bluuebunny/crossref_metadata_2025 huggingface dataset:
MECHANICAL PROPERTIES OF THE FLESH OF SWEET AND SOUR CHERRIES
Authors: BLAHOVEC JǏRÍ , JESCHKE JAN , HOUŠKA MILAN
Published: February 2007

The mechanical properties of the flesh of sweet and sour cherry varieties were studied using penetration of whole and skinned fruits by a cylindrical pin. Fresh and canned fruits were included in the study. The results obtained, and their relation to results obtained previously, show that the cherry flesh plays a more important role in the deformation process when its apparent modulus of elasticity is greater than approximately 0.15 MPa. At lower values compression behaviour of the cherry flesh seems to resemble the behaviour of liquids, and the fruit skin has a more important role in a fruit integrity.
MEASURING ELONGATIONAL PROPERTIES OF MOZZARELLA CHEESE
Authors: AK M. M. , GUNASEKARAN S.
Published: February 2007

A vertical uniaxial extension apparatus was developed for determining elongational properties of Mozzarella cheese over the course of one month of refrigerated storage. Cheese specimens suspended in hot oil (60C) first underwent melting and then stretching under the influence of a constant force. Samples did not break even after 400% extension. Strain rate and sample temperature both increased during a test. Transient elongational (TE) viscosity of Mozarella cheese decreased with increasing strain rate and sample temperature. Proteolysis of caseins in Moz‐zarella, determined by gel electrophoresis, did not alter its TE viscosity to an extent measurable by our method.
TEXTURE ANALYSIS OF BEEF COOKED AT VARIOUS TEMPERATURES BY MECHANICAL MEASUREMENTS, SENSORY ASSESSMENTS AND ELECTROMYOGRAPHY
Authors: MATHEVON E. , MIOCHE L. , BROWN W. E. , CULIOLI J.
Published: February 2007

The potential of mechanical measurements, sensory assessments and electromyography (EMG) to detect the variation in texture properties of beef induced by cooking at temperatures of 45–80C was determined. The mechanical behaviour of meat, from two Semimembranosus muscles from one animal, was studied by compression and shear tests in destructive and nondestructive conditions. Electromyographs from the masticatory muscles of 14 trained subjects were recorded during mastication of the meat samples. Texture profiles were completed at the end of each masticatory sequence. Increase in cooking temperature produced an overall increase in shear and compression parameters as well as in meat elasticity. Sensory hardness and total muscle work developed during mastication also increased with cooking temperature. Mechanical measurements, EMG parameters and sensory assessment of texture were highly correlated. EMG, on which the influence of psychological factors is limited, can be used to characterise meat texture objectively.
CREEP BEHAVIOUR OF TOMATO PERICARP TISSUE AS INFLUENCED BY AMBIENT TEMPERATURE RIPENING AND CHILLED STORAGE
Authors: JACKMAN ROBERT L. , STANLEY DAVID W.
Published: February 2007

The influence of normal ripening and chilling stress on viscoelastic properties of tomato pericarp tissue were investigated by measuring creep behaviour of tissue from fruit stored at 22C (nonchilled) or 5C (chilled) for 28 days, or at 5C for 16 days prior to transfer to 22C for an additional 12 days (prechilled). Creep compliance of tissue from all treatments subjected to a constant shear stress of 150 Pa for 5 min was best represented by a 6‐element Burgers model containing two discrete Voigt‐Kelvin units characterizing fast and slow rate viscoelastic properties. The magnitude of instantaneous elastic, viscoelastic and steady‐state viscous compliances each increased steadily and contributed to the overall softening of nonchilled and prechilled tissues during ripening, but remained unchanged during chilling of tomato fruit. Increased fluidity of ripening tissues occurred at the expense of elasticity, consistent with a decrease in molecular weight‐size distribution of structural elements contributing to respective viscoelastic properties. The physico‐mechanical changes in prechilled tissue preceded those in nonchilled tissue by several days, and occurred at a faster rate. The 6‐element Burgers model defining the creep behaviour of tomato pericarp tissue was interpreted with respect to general plant cell wall structure and biochemical changes known to occur during ripening of tomato fruits. Multiple mechanisms of softening were thereby consolidated into a single physico‐mechanical model.
RHEOLOGY OF RICE‐FLOUR PASTES: RELATIONSHIP OF PASTE BREAKDOWN TO RICE QUALITY, AND A SIMPLIFIED BRABENDER VISCOGRAPH TEST
Authors: RANI M. R. SANDHYA , BHATTACHARYA K. R.
Published: February 2007

Flours from 21 nonwaxy rice cultivars, varying in amylose‐equivalent (AE) content and eating quality, were pasted at 12–13% concentration at 95C and then further cooked at the same temperature for another 60 min. The fall in apparent viscosity, measured in a coaxial cylinder viscometer, of the 95C–50 min as compared to that of the 95C–0 min paste (paste breakdown, bdp) was calculated. The bdp values were inversely correlated to the sensory and viscoelastograph hardness of cooked rice as well to the AE contents. Paste breakdown was clearly a fundamental attribute of rice quality. It appears that starch granule rigidity/fragility, as determined by its AE, is the basic element in rice quality. This principle was then used to devise an abridged Brabender viscograph procedure. The slurry concentration was adjusted, by a simple technique described, to give a predetermined viscosity value at 95C. Then the paste was heated for another 10 min at 95C. The breakdown at 95C (BD95) of the samples correlated excellently with their total and insoluble AE, sensory and instrumental measures of cooked‐rice texture, and with bdp.
TEXTURE EVALUATION OF FRENCH ACID‐TYPE FRESH CHEESES
Authors: BEN OMAR Z. , RAPHAELIDES S. , KESTELOOT R.
Published: February 2007

A range of French acid‐type fresh cheeses of various commercial brands was tested by a trained sensory panel which detected significant differences in thickness, smoothness and slipperiness. The cheeses exhibited thixotropic behaviour. The perceived thickness of the samples was highly correlated with the shear stress values obtained for a limited range of shear rates (30–80 S−1). The area of the hysteresis loop formed during the first shearing cycle of the samples over a wide range of shear rates (4.5–450 S−1) was negatively correlated to slipperiness. The correlation matrix showed that the sensory attributes were independent of the chemical composition of the products. Principal components analysis indicated the way the three sensory attributes were related to each other and to the rheological parameters.
CHARACTERISATION OF A COMMERCIAL SOY ISOLATE BY PHYSICAL TECHNIQUES
Authors: CHRONAKIS IOANNIS S. , KASAPIS STEFAN , RICHARDSON ROBERT K. , DOXASTAKIS GEORGIOS
Published: February 2007

The mechanical features of a partially denatured commercial soy isolate (PP 500E) have been explored for comparison with data available on the gelation characteristics of native globular proteins and to improve the understanding of its textural properties as a structuring ingredient in the production of low fat products. The soy sample was reconstituted at 30C and networks were developed either during cooling to 5C or on heating to 90C (complete denaturation of the protein) followed by cooling to 5C. Throughout the course of experimentation, dynamic oscillatory (time, temperature, frequency and strain sweeps) and creep testing (in aqueous or urea solutions) measurements were recorded. Reduction in the thermal energy of the system causes a monotonic increase in storage modulus (G′) whereas the temperature rise results in equilibrium G′ values well below the elastic response observed at 30C. The absence of a positive thermal transition, observed in the gelation of native globular proteins, indicates a different mechanism for structure formation in commercial soy isolates. Application of the cascade treatment to the concentration dependence of the storage modulus argues that the heated and cooled networks possess a higher degree of bond permanency than their cooled‐only counterparts. Mechanical spectra in combination with the pattern of network breakage at high deformations suggests that disulphide bonds participate in the network formed by totally denatured soy protein (heated and cooled samples). Inclusion of urea in the aqueous preparations destabilises the predominantly physical forces of attraction in the unheated gels. By contrast, the heated and cooled samples achieve an equilibrium deformation whose storage modulus can be employed in the constitutive equation of rubber elasticity theory. On that basis the number of disulphide bridges per molecule was found to vary between 2.0 and 2.03. This result is consistent with the “string of beads” model proposed for the three‐dimensional structure of globular protein gels, where a dendric network is built by the occasional cross‐linking of corpuscular strands.
THE RELATIONSHIP BETWEEN THE RHEOLOGICAL AND SENSORY PROPERTIES OF A LEMON PIE FILLING
Authors: HILL M.A. , MITCHELL J.R. , SHERMAN P.A.
Published: February 2007

A range of lemon pie fillings containing the ingredients corn starch, sugar, egg yolk, lemon juice and water were prepared using a constant weight mixture design. There were five ingredients in the system and four ratio variables were employed resulting in 25 formulations. Dynamic rheological and sensory measurements were performed. The latter used magnitude estimation to evaluate the characteristics of thickness, sweetness and lemon flavour. The relationship between the complex viscosity (η*) and perceived thickness was in good agreement with previous work on simpler model systems. Perceived sweetness showed a greater decrease than perceived lemon flavour with increased viscosity. The decrease in sweetness with increasing viscosity increased with increasing sucrose concentration, but was less than has been observed for systems thickened by random coil polysaccharides. An attempt has been made to explain this in terms of solution structure.
MEASURING HARDNESS DISTRIBUTION OF COOKED RICE BY SINGLE‐GRAIN PUNCTURE
Authors: PEREZ CONSUELO M. , BOURNE MALCOLM C. , JULIANO BIENVENIDO O.
Published: February 2007

A 0.71‐mm‐diameter punch mounted in the Instron Universal Testing Machine was used to measure hardness of 100 individual grains of 15 rices after cooking. A hardness distribution curve for each rice was obtained. The puncture forces of rices cooked at a fixed water:rice weight ratio of 2 were more variable than those for rices cooked in excess water for the optimum cooking time. High‐ and intermediate‐amylose rices cooked using a water:rice ratio of 2 were harder than corresponding rices cooked in excess water. For waxy and low‐amylose rices, the reverse was generally true. Pairs of rices with almost identical physicochemical properties but which differed in preference tests by consumers also differed in their hardness distribution profile.
ELECTRORHEOLOGICAL BEHAVIOR OF MILK CHOCOLATE
Authors: DAUBERT C.R. , STEFFE J.F.
Published: February 2007

Electrorheology is an area of study that evaluates changes in flow properties upon the application of an electric field. Electrorheological fluids generally exhibit an increase in apparent viscosity and a greater yield stress over an unelectrified sample. The phenomenon requires an electric field, polar particles in suspension, and an insulating oil. Milk chocolate meets these criteria and displays unique behavior when exposed to an electric field. A concentric cylinder viscometer, fitted with special electrical attachments, was used for data collection. This system allowed for control of the applied dc voltage, fluid temperature, and shear rate while observing the resulting effects on the shear stress. Data analyses show that, at constant temperature, the shear stress increases as the voltage increases. Continued analyses depict that shear stress increases as temperature increases when subjected to a constant shear rate and voltage. These results establish milk chocolate as a bona fide electrorheological fluid. The chocolate industry may benefit from this research by gaining knowledge of a new technique to externally control the flow properties of milk chocolate, allowing the development of unique processes and products.
CHARACTERIZATION OF BRITTLE FOOD PRODUCTS: APPLICATION OF THE ACOUSTICAL EMISSION METHOD
Authors: AL CHAKRA W. , ALLAF K. , JEMAI A.B.
Published: February 2007

The structural properties of pasta have been characterized based on sound emisison which generally accompanies rupture of brittle products. This paper presents the principal evolution tendency of the different mechanical and acoustical parameters by varying the relative humidity of the product, and the correlation existing between these two parameters. The correlations suggest that sound emission during rupture may well be utilized to characterize a given product in parallel to or in replacement of commonly measured mechanical properties.
CREEP AND DYNAMIC RHEOLOGICAL BEHAVIOR OF TOMATO CONCENTRATES: EFFECT OF CONCENTRATION AND FINISHER SCREEN SIZE
Authors: YOO BYOUNGSEUNG , RAO M.A.
Published: February 2007

Based on laser diffraction, pulp particles > 900 μm were detected in tomato concentrates; particles greater than 100–200 μm were found in serum from a concentrate. Creep‐compliance and dynamic rheological data showed that viscoelastic properties of 21 °Brix tomato concentrates using a 0.84 mm finisher screen were higher than those from a 0.69 mm screen. Both types of viscoelastic properties were sensitive to increase in concentration in that they increased with increase in Brix of the concentrates. Magnitudes of instantaneous modulus (G0= 1/J0) of the tomato concentrates were of the same order of magnitude as the storage modulus (G') at 1 rad s‐1.
RELAXATION BEHAVIOR AND THE APPLICATION OF INTEGRAL CONSTITUTIVE EQUATIONS TO WHEAT DOUGH
Authors: RAMKUMAR D.H.S. , BHATTACHARYA M. , MENJIVAR JUAN A. , HUANG T.A.
Published: February 2007

The small amplitude rheological properties of doughs of different compositions were measured using a dynamic rheometer. In the first study, the effect of water, flour, and added gluten on the dynamic properties was investigated. Frequency sweep was carried out in the range of 0. 1 to 100 s−1 at an applied strain of 0. 1%. Storage (G') and loss (G”) moduli for each composition were recorded. The storage modulus versus frequency plots were a series of parallel curves indicating that the moisture‐to‐flour ratio was the most important parameter. The loss modulus versus frequency plot showed a falling‐off after a frequency of 40 s−1. A plot of tan δ versus frequency indicated a more elastic dough at shorter time
EVALUATING RHEOLOGICAL PROPERTIES OF MOZZARELLA CHEESE BY THE SQUEEZING FLOW METHOD
Authors: AK M.M. , GUNASEKARAN S.
Published: February 2007

We adapted the squeezing flow technique to make compression and relaxation tests on Mozzarella cheese at temperatures ranging from 30 to 60C during one month of refrigerated storage. The deformability modulus of the cheese decreased with aging and temperature but increased with deformation rate. The average decrease in the deformability modulus was 0.4 kPa/day and 0.5 kPa/C. Relaxation data also indicated a continuous increase in viscous character of Mozzarella with aging and temperature. Apparent relaxation time was less than 10 s. Relaxation parameters showed a strong temperature dependency in the range of 10‐60C. Lubricated squeezing flow data showed that the resistance of Mozzarella to flow decreased with aging and temperature indicating an increased meltability.
FIBER DIAMETER AND FISH TEXTURE
Authors: HURLING R. , RODELL J.B. , HUNT H.D.
Published: February 2007

Cross‐sections of cooked muscle were prepared using a vibrating microtome. Average fiber cross‐sectional area was measured by confocal scanning laser microscopy and image analysis. Fiber cross‐sectional area significantly correlated with sensory perception of firmness (r = ‐0.91, p < 0.01). Sensory firmness decreased with increasing fish species fiber cross‐section.
SMALL DEFORMATION PROPERTIES OF MODEL SALAD DRESSINGS PREPARED WITH REDUCED CHOLESTEROL EGG YOLK
Authors: PARASKEVOPOULOU ADAMANTINI , KIOSSEOGLOU VASSILIS , ALEVISOPOULOS STEFAN , KASAPIS STEFAN
Published: February 2007

Low‐fat, low‐cholesterol materials were extracted from spray‐dried egg yolk using as solvents petroleum ether, petroleum ether/ethanol, ethanol/water, and supercritical CO2. The four extracts and their source (spray‐dried yolk) were incorporated into traditional recipes for oil in water salad dressings. The linear viscoelasticity of these systems was characterised by dynamic oscillation and creep/relaxation curves on a stress‐controlled Carri‐Med rheometer. The high protein content of the extracts generates stronger and more elastic structures than those of commercial salad dressings but they are comparable to the viscoelastic properties of commercial mayonnaises which contain high cholesterol egg yolk. Measurements of the size of oil droplets over a period of eleven days demonstrate that these emulsions maintain acceptable consistency. The methodology adopted and the conclusions derived might assist in the purposeful formulation of low‐cholesterol salad dressings.
CHANGES IN SIZE OF GAS CELLS IN DOUGH AND BREAD DURING BREADMAKING AND CALCULATION OF CRITICAL SIZE OF GAS CELLS THAT EXPAND
Authors: SHIMIYA Y. , NAKAMURA K.
Published: February 2007

Microscopic observation showed that a group of small air cells entrained during the early stage of mixing is the original cause of cell structure of bread. At the beginning of fermentation, about 3 × 108/m2 gas cells with diameters between 3 × 10−6 and 8 × 10−4 m were entrained in the dough. The distribution curve of cell size was approximately normal on a logarithmic scale. During fermentation and proofing, a great portion of carbon dioxide was released into cells larger than about 10−4 m in diameter that was equivalent to a few percentages of total number of gas cells. After baking, gas cells smaller than 10−4 m in diameter were not observed and the total number of cells in baked bread reduced to about 106/m2 with diameters between 10−4 and about 5 × 10−3 m. The critical cell size to expand generally agreed with the calculated value using an equation, rc’= 3s/E (re': critical radius to expand, s: surface tension, E: elasticity), and cited value of s and E.
CORRELATION BETWEEN TRANSIENT ROTATIONAL VISCOMETRY AND A DYNAMIC OSCILLATORY TEST FOR VISCOELASTIC STARCH BASED SYSTEMS
Authors: NAVARRO A.S. , MARTINO M.N. , ZARITZKY N.E.
Published: February 2007

Gelatinized starch formulations including lipids and xanthan gum, typical of viscoelastic foodstuffs, were analyzed using a rotational viscometer (transient conditions) and an oscillatory rheometer. Ultra‐rapid and slow freezing processing conditions, which can modify product stability, were also tested. Transient shear stress curves showed a typical overshoot and a structural breakdown; the Bird‐Leider model satisfactorily fitted these curves. Model parameters were correlated with characteristic peak stress (αmax), peak time (tmax) and relative overshoot corresponding to the α vs time curve. Relationships between transient shear stress data and dynamic measurements (G′, G*, δ) for viscoelastic ranges were found for the starch‐based systems and were used to assign a physical meaning to Bird‐Leider parameters. Viscoelastic starch systems were grouped in different zones of the correlation diagrams based on structure properties like rigidity, stability to the applied strain and fluid characteristics after breakdown.
RHEOLOGICAL PROPERTIES OF UF‐FETA CHEESE DETERMINED BY UNIAXIAL COMPRESSION AND DYNAMIC TESTING
Authors: WIUM H. , QVIST K.B.
Published: February 2007

Rheological characteristics of three Feta cheeses produced from ultrafiltered milk (UF‐Feta cheeses) with different textures were evaluated using uniaxial compression and dynamic testing (strain and frequency sweeps). Stress at fracture was 20–46 kPa, Hencky strain at fracture was 0.20–0.35, modulus of deformability was 176–465 kPa, and work up to fracture was 4.4–6.7 kj/m3, depending on the type of cheese and the strain rate. Stress at a given strain, and stress at fracture increased with strain rate: the slope of the log (stress at fracture) versus log(in‐itial Hencky strain rate) plot was 0.06–0.21, indicating a partially viscous behavior. Stress at fracture discriminated between all three Feta textures, and Hencky strain at fracture discriminated a Tin Feta texture from two Brick Feta textures at every compression rate. In dynamic testing the complex modulus was 40–173 kPa, and tan (δ) was 0.17–0.25 depending on the type of cheese and the frequency of oscillation. The slope of log(complex modulus) or log(storage modulus) versus log (frequency) was 0.12–0.14, and the slope of log(loss modulus) versus log (frequency) was 0.07–0.11 for all three types of cheese. The complex modulus from strain and frequency sweeps in the dynamic testing distinguished the Tin Feta texture from the Brick Feta textures, and the phase angle (δ) measured in strain sweep could differentiate the Blue Brick Feta texture from the Red Brick Feta texture in the strain interval 0.0003–0.024.
Correlation Between Fracture of Semi‐sweet Hard Biscuits and Dough Viscoelastic Properties
Authors: PIAZZA L. , SCHIRALDI A.
Published: February 2007

Semi‐sweet hard dough biscuits were considered in the present work which aims at assessing whether biscuit failure mode and dough viscoelastic properties, which depend on the resting time after mixing, can be correlated to one another. Uniaxial compressions were performed on rested biscuit doughs to determine biaxial extensional viscosities. The experimental data seemed strongly dependent on the compression rate in the 1‐20 mm/min range of crosshead speed. The stress growth trend observed for doughs of different resting time showed that the extent of structural recovery increased with resting. The rheological behuviour of dough under higher extensional deformation was evaluated by means of tensile and tensilerelaxation tests, the result of which can be directly related to the sheeting extensional deformation. These data confirmed the picture of dough structural recovery. Rheological investigations were coupled with DSC determinations of the glass transition temperature, The higher Tg found for rested doughs was tentatively attributed to gluten protein polymerisation. It was finally shown that the failure mode of biscuits changes with the resting time after mixing: the longer the rest, the less the biscuit strength.
SEM IMAGE PROCESSING FOR FOOD STRUCTURE ANALYSIS
Authors: TAN J. , ZHANG H. , GAO X.
Published: February 2007

Image processing techniques were developed to characterize the cellular structure of puffed corn meal extrudates from their scanning electron microscope (SEM) images. Cross‐section SEM images were taken and digitized for product samples of different degrees of expansion. Two major approaches were developed to extract structure‐related image features. The air cells were also manually measured as the true characteristics of the cellular structure. Correlation and regression analyses were conducted to determine the effectiveness of the image features as measures of the structural characteristics. A number of image features were found to be good indicators of cell size and cell uniformity (R2‐values up to 0.95). The image processing techniques developed were useful in cellular structure characterization and they provide a rapid and consistent way for food cellular structure quantification and analysis.
ESTIMATION OF THE MECHANICAL PROPERTIES OF INDIVIDUAL BRITTLE PARTICLES FROM THEIR BULK COMPRESSIBILITY1
Authors: SUWONSICHON THONGCHAI , NORM MARK D. , PELEG MICHA
Published: February 2007

Two puffed cereal particles were compressed both individually and in cells of different diameters and heights. The degree of jaggedness of their force‐displacement curves were expressed in terms of their apparent fractal dimension determined from the Richardson plot and by the box counting method (Kolmogorov's dimension). Plots of the degree of jaggedness versus cell diameter and height produced approximately planar relationships in a three dimensional space. Their extrapolation to the individual particle characteristic dimensions gave jaggedness values in agreement with those determined experimentally on the individual particles. This demonstrates that it is possible, at least in certain products, to assess the “brittleness” of individual particles from their bulk compressibility pattern. The same procedure could also be used to estimate the particle “stiffness” expressed in terms of the force at a preselected displacement level (e.g., 15 or 25%).
PERCEPTION AND MEASUREMENT OF STICKINESS IN SUGAR‐RICH FOODS
Authors: KILCAST DAVID , ROBERTS CLIVE
Published: February 2007

The subject of stickiness is reviewed briefly in this paper, together with the factors influencing perceived stickiness in different contexts. A clear understanding of the difference between adhesive and cohesive failure mechanisms, and the factors influencing them, is a key requirement in developing successful tests to measure stickiness. This has led to the development of an instrumental test for measuring the stickiness of confectionery products, and recommendations are made for minimising sticking of confectionery products to surfaces.
USE OF COMBINED ELECTROMYOGRAPHY AND KINESTHESIOLOGY DURING MASTICATION TO CHART THE ORAL BREAKDOWN OF FOODSTUFFS: RELEVANCE TO MEASUREMENT OF FOOD TEXTURE
Authors: BROWN WENDY E. , EVES DAVID , ELLISON MILES , BRAXTON DENISE
Published: February 2007

This paper describes a method for obtaining detailed information about the velocities, directions and relative forces involved in mastication, and how these change throughout the chewing sequence, from combined electromyograph and kinematic records in human subjects. Differences in the temporal breakdown patterns of apple, carrot and biscuit are highlighted. Mastication of apple and carrot relied on vertical compression for each chew, with decreasing effort applied over the course of the chewing sequence. Differences between these products were related principally to the chewing effort exerted. For biscuit, compression was the predominant mechanism of breakdown in early chews but this was transferred to a shear action over the course of the sequence.
INFLUENCE OF WATER ON THE CRISPNESS OF CEREAL‐BASED FOODS: ACOUSTIC, MECHANICAL, AND SENSORY STUDIES
Authors: ROUDAUT G. , DACREMONT C. , MESTE M. LE
Published: February 2007

The texture properties of crispy breads were studied as a function of water content using compression tests, acoustic measurements and sensory analysis. The addition of water slowly lowers the characteristics associated with crispness up to 9%, after which they steeply decrease. Dynamic Mechanical Thermal Analysis (DMTA) measurements were carried out, at room temperature and at 5 Hz, on the same bread samples. The evolution of the textural properties of crispy bread are accompanied by an increase of the loss factor prior to the one associated to the glass transition. It was therefore proposed that the effect of water on the brittle character, on crispness and on the intensity of the sound emitted at fracture were due to the onset of molecular motions preceding or accompanying the glass transition.
BOOK REVIEWS
Authors: RAO M.A.
Published: February 2007

FOOD PROPERTIES HANDBOOK

Handbook of BIOSENSORS and ELECTRONIC NOSES.
MICROSTRUCTURE AND TEXTURE OF CHEESE ANALOGS CONTAINING DIFFERENT TYPES OF FAT
Authors: LOBATO‐CALLEROS C. , VERNON‐CARTER E. J. , HORNELAS‐URIBE Y.
Published: February 2007

The texture of cheese analogs, whose fat fraction was composed of butterfat, soybean oil or soybean fat and their blends was measured by instrumental Texture Profile Analysis (TPA), and sensorially by a trained panel and the results were subjected to Response Surface Methodology (RSM). The microstructure was examined by Scanning Electron Microscopy (SEM). The models showed that the diverse fat types differently influenced the instrumental characteristics of hardness and springiness, and the sensory characteristics of firmness, elasticity, shear resistance, mouthfeel and creaminess of the cheese analogs. Scanning electron micrographs indicated that the morphology, size and distribution of fat droplets also varied with the fat type.
THE EFFECTS OF pH AND TIME ON RHEOLOGICAL CHANGES DURING EARLY CHEESE MATURATION
Authors: RAMKUMAR C. , CAMPANELLA O. H. , WATKINSON P. J. , BENNETT R. J. , CREAMER L. K.
Published: February 2007

Changes in rheological properties of cheese curd during the initial stages of ripening, with pH (5.45–6.05) and with time (2–14 days), were evaluated using a small strain oscillatory test and a newly designed large strain deformation test. The new test method developed for evaluation of grated cheese employed extrusion flow technique and was carried out using the Instron Universal Testing Machine. The values for the storage modulus (G') measured using the small strain test increased with an increase in the pH of cheese curds from 5.45 to 5.90. The results from the large strain test showed essentially similar trends. The samples of curd also showed an increased solid‐like behaviour as the pH increased and appeared to become more elastic with time during the two‐week period of analysis.
EFFECTS OF VARIOUS INGREDIENTS ON THE TEXTURE OF MILK JELLY
Authors: MORITAKA HATSUE , NAITO SHIGEHIRO , NISHINARI KATSUYOSHI , ISHIHARA MIKI , FUKUBA HIROYASU
Published: February 2007

Effects of various ingredients on the texture of milk jellies prepared from gellan gum, milk powder, sweetener were examined using a sensory test and physical measuring apparatus. The data were analyzed by use of the modification ofScheffé's mixture experiment method in rectangular experimental area in the Scheffé's triangle. “Hardness” and “smoothness” of milk jellies estimated by a subjective method were influenced by the content of gellan gum. The evaluations of “milk flavor” and “sweetness” estimated by a subjective method were varied with the content of sweetener and evaluated as higher for softer milk jellies. The correlation coefficients between “hardness” estimated by a subjective method and “smoothness”, “milk flavor”, and “sweetness” estimated by a subjective method were negative.
SENSORY, INSTRUMENTAL AND ACOUSTIC CHARACTERISTICS OF EXTRUDED SNACK FOOD PRODUCTS
Authors: DUIZER L.M. , CAMPANELLA O.H. , BARNES G.R.G.
Published: February 2007

Corn based extrudates produced at three moisture contents and stored at four water activities were evaluated by sensory evaluation and instrumental tests in order to assess how processing and storage affect the sensory characteristics of the products. Acoustic signatures were collected by recording the sounds produced as the samples were bitten through with the back molars. These signatures were analyzed by fast Fourier transformation and the Kolmogorov dimension of fractal analysis. Products with a low moisture content and water activity were crisper than those at a higher moisture content and water activity. Fourier transformations of the data showed peaks between 1 and 2 kHz and between 6 and 7 kHz. Fractal analysis of the normalized raw time‐amplitude curves showed significant positive correlations between fractal dimensions and the sensory characteristics of crispness, crumbliness and pitch.
WHEY SEPARATION IN ACID SKIM MILK GELS MADE WITH GLUCONO‐δ‐LACTONE: EFFECTS OF HEAT TREATMENT AND GELATION TEMPERATURE
Authors: LUCEY JOHN A. , MUNRO PETER A. , SINGH HARJINDER
Published: February 2007

The effects of heat treatment and gelation temperature on whey separation in acid milk gels made with glucono‐δ‐lactone were studied using three empirical methods, two of which were developed specifically to quantify spontaneous whey separation from set acid gels. Gels were made in volumetric flasks and petri dishes and the amount of surface whey produced by gels after 16 h was compared with the amount of supernatant expressed by low speed centrifugation (100 g X 10 min) of gels made in tubes. A central composite experiment design and response surface methodology were used. Using regression analysis a second order polynomial model satisfactorily predicted the effect of heat treatment and gelation temperature on whey separation for gels made in volumetric flasks (R2= 0.89). Whey separation was significantly increased by heat treatment (P < 0.001), gelation temperature (P < 0.01) and the quadratic term for heat treatment (P < 0.01). A significant (P < 0.01) positive correlation (r = 0.71) was observed between whey separation in volumetric flasks and petri dishes. It was suggested that high heat treatments and gelation temperatures favour more rearrangements of the network just after formation, making gels unstable and sensitive to spontaneous whey separation.
QUANTITATIVE MEASUREMENT OF FOOD SPREADABILITY USING THE VANE METHOD
Authors: DAUBERT C.R. , TKACHUK J.A. , TRUONG V.D.
Published: February 2007

This study was performed to describe an application of the vane method for the rapid, quantitative measurement of spreadability, a subjective, textural property. Yield points of thirteen commercial food items were determined and related to spreadability using models HBTDV‐I and 5X HBTDV‐I Brookfield viscometers equipped with three different vanes. Spreadability strongly impacts consumer approval of a food. This textural property has been linked to the yield stress of a material, but observations support that strain at yielding may also be important. A textural map, showing yield stress and yield strain of the selected foods was created to chart regions of spreadability.
ASSESSMENT OF COHESION IN GRUYERE‐TYPE CHEESE BY RHEOLOGICAL METHODS
Authors: PESENTI V. , LUGINBÜHL W.
Published: February 2007

The quantitative assessment of cohesion in unripened hard cheese was studied using static methods (uniaxial compression and tension, 3‐point bending, and cutting) and transient methods (stress relaxation and creep). The two levels of cheese cohesion (denoted as weak and strong, according to the judgement of the cheesemaker) were obtained by two different manufacturing procedures. Statistical analysis showed that all static methods can be used to discriminate various levels of cohesion. Uniaxial tension proved to be the most powerful test to assess quantitatively the cohesive properties of hard cheese since the values of all parameters (fracture stress, fracture strain, work to fracture, modulus of deformability, and apparent flow modulus) depend significantly (α < 0.01) on the level of cohesion. Stress relaxation and creep tests were not as powerful as the rapid static methods in distinguishing the two levels of cheese cohesion.
RHEOLOGICAL CHARACTERIZATION OF “DULCE DE LECHE” BY DYNAMIC AND STEADY SHEAR MEASUREMENTS
Authors: NAVARRO ALBA S. , FERRERO CRISTINA , ZARITZKY NOEMI E.
Published: February 2007

Rheological properties of three commercial samples of the typical Argentine sweet spread “Dulce de Leche” (common, low calorie and confectionery types) were measured by transient tests (constant shear rate time dependency) using rotational viscometry and dynamic measurements with oscillatory rheometry. All the samples showed a strong time dependency but no recovery of the structure was detected in a 24‐h period. A prominent overshoot was evidenced in all transient assays; at long times, the Leider‐Bird model converges to the power law equation. The linear‐viscoelastic range for the confectionery “Dulce de Leche” determined by the dynamic test ranged up to a limit deformation of 9% whereas the other two types had a range up to 3.5%. The behavior of the three types of “Dulce de Leche” was intermediate between a concentrated solution and a gel but the confectionery type was closer to a gel‐like behavior than the other two. Differences found in the rheological behavior of the three “Dulce de Leche” types were related to their different compositions and the presence or absence of thickening agents.
RHEOLOGICAL CHARACTERIZATION OF RICOTTA CHEESES BY IMPERFECT SQUEEZING FLOW VISCOMETRY 1
Authors: SUWONSICHON THONGCHAI , PELEG MICHA
Published: February 2007

Samples of three commercial ricotta cheeses made from whole milk, part skim milk and fat free, were compressed in a 140 mm diameter shallow Teflon® container with a wide Teflon® plate, of 64 or 100 mm in diameter, to induce imperfect lubricated squeezing flow. The log force versus log specimen height relationship had a linear region from which the region of a dominant squeezing flow regime could be clearly identified. Its slope was on the order of −1.0 to −0.8 in the whole milk ricotta, −1.6 to −0.9 in the part skim milk and −1.7 to −1.2 in the fat free cheese. The apparent stresses at two selected heights (1 and 2 mm) and at two given times after relaxation (60 and 120 s) were sensitive measures of consistency and could be used to distinguish between the ricottas of the three types. The coefficient of variation of these measures was 10% or less, while the differences between the ricottas or the different brands were 20 to 100%. The apparent stresses, before and after relaxation, had a modest dependence on the upper plate diameter, but the latter had no effect on their sensitivity as measures of consistency. Doubling the compression rate, from 0.1 to 0.2 mm. s−1, had a relatively small effect on the magnitude of the apparent stresses, probably a consequence of the high yield stress.
INSTRUMENTAL SINGLE AND DOUBLE COMPRESSION TESTS TO PREDICT SENSORY TEXTURE CHARACTERISTICS OF FOODS
Authors: MEULLENET J.‐F. C. , GROSS J.
Published: February 2007

Twenty four commercial food samples were evaluated by a professionally trained descriptive panel who profiled hardness, springiness, fracturability, cohesiveness, cohesiveness of mass and chewiness in the test samples. Instrumental evaluation was carried out using both single and double compression tests with the TAX‐T2 Texture Analyzer and a probe consisting of a set of dentures (B.I.T.E. masterII). Multiple instrumental parameters were extracted from the force‐deformation curves of single and double compression tests and used for predicting sensory attributes using Partial Least Squares Regression. Relative Ability of Prediction (RAP), the equivalent of an R2 taking into account the unexplained variation of the sensory data, were calculated to evaluate the models'predictive quality. Hardness (RAP=0.84), cohesiveness (RAP=0.72), and fracturability (RAP=0.85) were somewhat accurately predicted, while springiness (RAP=0.52), cohesiveness of mass (RAP=0.34), and chewiness (RAP=0.25) were unsatisfactorily predicted using a single compression test. Even though the test methods used differed significantly from traditional TPA testing, a double compression test did not offer significant improvements over the single compression test for the prediction of textural characteristics, except for the attributes springiness (RAP=0.79) and cohesiveness of mass (RAP=0.49).
MECHANICAL PROPERTIES OF A CORN STARCH PRODUCT DURING THE POST‐FRYING PERIOD
Authors: ROVEDO CLARA O. , PEDREÑTO‐NAVARRO MARIA M. , SINGH R. PAUL
Published: February 2007

The mechanical properties of the crust and core regions of an immersion‐fried corn starch patty containing different amounts of gluten, amylose, and amylopectin were studied after various storage times. Moisture and oil profiles for the different gluten contents were also determined during post‐frying storage. The addition of gluten did not affect the hardness of the crust region of the fried samples during storage, but the addition of amylose and amylopectin significantly increased the hardness of the crust. Samples with 5% added amylopectin showed a similar behavior, but in this case the puncture force significantly increased during the first hour of storage and remained constant thereafter. The range of linear viscoelastic behavior for fried corn starch patties in compression was for strains up to 4%. Stress relaxation curves showed that the elasticity of corn starch patties increased with time of storage, but decreased with the addition of gluten. The addition of 5% amylose caused a significant increase in elasticity, whereas with 5% amylopectin, the increase in this variable was less noticeable.
TEXTURE PROPERTIES OF GELLAN GELS AS AFFECTED BY TEMPERATURE
Authors: MAO RUNSHENG , TANG JUMING , SWANSON BARRY G.
Published: February 2007

Gellan gels can be made very brittle, similar to agar gels, or very flexible, like gelatin gels. The entropy or enthalpy nature governing those gellan gel behaviors was studied by mechanical testing at temperatures varying from 2 to 62C. Both failure stress and strain for 1% low acyl and low acyl/high acyl mixed gellan gels decreased with increasing temperature, indicating that the hydrogen bonding contributed significantly to the stabilization of gellan gels in addition to the polyanion‐calcium‐polyanion bonding. Hydrophobic interactions were less important. The initial Young's modulus for two mixed high and low acyl gellan gels containing 2 mM Ca++ increased with temperature from 2–42C, indicating entropy elasticity. Average molecular weight between adjacent crosslinks for these two mixed gels was larger than 104. For other gels, the entropy elasticity was not a dominant mechanism for elastic force because of molecular weights between crosslinks and from the observation of negative temperature dependence of the modulus.
PREDICTION OF RICE TEXTURE BY SPECTRAL STRESS STRAIN ANALYSIS: A NOVEL TECHNIQUE FOR TREATING INSTRUMENTAL EXTRUSION DATA USED FOR PREDICTING SENSORY TEXTURE PROFILES
Authors: MEULLENET JEAN‐FRANCOIS C. , SITAKALIN C. , MARKS B. P.
Published: February 2007

Sensory texture characteristics of cooked rice for three cultivars (74 samples) were predicted using an extrusion cell and a novel data analysis method (i.e. Spectral Stress Strain Analysis). Eight sensory texture characteristics were evaluated and force values from the instrumental tests were used in combination with Partial Least Squares regression to evaluate predictive models for each of the sensory attributes studied. Relative Ability of Prediction (RAP) values were evaluated for each model; they ranged from 0.06 to 0.85. Satisfactory models are proposed for the two major texture characteristics of cooked rice, namely hardness (RAP=0.85) and stickiness as evaluated by adhesion to lips (RAP=0.76). Other sensory attributes such as roughness of mass (RAP=0.73) and toothpack (RAP=0.81) were also satisfactorily predicted. Sensory attributes such as toothpull (RAP=0.12) and loose particles (RAP=0.06) could not be predicted using the Spectral Stress Strain Analysis.
RELATIONSHIP BETWEEN INSTRUMENTAL AND SENSORY MEASUREMENTS OF CHEESE TEXTURE
Authors: DRAKE M.A. , GERARD P.D. , TRUONG V.D. , DAUBERT C.R.
Published: February 2007

The relationship between sensory and instrumental texture measurements of natural and processed cheeses was studied. A descriptive analysis panel evaluated seven mouth‐evaluated and five hand‐evaluated texture terms. Instrumental measurements included texture profile analysis (TPA), frequency sweeps, and creep. Multivariate analyses showed that many of the sensory and instrumental analyses were highly correlated. Principal component analysis showed similarities and differences in how the cheeses were differentiated by sensory and instrumental techniques. TPA and fundamental rheological tests worked equally well at predicting sensory attributes of the cheeses, but TPA was better at predicting sensory attributes when cheeses were divided into two groups, natural and processed. Instrumental measurements predicted sensory attributes of processed cheeses better than natural cheeses. While fundamental rheological tests reveal important information on network structure and molecular arrangement, these results indicate that empirical texture evaluations work equally well or better at predicting sensory texture properties.
NONDESTRUCTIVE CHARACTERIZATION OF APPLE FIRMNESS BY QUANTITATION OF LASER SCATTER
Authors: CHO YONG‐JIN , HAN YOUNG J.
Published: February 2007

A laser technique for characterization of apple firmness was developed on the assumption that laser scatter was affected by firmness. Saturated area ratios and relative areas, defined as laser scatter parameters, were measured for Tsugaru and Fuji apples and the effects of laser wavelengths and optical power levels on the parameters were investigated. When a laser beam with longer wavelength, 632.8 nm, and lower power, 1.7 mW was used, the laser parameters showed significant correlation with firmness parameters. Varietal difference had significant effects on the correlation between different compressive properties and laser scatter parameters. For Tsugaru apple, bio‐yield force and rupture force showed high correlation with laser features, while for Fuji apple, bio‐yield deformation and rupture deformation were more significant than the bio‐yield and rupture forces. The initial slope and secant slope showed high correlation with laser features regardless of cultivar.
SENSORY AND FIRMNESS MEASUREMENTS OF CALCIUM‐ AND HEAT‐TREATED APPLES
Authors: ABBOTT JUDITH A. , KLEIN JOSHUA D. , CAMPBELL T. AUSTIN , CONWAY WILLIAM S. , SAMS CARL E.
Published: February 2007

‘Golden Delicious’ apples were held at 38C for 0 or 4 days and treated with 0 or 0.14 mol · L−1 CaCl2· 2 H2O, stored at OC for six months, and then held at 20C for 7 days. Texture and quality were measured by nondestructive sonic vibration, Magness‐Taylor (MT) puncture and axial compression of tissue
DYNAMIC MECHANICAL ANALYSIS OF MARINATED CHICKEN BREAST MEAT
Authors: KERR W. L. , LI R. , TOLEDO R. T.
Published: February 2007

Chicken breast muscle was marinated and tumbled in solutions of 7% NaCl and 1.2% of disodium pyrophosphate (DSPP), tetrasodium pyrophosphate (TSPP), tetrapotassium pyrophosphate (TKPP), sodium tripolyphosphate (STPP), or glass phosphate. Dynamic mechanical thermal analysis was used to measure storage modulus and Tan δ as samples were heated from 25 to 75C. For untreated samples, four thermal transitions were noted with the most significant transition at 55.8C. Addition of NaCl and phosphate reduced the number of distinct events, and decreased the major transition to temperatures around 46–48C. Uncooked, marinated samples had lower G’ and Tan δ. Treated samples also showed an increase in G’ over the 25–45C range. Heating caused the greatest changes in treated samples, with values of G'75C and Tan δ75C similar to untreated samples. Different phosphate types resulted in significant differences in G’ and Tan δ values. G’ values correlated well with Young's modulus, but not with Warner‐Bratzler shear values or expressible moisture. Results are discussed in terms of changes in muscle proteins resulting from exposure to NaCl and phosphates, as well as to heat.
PREDICTION OF INSTRUMENTAL AND SENSORY TEXTURAL CHARACTERISTICS OF MAHON CHEESE FROM ULTRASONIC MEASUREMENTS
Authors: BENEDITO JOSE , CÁRCEL JUAN A. , GONZALEZ REMEDIOS , SANJUÁN NIEVES
Published: February 2007

Ultrasonic velocity was related to sensory and instrumental texture measurements. A semi‐logarithmic model (Weber‐Fechner) was used to relate the sensory and instrumental texture measurements. The ultrasonic velocity ranged from 1650 to 1723 m/s for the softest and hardest cheese, respectively. As expected from theoretical equations, the ultrasonic velocity was related to the square root of the instrumental measurements. The deformability modulus (r2=0.93) and the slope in puncture (r2=0.85) were the most closely related parameters. A model developed from the relationship between sensory and instrumental texture and the relationship between ultrasonic velocity and instrumental texture, was used to relate velocity to sensory measurements. Elasticity (r2= 0.84) and firmness (r2= 0.81) were the sensory attributes which best correlated with ultrasonic velocity. From the obtained results, it was concluded that ultrasonic velocity measurements could be used to assess instrumental and sensory properties of Mahon cheese texture nondestructively, and therefore could be used for grading purposes.