bluuebunny/crossref_metadata_2025_split huggingface dataset:
A COMPARISON OF THE VISCOELASTIC PROPERTIES OF CONVENTIONAL AND MAILLARD PROTEIN GELS
Authors: ARMSTRONG HELEN J. , HILL SANDRA E. , SCHROOYEN PETER , MITCHELL JOHN R. 
Published: February 2007

ABSTRACTThe properties of gels prepared by heating solutions of bovine serum albumin (BSA) for 30 min at 121C in the presence and absence of glucono‐delta‐lactone (GDL gels) and xylose (Maillard gels) were compared. During formation the pH of the Maillard and GDL gels decreased to 4.9 whereas the pH of the gels formed in the absence of GDL or xylose remained near neutral. Maillard gels show much less syneresis compared with the GDL gels and contained nondisulphide covalent crosslinks as evidenced by very low protein solubilities in mixtures of sodium dodecyl sulphate and β‐mercaptoethanol. Both the GDL and Maillard gels could be formed at much lower protein concentrations than the neutral conventional gels. The stress relaxation of the gels in compression was measured and the response analyzed using Peleg's equation. The parameters in this equation were not strongly dependent on protein concentration or degree of deformation. The neutral pH gels were far more elastic than the low pH gels, but despite the difference in crosslinking mechanisms the viscoelastic behaviour of the Maillard and GDL gels was similar. However, the break strength and asymptotic residual modulus of the Maillard gels were higher. It is suggested that the stress relaxation occurs in weaker, noncovalently linked regions of the gel, whereas the nondisulphide covalent crosslinks in the Maillard gels reinforce strong regions already containing disulphide linkages.
EFFECT OF SAMPLE VOLUME ON THE COMPRESSIVE FORCE‐DEFORMATION CURVES OF CORN FLAKES TESTED IN BULK1
Authors: NIXON RICHARD , PELEG MICHA 
Published: February 2007

ABSTRACTTwo national brands of cornflakes were compressed in cells of various dimensions (height 38–76 mm and diameter 50–91 mm) using a Universal Testing Machine. The stress‐strain (σ vs. ε) relationships could be described by a four parameter model originally developed for cellular materials, i. e., σ(ε) = k1εn1+ k2εn2 where the k's and n's are constants (n1 < 1, n2 > 1). The scatter around the fitted relationships was normalized and its jaggedness determined in terms of an apparent fractal dimension and the mean magnitude of the power spectrum after filtering. The magnitude of both depended on the cell diameter and height indicating that the observed degree of jaggedness is influenced simultaneously by “averaging” and “cushioning” effects.
SENSORY TEXTURE PROFILE, GRAIN PHYSICO‐CHEMICAL CHARACTERISTICS AND INSTRUMENTAL MEASUREMENTS OF COOKED RICE
Authors: ROUSSET SYLVIE , PONS BRIGITTE , PILANDON CARINE 
Published: February 2007

ABSTRACTThree samples of raw‐milled rice, and 4 differently parboiled rices were used to study and to relate sensory perception to instrumental measurements. Variance analysis showed that some physico‐chemical characteristics indicated great differences among rice samples: thickness of cooked grain, length/width ratio, water uptake, elastic recovery, white core rate and amylose and protein contents. The most discerning sensory attributes were: elasticity, stickiness, pastiness, mealiness, length of grain, firmness, crunchiness, time in mouth, brittle texture and juiciness. The correlation circle of the principal component analysis (PCA) showed high correlation between some sensory characteristics and instrumental measurements. Melting texture, surface moistness, juiciness, were positively correlated with water uptake (r = 0.70, 0.61, 0.71). Granular texture, crunchiness, brittleness and mealiness were significantly affected by white core presence (r = 0.81, 0.74, 0.86, 0.83). Elasticity was dependent upon elastic recovery and firmness measured by the Viscoelastograph, but not linearly. Length of cooked grain was correlated with the length/width ratio of raw grain (r = 0.83). Pastiness, compactness, stickiness were slightly influenced by the thickness of raw grain (r = 0.81, 0.67, 0.72). To a weaker extent, the sensory firmness was associated with the firmness measured by extrusion force using an Ottawa cell (r = 0.58). PCA showed greatdifferences in texture between rices. Two of the parboiled rices were very elastic, another was firm, granular, crunchy and mealy. The remaining two, cooked longer, were moister and more melting. Among the 3 samples of raw‐milled rices, differences in grain length feeling and melting‐granular‐brittle characteristics. were distinguished.
RHEOLOGICAL BEHAVIOUR OF KIWI FRUIT JUICE CONCENTRATES
Authors: IBARZ A. , GINER J. , PAGAN J. , GIMENO V. , GARZA S. 
Published: February 2007

ABSTRACTThe rheological behaviour of diluted kiwi concentrates (22.5–63.0 °Brix) over the temperature range 4 to 70C, was studied. The values below 55.7 °Brix fit the power law while above 55.7 °Brix fit the Herschel‐Bulkley equation. Maximum and minimum consistency index values were 62225 and 16 mPa. sn. Concentrates showed a yield stress at 55.7 °Brix, from 5 to 11 Pa, and 63.0 °Brix, from 19 to 53 Pa. Yield stress was correlated with temperature by means of a linear equation. Arrhenius activation energies were in the range of 28.97 to 33.89 kJ/mol. The average value of the flow behaviour indexes varied from 0.85 (sample at 22.5 °Brix) to 0.59 (sample at 63.0 °Brix). Simple equations are proposed to describe the combined effect of temperature and soluble solids content on consistency index and rheological behaviour index.
ASSESSMENT OF A PIN DEFORMATION TEST FOR MEASUREMENT OF MECHANICAL PROPERTIES OF BREAKFAST CEREAL FLAKES
Authors: GEORGET D. M. R. , PARKER R. , SMITH A. C. 
Published: February 2007

ABSTRACTA pin deformation test is assessed for the measurement of the mechanical properties of breakfast cereal flakes where well‐defined procedures like the three point bend test are not easily carried out. These properties are compared with the literature on formed specimens of cereal components, starch polymers and proteins. A classical analysis of a centrally loaded disc on a circular support was used to obtain the Young's modulus, the maximum stress and the maximum strain from the force‐displacement curve. The technique was validated for synthetic polymer discs of known modulus. The Young's modulus for formed discs of starch and gluten as a function of water content agreed reasonably well with independent results using a three point bend test. Formed discs of ground flake showed a similar response to that of gluten. The technique was then applied to individual flakes which were flattened by a hydration‐dehydration procedure and conditioned to different water contents. The stiffness and stress at failure decreased with increasing water content as reported for gluten but their magnitudes were lower, which was attributed to the greater porosity relative to pressed specimens. Some unflattened and low water content flakes were also tested and (although not conforming to the planar geometry of the analysis) showed similarity in stiffness (although not in strength) with their flattened counterparts.
KINETIC OF SOFTENING OF CARROT BY GAMMA RADIATION
Authors: BOURNE MALCOLM C. 
Published: February 2007

ABSTRACTRaw carrots were diced into 9.5 mm cubes, and subjected to gamma radiation between an array of Co60 pencils. A series of doses ranging from 0 to approximately 50 kGy was given. A plot of log (extrusion force) versus dose showed two distinct regions; the first is a rectilinear plot with a steep negative slope for doses up to about 15 kGy. The second is also a rectilinear plot with a shallow negative slope beyond 15 kGy. Sixty‐seven percent of the firmness is lost with the first 15 kGy but only 4% of the firmness is lost with the highest 15 kGy increase in dose. This two‐stage softening rate curve is consistent with the model of two first‐order kinetic rate processes and is qualitatively similar to that for thermal softening of carrot. The term “radiation firmness” is proposed to describe the amount of firmness that is resistant to degradation by irradiation.
OSCILLATORY RHEOMETRY: THE NECESSITY FOR SAMPLE TEMPERATURE CORRECTION1
Authors: PETROFSKY E.A. , HOSENEY R.C. 
Published: February 2007

ABSTRACTPreliminary results using an oscillatory probe rheometer to follow sol to gel transformations of pasted starch gave illogical results. G″ appeared to increase instead of decrease, as would be expected for a gelling sol. The increase was dramatic at high temperatures. In many instances the viscosity loss values (η') were negative, which is physically impossible. Therefore, the equations used were examined for a source of error. It was found that no temperature correction was made for probe frequency in the test sample. Use of the temperature correction for probe frequency in the sample along with the equations provided with the instrument showed that the oscillatory probe rheometer effectively measured viscous and viscoelastic properties of starch gel systems throughout the sol to gel transformation.
EFFECTS OF HYDROCOLLOIDS AND ASPARTAME ON SENSORY VISCOSITY AND SWEETNESS OF LOW CALORIE PEACH NECTARS
Authors: PASTOR M.V. , COSTELL E. , DURÁN L. 
Published: February 2007

ABSTRACTEffects were studied of interactions between each of three hydrocolloids‐xanthan gum, guar gum and methylcellulose‐ and aspartame on sweetness intensity and sensory viscosity of low‐calorie peach nectars (60% fruit purée with no sucrose added). The flows of the nectars were characterized as near Newtonian without hydrocolloids, as Bingham plastic at lower hydrocolloids concentrations and as pseudoplastic at higher concentrations (Ostwald flow for guar and methylcellulose, and Herschel‐Bulkley for xanthan). Hydrocolloids concentrations were selected to cover viscosity range of commercial whole nectars: 0.10 and 0.20% xanthan or guar, and 0.15 and 0.30% methylcellulose. Aspartame concentrations tested were derived from the calculation of equisweet concentration as referred to a control nectar sample with sucrose (14°Brix) and of the upper and lower limen value: 0.216, 0.360 (equisweet), 0.502, and 0.644 g/L. Addition of either guar or methylcellulose did not alter the perceived sweetness in aspartame‐sweetened peach nectars. Xanthan addition, even at 0.10%, significantly lowered sweetness of samples sweetened with the highest aspartame concentration (0.644 g/L). Addition of aspartame did not modify the perceived viscosity in samples thickened with either xanthan or guar gums. At all methylcellulose concentrations tested, samples with the lowest aspartame concentration (0.216 g/L) were perceived as less viscous.
EVALUATION OF THE RHEOLOGICAL PROPERTIES OF FRESH CORN MASA USING SQUEEZING FLOW VISCOMETRY: BIAXIAL EXTENSIONAL VISCOSITY1
Authors: RAMÍREZ‐WONG B. , SWEAT V.E. , TORRES P.I. , ROONEY L.W. 
Published: February 2007

ABSTRACTAlkaline corn was cooked for 20, 55 or 80 min, and the nixtamal was ground into masas with medium or coarse particle size distributions. Water was added to each corn masas in order to obtain the same adhesiveness. Rheological properties of these masas were evaluated with the squeezing flow viscometry technique with lubrication at crosshead speeds of 0.05, 0.2 and 0.5 cm/min, respectively. From the data collected, stress‐strain and biaxial elongational viscosityradial extension rate curves were obtained. All the fresh corn masas gave the same stress and elongational viscosity at any given specific strain and radial extension rate, respectively, regardless of the cooking time and degree of grinding. The elongational viscosity could be useful to predict fresh corn masa behavior during molding and cutting steps in the tortilla‐making process.
KINETIC MODELING OF VEGETABLE COOKING AT 100C
Authors: RAMESH M.N. , SATHYANARAYANA K. , GIRISH A.B. 
Published: February 2007

ABSTRACTKinetics of cooking of green peas, carrot, radish and knolkol were determined from the compression force ratio of the vegetables before and after cooking. The kinetics of rice and potato cooking, both starchy products were found to be suitable in explaining the kinetics of cooking of vegetables. The degree of cooking was correlated to cooking time and the reaction rate constant, K, value was determined for four vegetables. With this K value the degree of cooking at various other cooking times was predicted. The R2 value and standard error of estimate were determined.
FINITE ELEMENT ANALYSIS OF MODES OF VIBRATION IN APPLES
Authors: LU RENFU , ABBOTT JUDITH A. 
Published: February 2007

ABSTRACTThree‐dimensional finite element models were developed to study modes of vibration in apples. The apple models were created using two mathematical equations, in which the geometry of the apple was described by a four‐parameter equation and the core structure by an exponential function. Modal analyses were performed to identify the vibrational modes and to study the effects of material properties, structure (i.e., the skin and core), shape, and size on them. There were three classes of vibrational modes in apples: torsional, spheroidal, and nonaxisymmetric. A majority of modes between 0 and 2000 Hz belonged to the nonaxisymmetric class. The square of natural frequency was linearly related to Young's modulus of the apple. The presence of apple skin could increase the natural frequency by 7% for torsional modes and less than 4% for spheroidal modes. As the elastic modulus of the core was doubled, the natural frequency increased by up to 7% for spheroidal modes and well below 1% for torsional modes. The natural frequency for the first mode of each class decreased by no more than 8% as Poisson's ratio was doubled. Apple shape had a large effect on the natural frequencies of all three mode classes; spheroidal modes, however, were less affected by apple shape. The natural frequencies decreased with increasing apple size, but use of the firmness index f2m2/3, where f is the natural frequency and m is the mass of the apple, minimized the size effect.
RHEOLOGICAL AND CALORIMETRIC PROPERTIES OF HEATED CORN STARCH‐SOYBEAN PROTEIN ISOLATE DISPERSIONS
Authors: LIAO H‐J. , OKECHUKWU P.E. , DAMODARAN S. , RAO M.A. 
Published: February 2007

ABSTRACTDifferential scanning calorimetric (DSC) data on 10% (w/w) corn starch dispersion showed one endothermic peak and on soybean protein (SP) isolate dispersions two peaks attributed to 7S and 11S globulins. In corn starch‐SP isolate mixtures, thermal transitions appear to occur independently of one another. Dynamic rheological data over 0.63–62.9 rad s‐1 revealed weak gel‐like behavior of both 10% corn starch and SP isolate dispersions with magnitudes of storage modulus (G′) being significantly higher than those of loss modulus (G″) and both exhibiting slight frequency‐dependence; G′ of corn starch dispersion was higher than that of SP isolate and in mixed dispersions its magnitude decreased with increase in proportion of protein. The Maxwell model described creep‐compliance data on dispersions high in corn starch, while the Burgers model described dispersions high in SP isolate. Plots of protein/starch ratio versus G′ and instantaneous elastic modulus showed similar trends in phase separation and inversion.
RHEOLOGICAL PROPERTIES OF HEATED CORN STARCH + SOYBEAN 7S AND 11S GLOBULIN DISPERSIONS
Authors: CHEN C‐J. , LIAO H‐J. , OKECHUKWU P.E. , DAMODARAN S. , RAO M.A. 
Published: February 2007

ABSTRACTAt 10% solids content, magnitudes of G′ and G″ of soybean 7S dispersion were substantially lower than those of corn starch dispersion, while those of soybean 11S dispersion were much higher than those of starch. Profiles of G′ at 30 Hz as a function of starch concentration of starch + 7S and starch + 11S gels were asymmetrical reflecting phase separation due to thermodynamic incompatibility. However, the starch concentration corresponding to the critical point below which no phase separation occurs for the starch + 7S dispersion was about 7% and for the starch + 11S dispersion it was about 3%. At equal starch fractions, values of G′ at 30 rad s‐1 of corn starch + 7S dispersions were nearly equal to those of only corn starch. In contrast, at starch concentrations between 6–8%, G′ values of the corn starch + 11S dispersions were much higher than those of only starch and a minimum value occurred at a starch concentration of about 5%. Based on frequency dependence of G′ values, heated corn starch + 7S dispersions may be classified as weak gels, while heated corn starch + 11S dispersions may be classified as true gels.
GLASS TRANSITION AND TEXTURE IN A TYPICAL SPANISH CONFECTIONERY PRODUCT: XIXONA TURRON
Authors: MARTINEZ NURIA , CHIRALT AMPARO 
Published: February 2007

ABSTRACTThe water sorption isotherm at 25C and glass transition temperature were determined in a typical Spanish confectionery product (Xixona turrón), as well as in the fat‐free product. The samples were equilibrated at water activity levels from 0.113 to 0.755. The GAB and BET models were fitted to sorption data and the monolayer moisture contents were 2.8 and 6.0 (g of water/100 g of dried sample) for turrón and fat‐free turrón, respectively. The sorption data indicate a lipid interaction with hydrophilic constituents. The analysis of the glass transition temperature (Tg) of the product as a function of its moisture content is used to determine the critical water content (CWC) at which the product becomes rubbery, at a determined temperature. From sorption isotherm at the same temperature (25C) we can also determine the critical water activity (CWA). The plasticizing effect of water in Xixona turrón can be modeled by the Gordon and Taylor equation. The fat also has a plasticizing effect, which is more obvious at low water content. A Texture Profile Analysis (TPA) was performed on samples with different moisture contents. Only samples with a moisture content lower than CWC showed fracturability, due to its glassy state. In the rubbery state hardness, gumminess and chewiness decrease when water content increases. Elasticity and cohesiveness increase in line with water content, more strongly for those moisture levels which are higher than BET monolayer value.
CONSTANT STRAIN RATE COMPRESSION OF BIOPOLYMER GELS
Authors: ROHM H. , JAROS DORIS , BENEDIKT JULIA 
Published: February 2007

ABSTRACTUsually, uniaxial compression of food materials is performed at constant speed, which causes an increase of the true strain rate during experiments. By using a method described previously (Jaros and Rohm 1994) highly elastic biopolymer gels were compressed at standard conditions and with decreasing crosshead speed in order to maintain constant strain rate conditions during test. In the case of gels showing failure at a Hencky deformation of > 0.5‐0.6, significantly lower values for apparent fracture strain were found in constant strain rate compression. Differences in stress at apparent fracture showed good agreement with respect to this critical value. Implications and consequences on interrelation between sensory and instrumental measurements as well as on relationships between rheological and fracture properties are discussed.
EFFECTS OF OIL DROPLETS ON PHYSICAL AND SENSORY PROPERTIES OF O/W EMULSION AGAR GEL
Authors: KIM KYUNG‐HEE , GOHTANI SHOICHI , YAMANO YOSHIMASA 
Published: February 2007

ABSTRACTEffects of oil droplets in an agar gel matrix were investigated by mechanical analyses and sensory evaluation. The results for compressive and puncture properties were expressed in terms of relative values. All compressive properties; stress, strain and compressive energy of emulsion gels, as obtained by compression tests, decreased with both increases of oil droplet size and oil volume fraction. The stress, strain and energy of the emulsion gels obtained by puncture tests did not change with an increase in oil droplet size. Results of sensory evaluation showed that the sample containing small oil droplets was harder than that with large oil droplets. On the other hand, the large oil droplet sample was oilier than that with small oil droplets. The sensory evaluations for hardness and oiliness of emulsion gels did not exhibit significant relations to most of the properties of mechanical analyses.
MICROSTRUCTURAL CHARACTERISTICS AND COMPRESSION RESISTANCE AS INDICES OF SENSORY TEXTURE IN A CRUNCHY SNACK PRODUCT
Authors: GURAYA H.S. , TOLEDO R.T. 
Published: February 2007

ABSTRACTIdentically formulated drum dried and cold formed half‐products were puffed in hot air or by frying to determine microstructure‐texture relationships. Structural attributes measured were cell size (CS), number of cells per unit area (CN), cell wall thickness (CW) and product specific volume (SV). Sensory attributes of crunchiness, hardness and density were also evaluated. Puffed product microstructure depended more on the half‐product preparation process than the method of puffing. Similarly prepared half products had the same microstructural attributes whether fried or hot air puffed. Sensory scores for crunchiness were not significantly different among all samples but scores for hardness and density were significantly different between hot air puffed and fried products even when microstructural attributes were similar. Higher compression force values reflected lower sensory scores for crunchiness and hardness of puffed products. Compression force was significantly correlated with microstructural attributes of CS, CW and SV.
UNIAXIAL COMPRESSION OF UF‐FETA CHEESE RELATED TO SENSORY TEXTURE ANALYSIS
Authors: WIUM H. , QVIST K.B. , GROSS M. 
Published: February 2007

ABSTRACTRheological characteristics of seven Feta cheeses with different textures and produced from ultrafiltered milk (UF‐Feta cheeses) were evaluated by uniaxial compression and sensory texture analysis. The effect of uniaxial deformation rate (50–2500 mm/min) on four rheological parameters: Stress at fracture s̀f), Hencky strain at fracture (ɛf), deformability modulus (E) and work to fracture (Wf) was examined. Three Principal Components (PC) described 76, 16 and 4% respectively, of the variation in the uniaxial compression data set (4 parameters at 12 deformation rates). Statistically αf, E and Wf described the same type of information in the data set. Six sensory texture attributes of the UF‐Feta cheeses were evaluated by a sensory texture panel: nonoral firmness, nonoral brittleness, nonoral spreadability, oral crumbliness, oral firmness and oral stickiness. One PC described 93% of the variation in the sensory texture data and grouped the sensory variables into two negatively correlated groups: nonoral firmness nonoral brittleness, oral firmness and oral crumbliness versus nonoral spreadability and oral stickiness. Correlations and Partial Least Squares regression (PLS) between instrumental and sensory texture variables showed that nonoral and oral firmness were the nonoral and oral sensory variables best predicted from instrumental measurements. αf, E and Wf were all able to predict nonoral and oral firmness. Of the instrumental parameters, αf generally gave the best correlation to nonoral firmness at all deformation rates. Above a deformation rate of 50 mm/min correlations between αf and nonoral firmness were almost independent of deformation rate, and at any deformation rate correlations between αf and oral firmness
USING BROOKFIELD DATA AND THE MITSCHKA METHOD TO EVALUATE POWER LAW FOODS
Authors: BRIGGS JENNI L. , STEFFE JAMES F. 
Published: February 2007

ABSTRACTMitschka proposed a simple technique to calculate average shear stress and average shear rate from data obtained with Brookfield viscometers. It allows for estimation of the apparent viscosity, the flow behavior index, and the consistency coefficient of power law fluids. This method was evaluated for typical shearthinning foods (banana puree, salad dressing, enchilada sauce, and pancake syrup) and found to have excellent potential for quality control testing in the food industry. Results compared favorably with those obtained with a standard cone and plate viscometer.