bluuebunny/crossref_metadata_2025_split huggingface dataset:
ORAL PERCEPTION OF HARDNESS IN VISCOELASTIC PRODUCTS
Authors: MIOCHE L. , AUROY P. , LEPETIT J. , COMPAGNON D. 
Published: February 2007

ABSTRACTThe problem of hardness perception was examined by means of a psycho‐physical approach. The differential sensitivity was studied over a wide range of hardness (approximately 100 to 600 × 104 Pa) with products displaying mainly elastic behavior.A series of five silicon elastomer samples were prepared, each series containing 6–8 samples of varying degrees of hardness. The rheological characteristics of these products were measured. Differential threshold and magnitude estimation tests were carried out by 10 subjects who were asked to make hardness comparisons by biting or squeezing the samples. There was no significant difference in sensitivity between molars and incisors as shown by the differential thresholds which varied between 4 and 11% depending on the hardness range. Pressing between the fingers gave less accurate performances than biting. The difference in sensitivity detected by the threshold measurements was not shown in the magnitude estimation tests.
RHEOLOGICAL PROPERTIES OF GOAT MILK CHEESE: METHOD OF TRUE AXIAL STRESS VERSUS APPARENT AXIAL STRESS
Authors: RISCH ERIC 
Published: February 2007

ABSTRACTCompressive moduli of elasticity and stress relaxation characteristics of soft goat milk cheese were compared with those of cow milk judged to be of comparable consistency. The true stress applied to a cheese sample was calculated from the variation of cross‐sectional area of a cylindrical specimen during compression. Stress relaxation data were developed by measuring the force decay resulting from imposed compression of 5, 10, 20 and 40. The compressive elastic moduli for goat milk cheese were found to be lower than those for cow milk cheese. For cheese prepared from fresh goat milk, at least two distinct periods of stress relaxation were found for each compression level. Cheese prepared from reconstituted dehydrated goat milk showed one period of stress relaxation for each compression level.
THE EFFECTS OF TURGOR PRESSURE ON PUNCTURE AND VISCOELASTIC PROPERTIES OF TOMATO TISSUE
Authors: JACKMAN ROBERT L. , MARANGONI ALEJANDRO G. , STANLEY DAVID W. 
Published: February 2007

ABSTRACTThe effects of turgor pressure on puncture and viscoelastic properties of mature‐green tomato pericarp were examined using tissue discs soaked in a range of osmotica (0.0–0.6 M mannitol) for at least 36 h at 4C. Turgor pressure was estimated from the osmotic potential of soaking solutions that induced incipient plasmolysis. Based on volume changes, the osmotic potential and turgor pressure of fresh tissue were estimated to be −0.56 ± 0.08 MPa and 0.20 MPa, respectively. However, puncture and viscoelastic properties corresponded to a turgor pressure of 0.15 MPa. The discrepancy between calculated and actual turgor pressures was attributed to the presence of apoplastic solutes. The data from this study revealed a general increase in cell wall stress, strain and elasticity with increasing turgor. With increases in turgor above that of untreated tissue both wall extensibility and elasticity became limiting and thus cell wall stiffness increased. Conversely, a decrease in turgor below that of untreated tissue led to an increase in viscoelasticity. Increases in bioyield and pseudoplastic bioyield strains with a variation in turgor from that of untreated tissue were consistent with cell debonding as a dominant mechanism of tomato tissue bioyielding. The reduced failure force, deformation and firmness with increasing turgor were consistent with cell rupture as a predominant mechanism of failure of mature‐green tomato pericarp tissue.
EFFECT OF STRAIN LEVEL AND STORAGE TIME ON THE RECOVERABLE WORK OF COMPRESSED BREAD CRUMB 1
Authors: NUSSINOVITCH A. , STEFFENS M. , CHINACHOTI P. , PELEG M. 
Published: February 2007

ABSTRACTCylindrical specimens of bread crumbs were subjected to a compression‐decompression cycle using a computer interfaced Universal Testing Machine during 11 days of storage at ambient temperature. The strain (% deformation) was set at various levels in the range of 20–80%. The overall work per unit volume, calculated from the area under the stress‐strain curve, increased exponentially with the imposed strain while the percent recoverable work, calculated from the area under the decompression curve, decreased exponentially with the strain. The loss of elasticity that accompanies bread aging was clearly manifested in the percent recoverable work, irrespective of the imposed strain. It declined in a manner that could be described by a power law or an exponential decay model at the same degree of fit as judged by statistical criteria.
VISCOELASTIC BEHAVIOUR OF AMYLOSE‐FATTY ACID GELS
Authors: RAPHAELIDES S.N. 
Published: February 2007

ABSTRACTRheological measurements were used to study the gelation of amylose in O.01M KOH (pH 12) in the presence of fatty acid potassium salts. Creep compliance‐time experiments indicated that addition of the fatty acids caused considerable changes in the rigidity of the amylose gels. The effect was dependent on fatty acid concentration, molecular conformation and lipid acyl chain length. Dynamic measurements on aged amylose‐potassium stearate gels showed that the development of rigidity modulus was rapid and dependent on the fatty acid concentration.
RHEOLOGICAL INDICES OF FRUIT CONTENT IN JAMS: EFFECT OF FORMULATION ON FLOW PLASTICITY OF SHEARED STRAWBERRY AND PEACH JAMS
Authors: COSTELL E. , CARBONELL E. , DURAN L. 
Published: February 2007

ABSTRACTThe effect of formulation factors on Casson yield values measured at low shear rates (0.08 ≤γ≤ 1.01s‐1) (σ01) and at medium shear rates (2.58 ≤γ≤ 387.30s‐1) (σ02) was analyzed in previously sheared strawberry and peach jams. Twenty three samples of each fruit jam were prepared according to a second order composite rotatable design. Composition ranges were: fruit content, 25–55%; soluble solids content, 60–70° Brix; added pectin in strawberry jams, 0.3–0.7% and in peach jams, 0.1–0.5%. Variation of σ01 values in strawberry jams depended mainly on the interactions between fruit and soluble solids and between fruit and pectin, while in peach jams, it depended on fruit‐soluble solids and soluble solids‐pectin interactions. Patterns of change of σ02 values with composition were similar to those observed for σ01 in both strawberry and peach jams. Predictive power of σ01 and σ02 values for estimation of fruit content was low, but taken in conjunction with soluble solids content and total pectin values, 79.5% of the variability of fruit content in strawberry jams and 91.1% of same in peach jams could be explained.
RHEOLOGICAL PROPERTIES OF WHEY PROTEIN CONCENTRATE GELS
Authors: COONEY M.J. , ROSENBERG M. , SHOEMAKER C.F. 
Published: February 2007

ABSTRACTThe rheological properties of heat whey protein concentrate gels were studied by dynamic oscillation rheometry. A whey protein concentrate of 75% protein was used to make solutions of 10.3, 12.5 and 14.5% protein (w/w), which were heated to 90C for gel formation. Specific attention was focused on the temperature dependence of the mechanical properties of the gels during cooling and reheating. In all cases the magnitude of the complex modulus |G*| was found to increase with decreasing temperatures from 90 to 30C. The tan δ, which is related to the relative viscoelasticity of the gels, increased with decreasing temperatures from 90 to 60C. At temperatures between 60 and 30° C, tan δ remained constant. The dependence of |G*| and tan δ on temperature was found to remain constant during heating and cooling between 30 and 70C, indicating that rheological changes were reversible within this temperature range.
EFFECTS OF STARTER CULTURES ON LINEAR VISCOELASTIC AND PHYSICAL PROPERTIES OF YOGURT GELS
Authors: ROHM H. , KOVAC ALESA 
Published: February 2007

ABSTRACTSet‐style yogurts were produced from cow's milk under standard conditions by using 11 commercially available starter cultures. Samples were prepared in control beakers and within the Couette device of a dynamic rheometer. Repeatability of rheometer yogurt fermentations proved to be satisfactory. Within the linear viscoelastic region a significant inverse relationship between storage modulus and tan δ of yogurt samples was found. Specific properties of starter cultures clearly affected response in dynamic frequency sweeps and in stress relaxation experiments. Dynamic and relaxation data showed good agreement. Relaxation spectra H(τ) were obtained from dynamic measurements and stress relaxation by approximation methods. Both the shape of H‐τ curves and the magnitude of H was affected by starter cultures. As compared to literature data on model casein gels and microstructural findings on yogurt the results imply that (a) a permanent network exists in yogurt, (b) interactions with long relaxation times contribute less to viscoelasticity in the case of yogurt produced with viscous starter cultures, and (c) attachment of mucogenic bacteria to the protein matrix via exogenic polysaccharides decreases yogurt firmness.
IDENTIFICATION OF THE MAIN TEXTURAL CHARACTERISTICS OF CANNED PEACHES AND THE EFFECTS OF PROCESSING VARIABLES
Authors: APOSTOLOPOULOS C. , BRENNAN J. G. 
Published: February 2007

ABSTRACTThe texture profile of canned peach fruits was studied using magnitude estimation as a scaling method. Their sensory characteristics were assessed using as a modulus either a model fruit or a real fruit sample. The sequence of appearance of the textural characteristics was determined during 4 stages of assessment (nonoral, first bite, during mastication, after effects). Four different varieties of peach fruits were canned and the effect of four processing variables (level of heat treatment, degree of ripeness, sugar concentration in the processing liquid and hardness of the processing liquid) on the texture profile of the fruits was examined. The results showed that an increase in the severity of the heat treatment and the degree of ripeness of the fruit resulted in a decrease in the firmness, crunchiness and chewiness of the canned fruit. Fibrousness was similarly affected but to a lesser extent. Freshness and juiciness were also negatively affected by these variables. An increase in the sugar concentration and hardness of the processing liquid resulted in an increase in the firmness, crunchiness and chewiness of the canned fruit. Fibrousness, freshness and juiciness were similarly affected but to a lesser extent.
MODELLING THE GELLING BEHAVIOUR OF LINSEED POLYSACCHARIDE: EFFECT OF SALTS AND pH
Authors: SUSHEELAMMA N.S. , CHAND NAGIN , RAJALAKSHMI D. 
Published: February 2007

ABSTRACTThe rheological properties of linseed polysaccharide gels in the presence of citric acid, calcium and magnesium carbonates were studied using a factorial design and the Herschel‐Bulkley model. The yield stress and consistency index increased with the concentration of calcium and magnesium ions, while the flow behaviour index decreased, imparting stability to the gel. With citric acid, s̀o and k reached a maxima and then decreased, while n increased after an initial dip. The effect of pH (3.4–9.3), sucrose (45–55%), and polysaccharide (0.6–0.8%) on rheological constants were modelled using polynomials where up to fifth power of pH was required. Ln(s̀o), ln(k), and n were fitted to the standardised (normalised) forms of pH, In (sucrose) and In (polysaccharide) with multiple correlations of 0.95, 0.97 and 0.98, respectively. The two optima (with pH) were computed using Nelder and Mead's flexible polyhedral search method. Both required 55% sucrose and 0.8% polysaccharide with pH of 4.3 and 7.3, respectively. The models at the two optima are discussed through 3‐D graphs. The technological implications of the dual optima have been indicated. This is, probably, the first report where two optima, with pH, have been observed for a gel forming polysaccharide.
CHARACTERISATION OF PATTERNS OF CHEWING BEHAVIOUR IN HUMAN SUBJECTS AND THEIR INFLUENCE ON TEXTURE PERCEPTION
Authors: BROWN WENDY E. , LANGLEY KEITH R. , MARTIN ALAN , MacFie HALLIDAY J.H. 
Published: February 2007

ABSTRACTElectromyography was used as a noninvasive and unobtrusive technique to characterise chewing patterns for a range of foods. Differences between subjects for a variety of aspects of chewing sequence are recorded for a range of foods (carrot, apple, roast pork, salami, biscuit and toast). Identifiable subgroups of subjects differing in chewing behaviour existed within the random sample of 52 dentate subjects. The five subgroups accounted for 52%, 21%, 11%, 10% and 6% of the sample population. Major discriminating factors between the behavioural groups lie in their chewing time and the muscle work rate during chewing. Sensory ratings for firmness and rubberiness of model foods differed significantly between the subjects exhibiting different chewing behaviours. Chewing behaviour may influence consumers’ perceptions about the texture of a food.
MEASUREMENT OF FLOW ABILITY OF BUTTER BY CAPILLARY RHEOMETRY
Authors: SHUKLA A. , RIZVI S.S.H. 
Published: February 2007

ABSTRACTCapillary rheometry was used to study and compare the rheological behavior of butters made from supercritically fractionated high melting triglyceride (HMT) and anhydrous milk fat (AMF) at different temperatures. Application of shear rates in the range of 17.37 to 346.93 S−1 showed a strong dependency of flow behavior on the capillary diameter, indicating slippage at the walls. Shear rates were corrected for wall‐slippage using capillaries with different diameters but the same length, and for non‐Newtonian behavior using the Rabinowitsch procedure. Shear stresses were corrected for entrance effect using capillaries of the same diameter but different lengths. Power law consistency indices (K), determined from loglog plots of corrected shear stresses versus shear rates, were found to have a negative correlation with temperature. Higher K values were observed for HMT butter depicting its more solid‐like behavior due to greater concentration of high melting triglycerides. A slight increase in the K values was observed on storage probably due to rearrangement of fat crystals and formation of secondary bonds between them. Flow indices were found to be relatively insensitive to both time and temperature of storage. From the flow curves (apparent viscosity versus shear rates), master curves were generated using the time‐temperature superposition principle.
STIFFNESS ASSESSMENT FROM JAGGED FORCE‐DEFORMATION RELATIONSHIPS1
Authors: PELEG M. , NORMAND M.D. 
Published: February 2007

ABSTRACTBrittle and crunchy foods are notorious for their irregular and irreproducible force‐deformation relationships which cannot be converted to stress‐strain relationships because of geometric considerations. However, a fairly consistent assessment of their stiffness can still be extracted from their jagged force‐deformation curves. For example, either the averaged force at a given deformation (e.g., 20%), determined directly or calculated by fitting the curves of several specimens with a polynomial model, can be considered a legitimate stiffness measure albeit a relative one. But since the magnitude of such parameters is affected by occasional force lows and minima as well as failure and sliding events at preceding deformations, they can only provide a low estimate of the material actual stiffness. Application of an algorithm that identifies the peak forces in the force‐deformation relationship produces a new relationship that has a fairly regular and much smoother shape. Derivation of stiffness parameters from such curves is not only easier because of the regular shape and reduced number of points but also provides a closer estimate of the material actual stiffness.
CONSTITUTIVE MODELS OF FOODS
Authors: KOKINI J.L. , WANG C‐F. , HUANG H. , SHRIMANKER S. 
Published: February 2007

ABSTRACTLinear and nonlinear viscoelastic properties of food materials are important to product design and process design if they can be quantitatively defined. This paper covers prediction of dilute and concentrated solution, linear viscoelastic properties and models for nonlinear viscoelastic properties. The usefulness of various constitutive models in predicting these properties are discussed and demonstrated.
EFFECT OF POSTRIGOR SARCOMERE LENGTH ON MECHANICAL AND STRUCTURAL CHARACTERISTICS OF RAW AND HEAT‐DENATURED SINGLE PORCINE MUSCLE FIBRES
Authors: WILLEMS MARK E.T. , PURSLOW PETER P. 
Published: February 2007

ABSTRACTLight microscopy during tensile tests was used to examine the effect of postrigor sarcomere length (SL) on mechanical and structural characteristics of raw and heat‐denatured (1 h at 80C) muscle fibres of porcine longissimus lumborum and the structural deformation mechanisms of such fibres inducing mechanical differences. The effect of the collagenous network associated with single coldshortened muscle fibres on maximum stress was analysed. Muscle bundles developed rigor at 2C (cold‐shortened = CS), at22C (control = C), and at 22C
EFFECT OF STORAGE ON THE RHEOLOGICAL BEHAVIOUR OF BABY FOODS
Authors: ALONSO M.L. , ZAPICO J. 
Published: February 2007

ABSTRACTThe effect of storage temperature on rheological behaviour of four varieties of baby foods was studied. After 24‐month storage at 15C and 25C, the constant A in Weltman model increased significantly for the vegetables, meat and fish samples, and decreased significantly for the fruit samples. After 24‐month storage at 5C and 15C there were no significant changes in flow behavior index, consistency index and yield stress of the Herschel‐Bulkley model for the vegetables, meat, fish and fruit samples. Increase in storage temperature decreased the consistency index and yield stress of the fruit samples.
RHEOLOGY OF SODIUM CASEINATE‐CARRAGEENAN MIXTURES
Authors: KEOGH M. KIERAN , LAINÉ KARINE I. , O'CONNOR J. FINBARR 
Published: February 2007

ABSTRACTThe main effects and interactions of mixtures of sodium caseinate, k‐ or t‐ carrageenan, sodium chloride, calcium chloride and hydrogen ions on the rheological properties in aqueous systems cooled to 5 C were quantified. Response surface methodology was used to display the results for five different response variables: gelation temperature, consistency index (k*), dynamic power law factor (n*), critical strain (γc), and syneresis. The gelation profiles observed for both k‐ and t‐carrageenan systems demonstrated that the sol‐gel transition in sodium caseinate‐carrageenan mixtures was due to electrostatic interactions of free carrageenan loops or tails with the intervention of cations. Caseinate molecules did not play a major role in this process. The electrostatic nature of the interactions was further demonstrated by the significant influence of salts and pH on the consistency and brittleness of the gels (represented by k*and γc, respectively). Consistency and brittleness were inversely related as well as consistency and syneresis. Syneresis was negligible in t‐carrageenan gels and was reduced by sodium caseinate and sodium chloride in the k‐carrageenan systems.
ON THE APPARENT FRACTAL DIMENSION OF SOUND BURSTS IN ACOUSTIC SIGNATURES OF TWO CRUNCHY FOODS1
Authors: TESCH RALF , NORMAND MARK D. , PELEG MICHA 
Published: February 2007

ABSTRACTThe jaggedness of the filtered and compressed acoustic signatures of cheese balls and croutons at various levels of water activity was determined in terms of an apparent fractal (Kolmogorov) dimension. The plot of the mean dimension vs water activity had a characteristic sigmoid shape that could be adequately described by a modified version of the Fermi equation. Regression analysis yielded that the apparent fractal dimension, DfK, of the cheese balls and croutons when dry was around 1.45 and 1.38, respectively. The inflection point, awc, that is, the water activity level where half the drop in DfK occurred, was awc= 0.50 and awc= 0.55, respectively. The steepness of the jaggedness versus water activity relationship in terms of the aw range where about 90% of the drop of jaggedness occurred was 0.27 in the cheese balls and about 0.29 in the croutons.
RHEOLOGY OF PURE AND MIXED KAPPA‐CARRAGEENAN GELS IN LACTIC ACID FERMENTATION CONDITIONS
Authors: ARTIGNAN JEAN‐MICHEL , CORRIEU GEORGES , LACROIX CHRISTOPHE 
Published: February 2007

ABSTRACTTexture profile analysis and rupture tests, respectively, at a deformation of 5 and 80%, were carried out on commercial kappa‐carrageenan gel cylinders (3% w/v concentration) and on mixed gel cylinders (kappa‐carrageenan/iotacarrageenan or locust bean gum [LBG], in different proportions), to select the best gel composition as an immobilization matrix for continuous lactic acid fermentations of dairy media. Mixed gel cylinders were soaked in a model system for lactic fermentations consisting of 36 dairy media: milk, whey and whey permeate, with 4 lactate concentrations (5, 20, 35 and 50 g/L of medium), combined with 3 pH values (6.5, 6.0, 5.5). GENUGEL X‐0909 n°5180850 was the most resistant of all commercial kappa‐carrageenans available; mixing this kappacarrageenan with LBG in the respective proportions of 2.75%/0.25% gave the best rheological properties to the resulting mixed gel. Our study of the impact of fermentation parameters showed that pH has a significant effect on hardness, cohesion and percentage of deformation at rupture in milk (but not in the other 2 media). A pH drop of milk from 6.5 to 5.5 resulted in more brittle gels which may be explained by an increase in the amount of soluble calcium cations. Generally, soaking in milk produced the most brittle gels due to its calcium content, whey produced the hardest gels and whey permeate, the softest. An increase in the amomonium lactate concentmtion significantly improved hardness, rupture force and percentage of deformation at rupture, while reducing cohesion and resilience: NH4+ cations would account for this effect. The differences in rheological behuviour of immobilization gel beads during continuous Eactic fermentations of milk and whey permeate would be due to the cation content and more specijically to the higher calcium concentmtion in milk.
LOW‐LEVEL BRUISING OF STORED APPLES DUE TO QUASISTATIC LOADING UP TO CONSTANT COMPRESSION STRAIN
Authors: BLAHOVEC J. , PATOČKA K. , BAREŠ J. 
Published: February 2007

ABSTRACTGold Delicious and Spartan apples were compressed between two plates and the bruise‐spot volume was subsequently inspected. Fruits were loaded and unloaded at a strain of about 8%. Tests were performed from harvest to the end of storage under: normal conditions (cold storage at 2C for Spartan and OC for Golden Delicious) and modified conditions (the same temperatures but the Biofresh solution was applied to the fruits before being cooled in storage). The contact Hertz theory can be used to describe the compression curve up to the bioyield point. The parameter BMR (bioyield stress to apparent modulus of elasticity ratio) was used for classification of the whole storage period; it was divided into three parts: softening Ia, weakening Ib, ripened II. There was a linear relation between bruise volume and the absorbed energy for fruits tested at all storage times. But over Ib and II the bruise volume was a relatively stable exponential function of the absorbed energy only. The lowest value of the energy absorbed by a fruit without any bruising decreased in Ia and was relatively stable in other parts. The effect of the Biofresh solution on the mechanical parameters was very limited, affecting only the hysteresis losses in Golden Delicious apples.