bluuebunny/crossref_metadata_2025 huggingface dataset:
SENSORY AND INSTRUMENTAL EVALUATION OF MATERIAL PROPERTIES OF FISH GELS
Authors: HAMANN D. D. , WEBB N. B.
Published: February 2007

Over 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

A 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

Compressive 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

An 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

Imitation 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

Bacon 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

Melting 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

Structural 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

When 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 n̈=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.
EFFECT OF ALKALI METAL IONS ON THE RHEOLOGICAL PROPERTIES OF κ‐CARRAGEENAN AND AGAROSE GELS
Authors: WATASE MINEO , NISHINARI KATSUYOSHI
Published: February 2007

Stress relaxation and dynamic measurements were carried out on κ‐carrageenan and agarose gels to examine the effect of alkali metal ions. The elastic modulus of κ‐carrageenan gels increase remarkably by adding alkali metal ions Li+, Na+, K+, Cs+. This was explained as follows: the electrostatic repulsion of sulfate groups in κ‐carrageenan gels are prevented by the shielding action of the alkali metal ions stabilizing the double helical structure of κ‐carrageenan gels. The increase of the modulus was in the order: Cs+ > K+≫ Na+ > Li+. The difference between these two groups (Cs+, K+) and (Na+, Li+) is that the former group belongs to the structure disordering ions while the latter group belongs to the structure ordering ions. Thus, the former group prevents the repulsion of sulfate groups more directly than the latter. Agarose gel, which lacks sulfate groups, is not influenced so much by adding the alkali metal ions.
A PRESSING‐DEVICE TO MEASURE THE TEXTURE OF COOKED RICE
Authors: PILLAIYAR P. , MOHANDOSS R.
Published: February 2007

Cooked rice held between glass plates was pressed by dropping a 2.5 kg load from a predetermined height. A significant variation (1.90 to 3.45 cm2) in the pressed area for raw cooked samples was found. Cooking methods exerted a significant influence on the pressed area. The pressed area of the cooked rice and the L/B ratio of uncooked samples correlated positively. This test significantly differentiated parboiled rices. The pressed area correlated negatively with the temperature of parboiling. Besides the varieties, the cooking methods and the testing time significantly influenced the pressed area of parboiled samples, thus indicating the reliability of this test even under varying testing conditions.
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.
TRIAL METHOD FOR MEASURING THE EFFECT OF LIPIDS ON THE RHEOLOGICAL PROPERTIES OF STARCH PASTE DURING THE GELATION PROCESS
Authors: NIIHARA RITSUKO , MATSUMOTO SACHIO
Published: February 2007

An attempt was made to measure the effect of lipid components on the viscosity and thixotropy of wheat starch paste in a short aging time after gelatinization. Viscometry was used to follow periodically the changes in apparent viscosity (at 76.8 s−1) of the mixed paste of wheat starch and one of a series of lipids in a cone‐plate viscometer for 210 min after gelatinization, i.e. a procedure of eight cycles of measurement with a sample. Each cycle of the measurement consisted of viscometry for 3 min and a rest period for 27 min at 30°C. The apparent viscosity of all the samples decreased greatly during the 3 min measurement due to thixotropic breakdown of the macroscopic structure in the samples. The results suggest that the presence of a small amount of free fatty acid and monoglyceride may play a role in reducing starch paste gelation.
DYNAMIC VISCOELASTIC PROPERTIES OF SOY ISOLATE DOUGHS
Authors: BAIRD D. G.
Published: February 2007

The 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

Two 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.
PERCEIVED TEXTURAL DIMENSIONS OF FRUIT‐BASED BEVERAGES
Authors: INGATE MARGARET R. , CHRISTENSEN CAROL M.
Published: February 2007

The major sensory dimensions of the mouthfeel of fruit based beverages were determined by principal components analysis and the degree of correlation between mouthfeel characteristics and the taste and pleasantness of beverages was assessed. Untrained college students rated 35 different beverages on 16 different 10‐point scales containing mouthfeel, taste and hedonic terms. Two major mouthfeel dimensions emerged with this set of beverages and they were termed density/thickness and chemical irritant effect. An interdependence between mouthfeel and taste ratings was also found. Sweetness ratings were negatively correlated and sour, salty and bitter tastes were positively correlated with mouthfeel terms describing oral mucosal irritation.
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

The 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

A 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

Fourteen 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

The 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

Thickness‐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.
MAJOR FACTORS AFFECTING COOKED MILLED RICE HARDNESS AND COOKING TIME
Authors: JULIANO BIENVENIDO O. , PEREZ CONSUELO M.
Published: February 2007

A study was made of factors affecting cooking time and the relationship between water:rice ratio (water content) in the rice cooker method and Instron hardness of cooked rice using 10 milled rice samples of diverse properties. Water:rice ratio for acceptable soft texture (< 10 kg hardness) increased with increasing amylose content of the sample from 1.1 (56% water in cooked rice, wet basis) to 1.9 (68% water). The spread in cooked‐rice hardness values was higher at a water:rice ratio of 1.9 (68% water) than at 2.65 (75% water), which was equivalent to the water content of rice cooked in excess water for an optimum cooking time. Cooking time correlated better with starch final gelatinization temperature (r=0.75*) than with surface area per gram (r=−0.49) confirming the results of earlier kinetic studies that cooking rate was mainly influenced by the reactivity of the grain constituents with water.
SOY AND MEAT PROTEINS AS FOOD EMULSION STABILIZERS 1. VISCOELASTIC PROPERTIES OF CORN OIL‐IN‐WATER EMULSIONS INCORPORATING SOY OR MEAT PROTEINS
Authors: RIVAS H. J. , SHERMAN P.
Published: February 2007

The creep compliance‐time response of 50% (wt/wt) corn oil‐in‐water emulsions has been studied at a constant stress of 47.8 dyne cm−2 over the pH range 2.5–7.5. The emulsions were stabilised by acid precipitated (APSP), 7S(7SPRF) or 11S(11SPRF) soy protein fractions, water soluble (WSMP) or salt soluble (SSMP) meat protein fractions. All the emulsions exhibited viscoelasticity. WSMP emulsions exhibited the highest initial viscoelasticity parameter values and this was attributed to the strong interlinking of WSMP loops adsorbed on the surfaces of adjacent oil drops. The parameter values of all the emulsions increased during the first 5–7 days storage and then they decreased. At any selected pH the 7SPRF emulsions exhibited the largest relative increase in parameter values. The changes in viscoelasticity during storage were explained on the basis of the relative effects of further protein loop interlinkage and drop coalescence.
SOY AND MEAT PROTEINS AS FOOD EMULSION STABILIZERS 2. INFLUENCE OF EMULSIFICATION TEMPERATURE, NaCl AND METHANOL ON THE VISCOELASTIC PROPERTIES OF CORN OIL‐IN‐WATER EMULSIONS INCORPORATING ACID PRECIPITATED SOY PROTEIN
Authors: RIVAS H. J. , SHERMAN P.
Published: February 2007

The rheological properties of concentrated corn oil‐in‐water emulsions stabilised by acid precipitated soy protein have been studied as a function of emulsification temperature, methanol and salt concentration. Viscoelasticity parameters were derived from the creep compliance‐time response of the emulsions at a constant stress of 47.8 dyne cm−2. All of the emulsions exhibited higher parameter values, both immediately after preparation and during storage, than comparable emulsions prepared at ambient temperature in the absence of methanol or NaCl. This was attributed to the increased unfolding of adsorbed protein molecules which permits greater interlinking, by hydrophobic bonds, of molecular segments projecting from the surfaces of adjacent oil drops.
TEXTURE—STRUCTURE RELATIONSHIPS IN SCALLOP
Authors: FINDLAY C. J. , STANLEY D. W.
Published: February 2007

Warner‐Bratzler shear, Instron compression and extension were screened for sensitivity to the textural changes caused by heating scallop (Placopecten magellanicus) adductor muscle. Instron compression, expressed as hardness, was selected since it gave the greatest slope with respect to temperature. Previously frozen commercial scallop were heated to internal temperatures of 25 to 80°C. A linear increase in hardness of 0.033 N/g/°C occured during heating from 25 to 60°C; this increase was primarily a function of water loss. This was followed by a stepwise increase of 0.14 N/g/°C between 60 and 65°C which is considered to be a result of denaturation of myofibrillar proteins. Hardness continued to increase above 65°C at a rate of 0.055 N/g/°C. Quantitative scanning electron microscopic (SEM) measurement of the proportion of irregular muscle fibers, expressed as % damage, was performed on the same heated scallop used for texture analysis. Scallop heated from 25 to 50°C exhibited 30% damaged fibers; from 55 to 65°C, damage increased from 45% to 63%, paralleling the increase in hardness. Above 65°C, damage reached a maximum of 70%. The relationship between hardness and damage fit a linear model, with an R2 of 0.86 (P = 0.004); thus, the microstructural measurement of damage to scallop muscle can be used to predict the textural property of hardness.
CRISPNESS AND CRUNCHINESS ‐ A DIFFERENCE IN PITCH?
Authors: VICKERS ZATA M.
Published: February 2007

Initially two groups of foods were selected, one containing foods that were more crunchy than crisp and the other containing foods that were more crisp than crunchy. Subjects then compared each of the crisper foods with each of the crunchier foods and selected the product producing the higher‐pitched sound. More crisp than crunchy foods nearly always produced higher‐pitched sounds than the more crunchy than crisp foods. When the pitch of the eating sounds was altered (lowered) by changing the eating technique from a bite to a chew, judgments ofcrispness were depressed.
RECENT RESEARCH IN FOOD TEXTURE (MOUTHFEEL) AND ITS INSTRUMENTAL MEASUREMENT IN JAPAN
Authors: TSUJI SHOJIRO
Published: February 2007

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COMPARISON BETWEEN VARIOUS CORRECTION FACTORS IN THE CALCULATION OF THE CREEP COMPLIANCE2
Authors: PELEG M.
Published: February 2007

Uniaxial creep tests of food sometimes involve considerable deformation and consequently a progressive alteration of the specimen's cross‐sectional area. Under such conditions the difference between constant force and constant stress histories becomes substantial, and the strain needs to be represented by one of several possible large strain measures. Correction factors for creep curves, based on the assumption of incompressibility, were calculated employing Green's, Cauchy's, Hencky's, Swainger's and Almansi's strain definitions. The relationships between these correction factors and the extension or compression ratio are presented in a graphical form, and their possible role in the interpretation of creep data of solid foods is evaluated.
SMALL AMPLITUDE OSCILLATORY TESTING (SAOT). INSTRUMENTATION DEVELOPMENT AND APPLICATION TO COAGULATION OF EGG ALBUMEN, WHEY PROTEIN CONCENTRATE AND BEEF WIENER EMULSION3
Authors: BEVERIDGE T. , TIMBERS G. E.
Published: February 2007

An instrument to measure the development of protein gels during thermal coagulation was developed. Very small oscillatory movements, sufficiently small to avoid damaging forming structures, were imposed on the sample trapped within a specially constructed cell, and the torques transferred through the sample sensed with strain gauges. Temperatures were controlled with one heating and one refrigerated (20°C) bath and the sample properties determined through both heating and cooling cycles. Egg white (EW) whey protein concentrate (WPC) and beef wiener emulsion (BWE) were tested. EW and WPC were characterized by delayed onset of gelation followed by high temperature thickening. Cooling further stiffened the gel in both cases. B WE was characterized by an initial decrease in transmitted torque as fat melting was detected. This was followed by a rapid rise in transmitted torque as the protein coagulated, followed by a further increase or stiffening on cooling. Detailed parameters describing the thermal gelation of the three materials are given.
GELATION OF CASEIN AFTER MODIFICATION BY DIALDEHYDE STARCH‐CHEMICAL AND PHYSICAL ASPECTS2
Authors: SCHWENKE K. D. , PRAHL L. , NOACK J. , BRAUDO E. E.
Published: February 2007

The gelation of casein after modification by dialdehyde starch (DAS) was studied by measuring its mechanical and swelling properties, the amount of sol fraction, its melting behaviour, amino acid analysis and polyacrylamide gel electrophoresis. Depending on the concentration of protein and DAS, fusible and infusible gels are formed. The transition from fusible into infusible gels takes place after increasing the amount of DAS, owing to an enhanced blockage of basic amino acid residues and crosslinking of polypeptide chains. The higher the concentration of protein, the lower is the concentration of DAS necessary for gelation. When the DAS concentration is high enough to form a pervading crosslinked network the crosslinking proceeds relatively fast and is nearly completed after one day. The correspondence of the time dependence of chemical andphysical parameters, the irreversible blocking of basic amino acids, especially lysine, the decrease of swelling and nitrogen extractability, the elastic component of creep compliance indicates that during a 7 day storage period the gels are completely crosslinked. Using a corrected Flory relation it was shown that an average of 3.5 crosslinks exist per one polypeptide chain. This number is similar to the number of blocked lysine groups of the same gels (3.6 ‐ 4.5). The melting and creep behaviour of the gels, and especially the effect of sodium do‐decyl sulphate on the creep compliance, point to the formation of a heterogeneous network which includes noncovalently connected mi‐croassociations and covalently connected polypeptide chains as structural elements.
REVIEW FOOD TEXTURE AND DENTAL SCIENCE
Authors: BOYAR M. M. , KILCAST D.
Published: February 2007

The techniques used in dentistry which enable the monitoring of mastication include gnathosonics, electromyography, cinematography and the use of various electronic, intra‐oral, instruments. The forces involved during the masticatory cycle have been estimated using a variety of both extra‐and intra‐oral devices. The possible implications of this knowledge are discussed in relation to obtaining greater information from instrumental techniques, developing more meaningticl mechanical test methods, improving methodology used in the establishment of texture panels and in acquiring a greater understanding of results obtained from such sensory evaluations.
OBJECTIVE MEASUREMENTS OF THE CONSISTENCY OF CHAPATI DOUGH USING A RESEARCH WATER ABSORPTION METER
Authors: RAO P. HARIDAS , LEELAVATHI K. , SHURPALEKAR S.R.
Published: February 2007

A Research Water Absorption Meter (RWAM) was adapted to measure the consistency of chapati doughs made from whole wheat flour (WWF). Doughs of optimum consistency were characterized by an extrusion time of 60 ± 5 s when extruded with an additional weight of 2 Kg, after resting the dough for 20 min. The RWAM consistency was Significantly correlated to the farinograph consistency (r=+ 0.97), as well as to hardness (r=+ 0.96) recorded on a General Foods Texturometer. The water required to prepare a chapati dough of this consistency can be determined from a semi‐logarithmic plot of the extrusion time of doughs of varying water contents against the water added. Chapati water absorption can be determined by multiplying the farinograph water absorption measured at 500 B. U. by a factor of 0.85, or by adjusting the farinograph consistency to 460 ± 20 BU at a lever setting of 1:3 instead of 1:1. A multiple regression equation, derived for predicting chapati water absorption based on particle size, damaged starch, and protein content, accounted for 88% of the variation.
RHEOLOGICAL CHARACTERISTICS OF SELECTED FOOD GUM MIXTURES IN SOLUTION2
Authors: KALETUNC‐GENCER G. , PELEG M.
Published: February 2007

The viscosity of pure and mixed dilute solutions of commercial alginate, carrageenan, guar gum, CMC and gelatin solutions at different mixing ratios were measured by a coaxial viscosimeter at different shear rates. The results are presented in the form of measured viscosity divided by the expected viscosity, if no interaction between the gums existed. This technique provides a clear demonstration of the existence of synergism or antagonism between the gums and helps in quantitatively assessing their extent.
PREDICTING STEADY AND OSCILLATORY SHEAR RHEOLOGICAL PROPERTIES OF CMC/GUAR BLENDS USING THE BIRD‐CARREAU CONSTITUTIVE MODEL
Authors: KOKINI JOSEF L. , PLUTCHOK GARY J.
Published: February 2007

The Bird‐Carreau constitutive model, a five parameter semi‐empirical set of equations, was used to predict the steady shear viscosity η, the dynamic viscosity η′, and the out‐of‐phase component of the complex viscosity divided by frequency η″/ω, for aqueous blends of sodium carboxymethylcellulose (CMC) and guar gum. The five Bird‐Carreau constants were derived from equations which correlate the constants to concentration and molecular weight of the CMC/guar blends. Blends of ratios 3:1, 2:1, 1:1, 1:2, and 1:3 by weight were studied in concentrations of 0.5, 0.75, 1.0, and 1.5% by weight. For most blends the model accurately predicted the experimental η and η′ data in the frequency/shear rate range of 0.1–100 s‐1 and the experimental η″/ω data in the frequency/shear rate range of 1.0–100 s−1.
BACK EXTRUSION OF POWER LAW FLUIDS1
Authors: OSORIO FERNANDO A. , STEFFE JAMES F.
Published: February 2007

A mathematical model, using dimensionless terms, was developed to describe the behavior of power law fluids in a back extrusion (annular pumping) device. A graph and a table were prepared to determine rheological properties from experimental data. Expressions to calculate shear stress and shear rate at the plunger wall were obtained. The model was experimentally validated by comparing values obtained with the back extrusion device to those obtained with a concentric cylinder viscometer.
TEXTURAL AND MICROSTRUCTURAL PROPERTIES OF RENNET‐INDUCED MILK COAGULUM AS AFFECTED BY THE ADDITION OF SOY PROTEIN ISOLATE
Authors: MOHAMED M.O. , MORRIS H.A.
Published: February 2007

The effect of the addition of soy protein on the textural properties and microstructure of reconstituted nonfat dry milk coagulum with time after rennet addition was studied using an Instron Universal testing machine with a newly developed test cell, and by scanning electron microscopy. Soy protein added to reconstituted nonfat dry milk at 5% of the total solids resulted in a reduction in firmness, a decrease in syneresis and a looser microstructure of the coagulum at any given time up to two hours after rennet addition as compared to the control without added soy protein. An increase in the level of soy protein to 10 and 20% of the total solids resulted in a further reduction in coagulum firmness and in syneresis. Syneresis was also followed during changes in coagulum firmness. Analysis of the textural as well as microstructural data suggests that changes in coagulum firmness and syneresis of rennet‐induced milk coagulums (with or without added soy protein) with time after rennet addition were associated with the extent to which casein micelles coalesced during coagulum formation. The Instron test and the syneresis test developed in this study were simple and practical.
PHYSICAL AND RHEOLOGICAL CHARACTERISATION OF A CONFECTIONERY PRODUCT
Authors: McMASTER T. J. , SMITH A. C. , RICHMOND P.
Published: February 2007

The mechanical and rheological properties of caramel have been measured in the context of a continuous extrusion forming operation, including a repetition of the processing route. The sensitivity of mechanical testing of samples to processing is borne out by the changes in microstructure, as observed using the scanning electron microscope, which also affect the velocity of transmitted ultrasound. The effect of repeated processing is also greater at a lower processing temperature.
CREAMY PERCEPTION I: IN MODEL DESSERT CREAMS
Authors: DAGET N. , JOERG M. , BOURNE M.
Published: February 2007

Model caramel creams containing four levels of dairy fat and nine levels of xanthan gum as thickener were tasted and submitted to viscometric measurements. The panel of 15 tasters evaluated their liking of the consistency, the perceived creaminess and the thickness, using a magnitude estimation scoring method. Results were correlated with rheological parameters: viscosity and flow behavior index. There is a quadratic relationship between rheological parameters and both liking consistency and perceived creaminess, with an optimum value. The optimum liking does not coincide with that for maximum creaminess; these values depend on the amount of the two ingredients: fat content and thickener. They can be obtained from response surfaces. The perceived thickness is related to viscosity. Some modalities of changes in optimal values for different groups of people are considered.
TEMPERATURE DEPENDENCE OF FLOW FOR PLASTIC FATS FROM PENETRATION DATA
Authors: DAVEY KENNETH R.
Published: February 2007

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RHEOLOGICAL BEHAVIOR OF KAPPA‐CARRAGEENAN/ LOCUST BEAN GUM MIXED GELS
Authors: ARNAUD J. P. , CHOPLIN L. , LACROX C.
Published: February 2007

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ON FOOD COMPRESSION BY SOFT MACHINES1
Authors: CAMPANELLA O. H. , PELEG M.
Published: February 2007

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MEASURING MILK GELIFICATION BY MEANS OF AN INSTRON UNIVERSAL TESTING MACHINE OPERATING IN DYNAMIC MODE1
Authors: MASI P. , ACIERNO D. , ADDEO F.
Published: February 2007

This note describes a simple method to measure the kinetics of milk coagulum formation using an Instron Universal Testing Machine operating in dynamic mode. Coaxial cylinder geometry is used, applying to the internal cylinder a vertical periodical motion of 2 mm amplitude and constant speed of 1 cm/min. The flow conditions are similar to that applied in a sliding rheometer. The experiment can be equated to a periodical stress growth experiment as coagulation proceeds. Data produced according to this technique provides information on the kinetic parameters which characterize the kinetic model currently used to describe milk coagulation
THE EFFECT OF MONOVALENT CATIONS AND ANIONS ON THE RHEOLOGICAL PROPERTIES OF KAPPA‐CARRAGEENAN GELS1
Authors: WATASE M. , NISHINARI K.
Published: February 2007

The change in dynamic Young's modulus E' and in volume of 2% and 4% kappa‐carrageenan gels induced by immersion in alkali metal salt solutions was observed for various kinds of salts, LiCl, NaCl, KCl, CsCl, LiBr, NaBr, KBr, CsBr, Nal, KI, Csl, and for various salt concentrations. E' of the gels increased rapidly up to 1 h after immersion, and then it increased more gradually. However, E' decreased after a certain immersion time when the concentration of the salt exceeded a certain value which depended on the kind of the salt. The volume of the gel immersed in salt solutions for 24 h decreased with increasing concentration of the salt except in the case of Nal where the gel swelled remarkably.
EVALUATION OF TEXTURE OF PECTIN JELLIES WITH THE VOLAND‐STEVENS TEXTURE ANALYZER
Authors: RAO M.A. , COOLEY H.J. , WALTER R.H. , DOWNING D.L.
Published: February 2007

Texture profile analysis (TPA) parameters were determined with a Voland‐Stevens Texture Analyzer‐1000 (VSTA) and an Instron Universal Testing Machine. Because of the nature of the design of VSTA, reliable magnitudes of TPA parameters based on the force‐time curves recorded during the down stroke can be calculated. With a 2.54 cm diameter plexiglas plunger, the TPA parameters with the VSTA were higher than those with the Instron by 1.45% for hardness to 16.1% for fracturability.
RESEARCH NOTE EFFECT OF SELECTED ADDITIVES ON THE FLOW PARAMETERS OF 1:1 MIXTURES OF CARRAGEENAN‐GUAR AND CMC‐LOCUST BEAN GUM
Authors: GENCER G.
Published: February 2007

Flow parameters of 1:1 mixtures of carrageenan‐guar and CMC‐locust bean gum in the presence of common food ingredients, namely, sugar, salt and proteins, were determined by using a coaxial viscometer. The effect of additives on yield stress, and power law model constants varied depending on the type of ingredient and its concentration, and the nature of the gum. Although, it is interesting to see the flow behavior of gum blends together with the additives in concentrations that are common in food products, it is necessary to study an enormous number of combinations in order to analyze a multicomponent system quantitatively.
FLOW BEHAVIOR AND FUNCTIONAL PROPERTIES OF MALT EXTRACT CONCENTRATES
Authors: SINGH T.
Published: February 2007

Flow characteristics and functional properties of malt extract concentrates were investigated. Flow behavior was studied using a coaxial viscometer over shear rates of 0.6–145.8 s‐1. The shear rate‐shear stress data followed the power law, Casson, Herschel‐Bulkley and Bingham plastic models. Herschel‐Bulkley values for flow behavior index which ranged from 0.73–0.94, and presence of yield stress indicated the Bingham plastic nature of malt extract concentrates. The activation energy of flow for various concentrates was in the range of 14.8–17.7 kcal/gmole. Magnitudes of Reynold numbers (0.0–49.9) for all concentrates were lower than 2100. Temperature, yield stress and plastic viscosity considerably influenced the flow of concentrates in straight pipes. The pressure drop and power requirements for flow of concentrates in pipes at 50°–60°C were lower than those at 30°C, but negligibly different from those at 80°C. Coefficients of correlation between the Bingham plastic values for pressure drop and yield stress (r = 0.86, P < 0.01), and plastic viscosity (r = 0.97, P < 0.01) were highly significant. Hulled barley and corn concentrates containing high amounts of reducing sugars, showed low viscosities and yield stresses, and required desirably low power for flow in pipes at 50°–60°C. The high protein concentrates of wheat and triticale malts showed high whip volume and good foam stability. Wheat concentrate was superior in fermentability. Hulless barley and finger millet malts produced concentrates with high viscosities which might facilitate their utilization in gums, candies and other such products.
BOOK REVIEWS
Authors: SHERMAN P. , BOURNE MALCOLM C. , RAO M. A.
Published: February 2007

EXTRUSION COOKING. (C. Mercier, P. Linko, and J. M. Harper, eds.), American Association of Cereal Chemists, Inc., St. Paul, MN, 1989. 471 pp., $89.00.

WHEAT IS UNIQUE. (Y. Pomeranz, ed.) American Association of Cereal Chemists. 1989. 715 pp. $68.00.
STRENGTH‐TIME RELATIONSHIPS OF AGAR AND ALGINATE GELS 1
Authors: NUSSINOVITCH A. , PELEG M.
Published: February 2007

The compressive strength of 2% agar and alginate gels was monitored periodically during the first 50–80 h after preparation. The strength increased rapidly in the first 6 h in the former and about 15 h in the latter, and then tended to stabilize, asymptotically. An empirical, two parameter mathematical model was used to estimate the asymptotic value on the basis of data obtained during the first 8 or 20 h, respectively. The common procedure of testing these gels after 24 h is satisfactory, since changes after this time are relatively small. A similar two parameter model was also applied to the weight loss of the alginate gels and it enabled prediction of the gel's final weight with reasonable accuracy. Since both models can be presented in a linear form, testing their applicability and calculation of their constants can be done by linear regression.