bluuebunny/crossref_metadata_2025_split huggingface dataset:
STRUCTURAL AND MECHANICAL PROPERTIES OF TEXTURED PROTEINS
Authors: STANLEY D. W. , DeMAN J. M. 
Published: February 2007

ABSTRACTMechanical properties of foods are a direct consequence of micro‐structure which, in turn, results from an interaction of chemical composition and physical forces. In thermally‐extruded soy grits voids, caused by the escape of superheated steam as the textured vegetable protein product strikes the atmosphere, are thought to be responsible for the spongy, porous nature of the material. A breakdown of soy protein subunits followed by their reassembly into larger molecular weight aggregates, possibly via intermolecular amide bonds, may account for the formation of protein fibers that become aligned as they leave the extruder barrel. This structure persists after rehydration and imparts a desirable meat‐like texture to the product. By correlating mechanical properties to sensory analysis, an objective method has been developed for assessing the texture of extruded textured vegetable protein. This method has also proved useful in response surface investigations of the influence on texture of processing variables, including machine parameters and composition of the starting material. Other processes useful for producing textured vegetable proteins include freeze‐texturization and film formation and the formation of co‐extrudates.
TEXTURE OF TABLE OLIVES AND PIMENTOS
Authors: DÍEZ MATIAS J. FERNÁNDEZ 
Published: February 2007

ABSTRACTMechanical and chemical methods applied to quantifying the texture of table olives and pimientos are reviewed, and examples are given of studies on factors affecting the texture of these products (such as fruit maturity and processing) in which these methods have been used. The four instruments found applicable to olives are: Christel Texturometer, FFL Penetrometer, IG Texturometer and Kramer Shear Press (compression and shear/compression cells). The latter has also been used with pimientos. Advantages and disadvantages of each are discussed. Additional work is needed on correlating the mechanical tests with sensory evaluation. The chemical methods involve quantification of pectic substances and their degradation products.
SENSORY AND INSTRUMENTAL EVALUATION OF MATERIAL PROPERTIES OF FISH GELS
Authors: HAMANN D. D. , WEBB N. B. 
Published: February 2007

ABSTRACTOver 100 heat coagulated fish pastes with widely varying sensory texture properties were prepared and evaluated. Variations in species, geographical source of fish, cooking procedure and other variables provided a wide range in material properties. Small strain material properties were evaluated instrumentally using uniaxial sinusoidally varying force at a frequency of 2 Hz and recording stress, strain and the phase angle between the two. A multiblade shear/compression cell mounted in an Instron Universal Testing machine was used to measure the shear/compression failure force. The products were also evaluated by a trained texture profile panel using 13 character notes. The maximum shear/compression cell force was a good predictor of sensory springiness, firmness, cohesiveness, and gel strength for the heat coagulated fish pastes tested. These four sensory notes were good predictors of each other so that a panel rating of any one could be used to rate the other three with numerical ratings for all four being very similar. Gumminess and adhesiveness ratings were also very similar and varied inversely with the shear/compression cell force and with the above four panel notes. These two notes were directly proportional to the loss tangent of the product, which correlated with them about as well as did the shearlcompression cell force. The relationships developed between panel notes support the modification of the General Foods Texture profile suggested by Sherman (1969). Statistically developed equations giving sensory texture notes as functions of instrumental material properties are given and their implications discussed.
A FORTRAN PROGRAM ‘FRAMOD’ FOR SIMULATION OF LARGE FRACTOVISCOELASTIC MODELS
Authors: DRAKE BIRGER 
Published: February 2007

ABSTRACTA computer program is described for simulating the behavior of uniaxial rheological models containing up to 8 chains, each with up to 4 groups of viscous and/or elastic elements together with fracture elements. The time course of force, or of deformation, can be prescribed and deformation, or force, simulated. Alternatively, the program can simulate a relaxation, starting after a prescribed time or at a prescribed force. If a suitable plotter is available, the specified time course and the simulated behaviour can be automatically plotted. The input‐output format has been designed to be useful to rheologists without computer experience.
DYNAMIC MECHANICAL PROPERTIES OF THE APPLE CORTEX IN RELATION TO SAMPLE LOCATION AND RIPENING
Authors: PETRELL R. J. , MOHSENIN N. N. , WALLNER S. 
Published: February 2007

ABSTRACTCompressive complex moduli were determined for two cultivars of apples at two ripeness stages by subjecting cylindrical tissues from various locations within the apple to sinusoidal stress. The complex moduli varied within sampling regions and with regional sampling depths. They also varied with the degree of ripeness, but only at certain storage temperatures and in certain sampling regions of the fruit. The data analysis showed that the sinusoidally varying stress and strain test and the Magness Taylor pressure test did not measure the same mechanical properties and that apparently the complex modulus was influenced by changes in the cellular structure of the fruit tissues.
FURTHER APPLICATIONS OF THE MODIFIED GEL RIGIDITY MODULUS APPARATUS
Authors: ATKIN G. , SHERMAN P. 
Published: February 2007

ABSTRACTAn apparatus previously used to evaluate the rheological properties of weak milk gels has proved suitable for studying the creep compliance—time behaviour of fruit yoghurt, mayonnaise and fruit jams. All samples exhibited viscoelastic properties. The equipment is recommended for its simplicity of design and operation, and because of its ability to test foods containing fruit pieces. The size and weight of the fruit must be known since these quantities influence the creep compliance behaviour.
INFLUENCE OF SKIM MILK POWDER/RECODAN RS RATIO ON THE VISCOELASTICITY OF GROUNDNUT OIL‐IN‐WATER IMITATION MILKS
Authors: SHERMAN P. , BENTON M. 
Published: February 2007

ABSTRACTImitation milks were prepared with different ratios of skim milk powder (SMP) and Recodan RS (R) as emulsifiers while keeping their total concentration constant. The ratio employed influenced the viscoelastic properties of the milks, as derived from creep compliance‐time studies, the electrophoretic mobility of the oil drops and the interfacial tension between the oil and aqueous phases. Optimum values of the viscoelastic parameters were obtained when the SMP/R ratio was between 4/1 and 8/1. Association occurs between the SMP and R under these conditions and stabilization of the flocculated oil drops is primarily by a steric mechanism. During storage of the milks the viscoelastic parameters initially increased due to continued growth of the flocculated oil drop structures, but subsequently the parameters decreased as drop coalescence became the predominant factor.
TEXTURE‐STRUCTURE RELATIONSHIPS IN BACON LEAN1
Authors: STANLEY D.W. , VOISEY PETER W. , SWATLAND H. J. 
Published: February 2007

ABSTRACTBacon lean was examined for its textural and structural characteristics and the influence upon them of cooking. Examination by light, scanning and transmission electron microscopy of cooked bacon lean led to the conclusion that the major effects of heating relative to texture include a decrease in interfiber spacing and fracturing. Cooking removed over 95% of the moisture and 75% of the lipids. Sensory analysis of bacon lean was accomplished by the use of a four‐stage evaluation form requiring tactile, audio and oral judgements. Of the eight instrumental methods evaluated for their ability to measure changes in bacon lean as a function of cooking, the blunt biting cell, 2 mm penetration and the Warner‐Bratzler Shear were judged the most useful. Both the sensory and instrumental measurements suggested that cooking produces a nonlinear progression in bacon lean from noncrisp to crisp to brittle. These changes are a consequence of structural alterations resulting from compositional changes. Several of the instrumental tests correlated well with sensory data. Regression analysis indicated that between 80 and 90% of the total variation in sensory data (with the exception of overall acceptability) could be explained by the initial slope of the force deformation curve in the Warner‐Bratzler test.
RHEOLOGICAL PROPERTIES OF AQUEOUS AGAROSE‐GELATIN GELS
Authors: MORITAKA HATSUE , NISHINARI KATSUYOSHI , HORIUCHI HISAYA , WATASE MINEO 
Published: February 2007

ABSTRACTMelting temperatures were determined for 1‐5% agarose gels, 7.5‐40% gelatin gels and mixed gels of different concentrations of the two hydro‐colloids. The dynamic viscoclastic constants were also quantified at 0.05 HZ for mixed gels containing 0.5% agarose and 2.5–20% gelatin.In single component gels, the melting temperature increased with hydrocolloid concentration. The melting temperature of gelatin gels was lower than that of agarose gels (22–31°C vs 69–80°C) and less concentration dependent. The melting temperature of mixed gels was more similar to that of agarose gels at low (2.5–6.25%) gelatin concentrations and more similar to that of gelatin gels at high (7.5–20%) gelatin concentrations. The storage modulus decreased with increasing temperature indicating that the thermal rupturing of the noncovalent crosslinks in the gels was stronger than the entropic behavior of the network. The temperature dependence of the storage modulus and of the dynamic viscosity increased with gelatin concentration. Based on these results and on the determination of the activation energy it is concluded that, in mixed agarose/gelatin gels, the two species form individual networks which interfere with one another at high concentrations.
TEXTURE‐STRUCTURE RELATIONSHIPS IN HEAT‐INDUCED SOY PROTEIN GELS
Authors: FURUKAWA TADAYASU , OHTA SHIGENORI , YAMAMOTO ATSUSHI 
Published: February 2007

ABSTRACTStructural factors responsible for textural properties of heat‐induced soy protein gels were investigated using microscopic and mechanical testing techniques. The gels were prepared by heating 20% soy protein pastes for 30 min at temperatures ranging from 25 to 130°C. Gel hardness increased linearly with the heating temperature up to 80°C, and decreased when the gels were heated at over 90°C, especially over 120°C. The equilibrium modulus estimated by tensile stress relaxation experiments was of the order of 104 ‐ 105 dyne/cm2, suggesting the presence of crosslinks, and there was a good correlation between the equilibrium modulus and the hardness of the gels. Solubility in phosphate buffer containing 2‐mercaptoethanol and/or urea suggested that the gel network was formed through crosslinking of the disulfide‐, hydrogen‐ and hydrophobic‐bonding types, and that the textural properties were governed by the degree of the network formation controlled by the heating temperature. SEM images of the 80°C‐induced hard gels revealed a porous structure having membranous walls of thin compact film. With the 40°C‐induced soft gels, the formation of the porous structure was not yet adequate, while a partial collapse of this structure was observed in the 120°C‐induced fragile gels.
RHEOLOGY OF GELATINISED STARCH SUSPENSIONS
Authors: EVANS I. D. , HAISMAN D. R. 
Published: February 2007

ABSTRACTWhen starch powders are mixed with water and heated at or above the gelatinisation temperature, the granules absorb large quantities of water and form a viscous paste. The gelatinised pastes are shear‐thinning fluids, whose flow curves fit the expression &#x006e;̈=kγm over a wide range of shear rates. Behaviour at very low shear rates indicates the existence of a yield stress. Under oscillatory shear the elastic moduli of the pastes considerably exceed the loss moduli, and both show only weak dependence on frequency over the range 0.002‐2.5 Hz.The apparent viscosities, pseudoplasticity constants, yield stresses and elastic moduli of the pastes are all concentration dependent, assuming significant values only when the starch level exceeds a minimum concentration. In many cases this threshold concentration corresponds closely to the point at which the volume of flocculated swollen starch granules just fills the total volume of the system.
AN ATTEMPT TO IDENTIFY AND MODEL TRANSIENT VISCOELASTIC FLOW IN FOODS2
Authors: KOKINI J. L. , DICKIE A. 
Published: February 2007

Shear stress development data for commercial ketchup, mustard, mayonnaise, apple butter, butter, margarine and canned frosting were obtained using the cone and plate geometry of the Rheometrics Mechanical Spectrometer. At sudden imposition of four shear rates, .1, 1, 10, and 100 s−1, shear stresses displayed different degrees of overshoots with margarine exhibiting a maximum overshoot of 320% that of the steady‐state value at a shear rate of 100 s−1. The actual extent of overshoot depended on the particular food and the particular shear rate applied.An attempt was made to explain observed transient shear stresses with the Bird‐Leider equation, a four parameter empirical model which incorporates both steady viscous and elastic properties of food materials. This model assumes both the steady viscosity function, η, and the steady primary normal stress coefficient Ψ to have a prominant power‐law region with increasing shear rate. This assumption is shown to be justified for all foods studied between shear rates of .1 s−1 and 100 s−1. When this assumption is justified a time constant Λ can be constructed. This time constant is found to be an approximate indicator of relative stress overshoot for the foods studied. It is found that the Bird‐Leider equation provides a moderately good prediction of peak shear stresses and peak times and only a crude prediction of shear stress decay. Nevertheless, the model is a definite improvement over time independent models such as the power‐law model.
DYNAMIC VISCOELASTIC PROPERTIES OF SOY ISOLATE DOUGHS
Authors: BAIRD D. G. 
Published: February 2007

AbstractThe linear viscoelastic properties of soy isolate doughs have been determined as a function of flour concentration and temperature using a Rheometrics Mechanical Spectrometer. The material of lowest concentration (15%) which is classified as a dispersion rather than a dough exhibited values of storage (G′) and loss moduli (G″) which increased with increasing temperature above 50°C. On the other hand, values of G′ and G″ for 20% and 25% doughs showed only a slight increase with increasing temperature. The shape of the G’ and G” versus frequency (ω) curves is suggestive of solid‐like behavior for the doughs. The shape of these curves does not change with temperature which indicates there is very little change in the ability of the protein molecules to undergo configurational rearrangements as the result of heating. The phenomenon of gelation does not arise in the doughs but only in the dispersion of lower concentration. The data indicate that the bonds between protein molecules are noncovalent in nature and that the process of cooking soy dough does not involve the formation of crosslinks.
LIQUID FOODSTUFFS EXHIBITING YIELD STRESS AND SHEAR‐DEGRADABILITY
Authors: HALMOS A. L. , TIU C. 
Published: February 2007

AbstractTwo rheological properties of liquid foodstuffs often encountered in practice are the yield stress and the shear‐degradability (irreversible time‐dependence). Both these properties were determined for meat and yeast extracts using two rotational viscometers. The material constants were obtained and fitted with Bingham Plastic and Herschel‐Bulkley models for the meat extracts. The shear‐degradability exhibited by the yeast extract was quantified in terms of the energy required to destroy the material structure.
EFFECT OF CELL SIZE ON THE PERFORMANCE OF THE SHEAR‐COMPRESSION TEXTURE TEST CELL
Authors: VOISEY PETER W. , KLOEK M. 
Published: February 2007

Shear compression cells were manufactured to have dimensions 0.75, 0.5 and 0.25% that of the standard cell and used to test a range of foods. Maximum force and energy increased nonlinearly with increasing cell size and sample weight. The results demonstrate that cells of various sizes are practical for testing foods.Friction in the cell is dependent on alignment of the cell components in the test machine. To obtain comparable readings the cell body must be oriented in the machine the same way for every test.
TEXTURAL CHANGES IN INTERMEDIATE MOISTURE MEAT DURING STORAGE AT 38°C
Authors: LEDWARD D. A. , LYMN S. K. , MITCHELL J. R. 
Published: February 2007

Intermediate moisture beef prepared by cook‐soak equilibration, with glycerol and sodium chloride as humectants, was stored at 38°C under both anaerobic and aerobic conditions for up to 12 weeks. Meat texture was measured by Warner‐Bratzler, tensile and objective texture profile methods. Covalent crosslink formation was monitored by solubility measurements in solutions of sodium dodecyl sulphate plus β‐mercaptoethanol.A decrease in the Warner‐Bratzler peak height on storage was observed though this did not depend strongly on the storage environment. In contrast, the large decrease observed in the tensile force required to rupture the meat when pulling perpendicular to the fibre direction was greater for aerobically stored meat. The cohesiveness and ‘elasticity’ of the meat as determined by objective texture profile measurements showed an initial decrease followed by a subsequent increase, but a similar increase was not shown by the hardness parameter. The results are discussed in terms of the crosslinking and degradative reactions known to occur in meat of this type.
MECHANICAL AND WATER‐HOLDING PROPERTIES OF HEAT‐INDUCED SOY PROTEIN GELS AS RELATED TO THEIR STRUCTURAL ASPECTS
Authors: FURUKAWA TADAYASU , OHTA SHIGENORI 
Published: February 2007

AbstractThe dependence of mechanical and water‐holding properties of soy protein gels upon their structures was examined. Gels varying in extent of network formation were prepared by heating 20% paste of the isolated soy protein (ISP) containing L‐cysteine hydrochloride (CySH) which has an ability to cleave intermolecular disulfide bonds. A rapid decrease in gel hardness and cohesiveness was observed with the increase in added amount of CySH up to 2.5 times 10‐5 mole/g ISP, and then a gradual decrease to 5.0 times 10‐5 mole/g ISP. The changes in these mechanical parameters appeared to depend on the degree of the network formation interpreted from the solubility changes of gels in the phosphate buffer containing 6 M urea. The relaxation time, estimated by compression stress relaxation, was also dependent on the degree of the network formation, while the modulus of elasticity was hardly affected. On the other hand, there was an inverse correlation between the NMR line width of the water proton and expressible water by the pressure method as an index of water‐holding properties of the gel; the broader the former, the lesser the latter. The change in the water‐holding capacity estimated from expressible water was also associated with that in the degree of the network formation. This confirms that both mechanical and water‐holding properties of the gel are qualitatively governed by the extent of the structure formation controlled by the intermolecular disulfide bonds.
A MACHINE FOR MEASURING YIELD POINT IN RAW MEAT
Authors: LOCKER R. H. , WILD D. J. C. 
Published: February 2007

AbstractA simple machine is described for measuring yield point in strips of raw muscle, by registering maximum tension generated at a low rate of extension. Values are not highly dependent on the rate or degree of extension. The method has been used to measure rate of ageing at 15°C and 2°C, with parallel measurements of shear force in the cooked muscle. The machine provides a sensitive tool, complementary to the tenderometer, and particularly suited to studies on ageing.
DIRECT STRESS‐STRAIN DYNAMIC CHARACTERISITCS OF LOW‐METHOXYL PECTIN GELS
Authors: GROSS M. O. , RAO V. N. M. , SMIT C. J. B. 
Published: February 2007

AbstractFourteen ammonia‐demethylated low‐methoxyl pectins were chemically defined. Each was used to prepare a 30% sucrose gel. The texture of each gel was evaluated by an eight member, semi‐trained sensory panel. Each gel was also subjected to dynamic uniaxial loading at seven frequencies ranging from 100 Hz to 280 Hz. Rheological response was found to be highly dependent on test frequency, and a resonance dispersion effect was revealed at several frequencies. The frequency that exhibited the greatest resonance dispersion was also the most sensitive in distinguishing between the 14 gels, based on absolute modulus. Ninety‐two percent of the total variation in absolute modulus could be significantly explained by the chemical composition of the pectin. Significant correlations were found between the sensory descriptors and the rheological parameters calculated from the dynamic tests.
EFFECT OF FISH PROTEIN PREPARATIONS ON RHEOLOGICAL PROPERTIES OF MEAT SAUSAGES
Authors: SADOWSKA MARIA , NACZK MARIAN , SIKORSKI ZDZISLAW E. , ZIMIŃSKA HALINA 
Published: February 2007

AbstractThe properties of sausage emulsions, containing up to 30% fish proteins in respect to total N × 6.25, were characterized by viscosity and water holding capacity and after heating by yield, quantity of expressible fluid, water holding capacity, yield limit, creep curve, and sensory quality. Substitution of 15% meat protein by fish protein does not decrease the sausage yield nor impair the rheological properties of the formulation or of the cooked product. Sensory differences were detectable between the controls and sausages containing up to 10% of fish isolate or 20% concentrate.
EFFECT OF SAMPLE THICKNESS ON THE DEFORMATION OF CHEWING GUM
Authors: BOGATY H. , TALMAGE J. M. 
Published: February 2007

AbstractThickness‐time data from plastometer tests of gums of different thicknesses using a range of compressive loads and specimen sizes yield consistent indices of compliance suggesting that thicker samples are softer than thinner ones. On staling of these gums by exposure to low humidity, the compliance of each gum decreases in a regular manner with exposure time. At comparable staling times, the thinner samples are found to be harder than the thicker ones by the plastometer criteria.Limited panel evaluation shows that the trend for each gum thickness to become harder during staling is perceived by the chewers, consistent with the physical data and with prior experience. In contrast, the panelists do not readily differentiate the hardnesses among samples of different thicknesses chewed at comparable staling times unless the difference in thickness is large; in such cases the thinner samples are judged to be softer in chew than the thicker, contrary to the plastometer indications. This suggests that cues other than compliance are invoked by chewers when sample dimensions differ widely but this issue will require more extensive and detailed study for resolution.