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Food Science

Food Structure

Protein matrix

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Full-Text Articles in Life Sciences

Mechanisms Of Hard-To-Cook Defect In Cowpeas: Verification Via Microstructure Examination, Keshun Liu, Yen-Con Hung, R. Dixon Phillips Jan 1993

Mechanisms Of Hard-To-Cook Defect In Cowpeas: Verification Via Microstructure Examination, Keshun Liu, Yen-Con Hung, R. Dixon Phillips

Food Structure

It has been hypothesized that part of the hard-to-cook (HTC) defect in cowpeas is due to decreases in solubility and thermal stability of intracellular proteins during storage since coagulated proteins would limit water to starch and prevent full swelling during cooking. To verify this hypothesis, effects of soaking and heating temperature on texture, water absorption, protein water extractability and microstructure of control and HTC cowpea seeds (aged or treated) were studied. Scanning electron microscopy showed no structural difference between dry control and dry aged seeds. However, after soaking, in contrast to the control, aged seeds exhibited a coarse protein matrix ...


Changes In The Microstructure Of A Comminuted Meat System During Heating, Peter A. Koolmees, Gerrit Wijngaards, Monique H.G. Tersteeg, Jan G. Van Logtestijn Jan 1993

Changes In The Microstructure Of A Comminuted Meat System During Heating, Peter A. Koolmees, Gerrit Wijngaards, Monique H.G. Tersteeg, Jan G. Van Logtestijn

Food Structure

As part of a series of experiments on heating of a comminuted meat system , image analyses were conducted to quantify microstructural changes that could be visualized by light microscopy. Three different batches of comminuted meat were investigated. Two batches (A and B) were prepared without polyphosphate; one of these (B) was deliberately overchopped. One batch containing 0. I% polyphosphate was prepared (C). All batches were heated at I I different temperatures ranging from 40 to 115 °C. The microstructure of the three types of meat batte rs at the end of the com minu tion process differed. These types of ...


Microstructural Differences Among Adzuki Bean (Vigna Angularis) Cultivars, Anup Engquist, Barry G. Swanson Jan 1992

Microstructural Differences Among Adzuki Bean (Vigna Angularis) Cultivars, Anup Engquist, Barry G. Swanson

Food Structure

Scanning electron microscopy (SEM) was used to study microstructural differences among five adzuki bean cultivars: Erimo, Express, Hatsune, Takara and VBSC. Seed coat surfaces showed different patterns of cracks, pits and deposits . Cross-sections of the seed coats revealed well organized layers of elongated palisade cells followed by many layers of amorphous parenchyma cells. Typical sub-epidermal layers of organized columnar, hour-glass cells were characteristica11y absent in the five cultivars of adzuki beans. The cross-sections of the cotyledons revealed intercellular materials between storage cells. Storage cells in Hatsune cultivar were loosely packed with many intercellular spaces as compared to the other four ...


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 Jan 1991

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 ...


Microstructure Of Adzuki Beans (Vigna Angularis Cv. Express), Anup Chilukuri, Barry G. Swanson Jan 1991

Microstructure Of Adzuki Beans (Vigna Angularis Cv. Express), Anup Chilukuri, Barry G. Swanson

Food Structure

Scanning electron microscopy (SEM) was used to study and compare the mic rostructure of adzuki, black and Mexican red bean seeds. The two cotyledons of the beans were separated by a deep fissure. A view of seed coat surface of adzuki beans revealed a characteristic pattern of convolutions and cracks, not observed on the seed coat surfaces of black or red beans. The cro sssection of seed coat of adzuki beans exhibited a thick layer of palisade cells in the epidermal layer followed by underlaid multiple layers of tightly packed parenchyma cells. A sub-epidermal layer comprised of a single layer ...


Effect Of Chemical Modifications On The Microstructure Of Raw Meat Batters, Andre Gordon, Shai Barbut Jan 1991

Effect Of Chemical Modifications On The Microstructure Of Raw Meat Batters, Andre Gordon, Shai Barbut

Food Structure

The microstructure and stability of raw meat batters treated with five chemical agents were investigated by electron and light microscopy. Six batters were made with NaCI (2.5%). five of which were treated with either hydrogen peroxide (H,O,), B- mercaptoethanol (B-ME), ethylenediamine- tetraacetic acid (EDTA), urea or Tween 80. The Tween 80 treatment produced a highly unstable raw batter with significant (P > 0.05) fat and water losses. None of the other treatments produced an unstable raw batter.

Microstructural examination revealed that, except for Tween 80, the chemically-treated raw batters were stable and showed some similarity to the control ...


Microstructure And Firmness Of Processed Cheese Manufactured From Cheddar Cheese And Skim Milk Powder Cheese Base, A. Y. Tamime, M. Kalab, G. Davies, M. F. Younis Jan 1990

Microstructure And Firmness Of Processed Cheese Manufactured From Cheddar Cheese And Skim Milk Powder Cheese Base, A. Y. Tamime, M. Kalab, G. Davies, M. F. Younis

Food Structure

Processed cheese (10 different types) was made from Cheddar cheese and a cheese base produced from reconstituted skim milk powder by blending and melting with commercial emulsifying salts at 9Q<>C. In one experiment, the cheese base was subjected 10 accelerated cheese ripening by added enzyme. The finished products had 50.1- 53.5% total solids, 18.2-19.3% protein, 47.4-49.7% fat in dry matter, and 2.7-3.0% salt in water; pH was 5.3-5.4 after three months of storage at 10 C and 30 C.

The experimental cheeses were markedly firmer than the control cheeses ...


Development Of Sorghum (Sorghum Bicolor (L.) Moench) Endosperm In Varieties Of Varying Hardness, J. M. Shull, A. Chandrashekar, A. W. Kirleis, G. Ejeta Jan 1990

Development Of Sorghum (Sorghum Bicolor (L.) Moench) Endosperm In Varieties Of Varying Hardness, J. M. Shull, A. Chandrashekar, A. W. Kirleis, G. Ejeta

Food Structure

Factors responsible for grain hardness in sorghum are not well understood. Therefore, a study was undertaken to observe differences in the developmental processes of three sorghum varieties which vary in endosperm texture: hard, intermediate, and soft. Grain samples were collected at 5 day intervals beginning at 5 days after half-bloom (DAHB) until physiological maturity (40 DAHB) and prepared for viewing with scanning electron microscopy and transmission electron microscopy.

Comparisons were made between vitreous and floury endosperm portions of each variety and among the three varieties. The major difference between vitreous and floury endosperm was the degree to which the protein ...


Microstructure And Texture Of Meat Emulsions Supplemented With Plant Proteins, Allan T. Paulson, Marvin A. Tung Jan 1989

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 ...


The Effect Of Chloride Salts On The Texture, Microstructure And Stability Of Meat Batters, A. Gordon, S. Barbut Jan 1989

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 ...


Functional And Microstructural Effects Of Fillers In Comminuted Meat Products, Frederick W. Comer, Paula Allan-Wojtas Jan 1988

Functional And Microstructural Effects Of Fillers In Comminuted Meat Products, Frederick W. Comer, Paula Allan-Wojtas

Food Structure

Fillers are used in comminuted meat products such as wieners to increase yield, improve stability, and modify textural properties. Light microscopy, scanning electron microscopy and transmission electron microscopy show that comminutred meat products are mechanical mixtures in which the microstructural features of starch and insoluble protein ingredients are largely retained. The water absorption and gelation properties of these ingredients contribute to the stability and textural firmness. Soluble proteins may improve stability through emulsion formation but the role of emulsion formation i s clearly secondary to that of gelation. The characteristic springy gel structure of wieners is determined by the gelation ...


Relationship Between Microstructure And Susceptibility To Syneresis In Yoghurt Made From Reconstituted Nonfat Dry Milk, V. R. Harwalkar, Miloslav Kalab Jan 1986

Relationship Between Microstructure And Susceptibility To Syneresis In Yoghurt Made From Reconstituted Nonfat Dry Milk, V. R. Harwalkar, Miloslav Kalab

Food Structure

Increase in the density of protein matrices i n yoghurt samples conta ining 10 to 30% total milk sol ids was studied by scanning electron micros copy and was corr e lated with a decrease in syneresis. Casein particles which formed chains and clusters in the protein matrix were largest in the 10% total solids yoghurt and their dimensions were decreased as the total solids contents were increased. This observation was confirmed by transmission electron microscopy of thin sections. An attempt has been made to explain the discrepancy between results on syneresis obtained by a drainage and a centrifugation method ...


Microstructure Of Mealy And Vitreous Wheat Endosperms (Triticum Durum L.) With Special Emphasis On Location And Polymorphic Behaviour Of Lipids, A. Al Saleh, D. Marion, D. J. Gallant Jan 1986

Microstructure Of Mealy And Vitreous Wheat Endosperms (Triticum Durum L.) With Special Emphasis On Location And Polymorphic Behaviour Of Lipids, A. Al Saleh, D. Marion, D. J. Gallant

Food Structure

Dark inclusions observed in osmiophilic zones, already described in mature wheat endosperm using transmission electron microscopy, were confirmed by freeze-fracture electron microscopy to be lipids. The polar lipids (glycolipids, phospholipids, free fatty acides, monoglycerides) were organized in a liquid crystalline phase. The reversed hexagonal or HII phase should be the main lattice which might arise from the transition of lipids present in membranous structures as a lamellar phase. This transition was caused by dehydration occurring during maturation. It is suggested that the water-dependent lamellar hexagonal phase transitions are of considerable importance in cereal food technology.


Processing Effects On Meat Product Microstructure, Glenn R. Schmidt Jan 1984

Processing Effects On Meat Product Microstructure, Glenn R. Schmidt

Food Structure

Animal species, meat ingredient properties, comminution equipment, mechanical action, product composition, type and level of non-meat ingredients, and thermal processing greatly affect the structural and organoleptic properties of meat products. However, additional research in the area of restructured meat products, meat protein functionality and lipid properties in meat products remains to be done. The interaction of meat proteins with lipids, water and ions should be further investigated. Considerable control of raw materials, mechanical action and heat processing is essential to make research applicable to product and process development.