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Full-Text Articles in Life Sciences

Preliminary Evaluation Of Lectins As Fluorescent Probes Of Seed Structure And Composition, S. Shea Miller, S. H. Yiu, R. G. Fulcher, I. Altosaar Jan 1984

Preliminary Evaluation Of Lectins As Fluorescent Probes Of Seed Structure And Composition, S. Shea Miller, S. H. Yiu, R. G. Fulcher, I. Altosaar

Food Structure

Several commercially available fluoresceinisothiocyanate and rhodamine isothiocyanateconjugated plant lectins have been applied to cereal and oilseed tissues to permit identification and localization of specific structures and carbohydrates by fluorescence microscopy . Ulex europeaus Agglutinin I (UEAl) and Ricinis communis Agglutinin I (RCA I) showed specificity for the amyloids in rapeseed cotyledonary cell walls . Wheat Germ Agglutinin (WGA) bound to rapeseed coat mucilage, as well as fungal hyphae in infected wheat . Lens culinaris Agglutinin (LCA) bound only to starch in cereal sections, and at higher magnifications of isolated starch granules , the annular structure was clearly visible.


X-Ray Microanalysis Of Hollow Heart Potatoes, W. P. Mohr, A. R. Spurr, P. Fenn, H. Timm Jan 1984

X-Ray Microanalysis Of Hollow Heart Potatoes, W. P. Mohr, A. R. Spurr, P. Fenn, H. Timm

Food Structure

Electron microprobe and X-ray fluorescence techniques were used to study elemental gradients associated with the physiological disorder hollow heart i n potato tubers. Gradients were found along the length and across the width of mature tubers. These were not rela ted to the disorder, however . Tubers with advanced symptoms of the disorder had elemental levels and gradients similar to those in healthy, control tubers. The results suggest that if the disorder is initially caused by an elemental deficiency, as has sometimes been proposed , the deficiency is temporary and no longer exists in mature tubers with advanced hollow heart. Radial gradients ...


Ultrastructural Studies Of Raw And Processed Tissue Of The Major Cultivated Mushroom, Agaricus Bisporus, E. M. Jasinki, B. Stemberger, R. Walsh, A. Kilara Jan 1984

Ultrastructural Studies Of Raw And Processed Tissue Of The Major Cultivated Mushroom, Agaricus Bisporus, E. M. Jasinki, B. Stemberger, R. Walsh, A. Kilara

Food Structure

Commercial mushroom processors currently lose approximately 30 percent of the mushroom weight due to shrinkage during processing (blanching and canning) , resulting in substantial economic losses . Microscopy was used to assess the extent and type of chemical and structural changes induced by processing mushrooms and causing shrinkage. Scanning electron microscopy revealed that the processing operations including vacuum hydration , blanching , and thermal treatment do not damage the integrity of the tissue. Light microscopy revealed that the morphology of the tissue, shape and spacing of cells, appear similar for raw and processed mushroom tissue . However, the intra ce ll ular material remained indistinct ...


Microstructural Changes In Winged Bean And Soybean During Fermentation Into Miso, K. Saio, H. Suzuki, T. Kobayashi, M. Namikawa Jan 1984

Microstructural Changes In Winged Bean And Soybean During Fermentation Into Miso, K. Saio, H. Suzuki, T. Kobayashi, M. Namikawa

Food Structure

Miso was prepared from winged bean, being substituted for soybean. Microstructural changes of winged bean miso at various stages of the manufacturing processes were studied by means of light and transmission electron microscopies. Soybean was also studied for comparison.

After steaming , winged bean and soybean cells were shrunken and intracellular spaces enlarged and cell wall structure was degraded, showing layered structures and aggregated lumps in intraspaces between cell walls during fermentation into misc . At the end of the fermentation , the PAS reaction with cell walls almost disappeared. Surprisingly the thick cel l walls of winged bean degraded as completely as ...


The Role Of Gap Filaments In Muscle And In Meat, R. H. Locker Jan 1984

The Role Of Gap Filaments In Muscle And In Meat, R. H. Locker

Food Structure

The neglected "gap filaments" are now beginning to receive close attention in several centers, in terms of organisation, composition and function. The author's model for their connections gave them a role as cores to A-filaments. This review attempts to weigh the implications of such a role, and relevant evidence, old and new. New ideas arising largely from PAGE*and immunochemkal studies on candidate proteins, and from the developing concept of the cytoskeleton, are considered.

The author's theory of meat tenderness, based on G-filaments, has been tested by PAGE studies on changes in the large structural proteins (particularly titin ...


Light And Scanning Electron Microscopy Of Wheat And Rye-Bread Crumb. Interpretation Of Specimens Prepared By Various Methods, Y. Pomeranz, D. Meyer Jan 1984

Light And Scanning Electron Microscopy Of Wheat And Rye-Bread Crumb. Interpretation Of Specimens Prepared By Various Methods, Y. Pomeranz, D. Meyer

Food Structure

The crumb of bread baked from wheat flour, rye flour, and rye meal was examined by light( LM ) and scanning electron-microscopy {SEM) . Whereas in the wheat bread the crumb is held together by a matrix of denatured protein, in the rye bread crumb highly expanded starch granules fulfill that r ole . Fractur i ng freeze-dried crumb ~rovided different information than sectioning !Jrior to freeze-drying . In the first case, little damage was caused to components of outer surfaces of vacuoles. In the second case , the protein matrix and starch granules were broken. At the same time, the presence of micropores in ...


The Effects Of Microwave Energy And Convection Heating On Wheat Starch Granule Transformations, N. K. Goebel, J. Grider, E. A. Davis, J. Gordon Jan 1984

The Effects Of Microwave Energy And Convection Heating On Wheat Starch Granule Transformations, N. K. Goebel, J. Grider, E. A. Davis, J. Gordon

Food Structure

Wheat starch-water dispersions at 1:1, 1:2, 1:4, and 5 95 (w/w) starch:water ratios, representing systems with varying levels of water availability , were heated under static conditions to 75°C by microwave energy at two power settings and by convection heating. Starch granule swe lling was evaluated by light and scanning electron microscopy. Six stages in swelling were identified on the basis of s welling of small and large granules and development of an extragranular matrix. The range of swelling stages found in different locations within a sample decreased as water became more available and less ...


Studies On The Microdistribution Of Aerobic Enzymes And Myoglobin In Pork, H. J. Swatland Jan 1984

Studies On The Microdistribution Of Aerobic Enzymes And Myoglobin In Pork, H. J. Swatland

Food Structure

Techniques were developed to study the microdistribution of aerobic enzymes and myoglobin directly on the surfaces of slices of meat. Despite its solubility, the in vivo distribution of myoglobin was preserved post mortem and, in pork, the distribution of myoglobin followed the distribution of aerobic muscle fibers. Aerobic fibers were grouped centrally in their fasciculi. Differences in oxidative enzyme activity between central and peripheral fibers within fasciculi were detected by staining with methylene blue in an atmosphere with controlled levels of oxygen and nitrogen. Within individual aerobic fibers, there was a radial gradient of SOH (succinate dehydrogenase) activity with more ...


Ultrastructural Aspects Of Spun Pea And Fababean Proteins, D. J. Gallant, B. Bouchet, J. Culioli Jan 1984

Ultrastructural Aspects Of Spun Pea And Fababean Proteins, D. J. Gallant, B. Bouchet, J. Culioli

Food Structure

The ultrastructure of pea and fababean spun proteins has been studied by SEM and TEM as a function of dope pH and washing bath salt concentrations. The textural properties {mechanical resistance, moisture content) and diameter of the fibres have been determined.

Spinning was only possible when dope pH was higher than 11. An increase in dope pH from 11.5 to 13 induced a shear strength increase whereas the moisture content and the diameter of the fibres decreased . The structure of the fibres became more compact and changed from an aggregate of spherical particles to a tridimensional network. When dope ...


An Analysis Of Microstructural Factors Which Influence The Use Of Muscle As A Food, R. G. Cassens, C. E. Carpenter, T. J. Eddinger Jan 1984

An Analysis Of Microstructural Factors Which Influence The Use Of Muscle As A Food, R. G. Cassens, C. E. Carpenter, T. J. Eddinger

Food Structure

Study of structure of muscle provides information on the location and arrangement of various components and the changes which may be inflicted upon them. The structura l features of muscle have been descr ibed in detail down to the molecular level, but rega rding its use as a food, special interest centers on the connective tissue component and on myofibri llar proteins . Muscle comprises about 1/3 of the live weight of the a ni mal and is not static , but rather is subject to major changes in properties associated with growth, repair and se nescence. It is apparent that ...


Morphological Development In Sorghum Grain, C. W. Glennie, N.V.D. W. Liedenberg, H. J. Van Tonder Jan 1984

Morphological Development In Sorghum Grain, C. W. Glennie, N.V.D. W. Liedenberg, H. J. Van Tonder

Food Structure

Immature sorghum grain was harvested at various stages of maturity and its development followed by transmission and scanning electron microscopy . This was done to study the developmental morphology of the sorghum grain. The period immediately following fertilization is a time of rapid development in the sorghum caryopsis. The endosperm expands crush i ng the nucellus and in the nonbirdres i stant sorghums the inner integument is also crushed during this expansion. The cells of the ovary wal 1 expand and elongate to form the peri carp . By the soft dough stage the endosperm has gained most of its storage material ...


Mineral Migration In The Wheat Kernel During Mill Conditioning, A. Al Saleh, B. Bouchet, D. J. Gallant Jan 1984

Mineral Migration In The Wheat Kernel During Mill Conditioning, A. Al Saleh, B. Bouchet, D. J. Gallant

Food Structure

The structure and histology of the kernel govern migration of water during conditioning or drying. Studies by the energy dispersive x-ray system under the SEM have shown that during an increase of water content from 11.5 to 16.5 per cent, soluble elements migrated from the peripheral bran, accumulated in the aleurone cells and passed through its walls to the endosperm of the kernel if the water content was above 14.5 per cent. Results of study were compared with analyses of milling fractions obtained under the same conditions.


Microstructure Of Set-Style Yoghurt Manufactured From Cow's Milk Fortified By Various Methods, A. Y. Tamime, M. Kalab, G. Davies Jan 1984

Microstructure Of Set-Style Yoghurt Manufactured From Cow's Milk Fortified By Various Methods, A. Y. Tamime, M. Kalab, G. Davies

Food Structure

Five different batches of skim milk were prepared and fortified by the addition of skim milk powder (SMP) or sodium caseinate (Na-cn) or by concentration using a vacuum evaporator (EV), ultrafiltration (UF), or reverse osmosis (RO) to contain similar levels of protein (5.0-5.5%). Yoghurts were made by inoculating the milks with one of 3 commercial yoghurt starter cultures and by incubating the mixes at 42°C for 2.5 h. The following factors were found in this study to affect firmness of the yoghurts: (a) Lactic acid production (acidity) - Yoghurts containing 1.02% of lactic acid or more ...


Effect Of Environment On The Physical Structure Of The Peanut (Arachis Hypogaea L.), Clyde T. Young, William E. Schadel Jan 1984

Effect Of Environment On The Physical Structure Of The Peanut (Arachis Hypogaea L.), Clyde T. Young, William E. Schadel

Food Structure

Peanuts produced under the drought conditions of 1980 were marred by off-flavors when processed. Several phys ical characteri stics of these peanuts were noted to be related to these flavor problems. This paper deals with the investigation of these physical peculiarities using scanning electron microscopy. Major findings include previously unreported physical abnormalities such as: (1) tissue damage which appears as spotting on the outer surface of the cotyledon which is a result of cracking and fissuring; (2) tissue damage which appears as a narrow band along the inner face of the outer rounded surface and the flattened edge of the ...


The Effect Of Salt And Pyrophosphate On The Structure Of Meat, C. A. Voyle, P. D. Jolley, G. W. Offer Jan 1984

The Effect Of Salt And Pyrophosphate On The Structure Of Meat, C. A. Voyle, P. D. Jolley, G. W. Offer

Food Structure

Our obective was to determine whether or not salt and pyrophosphate have the same effect on the structure of pieces of meat as they have on isolated myofibrils. Blocks of pig M. longissimus dorsi were incubated in solutions of sodium chloride at pH 5.5 or sodium chloride plus sodium pyrophosphate at pH 5.5 or 8.0. The blocks were obtained from fresh (24h post- mortem) or aged (72h post-mor tem) muscle and incubated for 5 or 24h with minimal agitation. There was considerable uptake of water by the tissue especially at the higher pH and longer times.

Electron ...


Electron Microscopic Investigations Of The Cell Structure In Fresh And Processed Vegetables (Carrots And Green Bean Pods), Monika Grote, Hans Georg Fromme Jan 1984

Electron Microscopic Investigations Of The Cell Structure In Fresh And Processed Vegetables (Carrots And Green Bean Pods), Monika Grote, Hans Georg Fromme

Food Structure

The cell structure of fresh, blanched, boiled. dried and rehydrated tissues from carrot roots and green bean pods was examined in the scanning and/or transmission electron microscope. The secondary phloem of carrot roots represents a typical plant storage parenchyma characterized by a high starch and lipid content. Green bean pods show many characteristics of assimilation tissue (e.g. chloroplasts). but they also contain a considerable amount of starch. Blanching, boiling, de- and rehydration affect the texture of both vegetables in a similar way: swelling of cell walls. maceration of tissue during blanching and boiling coupled with a granular denaturation ...


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.


Some Factors Influencing Ante-Mortem Changes In Muscle: A Brief Review, S. C. Seideman, S. H. Cohen, J. V. Schollmeyer Jan 1984

Some Factors Influencing Ante-Mortem Changes In Muscle: A Brief Review, S. C. Seideman, S. H. Cohen, J. V. Schollmeyer

Food Structure

Ante-mortem changes to muscle microstructure are influenced in many ways. During pre-natal cell differentiation and growth , myoblasts develop and mature into cells with quite different characteristics. Incorporated into the genome of these cells is the ability to synthesize a wide variety of filaments which occupy specific niches within each myofibril. During post-natal development , depending upon the particular precursor cell lines, different fiber types are produced. These are especially important in contributing to the ultimate palatability of meat. In this paper several factors which influence ante-mortem changes to muscle microstructure are discussed. While some of these are better understood than others ...


A Simple Procedure For The Preparation Of Stirred Yoghurt For Scanning Electron Microscopy, Paula Allan-Wojtas, Miloslav Kalab Jan 1984

A Simple Procedure For The Preparation Of Stirred Yoghurt For Scanning Electron Microscopy, Paula Allan-Wojtas, Miloslav Kalab

Food Structure

Stirred yoghurt is aspirated into agar gel tubes having 1.2 mm interior diameter, fixed in glutaraldehyde , dehydrated in ethanol freeze - fractured under liquid nitrogen and critical-point dried. Agar gel encapsulation protects the sample and prevents it from disintegration during the preparative steps. Scanning electron microscopy of the mounted fragments reveals the corpuscular microstructure of this type of yoghurt which develops due to stirring and pumping of the product during manufacture.


Ultrastructure Of Quinoa Fruit (Chenopodium Quinoa Willd), E. Varriano-Marston, Alicia Defrancisco Jan 1984

Ultrastructure Of Quinoa Fruit (Chenopodium Quinoa Willd), E. Varriano-Marston, Alicia Defrancisco

Food Structure

The structure of quinoa (Chenopodium quinoa) fruit before and after germination was studied using electron microscopy. Protective coverings include a perianth consisting of loosely adhering cell s which are readily removed by washing, a pericarp and two seed coat layers. Starch granules fill the perispenn cells and are arranged in 18 to 20 oblong aggregates. Limited hydrolysis of the starch occurs after 24 hrs of germination, with amylolytic erosion of large granules occurring at the hilum and periphery of the granul es. Ungerminated embryo cells contain protein bodies with phosphorus-containing globoid inclusions. Essentially complete hydrolysis of the embryo protein bodies ...


Artefacts In Conventional Scanning Electron Microscopy Of Some Milk Products, Miloslav Kalab Jan 1984

Artefacts In Conventional Scanning Electron Microscopy Of Some Milk Products, Miloslav Kalab

Food Structure

Artefacts develop due to changes in the microstructure of the sample under study because of inappropriate preparatory steps and/or due to distortion of the images of properly prepared samples during operation of the microscope. Of a wide variety of possible artefacts. only those occurring mast frequently have been selected and ilustrated with micrographs. In milk powders, the most common artefacts are the recrystallization of lactose in a humid atmosphere, "1 ine" and "dark-area" charging artefacts, and electron beam damage. In moist milk products, artefacts may arise at any preparatory step, such as sampling, fixation, dehydration and critical-point drying or ...