Food Science Commons^™

Relationship Between The Starch Granule Structure And The Textural Properties Of Heat-Induced Surimi Gels, V. Verrez-Bagnis, B. Bouchet, D. J. Gallant

Food Structure

Starch, used as a textural additive in heat-induced surimi gel, influences the rigidity of the protein gel matrix and hence the gel strength according to its botanical characteristics. The present study focuses on the correlations existing between the textural properties of heatind uced surimi gels obtained by physical measurements and the characteristics of different commercial starches. The gelatinization temperature of starch was closely related to the expressible moisture, work to fracture, and elongation. Behaviour of starchy components during thermal processing and its relationship to fish protein gel matrix were studied by light and electron microscopy. These studies showed differences in …

Cryo-Scanning Electron Microscopy Investigation Of The Texture Of Cooked Potatoes, J. T. Van Marle, A. C.M. Clerkx, A. Boekestein

Food Structure

The texture of steam-cooked potatoes was investigated by examining the fracture planes of four different cultivars, using cryo-scanning electron microscopy (cryo-SEM), which yielded a good preservation of the hydrated structures in potato tissue . For all cultivars , fracturing after steam -cooking took place between cells preferentially alongside the cell walls. However, textural difference appeared from the degree of intercellular contact, the cell shape and the appearance of cell surfaces. Cells in the fracture planes of firm potatoes had large intercellular contacts. In this case, most of the cells were flat and cell surfaces showed folds and cracks . For …

The Cellular Structure Of Selected Apple Varieties, K. G. Lapsley, F. E. Escher, E. Hoehn

Food Structure

Apple cultivars (Sauergrauech, Klarapfel, James Grieve, Granny Smith, Mcintosh, Robinette) which had different textures based on sensory and instrumental analysis (particularly in firmness and mealiness) were examined by conventional scanning electron microscopy (SEM), cold-stage SEM (cryoSEM) and confocal scanning laser microscopy (CSLM) using various preparative procedures. Advantages, lim itations and artifacts of each technique are discussed.

SEM with glutaraldehyde-fixation and criticalpoint- drying produced minimal tissue distortion and the fracture pattern and appearance of mealy versus non mealy tissue was different. Freeze-drying unfixed tissue caused cell collapse and firm versus soft varieties could not be differentiated. Freeze-fracturing and cryoSEM of apple …

Effect Of Chemical Modifications On The Stability, Texture And Microstructure Of Cooked Meat Batters, Andre Gordon, Shai Barbut

Food Structure

The effects of five chemical agents on the stability, texture and microstructure of cooked comminuted meat batters were studied. B-mercaptoethanol (/3-ME), hydrogen peroxide (H20~, ethylenediaminetetraacetic acid (EDT A), urea, and polyoxyetbylene sorbitan monooleate (fween 80) were used. The reduction of disulphide bonds by 8-ME or the oxidation of free sulphydryls by H20 2 prior to cooking did not affect liquid and fat losses during cooking as compared to the control (2.5% NaCI). However, texture profile analysis (fPA) showed that treatment with H20 2 resulted in a harder, more cohesive product than the control and ,8-ME treatments because a more fine-stranded, …

Functional Properties And Microstructure Of Chicken Breast Salt Soluble Protein Gels As Influenced By Ph And Temperature, S. F. Wang, D. M. Smith

Food Structure

The effects of different pH's (4 .5 , 5.5, 6.5 and 7.5) and temperatures (30-80 •c) on the functional properties and microstructure of chicken breast salt soluble protein (SSP) in 0.6 M NaCI were investigated. Protein solubility decreased from 98% at pH 6.5 to less than I% at pH 4.3 and below. Salt soluble protein at pH 4.5 produced a discontinuous gel which could not be measured by back extrusion and had an expressible moisture above 80% at all heating temperatures . Aggregated globular microstructures were observed at pH 4.5 by scanning electron microscopy (SEM). Thin-sectioned images as seen by …

Scanning Electron Microscopy Structure And Firmness Of Papain Treated Apple Slices, Yaguang Luo, Max E. Patterson, Barry G. Swanson

Food Structure

'Mcintosh' apple (Malus domesrica Borkh.) slices were treated with papain. Textural changes were recorded with an Instron Universal Testing Machine. Structural changes and distribution of microorganisms in apple tissues after treatment were observed with a scanning electron microscope (SEM). Apple slices submerg ed in a 1% papain solution were significantly firmer than apple slices submerged in the distilled water control for a 24 hour period (P < 0.05). Three and four days after slicing , a significantly smaller decay index was observed on the apple slices submerged in papain solution than on the control slices. Under SEM, less severe cell wall breakdown was observed on the apple tissues treated with papain than on apple tissues without treatment. Less spores were also observed on the papain treated apple slices than apple slices without treatment. Apple tissues treated with papain solution and distilled water also demonstrated noticeable st ru ctural differences. The apple tissues treated with papain solution for 18 hours retained the original cell structure while the cells in the apple tissues treated with distilled water collapsed.

Structure And Rheology Of Dairy Products: A Compilation Of References With Subject And Author Indexes, David N. Holcomb

Food Structure

No abstract provided.

Effect Of Extruder Die Temperature On Texture And Microstructure Of Restructured Mechanically Deboned Chicken And Corn Starch, V. B. Alvarez, D. M. Smith, S. Flegler

Food Structure

Proximate composition, textural properties and microstructural changes of mechanically deboned chicken/15% corn starch extrudates were evaluated when restructured at die temperatures of 25, 71, 82, 93 , 104 and ll5°C in a twin-screw extruder. Total sol ids and fat content decreased, whereas protein content increased die temperatures were increased. When die temperature was increased from 71°C to 104°C, apparent stress at failure of extrudates increased by 44 kPa , but decreased at a die temperature of 115°C. Changes in the protein matrix, fat globules and starch granules due to changes i n extruder die temperature were observed by scanning electron …

Microstructure And Texture Of Meat Emulsions Supplemented With Plant Proteins, Allan T. Paulson, Marvin A. Tung

Food Structure

A model meat emulsion system was used to evaluate the effects of cooking time and temperature on texture, microstructure and cook stability of meat emulsions containing soy or canola protein isolate. The plant proteins were incorporated either dry or rehydrated at replacement levels of 33.3% and 66.7% of the meat protein, and the emulsions were cooked at 70 or 95 C tor 25 or 50 min. Texture of the cooked emulsions was assessed by an instrumental texture profile analysis (TPA) using an lnstron tester . Analysis of TPA and stability data revealed several complex Interactions between experimental variables; however, level …

The Structural Basis Of The Water-Holding, Appearance And Toughness Of Meat And Meat Products, Gerald Offer, Peter Knight, Robin Jeacocke, Richard Almond, Tony Cousins, John Elsey, Nick Parsons, Alan Sharp, Roger Starr, Peter Purslow

Food Structure

A structural approach greatly clarifies which components of meat are responsible for its tenderness, water-holding and appearance, and the events occurring during processing.

In living muscle, water is held in the spaces between the thick and thin filaments. Changes in the content and distribution of water within meat originate from changes in this spacing. Myofibrils shrink laterally post mortem . The fluid expelled accumulates between fibre bundles and between fibres and is drain ed by gravity forming drip. In pale, soft and exudative meat, shrinkage of the myosin heads on denaturation increases myofibrillar shrinkage. In salt solutions used in meat …

The Effect Of Chloride Salts On The Texture, Microstructure And Stability Of Meat Batters, A. Gordon, S. Barbut

Food Structure

The stability, texture and microstructure of six mechanically deboned chicken meat bat.ters prepared with NaCL (1.25 and 2.5%) and replacement of the 2. 5 NaCl with HgC12 , CaC12 , KCl and LiCl based on isoionic strength were examined . The uncooked HgCL2 batter showed the poorest fat binding, The monovalent chloride salts produced stable cooked batters, whereas both divalent salts did not, CaC12 produced a more unstable batter than MgC1 2 High correlation was found between water and fat loss and total cookout losses from cooked batters. Texture was significantly affected by the type of chloride salt used. The …

Textural Properties And Structure Of Starch-Reinforced Surimi Gels As Affected By Heat-Setting, J. M. Kim, C. M. Lee, L. A. Hufnagel

Food Structure

The gel forming behavior of red hake (Urophycis chuss) surimi with and without starch and its relationship to the structure of the gel matrix were studied. For surimi gels without starch, a combination of preheat- setting at 40 C and cooking at 90 C resulted in significantly greater gel strength than cooking alone. However, preheat - setting of gels containing wheat or potato starch had no significant effect on gel strength demonstrating an opposite trend in gel strength due to the differences in swelling power, water holding ability and gelatinization temperature between potato and wheat starches. This difference in gel …

Texture And Microstructure Of Soybean Curd (Tofu) As Affected By Different Coagulants, J. M. Deman, L. Deman, S. Gupta

Food Structure

The coagulating properties of five coagulants and the nature of the curd obtained from soymilk was investigated . Viscosity changes during coagulation were studied using a Namctrc Vibrating Sphere Viscometer and texture measurements were made by compression and computer assisted analysis. pH and amount of solids in the whey were determined. The microstructure of the tofu was examined by sca nning electron microscopy. It was observed that CaCI2.2H20 and MgCI2.6H20 coagulaled the milk in stantl y while CaS04 .1/2H20. glucono delta l a~tonc (GOL) and MgS04 .7H20 acted comparatively slowly. The t exture of the curd was greatly influenced by …

A Review Of The Muscle Cell Cytoskeleton And Its Possible Relation To Meat Texture And Sarcolemma Emptying, D. W. Stanley

Food Structure

A review of the muscle cytoskeleton is presented. Current evidence leads to the concept of a muscle cell cytoskeleton consisting of at least two elements - gap filaments which are located parallel to the fiber ax~s and provide intracellular elasticity and tensile strength and intermediate filameots found in the zdisc area that function to connect adjacent Z- discs and promote lateral registration. The former constituent consists of the high molecular weight protein connectin (titinl while the latter is composed of the smaller protein desmin (skeletinl. Both proteins exist in filamentous form, are susceptible to proteolysis and are insoluble in physiological …

Sensory And Instrumental Texture Properties Of Flaked And Formed Beef, Armand V. Cardello, Ronald A. Segars, John Secrist, Joseph Smith, Sam H. Cohen, Robert Rosenkrans

Food Structure

Four experiments were conducted to assess the sensory textural properties, consumer acceptability and instrumental-sensory correlates of flaked and formed beef steaks. In Experiment 1, the effects of additions of NaCI, TPP and soy isolate on the texture of steaks were examined using a trained texture profile panel, and the texture of these steaks was compared to that of intact muscle (ribeye) steaks. Results showed large differences between the flaked and formed samples and the ribeye steak, as contrasted to small differences among the flaked and formed samples treated with different levels of NaCI, TPP and/or soy isolate.

In Experiments 2 …