bluuebunny/crossref_metadata_2025_split huggingface dataset:
MODELLING THIXOTROPY USING A NOVEL STRUCTURAL KINETICS APPROACH: BASIS AND APPLICATION TO A SOLUTION OF IOTA CARRAGEENAN
Authors: BARAVIAN C. , QUEMADA D. , PARKER A. 
Published: February 2007

ABSTRACTA new methodology for modelling the thixotropy of inelastic fluids is described and its application demonstrated. In order to validate the model, data from two measurement protocols are compared and shown to give coherent results. The structural kinetics approach uses a reduced structural variable, λ, which has values between zero, when the structure is totally broken down, and one, when the structure is complete. The new approach is applied to the thixotropy of a solution of iota carrageenan, a well known food hydrocolloid. Solutions were sheared before testing in order to eliminate their viscoelasticity. The measurement protocols used were: (1) stress jumps from above and below each shear stress tested, and (2) triangular ramp‐up/ramp down stress profiles, often called hysteresis loops. The first series of measurements was used to determine the equilibrium structure and kinetics of structural build‐up and breakdown at each shear stress. This data completely determines the parameters in the thixotropic model and allows prediction of the samples response to any stress/time profile. Without using any additional parameters, this model was then used to predict the shape of the hysteresis loops in the second series of measurements. The agreement between the predictions and measurements was very good, provided that the experimental data was first corrected for the efects of inertia and the finite gap‐width of the rheometer.
INSTRUMENTAL TEXTURE PROFILE ANALYSIS WITH PARTICULAR REFERENCE TO GELLED SYSTEMS
Authors: PONS M. , FISZMAN S.M. 
Published: February 2007

ABSTRACTInstrumental Texture Profile Analysis (TPA) was developed about 30 years ago, constituting an interesting way of analyzing a series of textural parameters in only one test. Since then much work has been done and new tools have been developed. This paper focuses on gelled food systems, reviewing and discussing the evolution of the initial terminology, testing conditions and sampling methods. New parameters, experimental and calculation methods, and some newly proposed are also analyzed, updating the instrumental TPA as applied to gelled systems.
THE RHEOLOGICAL BASIS OF DOUGH STICKINESS
Authors: DOBRASZCZYK B.J. 
Published: February 2007

ABSTRACTStickiness in wheat flour doughs was studied as a function of rheological and surface properties. Adhesion was measured using a modified peel test at various water additions, peel rates and peel layer thicknesses. Peeling energy gave a strong positive correlation with subjective bakery stickiness ratings. Peeling forces were highly rate dependent and showed transitions from sticky to nonsticky behvaiour with increasing rate of peeling. Dynamic storage modulus showed a negative correlation with stickiness ratings, suggesting stickiness is primarily a rheologically controlled process. Stress relaxation gradients were greater for sticky doughs and were very similar to peeling force vs. rate slopes, again indicating that adhesion is principally a function of the rheological properties of the dough. Surface tension measurements of sticky and nonsticky dough/liquor interfaces showed no significant differences and are typical of protein solutions. Calculated values of the interfacial surface energy between dough and interface were about 100 mJ/m2, typical of secondary bonding interactions such as polar or van der Waals bonding.
UNIAXIAL COMPRESSION OF GELS MADE FROM PROTEIN AND K‐CARRAGEENAN
Authors: IPSEN RICHARD 
Published: February 2007

ABSTRACTInvestigations of gels (18% total solids) made from pea protein isolates (PPI) or soy protein isolate (SPI) with differing amounts of K‐carrageenan added showed that the gel strength increased with the concentration of K‐carrageenan. When the concentration ofK‐carrageenan exceeded 0.4%, gels made with PPI were stronger and more stiff than equivalent gels made with SPI. Addition of K‐carrageenan stabilized gels made with PPI towards variations in brittleness (indicated by strain at fracture) with pH. This was not the case when SPI was used. Preheating (75C, 2 min) suspensions containing protein isolates and K‐carrageenan before gel formation increased the strength and stiffness of the final gels, most pronounced when SPI was used. Addition of NaCl (0.5–2%) reduced strength and stiffness of gels, whereas CaCl2 had no influence on gel properties. Mixtures of PPI and SPI proved to be weaker and more brittle than gels made from only SPI of PPI. Results indicate that using proteins of different origin can cause differences in gel structure.
SMALL AMPLITUDE OSCILLATORY SHEAR STUDIES ON MOZZARELLA CHEESE PART I. REGION OF LINEAR VISCOELASTICITY
Authors: SUBRAMANIAN R. , GUNASEKARAN S. 
Published: February 2007

ABSTRACTChanges in texture of a low‐moisture, part‐skim and a low‐fat, part‐skim Moz‐zarella cheese during heating were examined by measuring their rheological properties using small amplitude oscillatory shear (SAOS) tests after 1, 4 and 12 weeks of refrigerated storage. In general, the linear viscoelastic range decreases with increasing temperature and age because cheese behaves more like a viscoelastic solid at lower temperature and shorter ripening time. The dynamic rheological properties (η*, G′ and G″) were constant within a range of 0.05% shear strain. The dynamic rheological properties of low‐fat, part‐skim Mozzarella were found to be higher than that of low‐moisture, part‐skim Mozzarella within the linear viscoelastic range.
THIXOTROPY OF ORANGE CONCENTRATE AND QUINCE PUREE
Authors: RAMOS A.M. , IBARZ A. 
Published: February 2007

ABSTRACTOrange juice with pulp and pectins is thixotropic at soluble solids concentrations of 55 and 60 Brix in the range of temperatures from 0 to 20C and shear rate from 7.2 to 57.6 s−1. Quince purée is thixotropic at soluble solids concentrations of 12.3 to 28 °Brix in the range of temperatures between 0 to 20C and shear rate from 7.2 to 57.6 s−1. The thixotropic behaviour of orange juice and quince purée increases with increasing concentration and decreasing temperature and they can be described by the kinetic model proposed by Figoni and Shoemaker (1983):
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The thixotropic structure of orange juice was destroyed by applying a shear rate of 57.6 s−1 for 5 min, and for quince purée for 10 min. Quince purée shows a greater thixotropic character than orange juice, because it has a higher content of fiber, pulp and pectins and also because it shows a microscopic structure consisting of long particles and heterogeneous fibers.
TENSIPRESSER PRECISION IN MEASURING COOKED RICE ADHESIVENESS
Authors: NAITO SHIGEHIRO , OGAWA TOSHIO 
Published: February 2007

ABSTRACTPrecision in measuring cooked rice adhesiveness was studied using a Tensipresser and the “full cup” method. To determine the optimum adhesiveness parameter, 14 samples each from rice harvests in 1992 and 1993 were used. Out of the 42 parameters derived from a force‐distance curve, the ratio of cumulative adhesiveness to cumulative hardness, was used as the optimum because of its high correlation (r >0.9) with sensory adhesiveness, high precision (mean coefficient of variation (CV) of 14 samples <15% and maximum CV of 14 samples <25 %), and high resolution based on Kruskal‐Wallis test statistic H. For parameter , the maximum CV decreased with the increasing number of bites, and statistic H indicated that increasing the number of bites from 1 to 5 increased resolution, but bites exceeding 5 did not clearly do so.
INSIGHT INTO CONSUMERS’ ASSESSMENTS OF BISCUIT TEXTURE BASED ON MASTICATION ANALYSIS – HARDNESS VERSUS CRUNCHINESS
Authors: BROWN WENDY E. , LANGLEY KEITH R. , BRAXTON DENISE 
Published: February 2007

ABSTRACTNineteen ordinary consumers assessed the hardness, crunchiness and crumbliness of a series of biscuits exhibiting texture differences. Chewing patterns were obtained from all of the subjects eating the same samples by simultaneous recording of masticatory muscle activity and jaw movement. There was a strongly significant inverse correlation between hardness and crumbliness and weaker but significant correlations between hardness and crunchiness (positive) and between crunchiness and crumbliness (negative). The hardness/crumbliness dimension was well represented by several instrumental measures of the mechanical properties of the samples and by several descriptors assessed by a trained sensory panel. Crunchiness gave ambiguous relationships with these objective measures. Chewing data indicated an increase in masticatory muscle effort between the first 5 chews and the next 5 chews with a subsequent decline in effort to the end of the chewing sequence. This was associated with a transfer of effort from a principally compressive force during the initial chews, to a mixture of compressive (fracture) force and grinding (shear) force during later chews. Mastication of the harder and crunchier samples required more total chewing effort. Principal component analysis demonstrated a relationship between sensory hardness (and conversely, crumbliness) and the chewing effort during the first 5 chews, and between crunchiness and the chewing effort during the subsequent 5 chews. This study indicates the importance of the temporal changes occurring in the sample during mastication to perception of textural characteristics.
RELATING SENSORY TEXTURAL ATTRIBUTES OF CORN TORTILLAS TO SOME INSTRUMENTAL MEASUREMENTS
Authors: REYES‐VEGA M.L. , PERALTA‐RODRÍGUEZ R.D. , ANZALDÚA‐MORALES A. , FIGUEROA‐CÁRDENAS J.D. , MARTÍNEZ‐BUSTOS F. 
Published: February 2007

ABSTRACTTexture of corn tortillas from six commercial brands was measured with an Instron Universal Testing Machine by puncture with cylindrical (flat‐end) and spherical punches, tearing (tension), and Texture Profile Analysis (TPA). Peak force read from the curves for puncture and tearing, and TPA parameters (hardness, springiness, cohesiveness and chewiness) were correlated with sensory quantitative descriptive analysis (QDA) parameters (hand tearing, hardness, springiness, moisture, grittiness and stickiness). Pearson's (r) and
KAUFFMAN'S ABSTRACT MODEL OF PHASE TRANSITIONS1
Authors: NORMAND MARK D. , PELEG MICHA 
Published: February 2007

ABSTRACTAccording to Kauffman's abstract model (1995), a phase transition occurs when free nodes become interconnected through random linking. Despite the randomness of the process, the general patterns that it produces are idiosyncratic and highly predictable, demonstrating the universality of the phase transition phenomenon and its independence of the physical interpretation of the nodes and links. To make it more representative of real materials, the model was modified by introducing rules that restrict the distance between the nodes that are allowed to connect. This produced transition patterns that were very similar to those produced by allowing any pair of nodes to connect, and with a very similar cluster size distribution. The model does not account for all the specific mechanisms of phase transitions that cause the hardening of foods. But it does offer at least a partial explanation as to why certain consistent patterns emerge regardless of a food's variability at the molecular and microstructural levels, and it emphasizes the random character of the interactions between its components.
FLAVEDO AND ALBEDO CHANGES IN ‘EUREKA’ LEMONS CAUSED BY STATIC COMPRESSION AND IMPACT LOADING
Authors: UNDERHILL STEVEN J.R. , MCLAUCHLAN RICHARD L. , DAHLER JANELLE M. , BERTRAM JOHN 
Published: February 2007

ABSTRACTMature lemons (Citrus limon (L.) Burm. ‘Eureka') were subjected to increasing compression, impact and static loading, then stored at either 1C, 13C or 20C for 14 or 28 days. Following storage, fruit were assessed for cellular damage associated with the site of loading. Slow compression (1.7cm plunger driven at a loading rate of 200 mm min−1) resulted in cell damage in the mid to lower flavedo tissue. Tissue failure was characterised by cell rupture, with minor cell deformation and compression associated with damage to the oil glands. Impact loading caused relatively little lower flavedo damage, with most of the injury associated with the albedo, the upper flavedo and tissue surrounding the oil glands. Damaged albedo cells formed a distinct zone of ruptured and laterally compressed tissue which increased in area with drop height. Static loading (3.7 kg top weight) resulted in a similar mode of failure to that of impact loading, with extensive cellular damage observed in the lower albedo. Injury was distinct in that cells were not laterally compressed and flavedo damage was far more pronounced. While most of the tissue damage was directly
EVALUATING EXPANDED‐FOOD SENSORY PROPERTIES BY IMAGE ANALYSIS
Authors: GAO X. , TAN J. , SHATADAL P. , HEYMANN H. 
Published: February 2007

ABSTRACTThe objective of this study was to ascertain whether sensory properties of extruded corn puff texture can be predicted by digital image analysis. Gradient image statistics, such as third moment and standard deviation, run‐length statistics, and features computed from fuzzy edge‐detected image were used. Visually‐determined sensory properties included cell density, cell wall thickness, cell size uniformity. Crushing force between molars and biting force between incisors were among the hardness‐related sensory properties. All the sensory properties could be predicted with a coefficient of determination (r2) of 0.89 or higher. In most cases, a polynomial function of an image feature was the best model for predicting sensory scores. Image features derived from the intensity band of a hue, saturation, and intensity color model gave the highest r2 values for predicting visually‐determined sensory properties. For hardness‐related sensory properties, the features derived from saturation band resulted in the best r2 values.
STABILITY OF MODEL ACID MILK BEVERAGE: EFFECT OF PECTIN CONCENTRATION, STORAGE TEMPERATURE AND MILK HEAT TREATMENT
Authors: LUCEY J. A. , TAMEHANA M. , SINGH H. , MUNRO P. A. 
Published: February 2007

ABSTRACTAcid milk beverages were made by homogenizing and diluting acid milk gels made with glucono‐b‐lactone. A central composite experimental design and response suqace methodology were used. Colloidal stability was assessed by the amount of surface whey produced during storage, the flow behaviour and particle size distribution. Using regression analysis a second order polynomial model satisfactorily predicted the effect of pectin concentration on whey separation (R2= 0.88). Whey separation was significantly decreased by pectin concentration and increased by the quadratic term for pectin concentration (P < 0.001). Neither of the other variables had a significant effect on any of the indices of colloidal stability. The prediction equations for the variables flow behaviour index and particle size distribution had much lower values (I 0.63). It is suggested that pectin prevented the aggregation of casein‐gel fragments; evidence for this was also provided by confocal scanning laser micrographs of beverages made with various concentrations of pectin.
UNIAXIAL COMPRESSION AND STRESS RELAXATION TESTS ON ALGINATE GELS
Authors: MANCINI MARCO , MORESI MAURO , RANCINI ROBERTO 
Published: February 2007

ABSTRACTThe rheological behavior of alginate gels was analyzed using uniaxial compression and stress relaxation tests. The engineering compressive stress (σE)‐deformation (ɛE curves were found to be concave upward and independent of the crosshead speed (Vt for Vt≥ 120 mm/min. By considering all the stress (σE)‐time (t) data for t greater than 10 times the average loading period, the viscoelastic response of these gels was described by means of a 3‐element Maxwell body characterized by a relaxation time of 300 s. Such gels exhibited an apparent linear viscoelastic solid behavior for ɛE≤ 8% and a nonlinear one for larger deformations. However, for ɛE>32% their solid viscoelastic behavior tended to a liquid one. Empirical models allowed the viscoelastic properties, as well permanent deformation, of these gels to be quantitatively described as functions of the deformation applied and/or loading rate.
UNIAXIAL COMPRESSIBILITY OF BLACKGRAM DOUGHS BLENDED WITH CEREAL FLOURS
Authors: BHATTACHARYA SILA , BHATTACHARYA SUVENDU , NARASIMHA H.V. 
Published: February 2007

ABSTRACTThe uniaxial compression characteristics of papad dough (moisture content 62%, dry basis), made from blackgram flour as well as after incorporation of different types of cereal (rice, sorghum and wheat) flours at different levels (20 and 40%), were determined. The stress‐strain data can be interrelated by a power law type equation. The sensory attributes (stickiness, firmness, elasticity and ease of flattening/rolling) were correlated with the energy for compression, deformability modulus and apparent biaxial elongational viscosity. Inelastic doughs resulted from the blackgram dough; doughs with 20% rice or wheat blends were also inelastic but sorghum samples were elastic. The deformability modulus for sorghum doughs were extremely high. The blackgram dough as well as the wheat blended doughs were the easiest doughs to roll/flatten. Blended dough consisting of wheat flour (at 20 and 40% level) or rice flour up to 20% level was suitable for making cereal‐blended papad doughs.
TEXTURAL AND STRUCTURAL CHANGES IN LASAGNA AFTER COOKING
Authors: GONZALEZ J. J. , MCCARTHY K. L. , MCCARTHY M. J. 
Published: February 2007

ABSTRACTThe effects of cooking time (9.5, 11, and 15 min) and holding time of lasagna pasta after cooking (4 min to 185 min) on the textural properties (through mechanical testing) and internal structure (via nuclear magnetic resonance imaging) were studied. The peak force, which characterized firmness, decreased with increasing cooking and holding time. Work was strongly influenced by the value of the peak force and followed a similar trend. Corresponding NMR images revealed changes in proton signal intensity as a function of position. The NMR signal intensity increased at the center with increasing cooking and holding times. This change illustrates that water migration to the sample center was simultaneous with the decrease in the peak force. The initial slope, associated with the structure of the sample surface region, decreased with cooking time and increased with holding time. The NMR signal intensity of the surface region decreased with holding time; water migration from this region during this period was simultaneous with an increase in stiffness. NMR imaging is an effective technique to evaluate internal structural changes of pasta during holding. Furthermore, it supplements information provided by conventional mechanical testing, facilitating the interpretation of texture measurements.
FLOW AND STRUCTURAL CHARACTERISTICS OF CONCENTRATED MILK
Authors: VÉLEZ‐RUIZ J. F. , BARBOSA‐CÁNOVAS G. V. 
Published: February 2007

ABSTRACTThe flow and structural characteristics of concentrated milk were analyzed between concentrations of 12.5 and 46.7% solids content at room temperature. The rheological behavior of milk concentrates was represented by parameters corresponding to Newtonian, Power Law, or Herschel‐Bulkley equations depending on the solids content level. The resulting flow behavior indices and consistency coefficients were correlated to concentration by a single‐term exponential equation, with only milk concentrates above 40% solids content exhibiting yield stress. Milk concentrates were characterized by scanning electron microscopy (SEM), complemented by transmission electron microscopy (TEM) and image analysis (IA). Casein micelles appeared as granular particles (0.1–0.3 μm) with a rough surface. Fat globules, noted as small holes in the SEM pictures, appeared to be major spherical components (0.5–10 μm) in the transmission electron microscope images as well as in the image analysis inverted micrographs. Fat globules in the milk concentrates were surrounded by a membrane which was thicker in the concentrated milk than in the fresh milk. TEM images were very helpful in observing the interparticle interactions, as well as the thickness of the fat membranes that corroborated with the SEM observations. The IA pictures allowed the identification and characterization of the fat globule features.
MICROSTRUCTURAL FAILURE MECHANISMS IN COOKED AND AGED CARROTS
Authors: THIEL B. L. , DONALD A. M. 
Published: February 2007

ABSTRACTIn situ mechanical testing of hydrated carrot (Daucus carota) parenchymal tissue was performed in an Environmental Scanning Electron Microscope. Carrots were either aged or cooked for varying amounts of time in order to ascertain how these processes affect the mechanical response of the cellular microstructure to being sliced by a scalpel blade. In fresh tissues when the turgor pressure is high, the cells burst in the expected manner. Boiling the tissue reduced the ability of the cells to retain liquid, effecting a transition from closed‐cell to open‐cell behaviour and the cell walls were torn in tension, behind the blade. Ageing resulted in a drop in the turgor pressure and these materials failed in a manner similar to the fresh, raw tissue except they exhibited a transition in elastic modulus from a pliant to a brittle state when the cells were deformed sufficiently to increase the turgor pressure to the ‘fresh’ value.
STIFFNESS OF COMPRESSION TESTING MACHINES
Authors: ROHM HARALD , NOEL YOLANDE , SCHLEINING GERHARD 
Published: February 2007

ABSTRACTA ring test with six participating laboratories and rubber stoppers as reference material was performed to monitor the performance of commercial compression testing instruments. Testing conditions were chosen to be in the range of regular compression testing. Small, single screw instruments with a cantilever exhibited a significant deviation in the force/deformation‐response compared with double‐screw instruments with a crosshead. Additional tests made with an external device for displacement recording revealed that these differences have to be attributed to insufficient stiffness and some compliance in the cantilever of the tested single‐screw instruments. Some consequences of the test results for experiments on soft, semi‐soft and rigid food materials are discussed and an equation is developed to correct for the flexing of the cantilever beam in the single screw machine.
STUDY OF THE ANOMALOUS CAPILLARY BAGLEY FACTOR BEHAVIOR OF THREE TYPES OF WHEAT FLOUR DOUGHS AT TWO MOISTURE CONTENTS
Authors: BREUILLET CHRISTOPHE , YILDIZ ERHAN , CUQ BERNARD , KOKINI JOZEF L. 
Published: February 2007

ABSTRACTThe flow properties of wheat flour dough were evaluated using a capillary rheometer as a function of flour type (soft, hard and durum wheat flours) and dough moisture content (43 and 48% wb). The description of experimental flow properties was conducted using the classical Bagley approach and assuming linear relationships between pressure drop and L/D ratio (R2 ranging from 0.795 to 0.993). The entrance pressure drop (Po) increased (from 40 to 1870 kPa) with an increase in shear rate (from 40 to 1333 s−1) and a decrease in dough moisture content. Shear viscosities (7 to 160 Pa.s) and elongational viscosities (41 to 2840 kPa.s) demonstrated shear‐thinning behaviors that were characterized using power law models. Elongational and shear flows were compared by the Trouton ratio. The characterization of the capillary flow behavior for wheat flour dough was then discussed in regard with a possible nonlinear behavior of Bagley plots and related to possible changes in dough structure (i. e. dough hardening, strain hardening and dough deorientation).