bluuebunny/crossref_metadata_2025 huggingface dataset:
PARAMETERS OF TEXTURE CHANGE IN PROCESSED FISH: CROSS‐LINKAGE OF PROTEINS
Authors: MAO WEI‐WEN , STERLING CLARENCE
Published: February 2007

Soluble myosin and insoluble protein (i. e., soluble only in 5 % sodium dodecyl sulfate) were obtained from fresh and processed Sacramento blackfish and analyzed for the existence of possible cross‐links. Free sulfhydryl groups decreased somewhat in freezing and more in frozen storage. None were present after dehydration or cooking nor in any insoluble fractions, so that presumably these were oxidized in the formation of cross‐links. Ester bonds were much more numerous in insoluble protein than in soluble myosin, but their relative content was not clearly related to processing. Aldehyde groups decreased in myosin after cooking and dehydration, and were absent from insoluble protein. The presumptive Schiff base content was somewhat greater in soluble protein than in myosin and appeared to increase upon freezing and dehydration.
EFFECT OF MODE OF REHYDRATION ON TEXTURAL PARAMETERS OF PRECOOKED FREEZE‐DRIED SLICED BEEF*
Authors: SZCZESNIAK ALINA SURMACKA
Published: February 2007

Rehydration procedure had a significant effect on microscopic appearance, manner of liquid release on mechanical chewing, numerical values for the mechanical parameters of texture, correlations between objective measurements (Warner‐Bratzler Tenderometer, Kramer Shear Press and General Foods Texturometer) and the ability of instrumental measurements to show grade and cooking level effects. To a lesser extent, it also affected residual errors and coefficients of variation. As compared to cold distilled water, rehydration in warm 1% NaCl appeared to toughen the meat fibers while allowing more water to be absorbed intrafibrally. This water did not release easily on mechanical chewing. Overnight equilibration of drained samples increased the diameter of meat fibers, roughness of those rehydrated in the hot salt solution and smoothness of those rehydrated in cold distilled water. Best approximation to the microscopic appearance of fresh cooked beef was obtained by 20 min rehydration in room temperature distilled water followed by overnight equilibration in the refrigerator. This procedure also offered good differentiation of meat grade and cooking time effects by instrumental texture measurements.
Book Review
Authors: Sherman P.
Published: February 2007

Book reviews in this article:

Nuri N. Mohsenin, Physical Properties of Plant and Animal Materials, Vol. 1: Structure, Physical Characteristics, and Mechanical Properties, published by Gordon and Breach, New York.
APPLICABILITY OF RHEOLOGICAL MODELS TO THE INTERPRETATION OF FLOW AND PROCESSING BEHAVIOUR OF FLUID FOOD PRODUCTS
Authors: HOLDSWORTH S. D.
Published: February 2007

This review is concerned with the non‐Newtonian behaviour of selected fluid food products and, in particular, with the applicability of the power law. Some alternative models are included which food scientists might find useful in correlating flow properties. The interpretation of rheological characteristics in terms of structure and consistency is mentioned and the need for more detailed studies, particularly with regard to thermodynamic aspects, is pointed out. Application of the power law model to food processing is illustrated with principles of heat transfer and mixing of non‐Newtonian foodstuffs.
SCALES OF SUBJECTIVE VISCOSITY AND FLUIDITY OF GUM SOLUTIONS
Authors: MOSKOWITZ HOWARD R.
Published: February 2007

Subjective viscosity and fluidity of water soluble gums were investigated as a function of apparent physical viscosity (in poises), and as a function of the method of presentation. Subjective magnitude (S) appeared to grow as a power function of viscosity (P) with S=kPn, and the exponent n averaging about + 0.4 for subjective viscosity, and ‐0.4 for subjective fluidity. Stimuli appeared more viscous (and less fluid) when presented in narrow‐mouthed test tubes than in wide‐mouthed bottles. The growth rate of subjective magnitude, indexed by n, did not change, however, suggesting that the dynamics of subjective magnitude for viscosity and fluidity are independent of the presentation procedure.
PUNCTURE TESTING OF TIOGA STRAWBERRIES*
Authors: AHMED E. M. , FLUCK R. C.
Published: February 2007

Forces required to puncture firm ripe Tioga strawberries were dependent on the shape and physical dimensions of the punch used. They increased as the area, circumference or total contact surface area of the punch increased. The physical dimensions of the punch were responsible for 83 to 85% of variations in puncture forces. Punch circumference, punch area, and punch total contact surface area were equally effective in estimating the force required to puncture Tioga strawberries.
FACTORS AFFECTING TEXTURE OF COCKTAIL SHRIMP*
Authors: AHMED E. M. , KOBURGER J. A. , MENDENHALL V. T.
Published: February 2007

Texture of shrimp was influenced by pH, cooking time, and length of storage but not by the method of thawing the raw product or the soluble solids contents of the sauce. Shrimp cooked for 2, 5, 10, and 15 min required larger forces to shear than raw shrimp. Larger shear forces were also found with lengthening either the cooking or the storage periods. Shrimps packed in cocktail sauce maintained at pH 6.0 or 8.0 were more tender than those packed at pH 4.0.
MEASUREMENT OF PEA TENDERNESS: III. Field Comparison of Several Methods of Measurement*
Authors: VOISEY PETER W. , NONNECKE I. L.
Published: February 2007

Five objective techniques were compared with pea tenderometers to examine their performance under field operating conditions. The methods were a shear‐compression cell of the Kramer Shear Press, a back extrusion cell, wire and plate extrusion cells and a recording grinder. Results from the different methods were highly correlated allowing the choice of a test cell for possible replacement of the pea tenderometer to be based on practical considerations. The method selected for further development was the wire extrusion cell because it was inexpensive and suitable for a quality control instrument, where the maximum force during testing is a convenient value to record.
RELATIONSHIPS BETWEEN BINDING QUALITY OF MEAT AND MYOFIBRILLAR PROTEINS V. Effect of ‘Setting’ and Pyrophosphate on Rheological Properties of Heated Minced‐Meat Gel
Authors: NAKAYAMA TERUO , SATO YASUSHI
Published: February 2007

‘Setting’ was observed in minced hen meat stored with 3.5% wt/wt added NaCl. When gels were made from the ‘set’ sol the breaking energy was greatly increased and the relaxation modulus was characterized by a wide ‘quasi‐equilibrium’ region. The effect of added pyrophosphate on the rheological properties of the gel prepared at pH 6.0 from ground ‘set’ sol was very similar to that previously observed for ATP in gels prepared at pH 6.0 from ‘unset’ sols. When pyrophosphate or ATP were added at pH 7.0 to the ‘unset’ minced meat sol, the strain at the breaking point and the ratio of the equilibrium to the instantaneous modulus of the heated gel were increased. A comparison with previous results from a model system suggests that pyrophosphate brings about a change in gel structure by dissociating ‘myosin B’ into myosin A and F‐actin.
APPLICATION OF A VISCOMETRIC METHOD TO THE STUDY OF WHEAT FLOUR DOUGHS*
Authors: LAUNAY B. , BURÉ J.
Published: February 2007

The cone and plate viscosimeter was found applicable to studying the effect of experimental variables on the behaviour of flour doughs. A simple method of analysis based on the use of a power law is proposed. The variables studied were: type of flour, water content, mixing time, temperature and the presence of certain chemical compounds. Based on the results obtained, hypotheses were advanced on the importance of non‐covalent bonds in influencing the rheological properties of doughs.
MECHANICAL MEASUREMENTS OF MEAT TENDERNESS USING THE NIP TENDEROMETER
Authors: SMITH G. C. , CARPENTER Z. L.
Published: February 2007

Abstract. A series of evaluations to compare the sensory panel ratings for tenderness with the Warner‐Bratzler shear force and the Nip Tenderometer values was conducted using 150 pork chops, 239 lamb chops and 674 beef steaks. The Warner‐Bratzler shear force values were more highly correlated with panel tenderness ratings than were the Nip Tenderometer readings for samples of pork, lamb and beef tested after cooling to room temperature (23 °C). Nip Tenderometer determinations on hot samples of beef (75 °C) were more closely related to panel tenderness ratings (r=— 0.80) than were Nip Tenderometer readings (r=— 0.58) or shear force values (r=— 0.63) obtained on cold samples (23 °C). The combined advantages of ease and speed of application, correlation with sensory panel ratings and the demonstrated accuracy in identifying ‘tough’ vs ‘tender’ steaks suggest that the Nip Tenderometer has potential as an objective means for evaluating meat tenderness.
FREEZE‐THAW (AND BLANCH) DAMAGE TO VEGETABLE ULTRASTRUCTURE
Authors: MOHR WILLARD P.
Published: February 2007

The parenchyma cells of three vegetable tissues varying in starch content as well as in textural response to freeze‐thawing were studied ultrastructurally before and after controlled freeze‐thaw regimes. Similar tissue samples were also studied after blanching and after the blanch‐freeze‐thaw combination. Subcellular structures were altered more drastically by blanching than by freeze‐thawing. There was much less fine structural disruption in the high starch tissue (green pea cotyledon) than in the tissues of lower starch content (spinach leaf and green bean pod) following all processing treatments. As judged by sensory evaluation, peas also underwent less textural change on processing than the other tissues studied. The minimal ultrastructural change observed in peas may be associated with certain cell characteristics: high starch content, abundant protoplasmic structure, and resultant low degree of vacuolation. It is concluded that ‐ of these ‐ the starch granule component is the major contributor to texture. This probably applies in the case of most processed vegetable tissues of relatively high starch content. The protective role of cellular starch is discussed in relation to fine structure retention and to texture.
PROTEIN‐CARBOHYDRATE INTERACTIONS AT ELEVATED TEMPERATURES*
Authors: MOORE WILLIAM E. , CARTER JOSEPH L.
Published: February 2007

A series of protein types have been characterized with respect to their interaction with low dextrose equivalent corn starch hydrolysates. From an assessment of the chemical modification of selected functional groups, classical denaturation studies, gel filtration and precipitation with tri‐chloro‐acetic acid, the partial basis for molecular interaction has been elucidated. Although all proteins under investigation were prominent components of a variety of food systems, particular emphasis was placed on the behavior of β‐lactoglobulin and selected soy fractions. Results from the modification and denaturation studies indicated that several factors are required to account for the extent of interaction, but that the predominant effect appears to be non‐covalent in nature. In the case of commercial soy proteins, considerable polydispereity was detected prior to the interaction ‐ much of which was doubtless induced during isolation. Many such fragments of this preparation showed self‐interacting properties, which could provide a basis for texture in the reported system. The starch hydrolysates appear to exhibit a protective effect against excessive protein aggregation, which could have significance in retention of nutritional value during food processing.
MEASUREMENT OF EGGSHELL STRENGTH*
Authors: VOISEY PETER W. , HUNT J. R.
Published: February 2007

Techniques used to measure the eggshell strength and associated parameters are reviewed. Much of the early research was based on crude instruments that did not adequately control test conditions, particularly the rate of applying force to the shell. Better instruments have been used recently to obtain precise readings. A significant advance has been the development of techniques to describe the physical properties of the shell material. This is potentially more meaningful than the empirical comparisons of egg behaviour, and is leading to a better understanding of the shell fracture mechanism.

Two practical tests are currently available to the biologist for non‐destructive measurements: specific gravity of the egg and shell deformation under a non‐destructive force. Both predict ‐ with acceptable precision ‐ the shell fracture force.

Eggshell strength has been investigated for over 70 years, but an ideal test method has yet to be found, and research is still required.
METHOD FOR OBTAINING COMPRESSION AND SHEAR COEFFICIENTS OF FOODS USING CYLINDRICAL PUNCHES
Authors: BOURNE MALCOLM C.
Published: February 2007

The force required to puncture a food has been described previously as F=Ka?A+Kp? P++C where A and P are, respectively, the area and perimeter of the punch, C is a constant and Ka and Kp are two coefficients that are properties of the food. This paper describes how the equation can be rearranged for circular punches in a manner that allows the numerical values of the coefficients to be evaluated by a graphical method. A comparison of the numerical values obtained with the new method and those obtained with the older method using rectangular punches showed good agreement when carrots, two varieties of apples, agar gel, margarine, and polystyrene board were used as test materials. The method of deriving coefficients Ka and Kp is relatively easy and the coefficients may be more meaningful than the raw puncture data.
THE TEXTURE PROFILE: ITS FOUNDATIONS AND OUTLOOK
Authors: MOSKOWITZ HOWARD R. , KAPSALIS JOHN G.
Published: February 2007

The origins of the Texture Profile are traced from antecedent developments both in food science and in psychology. A variety of theoretical underpinnings of the Profile are considered: (1) selection of texture variables, (2) problem of standards in texture, (3) appropriate rules for measuring psychological magnitudes, (4) appropriate sensory‐instrumental functions, (5) combination rules whereby the observer combines different texture attributes and relates each attribute to a linear combination of others, and (6) interaction between users of the Texture Profile. In each of the above, the underlying assumptions are discussed and possible modifications are suggested in order to generalize the profile procedure.
ENGINEERING ASSESSMENT AND CRITIQUE OF INSTRUMENTS USED FOR MEAT TENDERNESS EVALUATION*
Authors: VOISEY PETER W.
Published: February 2007

A review of the methods used to measure meat texture indicates considerable confusion in terminology, test conditions, and interpretation of the readings that makes evaluation of the results a complex task. Standardization of the methods appears premature and until this is accomplished, the applied methodology must be reported fully. Errors due to instrument design can no longer be accepted since modern instruments that overcome this are readily available. A common error in terminology or interpretation is the use of the term shear to describe the rupture imposed on meat samples in popular tests. It is shown that meat generally ruptures in tension which is also the case during mastication; this explains why empirical measurements often relate to sensory readings. It is concluded that there is room for improvement in existing methods, particularly in the interpretation of the results using common sense, close observation and theoretical analysis.
STRUCTURAL AND OTHER ASPECTS OF MEAT TENDERNESS
Authors: HARRIS P.V.
Published: February 2007

This review summarizes the present knowledge of meat structure and factors affecting its mechanical strength. Methods used to assess mechanical strength are discussed in relation to (a) ability to discriminate between the strength of the different structural components of meat, and (b) ability to reflect organoleptic tenderness.
THE MICROSTRUCTURE OF MUSCLE TISSUE — A BASIS FOR MEAT TEXTURE MEASUREMENT
Authors: STANLEY D. W. , SWATLAND H. J.
Published: February 2007

A review is presented of meat texture and current methods employed for its measurement from the viewpoint of muscle microstructure. Experimental work was conducted with paired raw porcine sartorius muscles. One was stretched during rigor and the other was allowed to contract. Tensile properties were measured and compared with microstructural analyses (sarcomere length, scanning electron microscopy and histological examination of reticular fibers). Based on these data, a hypothesis is presented to explain the difference in Theological properties between the two treatments. The importance of microstructural factors is emphasized as a basis for meat texture measurements.
INSTRUMENTAL TESTING OF MEAT TEXTURE — COMMENTS ON THE PAST, PRESENT AND FUTURE
Authors: KAPSALIS JOHN G. , SZCZESNIAK ALINA S.
Published: February 2007

This paper summarizes briefly the current trends in meat texture research and presents concluding remarks. It is suggested that a full understanding of human sensory perception is not needed before a unified meaningful instrumental test can be adopted with practical implications in quality control, purchase specifications and consumer acceptance of meat. It is further suggested that sufficient information exists to make the selection of a unified test a reality, and that workshop sessions of interested researchers be initiated to implement this process.
BRUISING AND ENERGY DISSIPATION IN APPLES
Authors: HOLT J. E. , SCHOORL D.
Published: February 2007

A strong correlation was obtained between bruise volume and energy absorbed for both impact and slow compression of Granny Smith apples. Apple tissue was more easily bruised by slow compression than by impact. For the same amount of energy, bruise volumes were approximately 40% higher under slow compression.

There was no correlation between the stiffness (force/deflection) of apple flesh and bruise volume. It is unlikely that the theories of failure based on the theory of elasticity will prove useful in predicting the extent of bruising. The application of elastic theory to bruise initiation was not studied in this paper.

A simple model was formulated to explain the behaviour of apples under compression. Apple tissue was likened to an orderly arrangement of liquid‐filled, spherical cells bounded by viscoelastic membranes with air‐filled interstitials. It is postulated that on initial compression the cells are deformed into ellipsoids under a stress distribution similar to that found in an elastic sphere. Further compression would then result in cell wall fracture, i.e., cell bursting in regions of high shearing stress. Distortion and bursting of cells explains the energy dissipative mechanism.

The work showed that energy absorbed during compression is a good predictor of bruising and is, thus, a useful parameter in evaluating handling and packing systems.
COMPRESSION AND RELAXATION PROPERTIES OF CARROTS*
Authors: SEGERLIND L. J. , SNOBAR B. A. , HELDMAN D. R.
Published: February 2007

Compression force and relaxation properties of radially compressed carrot samples were determined as a function of the cortex moisture content. The compression force at 10% deformation increased with an increase in the moisture content. The compression force at 86% moisture was almost ten times greater than the value at the 76% level. Similar trends were observed for part of the visco‐elastic coefficients.
TEXTURAL CHANGES IN RIPENING PLANTAINS*
Authors: PELEG M. , BRITO L.GÓMEZ
Published: February 2007

Compression testing indicated that the ripening of plantains is accompanied by textural changes which include a considerable decrease in the apparent compressive strength and the overall textural uniformity. The magnitude of the apparent strength was found to depend on the specimen's diameter. The prefailure deformation increased during ripening and reached a maximum level of 40‐45%. After this stage, the prefailure deformation declined as the fruit's flesh continued to soften. Unripe fruits could be distinguished from ripe fruits not only by the magnitude of these parameters but also by the failure pattern. The failure of unripe fruits was characterized by an instant formation of a single inclined failure plane, and that of ripe fruits by a progressive development of multiple irregular planes. The shift in the failure pattern may serve as a textural criterion for fruit ripeness.
DYNAMIC AND STEADY SHEAR RATE ASPECTS OF MINCED MEAT ‘SETTING’
Authors: NAKAYAMA TERUO , HAUGEN PATRICIA
Published: February 2007

Dynamic and time‐dependent steady shear rate properties of minced chicken meat were studied immediately after preparation and following a 24 hr low temperature incubation. Incubation at 3d̀ C resulted in a significant increase in the storage moduli and a relatively constant decrease in the loss tangent over the range of strain amplitude (0.010‐0.126; at an angular frequency of 0.299 s
‐1. The stress relaxation behaviour was retarded and the equilibrium shear stress value was 30% higher when compared with the untreated samples. Time‐dependent studies of hysteresis loop areas revealed a significant increase in structure breakdown after incubation. The effects observed after low temperature incubation were ascribed to an intermolecular interaction between myosin A and F‐action.
CHARACTERIZATION AND FAILURE IN SOLID FOODS WITH PARTICULAR REFERENCE TO FRUITS AND VEGETABLES1
Authors: MOHSENIN NURI N.
Published: February 2007

The purpose of this paper is to point out the importance of understanding what the food materials are like, from the solid mechanics viewpoint, and how they fail under stress and strain. The difficulty in defining the threshhold of failure for solid foods is discussed, and suggestions are made with reference to three selected food materials. The importance of relating the mechanical behavior to structural changes in the plant and animal materials is pointed out. A comprehensive illustrated review of the stress‐strain‐time effect on solid food materials is given in a tabulated form. The review includes the type and location of stresses causing failure, the type of loading which has been shown to be more meaningful in characterization of the material, and failure‐related findings pertaining either to test specimens taken from the material or to the intact material in its natural shape. It is concluded that a basic approach requiring some mathematical manipulation and a knowledge of solid mechanics, a t least to apply the known theories i f not to develop new ones, is a prerequisite for understanding the mechanics of solid foods. Such knowledge is expected to be applied to many problems involving food handling and processing. The use of rheology in texture evaluation of food is only one of the many possible applications.
LIMITATIONS OF RHEOLOGY IN FOOD TEXTURE MEASUREMENTS1
Authors: BOURNE MALCOLM C.
Published: February 2007

Rheological measurements constitute an important part of food texture measurements but they d o not cover all the factors that make up the “texture” of a food. Mastication is a process in which lumps of food are ground into a fine state, mixed with saliva and converted into a liquid slurry at approximately body temperature ready. for swallowing. The processes of size reduction, wetting with saliva, melting, release of moisture or fat are not rheological processes. The perception of moistness, size, shape and roughness of food particles are important factors in texture sensations that are not rheological and yet these oral sensations are an important aspect of the acceptability of a food. This leads to the conclusion that food texture measurement lies partly with‐in and partly outside the field of conventional rheology.
A DIGITAL POSITION INDICATOR FOR THE INSTRON CROSSHEAD1
Authors: VOISEY PETER W. , KLOEK M.
Published: February 2007

An accessory for indicating the position of the crosshead of the Instron Universal Testing Machine relative to the machine frame is described. A linear displacement transducer allows the crosshead position to be selected within 0.35 mm or returned to a previous setting within at least 0.0083 mm. This facilitates accurate crosshead positioning and reproduction of the settings for different tests. The transducer also has the potential to indicate or record test sample deformations.
EVALUATION BY INSTRUMENTAL METHODS OF THE TEXTURAL PROPERTIES OF SOME TROPICAL FRUITS1: (A REVIEW)
Authors: PELEG M.
Published: February 2007

Published applications to tropical fruits of instrumental methods for texture evaluation are cited and tabulated. The comparability of the results is evaluated in light of the morphological characteristics of the fruits, the types of methods used and the test procedure employed.
STRUCTURE AND IMPORTANCE OF NONSTARCHY POLYSACCHARIDES OF WHEAT FLOUR1
Authors: D'APPOLONIA B. L.
Published: February 2007

Although a minor biochemical component of wheat flour, the nonstarchy polysaccharides have been the subject of investigation by various groups of workers. This review discusses primarily the studies conducted at the Cereal Chemistry and Technology Department at North Dakota State University and covers information pertinent to structure, properties and function of the nonstarchy polysaccharides.
ACOUSTIC IMPULSE RESPONSE METHOD FOR MEASURING NATURAL FREQUENCY OF INTACT FRUITS AND PRELIMINARY APPLICATIONS TO INTERNAL QUALITY EVALUATION OF APPLES AND WATERMELONS
Authors: YAMAMOTO HIROMICHI , IWAMOTO MUTSUO , HAGINUMA SHIKO
Published: February 2007

A nondestructive textural quality measurement technique that uses an acoustic property was studied for apples and watermelons. By means of digital Fourier analysis, the natural frequencies of intact fruits are obtained from the sound which is produced by hitting them with a wooden ball pendulum. The reliability of this method was confirmed. This method requires simpler instrumentation than the sonic vibrating resonance method.
RELATIONSHIPS BETWEEN SENSORY PROFILE PARAMETERS AND FUNDAMENTAL MECHANICAL PARAMETERS FOR RAW POTATOES, MELONS AND APPLES1
Authors: DIEHL K. C. , HAMANN D. D.
Published: February 2007

Ratings by a trained texture profile panel were compared with the mechanical properties (shear stress at structural failure, normal strain to failure and apparent elastic modulus) determined in torsion and uniaxial compression for apple, melon and Irish potato flesh.

Results indicated that, for melon and potato flesh, the structural failure stress levels were more frequent and significant indicators of sensory note magnitudes than the modulus values. The reverse was true for apple flesh. Of the sensory notes, moisture release correlated most consistently with the mechanical properties.

Melon flesh failed in uniaxial compression by widespread crushing rather than along a failure plane. Correlation of the mechanical failure stress with the first bite sensory notes dominated in this case. The structural failure of potato flesh in uniaxial compression generally occurred along a single plane of maximum shear stress which left two essentially intact pieces of specimen. First bite and mastication sensory notes for potato flesh correlated with shear stress at failure about equally well. The structural failure of apple tissue in uniaxial compression was caused by general compression failure with many fragmented pieces of tissue remaining. Apple flesh produced the most frequent correlations of both first bite and mastication texture notes with the instrumental modulus and failure values.
THE RHEOLOGY OF GELS
Authors: MITCHELL J. R.
Published: February 2007

The following aspects of the rheological behavior of polysaccharide and protein gels are discussed with particular emphasis on recent investigations: (1) Viscoelasticity of gels; (2) Validity of rubber elasticity theory; (3) Rupture strength of gels; and (4) Single‐point measurements of gel strength.

It is concluded that in contrast to most food materials gels show linear viscoelastic behavior up to strains of the order of 0.1. Results obtained from creep and stress relaxation experiments would suggest that noncovalent crosslinks in gels move or break when the gel is stressed. Activation energies associated with crosslink breakage have been estimated from the temperature dependence of viscoelastic parameters. For gelatin and polysaccharide gels energies ranging from 5–65 Kcals/mole have been reported.

The stiff and extended nature of polysaccharide chains make it unlikely that polysaccharide gels obey rubber elasticity theory, though it is possible that this theory holds for gelatin gels and also for ovalbumin gels in 6 M urea.

It is emphasized that the rupture strength of a gel is not necessarily related to its elastic modulus and therefore ‘single point’ measurements of ‘gel strength’ based on rupture tests will not always rank a series of gels in the same order as tests which involve small deformations without rupture. One of the reasons for this is that the elastic modulus and rupture strength depend in different ways on the primary molecular weight of the polymer from which the gel is formed.
RHEOLOGICAL AND TEXTURE STUDIES OF BUTTER3
Authors: KAWANARI MASAMI , HAMANN D. D. , SWARTZEL K. R. , HANSEN A. P.
Published: February 2007

Four commercial butters (conventional batch and Westfalia, Contimab and Cherry‐Burrell continuous churned) were stored at two temperatures and evaluated periodically for rheological and textural properties. Evaluation methods included four mechanical tests (quasistatic shear, quasistatic uniaxial compression, Penetrometer, and extrusion) and sensory ratings of spreadability, firmness, and other texture parameters. The first three mechanical methods produced quasistatic shear yield stress values that had close agreement. For quality control the three tests can be considered equivalent. Shear stress‐strain rate data from extrusion testing developed using the Rabinowitch‐Mooney equation could be represented well by the Casson model. Casson yield stress values were an order of magnitude lower than the quasistatic values. The power law equation with a yield stress also represented the butter flow well, and all four butters had similar power law exponents (approx. 0.56). The Cherry‐Burrell butter had much higher quasistatic and Casson model constants than the other butters. It was also the most temperature sensitive and most stable with storage time. Temperature‐shear rate equivalent effects on shear stress were demonstrated by developing shift factors. The quasistatic yield values for the butters best predicted sensory spread‐ability and hardness. The changes in flow properties (Casson yield stress and Casson slope) correlated with aging.
EFFECTS OF DIETARY SOYBEAN LECITHIN ON SOME SENSORY AND RHEOLOGICAL PROPER TIES OF FROZEN AND NON‐FROZEN CHICKEN MEAT
Authors: MORAES M. A. C. , SCHNEIDER I. S. , FORSTER R. J.
Published: February 2007

Soy bean lecithin was added to practical rations fed to 144 broiler chicks. The dark and white meats from frozen and non‐frozen carcasses were submitted to both mechanical (Warner Bratzler and Instron Universal Testing Machine) and sensory assessments of tenderness. A good correlation was observed between the two types of measurements. Regression equations indicated that higher lecithin contents in the rations decreased sensory toughness of the white meat. Freezing of the meats at – 40°C had little effect on texture.
DETERMINATION OF DYNAMIC MODULI OF SOY DOUGHS USING AN ORTHOGONAL RHEOMETER1
Authors: JASBERG B. K. , TAYLOR N. W. , MUSTAKAS G. C. , BAGLEY E. B.
Published: February 2007

The orthogonal rheometer in principle provides a relatively simple means of applying a dynamic strain to polymers to determine the dynamic storage and loss moduli (G′, G″) as functions of frequency and strain. In applying this technique to soy doughs, surface evaporation of water from the samples was found to be a serious problem, but when evaporation was controlled, good reproducibility for G′ and G″, was obtained. The moduli were very sensitive to dough moisture level, with G’ changing by a factor of 10 over the moisture range 40 to 50%. Plate diameter and percent strain both affected the absolute values of G′ and G″, though the effects were relatively small. Log G′ and log G″ increased linearly with decreasing nitrogen solubility index. The two major advantages of the orthogonal rheometer for such food systems are the ease of operation and the fact that sample thickness can be chosen to obviate problems associated with sample heterogeneity. Nevertheless, the effects of plate diameter and percent strain need more extensive study.
BOOK REVIEW
Authors: SHERMAN P.
Published: February 2007

The Effect of Polymers on Dispersion Properties. Th. F. Tadros, ed.
ACOUSTIC PROPERTIES OF PAPAYA
Authors: HAYES C.F. , CHINGON H.T.G.
Published: February 2007

The speed of sound in papaya pulp was found to be (1.6 ± 0.3) × 104cm/s. The absorption of sound varied, approximately, as the square root of the acoustic frequency. Measurements were made to test the tolerance of papaya to high acoustic intensity. Discoloration and softening occur at 43 W/cm2 for exposures of 30s.
THE USE OF A COMPUTER WITH AN INSTRON FOR TEXTURAL MEASUREMENTS3
Authors: ABBOTT J. A. , MASSIE D. R. , ADA A. E. WAT
Published: February 2007

A minicomputer was interfaced with an Instron so that force/deformation tests could be performed and analyzed automatically. The equipment eliminates time consuming measurements and transcription of data from recorder charts. The data extracted include force, deformation, slope and area variables not previously reported as well as the usual texture profile parameters. Procedures and analyses are illustrated by texture profile measurement of apple tissue. Comparison of visually and computer selected force at failure indicate satisfactory computer identification of the Texture Profile “yracturability” parameter, the parameter most difficult to interpret for apples.
TEXTURE PROFILE ANALYSIS OF PROCESSED FOODS USING THE TENSIPRESSER AND THE MULTI‐POINT MENSURATION METHOD
Authors: TSUJI SHOJIRO
Published: February 2007

This paper reviews a considerable amount of research that has been performed in Japan on the development and application of a modified Texture Profile Analysis (TPA) system using a new instrument. Most of this work has heretofore only been available in Japanese. The Tensipresser is an instrument that has some special features that allow it to perform TPA rather easily. The multi‐point mensuration method is a form of TPA that uses several variable degrees of compressions or bites on each piece of food. In ordinary work, two successive compressions or bites at predetermined clearances are applied to the sample. It is shown that the type of compressing or biting plunger plays an important role i n the shape o f the TPA curve. Examples of the use o f the Tensipresser and the multi‐point mensuration method are given using breads and other baked goods, cooked rice, bean curd, pudding, sweet potato, noodle dough and cooked noodles.
A CRITICAL STUDY AND IMPROVEMENT OF THE CHEESE CURD TORSIOMETER2
Authors: GERVAIS A. , VERMEIRE D.
Published: February 2007

The Scott Blair cheese torsiometer designed in the late 60's was rendered automatic by combining an angular transducer with the stress measuring system. A linear transducer was used to verify that the device had sinusoidal movement. The absolute error of the improved system was 3 times lower than that of the original.

Gelification kinetics were determined with the automated version. We report an example in which experimental points could be fitted to the Scott Blair model as well as to the Douillard equation (the former is biphasic with an inflection point, and the latter describes a simple exponential curve). In both cases, the standard error of estimation was smaller than or equal to the absolute error of the torsiometer.

Even the automated version cannot measure the phase difference between stress and strain with the required precision. Thus, neither the viscosity or elasticity modulus can be determined.
CRACKING IN POTATOES
Authors: SCHOORL D. , HOLT J.E.
Published: February 2007

Cracking in two varieties of potatoes was investigated by compressing whole tubers between flat plates at low compression rates. It was found that resulting crack areas correlated directly with the energy stored at cracking. Of the energy imparted to the tuber, a large proportion is dissipated during compression.

Cracking occurs when the stored energy exceeds a critical value, approximately 1.6 J for Sebago and 0.9 J for Pontiac. The extent of cracking is determined by the fracture toughness, calculated to be 1350 Jm−2 for Sebago and 1230 Jm−2 for Pontiac. The Sebago variety is thus more resistant to cracking than Pontiac. The energy dissipative mechanisms in hysteresis and crack propagation are explained in terms of the structure of potato tissue.
THE RHEOLOGICAL CONDITIONS ASSOCIATED WITH JUDGEMENT OF POURABILITY AND SPREADABILITY OF SALAD DRESSINGS
Authors: KIOSSEOGLOU V. D. , SHERMAN P.
Published: February 2007

A panel of 25 students compared the pourability and spreadability of two commercial brand salad dressings (non‐Newtonian) and a CMC‐sugar solution (Newtonian). Correlation of their responses with visco‐metric data for the 3 samples indicated that the shear stress and shear rate associated with the sensory evaluation of these two properties are 190–430 dyne cm−2 and 0.9–6.3 s−1, and < 190 dyne cm−2 and < 0.9−1, respectively.
INFLUENCE OF EGG YOLK LIPOPROTEINS ON THE RHEOLOGY AND STABILITY OF O/W EMULSIONS AND MAYONNAISE 1. VISCOELASTICITY OF GROUNDNUT OIL‐IN‐WATER EMULSIONS AND MAYONNAISE
Authors: KIOSSEOGLOU V. D. , SHERMAN P.
Published: February 2007

Viscoelastic properties of groundnut oil‐in‐water emulsions stabilized by egg yolk and of mayonnaise have been deduced from their creep compliance‐time response to a constant low shear stress. The viscoelastic parameter values, emulsion stability and initial mean drop size were influenced by pH and NaCl, due to disruption of the egg yolk components. When carboxymethylcellulose was incorporated in the continuous phase of the O/W emulsions an egg yolk‐carboxymethylcellulose complex was formed and this affected the rheological properties of the emulsions and also their stability. Mayonnaises exhibited more pronounced viscoelasticity and greater stability than the O/W emulsions. At elevated temperature the micelles adsorbed around oil drops degrade. Their lipoprotein structure unfolds so that more segments on adjacent drops are then available for interlinking and network formation.
MEASUREMENTS OF THE COMPRESSION PROPERTIES OF BREAD CRUMB
Authors: HIBBERD G.E. , PARKER N.S.
Published: February 2007

The resistance of bread crumb to compression between parallel plates has been measured using cyclic deformation at constant rate with an Instron universal testing machine. The effects of various factors on different measures of the “firmness” taken from the force/deformation records have been studied using a split‐plot factorial analysis with six factors: position in the loaf, rate of deformation, direction of deformation, position in the oven, tray and time. Multi‐factor analysis of variance shows that, although time since baking was the dominant factor, the results show a very highly significant dependence on the direction of measurement with a strong interaction within the loaf.
THE COMPRESSIVE BEHAVIOR OF SOLID FOOD SPECIMENS WITH SMALL HEIGHT TO DIAMETER RATIOS2
Authors: CHU C. F. , PELEG M.
Published: February 2007

Cylindrical specimens of height to diameter ratios between 0.12 to 1.0 of potato flesh, bologna sausage and process American cheese were uniaxially compressed to failure. The flatter the specimen the stiffer it appeared. This was also true with respect to strength. The magnitude of strain at failure also increased with the specimen's flatness. Application of two correction procedures for the calculation of a dimensionally independent modulus did not always yield consistent results, demonstrating that the stiffness‐strength‐shape relationships can depend not only on the material but also on the particular character of the end constraints.
W/O/W‐TYPE MULTIPLE EMULSIONS WITH A VIEW TO POSSIBLE FOOD APPLICATIONS1
Authors: MATSUMOTO SACHIO
Published: February 2007

W/O/W‐type multiple emulsions have potential applications for the formulation and processing of foods, as each dispersed globule in this type of emulsion consists of single or multiple aqueous compartments separated from the aqueous suspending fluid by a layer of the oil phase components. Three different methods can be applied to prepare W/O/W emulsions, such as mechanical agitation, the phase inversion technique and a two‐stage emulsification. The oil layer in the W/O/W emulsions appears to thin immediately after the preparation, and water permeates through the narrow oil layer under the osmotic pressure gradient between the two aqueous phases. Therefore, it is believed that the thin oil layer may contain the hydrophobic emulsifier in a lamella structure. Addition of electrolytes to the aqueous phase causes instability of the W/O/W‐type dispersion due to rupture of the thin oil layer, or aggregation formation amongst the dispersed globules. A systematic study of the W/O/W emulsion stability is desirable in view of possible applications of this type of emulsion in foods.
RHEOLOGICAL PROPERTIES OF MIXED GELS
Authors: KOBAYASHI MICHIKO , NAKAHAMA NOBUKO
Published: February 2007

The rheological properties of carrageenan/gelatin and agar/gelatin mixed gels were investigated by measuring the rupture properties, the texture parameters and the dynamic viscoelasticities. fie melting point, transparency and syneresis of these gels were measured in order to obtain the relationship with the rheological properties. The physical properties of the two mixed gels were slightly different. The agar/gelatin mixed gels generally showed the hindered effect of gelatin. The brittleness of agar gel disappeared on mixing with gelatin. It then became a flexible, cohesive and transparent gel. Carrageenan/gelatin mixed gels showed a decrease in the values of almost all of the mechanical properties when compared with carrageenan gels. However, the rupture properties of the C0.5 mixed gel were much higher than those of simple carrageenan gels.
QUANTIFYING THIXOTROPY IN STARCH‐THICKENED, STRAINED APRICOTS USING MIXER VISCOMETRY TECHNIQUES2
Authors: FORD E. W. , STEFFE J. F.
Published: February 2007

Starch‐thickened, strained apricots were found to exhibit irreversible thixotropy. Shear stress and shear rate were estimated from mixer viscometer data. A structural parameter, yield stress, flow behavior index and a consistency coefficient were determined to quantify the rate of breakdown and equilibrium structure of the product. The techniques developed in this study are useful in describing the time‐dependent behavior of suspensions because the slip at the wall is minimized.
STRESS RELAXATION OF STORED STIRRED CHEDDAR CURD
Authors: NOLAN E. J.
Published: February 2007

An introspective empirical method for reducing stress relaxation data of certain foods was proposed by Peleg (1979). In his method relaxation curves are normalized with respect to initial force. In the method described herein his resulting equation is rearranged as a straight line but with the normalized force and time variables written as reciprocals 1/f(t) = (1/ab)(1/t) + (1/a), a plot of 1/f(t) versus (1/t) will yield a more severe test of the experimental data since the time variable “t” no longer appears on both sides of the equation as it does in the former case. This empirical method has been applied to relaxation data of stirred curd cheddar cheese manufactured under government specifications and stored at −2 to 0°C. With this method there are apparently at least two relaxation periods for cheese, a primary period which occurs for about 2 min and a secondary period which commences thereafter. When the separate periods are compared to one another values of the “a” and “b” constants are completely different and show that the secondary relaxation rate is substantially slower than the first. This method provides a more sensitive tool for comparing aging effects in stored cheese.
CHARACTERIZATION OF HISTORY‐DEPENDENT STRESS‐RELAXATION BEHAVIOUR OF CHEESES 1
Authors: MASI PAOLO
Published: February 2007

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INFLUENCE OF SALTS AND pH ON THE FIRMNESS OF COOKED SNAP BEANS IN RELATION TO THE PROPERTIES OF PECTIN
Authors: VAN BUREN J. P. , KEAN W. P. , WILKISON M.
Published: February 2007

Solute conditions inside cooked bean pods were adjusted by soaking the pods in different solutions. Interactions of Ca++ and Na+ showed increasing firmness as Ca++ concentration was raised and decreasing firmness as Na+ was raised. Chelating agents removed Ca++ and decreased firmness. Higher pH gave lower firmness except in the presence of excess Ca++. The presence of Na+ decreased the effect of pH on firmness. Urea decreased firmness when pods had been previously treated with a chelator. The effects of treatments on firmness were related to the behavior of pectin solutions and gels.
EFFECT OF PRESSURE AND STORAGE TIME ON TEXTURE PROFILE PARAMETERS OF SOYBEAN CURD (TOFU)
Authors: GANDHI A. P. , BOURNE M. C.
Published: February 2007

The pressure applied to soybean curd during processing into tofu has a profound effect on the moisture content, yield and some textural parameters of tofu. As the pressure increased from 0.186P to 0.744 P the moisture content decreased from 82% to 60% and yield decreased from 2.0 kg to 1.2 kg per kg whole dry soybeans. Hardness‐1, hardness‐2, chewiness andgumminess increased linearly with increasing pressure. Springiness, cohesiveness, adhesiveness and stringiness were hardly affected by increasing pressure. During storage in water at 2–3°C for 3 weeks, hardness, gumminess, and adhesiveness increased moderately; springiness decreased moderately and the other texture parameters were almost unchanged.
The Effect of Moisture Content on Mechanical Properties and Texture Profile Parameters of Corn Meal Extrudates
Authors: HALEK GEORGE W. , PAIK S.W. , CHANG K.L.B.
Published: February 2007

Two corn meal extrudates with initial moisture contents of 22% and 31% W.B. were partially dried to moisture contents from 7% to 31% W.B. and stored in hermetically sealed containers to allow redistribution of the water. Compressive strength, compressive relaxation and instrumental texture profile analyses (fracturability, cohesiveness, springiness, gumminess and chewiness) were measured. Compressive strength increased with decrease in moisture content from 31‐15%, reached a maximum between 15‐10% and then decreased below 10%. Stiffness showed a similar relationship, with the maximum occurring between 10‐6%. Relaxation modulus increased with decrease in moisture content over the range studied. Relaxation time was a minimum at 15% moisture content. Fracturability had a similar relationship to moisture content as that of compressive strength. The textural behavior was ductile and chewy at moisture contents above 15% but became crisp or crunchy and collapsed with brittle fractures at lower moisture contents. Both compressive properties and texture profile parameters of the corn meal extrudates changed considerably with changes in moisture content.
EFFECT OF DISPERSED PHASE ON THE SLIP COEFFICIENT OF APPLE SAUCE IN A CONCENTRIC CYLINDER VISCOMETER
Authors: Qiu C‐G. , Rao M.A.
Published: February 2007

Slip coefficients for apple sauce in concentric cylinder viscometers were determined using concentric cylinders of different radii according to the theory of Mooney. Wall slip was relatively low for highly shear‐thinning samples and for highly viscous samples; it also decreased with increase in pulp content until tunneling of the sample by the bob condition was reached. Wall slip coefficient varied with the applied torque so that any comparison of slip between samples must be made by determining the slip coefficients for the samples at the same magnitude of applied torque.