels of concentration and cooking temperature. Starch drying temperature and paste concentration significantly affected the paste stability as measured by freeze‐thaw tests and paste retrogradation tendencies.
RHEOLOGY OF CHOCOLATE
Authors: CHEVALLEY J.
Published: February 2007

Abstract. This review covers mainly the rheology of chocolate above its melting point. The validity of the Casson relationship is discussed and two alternative equations are given. Different factors affecting viscosity are considered: fat content, lecithin or emulsifiers content, water content, conching time, particle size, temperature, degree of temper and vibration. Instrumental methods of viscosity measurement as well as the problem of thixotropy are also covered. Some information is given on the rheology of chocolate in the solid state.
FLOW BEHAVIOR OF SWEET POTATO PUREE AND ITS RELATION TO MOUTHFEEL QUALITY *
Authors: RAO V. N. M. , HAMANN D. D. , HUMPHRIES E. G.
Published: February 2007

Abstract. Flow behavior of baked sweet potato puree obtained from eight cultivars was studied in a concentric cylinder viscometer to determine parameters in the non‐Newtonian power law equation with a yield stress. This algebraic equation proved to be a suitable flow model. A computational technique to determine model parameters was developed. Yield stress of the cultivars was highly correlated with taste panel scores, an increase in yield stress indicating a less moist mouthfeel. It was observed that, in general, the mouthfeel of sweet potatoes becomes more moist with increased storage up to 40 days; no definite pattern was discovered thereafter.
SELECTING DEFORMATION RATES IN TEXTURE TESTS *
Authors: VOISEY PETER W.
Published: February 2007

Abstract. Since mastication involves high deformation rates (150cm min−1), the arbitrarily selected slow deformation rates usually used in instrumental texture tests can lead to erroneous results and lack of correlation with sensory evaluation with respect to the order of sample ranking. Sophisticated instrumentation that is costly to operate is required to accurately simulate the deformation rates operating in the mouth. It is suggested that instrumental data obtained at slow rates could be evaluated in a more meaningful manner if series of similar samples were tested at increasing deformation rates and the plotted force/deformation curves extrapolated to 150cm min−1. It is implied that recording systems would be more useful, if in addition to force, they sensed the rate of force change with deformation rate.
THERMAL CONTRACTION OF MEAT DURING COOKING AND ITS POSSIBLE INFLUENCE ON TENDERNESS
Authors: BOUTON P. E. , HARRIS P. V. , SHORTHOSE W. R.
Published: February 2007

Samples of beef muscles with different states of myofibrillar contraction were cooked at 80 °C, both restrained and unrestrained from thermal shortening. Samples restrained from thermal shortening lost similar amounts of moisture to the unrestrained samples and had significantly (P < 0.001) larger decreases in the cross‐sectional area. The effects of restraint on structural strength were assessed using adhesion, tensile and shear testing. Restraint decreased adhesion between the fibers and increased tensile, initial yield and peak force values in the control and stretched samples where, without the restraint, thermal contraction would normally have been large. Shear force values of the cooked meat showed the increase normally associated with cold shortening whether or not thermal shortening occurred.
PSYCHOMETRIC SCALING OF SENSORY TEXTURE ATTRIBUTES OF MEAT
Authors: HOWARD A.
Published: February 2007

The nature of psychometric scaling is considered and serious limitations in the use of unidimensional scales for characterizing multidimensional properties are pointed out. It is suggested that the ratio estimation has definite advantages over the commonly used subjective estimate scaling in that statistical tests of validity can be applied. Ratio estimation scales can also be used to test and calibrate other types of scales. Furthermore, it is suggested that multidimensional scaling techniques are valuable in that they provide evidence on (a) validity of scales, and (b) dimensionality and configuration of underlying data on differences between products with multidimensional properties.
EFFECT OF BLADE THICKNESS ON READINGS FROM THE F.T.C. SHEAR COMPRESSION CELL*
Authors: VOISEY PETER W.
Published: February 2007

The effect was examined of reducing the thickness of the blades in the shear compression cell of the Texture Test System in order to increase the clearance between the moving and the stationary cell components. The results indicated that blade thickness reductions up to 0.14mm did not affect the characteristic shape of the force‐deformation curves for the 9 foods tested. Friction between the cell components was eliminated and the force to operate the cell tended to decrease, but force variations within foods were unaffected. It was concluded that it would be useful to reduce the thickness of the blades to decrease friction and to promote standardization by making the blades more precisely of steel. The variation of blade thickness may account for some of the differences between the presently manufactured aluminum cells.
A VERSATILE FOOD RHEOMETER
Authors: VOISEY PETER W. , RANDALL C. J.
Published: February 2007

A new texture test instrument is described that applies linear or rotary deformations, singly or in combination, to food samples. A range of texture test cells and mixing, consistometer or viscometer attachments are adaptable to this apparatus so that many test methods presently used to measure the properties of foods can be performed with the instrument. Different transducers can be installed to detect force, torque, deformation and deformation rate, which are precisely recorded electronically. Environmental and sample temperature controls are built into the equipment. Application of the apparatus is illustrated with measurements of consistency during the formation of wiener emulsions and the rupture property of the wieners.
SALIVARY SECRETION IN RESPONSE TO MASTICATION OF CRISP BREAD1
Authors: PANGBORN ROSE MARIE , LUNDGREN BIRGIT
Published: February 2007

Using a precision sialometer, unilateral parotid saliva was collected from six subjects while they masticated and swallowed pieces and powders from four types of Swedish crisp breads. Significantly more saliva was required for oral manipulation of the powders than for the corresponding pieces, as the greater surface area of the former required more saliva for lubrication in preparation for deglutition. Significant differences were observed in response to the four types of bread, related to both their texture and their taste. Despite wide among‐subject variation in the amount of saliva secreted, there was agreement in all cases on the direction of the response. The results indicate that the measurement of the relation between the amount (and possibly the composition) of saliva secreted and the texture and chemical properties of foods can be quantitated, and merits further investigation.
NONLINEAR VISCOELASTIC MODEL CONTAINING A YIELD ELEMENT FOR MODELING A FOOD MATERIAL1
Authors: CHEN Y. , ROSENBERG J.
Published: February 2007

A series‐parallel model is introduced in which a yield element is incorporated in the parallel branch. Before the yield stress is reached, the stress‐strain behavior is determined by the series branch to exhibit the linear uiscoelasticity of the material. When the yield stress is reached, the stress in the model which was sustained by the yield element is suddenly transferred to the spring and dashpot in parallel. As a consequence, a stress rate discontinuity was created. It is this feature which makes possible the simulation of the yield behavior of the food material. Data from Instron tests on American cheese are used to illustrate the model.
MECHANICAL PROPERTIES OF SATSUMA ORANGE AS RELATED TO THE DESIGN OF A CONTAINER FOR BULK TRANSPORTATION1
Authors: CHUMA Y. , SHIGA T. , IWAMOTO M.
Published: February 2007

The mechanical properties of Satsuma oranges were studied under static, quasi‐static and impact loading in order to determine conditions leading to minimum fruit injury in containerized shipping. The results indicated that the use of containers is safe for a 70h transport provided the stacking height does not exceed 70 cm. The static load at the bottom of the container should not exceed 2 kg per fruit if permanent deformation is to be avoided; the fruit ruptures when the load exceeds 4.2 kg per fruit. The time‐deformation curve under static load was explained with a Burgers model modified with a sliding element. Bruising energy by impact was 3 times and that by quasi‐static loading 1.4 times as great as that by static loading. The relationship between impact acceleration and dropping height of single fruits agreed well with the Hertz’ theory of colliding spheres for dropping heights up to 15 cm.
TEXTURE OF TEMPERATE FRUITS
Authors: BOURNE MALCOLM C.
Published: February 2007

Temperate fruits may be classed into two groups on the basis of their texture. One group comprises fruits that soften greatly as they ripen. These are characterized by a soft melting texture and usually have a relatively short shelf life. The measurement of the texture of these fruits is relatively straightforward. The second group encompasses fruits that soften moderately as they ripen. These are characterized by a firm, crisp, fracturable texture and have a relatively long storage life. The measurement of their texture poses a number of complex problems. Some factors that affect the firmness of temperate fruits are the kind, size, variety, maturity and temperature of the fruit, and cultural factors.
FRUIT TEXTURE—AN OVERVIEW OF TRENDS AND PROBLEMS
Authors: BOURNE MALCOLM C.
Published: February 2007

The development of the Magness Taylor Pressure Tester in 1925 led to major advances in understanding and controlling factors that affect the firmness of fruits. Recent advances in elucidating the complex nature of texture and in improved instrumentation should lead to another round of major advances in understanding and controlling factors that affect the textural properties of fruits. The trend to mechanical harvesting will probably lead to fruits with firmer texture that can withstand the rigors of machine harvesting. The difficulty of duplicating the textural properties of fruits is the principal obstacle to the development of fruit analogs.
YIELD BEHAVIOUR OF CRUMBLY ENGLISH CHEESES IN COMPRESSION
Authors: DICKINSON ERIC , GOULDING IAN C.
Published: February 2007

Compression measurements on samples of Cheddar, Cheshire and Leicester cheeses with an Instron Universal Testing Machine indicate the presence of a yield point characteristic of crumbly foods. The force and nominal strain at the yield point were studied as a function of deformation rate, temperature and pre‐yield compression history. A recently proposed non‐linear viscoelastic model with a single fracture element fits individual compression curves, but the model has little predictive capability.
STRUCTURE OF FOODS1,2
Authors: RAEUBER H. J. , NIKOLAUS H.
Published: February 2007

A general classification scheme is proposed which recognizes organizational, architectural and relative meanings of food structure and how these relate to textural properties. Within the architectural (or constructive) meaning, one can recognize certain elementary structures which give rise to homogeneous or heterogeneous compounded structures, and permeated or embedded types. Depending on the level of magnification needed, one can also speak of macro‐, micro‐, and ultrastructures. Specific examples are given and the relatonship between structure and processing is pointed out.
EFFECT OF DE‐ESTERIFICATION ON THE RHEOLOGICAL PROPERTIES OF κ‐CARRAGEENAN GELS
Authors: WATASE MINEO , NISHINARI KATSUYOSHI
Published: February 2007

The effect of de‐esterification on the rheological properties of κ‐carrageenan gels was studied by stress relaxation and dynamic mechanical measurements. By means of de‐esterification, the elastic modulus of κ‐carrageenan gels increased. This was attributed to the increase of alternation of D‐galactose and 3,6‐anhydro‐D‐galactose, and then the stabilization of the double helical structure in the κ‐carrageenan gels.
INFLUENCE OF GROWING ENVIRONMENT AND STORAGE DURATION ON QUALITY OF FRESH‐PACK CUCUMBER PICKLES3
Authors: DAVIS DAVID W. , ACHAHBOUN MOHAMED , SHEHATA MANDO A. , BREENE WILLIAM M.
Published: February 2007

Fruit of several pickling cucumbers (Cucumis sativus L.) grown in 1978 and 1979 in several environments under two soil nitrogen levels (high vs. normal) were stored for various time periods before fresh‐pack processing. Firmness, color and general appearance as examined after equilibration were all highly affected by cultivar, growing environment, and storage duration but somewhat less by nitrogen level. Unexpectedly, color and appearance improved during the first 24 h after harvest. Acceptable firmness was maintained for at least 72 h after harvest. Fruit of genetically firm cultivars generally showed less change in firmness than did fruit of less firm cultivars.
TEXTURE CHANGES AND STORAGE OF RICE
Authors: PEREZ CONSUELO M. , JULIANO BIENVENIDO O.
Published: February 2007

Monthly texture assessments of seven milled rices, differing in amylose content and stored at 28–30°C, verified that three months was the minimum storage period for major changes to occur in hardness of cooked rice, gel consistency, and amylograph viscosity values. Therefore, texture measurements should be done on samples aged at least three months after harvest. Texture changes tend to be greatest for high‐amylose rice with hard gel consistency and least for waxy rice. Free fatty acids were highest in stored, waxy, milled rice. Storage under nitrogen instead of air had a slight retarding effect on storage changes of five rices in another study. Surface defatting with petroleum ether had little effect on storage change in cooked rice hardness and stickiness, but reduced the changes in gel consistency and amylograph setback and consistency.
TEXTURE AND COLOUR CHANGES IN MEAT DURING COOKING RELATED TO THERMAL DENATURATION OF MUSCLE PROTEINS1
Authors: MARTENS H. , STABURSVIK E. , MARTENS M.
Published: February 2007

Differential scanning calorimetry was used to select temperatures that diferentiated between thermal denaturation of the three major structural protein species in bovine muscle: myosin, collagen and actin.

Samples of m. semimembranosus, m. semitendinosus and m. psoas major were heated to those different temperatures and evaluated sensorially. Three groups of sensory properties were needed to describe the main texture changes observed in the meat:

1. Firmness

2. Fiber cohesivity, bite‐off force, residual bolus

3. Juiciness

Firmness increased with thermal denaturation of the myofibrillar proteins (myosin; 40‐60d̀C and actin; 66‐73d̀C). Fiber cohesivity etc. decreased with collagen denaturation (56‐62d̀C). Reduction in juiciness was primarily associated with actin denaturation, while cooking loss increased over the whole temperature range.

The property “total chewing work”, a composite of the first two texture groups mentioned, yielded like the judges' “total texture preference”, optimal texture in the 60‐67d̀C temperature region, implying denatured myosin and collagen but native actin. This meat was light pink‐gray in colour, while the cooking juice released was dark red.
BETWEEN‐SPECIES DIFFERENCES IN FRACTURABILITY LOSS: COMPARISON OF THE THERMAL BEHAVIOR OF PECTIC AND CELL WALL SUBSTANCES IN POTATO AND CHINESE WATERCHESTNUT1
Authors: LOH J. , BREENE W. M.
Published: February 2007

This study was undertaken to determine how the mode of chemical changes taking place during the cooking of two chemically similar vegetables (potato and waterchestnut) might explain the tremendous between‐species differences in cooked tissue fractura bility as determined by Instron Texture Profile Analysis. Although pectin breakdown and depolymerization by heat weakens the cell wall structure, loss of cell wall physical strength does not necessarily coincide with pectin depolymerization. Potato phosphate‐soluble pectin (PSP) showed a more rapid rate of depolymerization than waterchestnut PSP as proven by both chemical and gel chromatographic studies.

The unique composition (e.g., neutral sugar content) of the cell wall microstructure of a given vegetable species is the major determinant of the resistance of that plant tissue to fracturability loss during cooking. Based on GLC analyses of cell wall components, cell wall models have been proposed to illustrate the possible structural differences between potato and waterchestnut tissue. It appears that the cell wall character of edible plant tissue for a given species is determined genetically.
VISCOELASTIC PROPERTIES OF WHEAT FLOUR DOUGHS: VARIATION OF DYNAMIC MODULI WITH WATER AND PROTEIN CONTENT1
Authors: NAVICKIS L. L. , ANDERSON R. A. , BAGLEY E B. , JASBERG B. K.
Published: February 2007

The elastic and loss moduli of fiue types of wheat flour doughs were measured in an eccentric rotating disc (ERD) rheometer. G’ and G”, determined from the linear portions of the response curve, were very sensitive to water content, decreasing as water content increased. Differentiation among samples was greatest at the highest water content. Results also depended on protein level, with higher moduli being observed at higher protein level. Samples mixed in a Farino‐graph to constant consistency showed differing values of both storage and loss moduli. The ERD geometry thus appears suited to characterization of doughs and to study of component interactions in such systems.
AN INSTRUMENT FOR THE MEASUREMENT OF THE HARDNESS OF FAT ON SIDES OF CHILLED BEEF
Authors: DAVEY KENNETH R.
Published: February 2007

An instrument has been developed to measure the hardness of fat on sides of chilled beef. A 0.97 mm diameter cutting pin, 3.76 mm long, is inserted perpendicular to the subcutaneous fat and moved through the fat a fixed distance in a direction parallel to its surface by a pretensioned spring. The time for the pin to travel this distance is measured electronically. Times are recorded for the pin to travel through both air and fat and the average force to cut through the fat is then calculated from these readings. There was a linear relationship between the average force resisting the pin travel and the subjective ratings of fat hardness by five experienced boning room personnel. The instrument offers a simple, rapid and portable method of measuring fat hardness in abattoirs.
A SINUSOIDAL COMPRESSION SYSTEM TO STUDY RHEOLOGICAL PROPERTIES OF FOODS IN THE TRANSIENT STATE
Authors: SALE P. , NOEL Y. , LASTEYRAS A. , OLEON C.
Published: February 2007

A testing device specially designed to study rheological properties of meats and their relation to tenderness is described. Samples are submitted to a sinusoǐdal compression during 1 to 2 cycles with recovery delay of 0 to 10 s at frequencies between 0.05 and 25 Hz so that deformation rates thus attained overlapped those of chewing. The compression can be regulated between 10 and 90%, and adjusted to initial sample height from 3 to 30 mm. Sample strength is measured by a force quartz transducer connected to a high speed data acquisition and storage system, versus the deforming tool displacement whose specific law is given.
A RAPID TEST TO INDICATE THE TEXTURE OF PARBOILED RICES WITHOUT COOKING
Authors: PILLAIYAR P.
Published: February 2007

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COMPARISON OF INSTRUMENTAL AND SENSORY PANEL METHODS FOR MEASURING KIWIFRUIT FIRMNESS
Authors: ROBERSTON G.L. , KOOPMANSCHAP E.A. , SCRIVENS C.A.
Published: February 2007

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A NOTE ON THE VARIOUS STRAIN MEASURES AT LARGE COMPRESSIVE DEFORMATIONS1
Authors: PELEG M.
Published: February 2007

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COMPARISON OF SENSORY ANALYSIS AND ROTATIONAL RHEOMETRY IN THE TEXTURE EVALUATION OF MARGARINES
Authors: POKORNÝ J. , DAVÍDEK J. , DOBIÁŠOVÁ S. , ŠTERN P. , ČMOLÍK J.
Published: February 2007

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EVALUATION OF THE SEPARATE CONTRIBUTIONS OF VISCOSITY AND SWEETNESS OF SUCROSE TO PERCEIVED VISCOSITY, SWEETNESS AND BITTERNESS OF VERMOUTH3
Authors: BURNS D. J. W. , NOBLE A. C.
Published: February 2007

The separate effects of sweetness and viscosity of sucrose on the sensory properties of vermouth were evaluated in systems: (1) varying in sucrose concentration and viscosity (2) with constant sucrose concentration but varying in viscosity, and (3) constant viscosity, but varying sucrose concentration. Twenty‐one trained judges rated oral viscosity, sweetness and bitterness, while the physical viscosity of the Newtonian systems was measured by capillary viscometry. Both perceived sweetness and oral viscosity increased, while bitterness decreased as sucrose was increased, and as the physical viscosity of the vermouths increased. However, samples in which viscosity was increased by the nonsweet Polycose® were rated sweeter and less bitter than vermouth solutions of the same sucrose concentration, but lower physical viscosity. Similarly, when vermouths of identical viscosity were compared, the vermouths with higher sucrose concentration were judged to be more viscous. Viscosity alone contributed 20‐30% of the perceived increase in sweetness due to sucrose addition. The effect of viscosity in reducing bitterness was of the same magnitude. The increase in perceived viscosity caused by addition of sucrose arose from approximately equal contributions of physical viscosity and sweetness of sucrose.
MEASUREMENT OF THE HARDNESS AND MOUTHFEEL OF CHEESE USING A SLIDING PIN CONSISTOMETER
Authors: DAVEY KENNETH R.
Published: February 2007

A sliding pin consistometer (SPC) was used to differentiate between six commercial cheese products, including a hard, mature Cheddar and a soft, cream cheese, at a number of temperatures in the range 0.8 to 25.0°C. Average force values (Ff) decreased with increasing temperature and with decreasing relative cheese hardness. Measurements were also made on six Cheddar cheeses with a range of salt to moisture (s/m) ratio (2.95 × 10‐2 to 5.57 × 10‐2) at a sample temperature of 16°C at maturation periods of 22, 58, 100 and 183 days. A panel of 27 adults scored the hardness and mouthfeel of these samples at these maturation periods using 9‐point scoring scales. The SPC discriminated between samples and maturation periods and was more discriminating than the subjective evaluation of panelists. Mean Ff values decreased with maturation and increased linearly with increasing s/m. Panelists' hardness scores increased with s/m but were not influenced significantly by maturation. Mouthfeel increased with maturation and was a maximum at a s/m of between 4.36 × 10‐2 and 4.57 × 10‐2. The SPC provides objective information that could be useful in assessing the effect of treatment on cheese.
EFFECT OF SLURRY PREPARATION METHODS ON THE RHEOLOGICAL AND GELLING BEHAVIOR OF SOY PROTEIN
Authors: PILOSOF A.M.R. , DE OGARA M.C. LOPEZ , BARTHOLOMAI G.B.
Published: February 2007

The order of addition of solutes and soy protein during the preparation of slurries influenced rheological behavior of unheated and heated slurries. The effect of the order of addition of glucose, sucrose and Na2HPO4 into the slurries was small with respect to the influence of the order of addition of CaCl2 and NaCl. The effectiveness of salts in reducing apparent viscosity of both unheated and heated slurries was greater than that of glucose and sucrose. Na2HPO4 was the more effective salt in reducing viscosity followed by NaCl and CaCl2. When salts were added, an inverse relationship was obtained between viscosity and water‐holding capacity of gelled soy protein slurries.
INSTRUMENTAL TEXTURE STUDIES ON CHOCOLATE III. PROCESSING CONDITIONED FACTORS INFLUENCING THE TEXTURE
Authors: TSCHEUSCHNER H.‐D. , MARKOV E.
Published: February 2007

The texture characteristics of chocolate are greatly influenced by processing conditions. By means of instrumental texture studies the effect of variations in the conching process parameters, of precrystallization and after‐crystallization during storage is illustrated. In order to compare the results, the exact precrystallization of the chocolate masses before moulding is of special importance.
SENSORY AND MECHANICAL ATTRIBUTES OF GEL TEXTURE
Authors: MUÑTOZ ALEJANDRA M. , PANGBORN ROSE MARIE , NOBLE ANN C.
Published: February 2007

Sensory texture attributes of firmness (manual, oral, shear and compression), elasticity and type of breakdown of gelatin, sodium alginate, and kappa‐carrageenan gels at two concentrations, were evaluated by 18 experienced judges. Nine of the judges also evaluated oral temporal responses to firmness and sourness. The Instron Universal Testing Machine (IUTM) was utilized to measure compression and shear at 200 mm/min at varying deformations. Gelatin was the firmest and most elastic of the three gels. During mastication it broke down into a few large pieces. Carrageenan produced the least firm and least elastic gel which failed into a large number of small pieces. Time‐intensity recordings demonstrated that more oral manipulation time was required to break down carrageenan and alginate gels in contrast to thermally‐degradable gelatin gel. Whereas perceived oral firmness reached a maximum in less than 5 s after placement of a gel sample in the mouth, maximum sourness was not perceived until 13‐18 s. Greater discrimination between gel concentrations was obtained by sensory than by mechanical measures, and beyond rather than below the yield point. Estimates of sensory firmness by shearing were highly correlated with each other and with mechanical shear and compression force. Manual compression correlated only with surface rupture force, while oral compression correlated only with shear maximum force.
THE MEANING OF TEXTURAL CHARACTERISTICS ‐ CRISPNESS
Authors: SZCZESNIAK ALINA SURMACKA
Published: February 2007

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UNIAXIAL COMPRESSION OF A HARD WHEAT FLOUR DOUGH: DATA ANALYSIS USING THE UPPER CONVECTED MAXWELL MODEL
Authors: BAGLEY E. B. , CHRISTIANSON D. D. , MARTINDALE J. A.
Published: February 2007

The behavior of a hard wheat flour dough has been measured in lubricated uniaxial compression experiments at compressional rates (crosshead speeds) of 0.2, 2 and 20 cm/min. The appropriate differential equation, derived for an upper convected Maxwell model, while taking into account the changing strain rate during the compression at constant crosshead speed, was solved numerically. With a single choice of model parameters (a viscosity and a relaxation time) there was surprisingly good agreement between the experimental and calculated results. Best fits were obtained, however, when the parameters were allowed to vary with crosshead speed, reflecting the broad relaxation time distribution known to exist in doughs.
EFFECTS OF EMULSIFIERS, SORBITOL, POLYDEXTROSE, AND CRYSTALLINE CELLULOSE ON THE TEXTURE OF REDUCED‐CALORIE CAKES1
Authors: KAMEL B. S. , RASPER V. F.
Published: February 2007

The textural and sensory qualities of reduced‐calorie cakes prepared from non‐shortening batters in which sucrose was partly replaced with sorbitol or poly‐dextrose (with the addition of carboxymethylcellulose or microcrystalline cellulose to the latter) was studied. The batters were treated with different types and concentrations of emulsifier (Tandem 22H, Atlas A and MD‐SSL). At the 30% replacement of sucrose with 1.5% or 3.5% (on flour weight) of Tandem 22H or Atlas A, the cakes were of an acceptable quality. Higher levels of emulsifier treatment further enhanced the aeration capacity of the batters, but impaired the overall quality of the final product. The emulsifier MD‐SSL was found to be less suitable under the given conditions of cake baking because of the excessive aeration of batters. With cakes of acceptable quality, the calorie value reduction was in a 15 to 23% range compared with a standard full‐calorie cake.
QUANTIFYING THIXOTROPY OF BÉCHAMEL SAUCE UNDER CONSTANT SHEAR STRESS BY PHENOMENOLOGICAL AND EMPIRICAL MODELS
Authors: MARTINEZ‐PADILLA L. PATRICIA , HARDY JOEL
Published: February 2007

Experimental results for Béchamel sauce are used to prove the validity of two rheological models for the study of thixotropic behaviour. The rheological‐kinetic parameters are: structural parameter (Λ), rate of structural breakdown (kb2) and Herschel‐Bulkley constants at zero and 40 min of shear stress i.e. yield stress (τλ), consistency index (K), flow index (n). The empirical parameters, obtained by multiple logarithmic regression, are a time consistency index (K'), a time flow index (n') and a thixotropic index (p'). For the two models the correlation coefficient were greater than 0.9. Parameters of both models suggest the milk protein‐wheat starch interactions are mainly responsible for Béchamel consistency. The breakdown of this interaction can explain the thixotropy.
EFFECTS OF STORAGE TIME AND STATIC PRELOADING ON THE RHEOLOGY OF POTATO TISSUE 1
Authors: BRUSEWITZ G. H. , PITT R. E. , GAO Q.
Published: February 2007

Potatoes held in cold storage were periodically sampled over a period of 7 weeks. At each sampling, tissue specimens were soaked in mannitol solutions (0‐0.6 M) or statically preloaded (0‐1.20 MPa) and then loaded to failure at constant strain rate. Tissue stiffness, cell turgor pressure, and cell‐wall stress‐strain relation were affected by storage time. Cell turgor pressure decreased during the first 14 days of testing and then increased. Cell wall stiffness increased with time. Statically preloaded tissue did not undergo structural failure during preloading, but exhibited large unrecovered strain, loss of water, a reduction in tissue stiffness, and an increase in failure stress. The effects of preloading were not significantly different at different storage times. Failure strain varied nonmonotonically with preload level, possibly as a result of interactions between loss of turgor, cell wall plasticity, and cell reorientation during preloading.
Book Review
Authors: HILL M.
Published: February 2007

FOOD ACCEPTABILITY. (David M. H. Thompson, ed.) Elsevier Applied Science, London and New York. 1988. ISBN 1‐85166‐256‐1; 502 pp. £70.
CHARACTERIZATION OF GELLAN GELS BY UNIAXIAL COMPRESSION, STRESS RELAXATION AND CREEP 1
Authors: NUSSINOVITCH A. , AK M. M. , NORMAND M. D. , PELEG M.
Published: February 2007

The rheological properties of 0.5–2.5% gellan gels were evaluated by uniaxial compression, stress relaxation and creep tests. The gel's strength was in the range of 0.1–1 kg.cm‐2 and their deformability modulus 1–6 kg.cm‐2. The asymptotic modulus determined in relaxation tests at two strains and the asymptotic creep compliance determined under two loads indicated that gellan gels have a yielding structure. The strains sustained in creep were considerably higher than the failure strain in uniaxial compression. Weight loss due to syneresis was on the order of 4–38% depending on the gum concentration, the deformation level in relaxation or the load in the creep tests.
CLASSIFICATION OF AVOCADO BY FIRMNESS AND MATURITY
Authors: PELEG KALMAN , BEN‐HANAN URI , HINGA SHALOM
Published: February 2007

Table‐ripe soft avocado cannot be shipped or stored for more than a few days. Thus, it is common practice to store and ship firm, tree‐ripe avocado, while the consumer may soften the fruit as required. A human sorter cannot distinguish between a freshly picked firm avocado and a somewhat softer semiripe fruit, yet the accelerated evolution of ethylene by even several ripe fruits, may prematurely ripen a whole shipment. A sensor system, for nondestructive sensing of avocado firmness is presented, based on vibrationally exciting one side of the fruit, while measuring the transmitted vibration energy on its other side. Special signal processing hardware and software was developed for computing several alternative firmness indexes, highly correlated to the standard piercing force, destructive, test method. Optimal classification algorithms were developed, whereby the fruit may be classified into two or three firmness grades. In both cases, the actual contamination of the firm fruit class by soft fruits was only 3.3%, while the overall classification accuracy was about 90%.
CONSUMER AWARENESS OF FOOD TEXTURE IN AUSTRIA
Authors: ROHM H.
Published: February 2007

A word association test was performed to obtain free associations from 208 Viennese students. Frequency of associations confirms that texture is the most important characteristic of food materials besides flavor. The distribution of responses is comparable with data from previous studies in the U.S.A. and Japan. One hundred and five descriptive texture terms were registered.
RHEOLOGICAL BEHAVIOUR OF SHEARED JAMS. RELATION WITH FRUIT CONTENT
Authors: CARBONELL E. , COSTELL E. , DURÁN L.
Published: February 2007

Eight samples of jam were sheared to destroy gel structure and their flow behaviour was analysed in a concentric cylinder viscometer. Jams were prepared from 4 different fruits—strawberry, peach, plum, and apricot—at 50% and 30% fruit content approximately. Flow of sheared jam showed time dependence, which could be quantified by the Weltmann model and which was eliminated by shearing samples for 8 min at 300 rpm. Casson's yield stress values were obtained at two ranges of shear rates: 0.08–1.01 s−1 (O01) and 2.58–387.30 s−1 (o02). o02 values were about double the o01 values. Flow was adequately described by the Herschel and Bulkley model, introducing either of the yield stress values (o01 or o02). Significant differences were found for some of the rheological parameters studied (Weltmann A and B constants, o01, o02, K1, and n1) between samples containing 50% and 30% fruit. These results demonstrate the role played by fruit particles in the rheological behaviour of this type of product and suggest the possibility of using rheological parameters as indices of fruit content in jams.
RHEOLOGY OF STIRRED YOGURTS
Authors: RAMASWAMY H. S. , BASAK S.
Published: February 2007

Rheological characteristics of 2 commercial brands of stirred yogurt were evaluated using a Haake Rotovisco Model RV 20 with an M‐5‐Osc measuring head and MV‐1 rotor assembly from measured shear stress values under a programmed 3‐cycle up‐ and down‐shear rate at 100 s−1/min from 0–500 s−1 (5 min). The upward shear‐rate flow behavior of the yogurt samples could be described by a Herschel‐Bulkley model while the downward shear‐rate curves were essentially linear. Both upward and downward shear rate curves demonstrated progressive structural degradation with repeated shearing. The dependency of rheological parameters on temperature in the range 10–25°C followed both Arrhenius and Turian models.
EFFECTS OF DIMENSIONS OF AGAR AND GELATIN GELS ON PALATAL PRESSURE PATTERNS
Authors: TAKAHASHI JUNKO , NAKAZAWA FUMIKO
Published: February 2007

Eating of agar and gelatin gels in the mouth was studied dynamically in detail. The palatal presures on agar and gelatin gels of various concentrations and dimensions were detected by pressure transducers installed at three locations of the palate. For each of the gels, Pm (the maximum palatal pressure at the initial stage of mastication), P (the mean palatal pressure), W (work), and T (retaining time in the mouth) changed significantly when their concentrations increased. Moreover, gel dimensions also affected Pm, P and W. For a bite‐size gel, Pm, P and W increased or remained constant, while for a finer sized gel, Pm, P and W were nearly constant regardless of the increase in rupture strength or gel concentration.
TRANSIENT FLOW OF MAYONNAISE DESCRIBED BY A NONLINEAR VISCOELASTICITY MODEL
Authors: GALLEGOS C. , BERJANO M. , GUERRERO A. , MUNOTZ J. , FLORES V.
Published: February 2007

Dynamic and stress relaxation tests were carried out to verify the applicability of the Wagner model for describing transient flow of mayonnaise. Tests were done on two commercial brands at temperatures ranging between 10 and 40C. It was necessary to modify the model by introducing the Soskey‐Winter damping function to describe the nonlinear relaxation modulus of mayonnaise. This modified Wagner model fits transient flow better at low shear rates, because the damping function estimated from stress relaxation tests does take into account the irreversible breakdown of mayonnaise.
DELINEATION OF PUNCTURE FORCES FOR EXOCARP AND MESOCARP TISSUES IN CUCUMBER FRUIT 1
Authors: THOMPSON R.L. , FLEMING H.P. , HAMANN D.D.
Published: February 2007

A puncture test was used to differentiate exocarp (skin) and mesocarp tissues of fresh cucumbers for resistance to penetration. Optimum instrumental test conditions were a punch size of 3.15 mm diameter and crosshead speed of 5 cm/min. The force required to penetrate the exocarp of whole fruit was determined and was deemed to represent a composite of the exocarp and the underlying tissue. By placing 7 mm thick, longitudinal slices skin down on a die plate, failure forces representing the mesocarp and exocarp tissues were determined in fruit ranging from 2.5–5.5 cm diameter. Exocarp force measurements were not influenced by slice thicknesses greater than 1 mm. Mesocarp measurements were lower with thicker slices, and required uniformity of thickness to maximize precision. The exocarp was found to represent about 60% of the composite force required to penetrate whole cucumbers, regardless of fruit size. Toughness of both exocarp and mesocarp increased with fruit size. The relative contributions of exocarp to penetration of seven other fruits varied from 58 to 88%.
TRAINING A TEXTURE PROFILE PANEL AND CONSTRUCTING STANDARD RATING SCALES IN ARGENTINA
Authors: HOUGH GUILLERMO , CONTARINI ADRIANA , MUÑOZ ALEJANDRA
Published: February 2007

A method is described for constructing reference scales for the sensory texture profile method in countries outside the U. S., such as Argentina. A complete set of 13 reference scales were constructed for Argentine foods: hardness, adhesiveness to palate, fracturability, cohesiveness, denseness, wetness, adhesiveness to lips, roughness, selfadhesiveness, springiness, cohesiveness of mass, moisture absorption and adhesiveness to teeth. Scores given by the panel trained using these scales were compared to those given by a panel trained using the US scales and found to be similar, in direction and magnitude, among the tested food samples.
CELLULARITY, MECHANICAL FAILURE, AND TEXTURAL PERCEPTION OF CORN MEAL EXTRUDATES
Authors: BARRETT ANN H. , CARDELLO ARMAND V. , LESHER LARRY L. , TAUB IRWIN A.
Published: February 2007

Relationships among cellular structure, fracturability, and sensory properties in porous, brittle extrudates were investigated. Corn‐based extrudates intentionally processed to exhibit a range of physical structures were characterized in terms of cell size distribution, bulk density, mechanical strength, fracturability, and sensory attributes. These measurements show both mechanical strength, defined by average compressive stress during extended deformation, and fracturability, quantified by fractal and Fourier analyses of stress‐strain functions, increasing with either decreasing mean cell size or increasing bulk density. Fracturability parameters or structural characteristics are furthermore correlated with sensory scores for crunchiness, crispness, hardness and perceived density. These results indicate that cellularity strongly influences the pattern of mechanical failure and that failure characteristics, such as fractal dimension or power spectrum of stress‐strain functions, are reflective of sensory texture.
EFFECT OF LUBRICATION ON THE COMPRESSION BEHAVIOUR OF CHEESE AND FRANKFURTERS
Authors: BRENNAN J. G. , BOURNE M. C.
Published: February 2007

Cylindrical 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.
INFLUENCE OF GRANULE SIZE ON VISCOSITY OF CORNSTARCH SUSPENSION
Authors: OKECHUKWU PAUL E. , RAO M. A.
Published: February 2007

The influence of granule size and size distribution in gelatinized suspensions of 2.6% cornstarch heated at fixed temperatures between 70–90C on the power law viscosity was measured by laser diffraction. In the early stages of gelatinization, where the granule size standard deviation was less than 12 μm, dilatant behavior was observed over the shear rate range 200–1100 S−1. At constant starch concentration and without granule rupture, suspension consistency, K, increased exponentially with granule mean diameter while the flow behavior index, n, decreased linearly with increase in the extent of gelatinization and the standard deviation of the granule size. The variation of K with granule size and that of n with standard deviation were found to be independent of temperature over 70–90C. In the later stages of gelatinization, where the granules lose their integrity, suspension viscosity progressively decreased as granule rupture continued.
STRUCTURAL DEVELOPMENT IN ICE CREAM—DYNAMIC RHEOLOGICAL MEASUREMENTS
Authors: GOFF H. D. , FRESLON B. , SAHAGIAN M. E. , HAUBER T. D. , STONE A. P. , STANLEY D. W.
Published: February 2007

The influences of temperature, polysaccharide stabilizing agents and overrun on the rheological properties of ice cream mix and ice cream were measured using dynamic rheological techniques with a controlled stress rheometer. Storage and loss moduli and tan δ all decreased significantly with increasing temperature. Unstabilized samples demonstrated significantly greater storage and loss moduli at temperatures < –8C and tan δ at all temperatures than stabilized samples, however, polysaccharides increased mix viscosity and resulted in significant increases in viscosity as the mix was concentrated. This indicated the importance of considering both ice and unfrozen phases in determining the impact of stabilizers on ice cream rheology. Increasing overrun from 20 to 60% increased the storage modulus significantly but had less effect on the loss modulus, especially in the stabilized samples. However, as overrun increased, the maximum force required for large deformation decreased, emphasizing the need to consider the effects of small‐scale versus large‐scale deformation testing on structure. Dynamic rheological measurements can provide insights into the development of ice cream structure and are useful in complementing other techniques.
EFFECT OF pH AND CATIONS ON THE THERMALLY INDUCED GELATION OF OVALBUMIN
Authors: SAVOIE V.J. , ARNTFIELD S.D.
Published: February 2007

The gelation of ovalbumin in the presence of salts containing Ca+2 and Mg+2 at various pH values was investigated. Characteristics of the gels produced were evaluated using penetration measurements on an Ottawa Texture Measuring System as well as dynamic rheology on a Bohlin VOR rheometer. Gel properties were related to cation binding (equilibrium dialysis) and to changes in protein structure (differential scanning calorimetry). Cation binding generally increased with increasing salt concentration, and Mg+2 bound to a greater extent than Ca+2 at the higher levels studied. The impact of this binding on gel structure was dependent on pH and the technique used to evaluate structure. At pH 5 proteins tended to coagulate regardless of the type or amount of salt. At pH 7, the highest rigidity values from penetration measurements were obtained at salt levels of 0.005 M. At pH 9, the salt concentration for maximum rigidity varied with the salt, while the storage moduli (G') from dynamic rheology were highest at the highest salt concentration used. Based on rigidity data, the inclusion of 0.005 M MgSo4 would give a product with the greatest rigidity over a wide pH range.
SIMULATING VISCOELASTIC PROPERTIES OF SELECTED FOOD GUMS AND GUM MIXTURES USING A FRACTIONAL DERIVATIVE MODEL
Authors: MA L. , BARBOSA‐CÁNOVAS G.V.
Published: February 2007

A four parameter semi‐empirical model has been developed using the fractional derivative (FD) theory, which consists of applying a mathematical operator to a constitutive equation. The Fourier transform approach is used to obtain the analytical function of the derived model. Since a single four parameter model can predict both storage modulus (G′) and dynamic viscosity (η′), the developed FD model was appropriate in describing the viscoelastic properties of selected food gum dispersions, food gum mixtures and gellan gel. This fractional derivative model shows good simulation capability for selected food gum dispersions (0.5% xanthan gum, 0.5 and 0.75% locust bean gum, and 0.5, 0.75, and 1.0% guar gum), 0.6% gellan gel, and binary mixtures of carrageenan and guar gum, car‐rageenan and xanthan, as well as guar and xanthan gum.
A FRACTURE MECHANICS ANALYSIS OF THE TEXTURE OF POTATOES
Authors: FAHLOUL D. , SCANLON M.G.
Published: February 2007

The generalized fracture mechanics approach (GFM) developed by Andrews (1974) was applied to measure the fracture toughness of potatoes of the cultivar Shepody. Specimens were fashioned from the centre portions of 10 tubers, and were soaked in distilled water overnight to attain full turgor pressure in the cells. Tensile tests were performed on specimens with different initial crack lengths. The function k1(W0) for potatoes was evaluated. This function is an explicit distribution function of input energy in the specimen (work done on unit volume of the specimen). From the form of the function, a simple mathematical model was developed to describe k1(W0) for potatoes. The critical apparent energy release rate defined by GFM theory was found to be constant (T= 2650 J m−2) and independent of initial crack length and applied load. The fracture toughness (T0) of Shepody potato obtained from this value of T was 212 J m−2, which is in good agreement with the results of other researchers using uniaxial compressive and tensile tests.