Life Sciences Commons^™

Morphometry Of Meat By Scanning Light Microscopy, H. J. Swatland

Food Structure

Morphometric data can be collected from meat by using a scanning stage and a photometer, both controlled by a microcomputer. The passive counting of connective tissue boundaries is g1ven as an example to show that enumerative data may be biassed by the ratio of the width of the subject of measurement to the projected diameter of the photometer aperture. In a second example, the scanning stage is actively directed by the observer and is used to map the radial distribution of succinate dehydrogenase (SOH) activity in different histochemical types of muscle fibers. This is accomplished by the arbitrary fitting by …

An Alternive To Critical Point Drying For Preparing Meat Emulsions For Scanning Electron Microscopy, Edward J. Basgall, Peter J. Bechtel, Floyd K. Mckeith

Food Structure

A rapid sample drying technique is described which is useful for the simultaneous preparation of large numbers of samples as an alternative to critical point drying. The cryofractured face of meat emulsions was visualized after appl ying this technique . The fine structure of 1 ipids and proteins were found to be well preser ved in comparison to other reports which used critical point dried meat emulsions. Lipid was readily discerned from the protein matrix by selective fixation of the components in duplicate samples . Stereo imaging was useful in enhancing the texture of the cryofractured surface and as an …

Myofibrillar Characteristics Of Porcine Stress Syndrome, P. K. Basrur, Sandra Frombach, W. N. Mcdonell, H. D. Geissinger

Food Structure

Porcine Stress Syndrome (PSS) is a genetic trait causing considerable economic loss to the swine industry through stress related death and the poor quality meat known as pale, soft, exudative (PSE) pork . A scanning and transmission electron microscopic examination of muscle biopsies from stress susceptible pigs revealed contracture bands , wide separation of myofibers and focal distortion and dissolution of myofibril s . The changes affecting myofibrillar characteristics and intra and intercellular accumulation of material suspected to be myoplasmic fluid in biopsies of halothane reactors suqqest that the myopathic alterations presaging the carcass deterioration into pale, soft , exudative …

Ultrastructure Studies Of Pasta. A Review., P. Resmini, M.A. Pagani

Food Structure

Freeze-fracturing can be used effectively to study pasta microstructure both in the dry and cooked state. Aft er a walerglycerol soaking. conventional raw wheat pasta shows an uncoagulated protein matrix in which the starch granules are uniformly dispersed. Starch granules appear unswollen with a spherulitic structure. Extensive protein denaturation and starch swelling may occur during processing when a temperature greater than 60°C is attained in drying. Extensive structural transformations take place in cooking. A fibrillar protein network which envelops gelatinized starch is the typical structure observed in cooked durum wheat spaghetti. Whereas. in soft wheat products, there is a less …

Image Analysis Of Morphological Changes In Wiener Batters During Chopping And Cooking, A. G. Kempton, S. Trupp

Food Structure

Histological changes in wiener batters during chopping and cooking have often been illustrated with "representative" fields . The practice of selecting representative fields ignores variation and leads to word descriptions that cannot be correlated with numerical scores for functional or sensory tests . If wieners are regarded as a multi-component system, objectivity can be achieved by selecting many fields for each sample according to a rigid sampling plan. Image analysis quantified parameters of both the fat and protein components . The reduction in size of fat globules during chopping of a commercial formulation, for example, was a function of area …

The Structure Of Fresh Desiccated Coconut, J. F. Heathcock, J. A. Chapman

Food Structure

Light and electron microscopy have been used to study the structure of fresh coconut endosperm tissue and the changes which have occurred when this has been processed to the desiccated form. In fresh tissue, a marked gradation of cell size , shape and contents exists between inner and outer endosperm regions. Adjacent to the brown testa, cells are rigid, compact and lipid-filled while those cells lining the central water-filled cavity have thin, easily deformed cell walls and contain little lipid . Desiccated coconut be ing derived from fresh tissue, is similar in morphology but moisture is reduced from 50% to …

Effect Of Prerigor Pressurization On Bovine Lysomal Enzyme Activity, E. A. Elgasim, W. H. Kennick, A. F. Anglemier, M. Koohmaraie, E. A. Elkhalifa

Food Structure

Longissimus muscle from 8 dairy cows was prerigor pressure (PRP) treated at different pres sure levels (0, 34.5, 68.9 and 103.5 I·INm- ' ). a-Glucuronidase (indicator of lysosomal enzymes) activity in the unsedimentable (U) and sedimentable (S) fractions was fluorometrically assayed at ! ~ , 24 and 168 hr postmortem. At I ~ and 24 hr postmortem, the specific activity of a-Glucuronidase in the U-fraction from PRP treated samples was significantly (P

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 …

Infection Of Oriental Mustard By Nematospora: A Fluorescence And Scanning Electron Microscope Study, Richard A. Holley, Beverley E. Phipps-Todd, Suk H. Yiu

Food Structure

Fluorescence light microscopy and scanning electron microscopy were used to study penetration by the yeast Nematospora caryli through the seed coat and into the embryonic tissues of oriental mustard seed (Brasslca iuncea).

Infection of the seed was associated with its physical injury; however, it was evident that the yeast was capable of successfully invading healthy plant cells. The pathological process was followed in parallel using both the above types of microscopy. Foci of yeast infection on the seed coat outer surface were characterized by swelling of the infected epidermal cells. Nematospora hyphae were seen in the lumina of the seed …

Stranded Structure Development In Thermally Produced Protein Concentrate Gel, T. Beveridge, L. Jones, M. A. Tung

Food Structure

Scanning electron micrographs of thermally induced whey protein concentrate gels were taken. Sample preparation was accomplished by glutaraldehyde fixation, osmium tetroxide post fixation and critical point dehydration. Stranded or beaded gel structures were observed on the external surface of a gas bubble, suggesting that a "string-of-beads" gel microstructure may result from bubble formation during thermal treatment.

The Effects Of Commercial Processing On The Structure And Microchemical Organization Of Rapeseed, S. H. Yiu, I. Altosaar, R. G. Fulcher

Food Structure

Rapeseed samples collected from different processing stages were obtained from one commercial crushing plant for the present investigation. The samples included (A) whole seeds, (B) flaked seeds, (C) press cakes, (D) solvent extracted meal, (E) desolventized meal and (F) cooled, desolventized meal . Frozen and/or glycol met hacrylate-embedded sections of the samples were examined using the techniques of fluorescence microscopy. Mechanical crushing tended to disrupt cell walls. After cooking and expeller pressing, individual protein bodies fused to form large masses encompassing phytin containing globoids. Storage lipids also coalesced into larger droplets. Most of the oil was removed after solvent extraction …

Microstructure Of Winged Beans, K. Saio, Y. Nakano, S. Uemoto

Food Structure

Microstructures of seven plant introductions of winged beans (Psophocarpus tetragonolobus) produced in Okinawa, Japan were investigated. In cotyledonary cells of winged beans, protein bodies plus numerous lipid bodies were distributed in a cytoplasmic network. Starch granules were often found in some introductions but rarely in others. All seven introductions had very thick cell walls. The high protein, fat and hemicellulose contents of winged beans are consistent with the numerous protein bodies, lipid bodies and thick cell walls in the mature cotyledonary cells. The cell walls contained a number of depressions or cavities 1 to 2 lJ m deep which frequently …

B-Glucans In The Caryopsis Of Sorghum Bicolor (L.) Moench, C. F. Earp, C. A. Doherty, R. G. Fulcher, L. W. Rooney

Food Structure

Fluorescence microscopy was used to determine the location of B- glucans in sorghum. Sections from three genetically different sorghum cultivars were stained with Calcofluor or Congo Red , fluorochromes which have been reported to react with 13-glucans. Autofluorescence, indicative of ferulic acid in other cereals, was observed in untreated sections. When stained sections were treated with endo -B-glucanase , fluorescence was reduced or entirely eliminated in pericarp, aleurone and endosperm cell walls. 13-Glucans were i so lated from the endosperm of three sorghum cultivars. When reacted with the two dyes, Calcofluoror Congo Red , precipitates formed immediately, a reaction which …

Field Spectroscopy In The Food Production Chain, E. J. Brach

Food Structure

This paper reviews the application of field spectroscopy in the food production chain, particularly how field spectroscopy aids research and production of agricultural crops , and helps to understand the process of converting these crops into food.

The review discusses the nondestructive application of field spectroscopy such as ultraviolet, reflective , visible, near infrared and fluorescence techniques using conventional or laser light sources, to determine qualitative and quantitative properties of agricultural crops and produce.

Field spectroscopy can provide data on soil constituents and moisture, crop maturity, crop vigor, crop health, variety, variety within crops , and protein and moisture content …

Endosperm Degradation In Barley Kernels That Synthesize Amylase In The Absence Of Embryos And Exogenous Gibberellic Acid, A. W. Macgregor, P. B. Nicholls, L. Dushnicky

Food Structure

During germination at l6°C, whole seeds and distal half-seeds of Klages barley and two types of Clipper barley (Types A and B) were analyzed for a -amylase . Structural changes in the endosperms of these seeds and half-seeds were examined by scanning electron microscopy. In Clipper B half-seeds, Q-amy base activity increased significantly , there was a detectable amount of starch granule hydrolysis and endosperm structure was markedly degraded. No starch hydrolysis and only trace amounts of a-amylase and endosperm degradation were detected i.n Clipper A and Klages halfseeds. The rewns significant a -amylase synthesis, starch hydrolysis and endosperm degradation …

Composition And Microstructure Of Soft Brine Cheese Made From Instant Whole Milk Powder, Mohamed M. Omar, Wolfgang Buchheim

Food Structure

Comparative studies were made on the composition, microstructure and organoleptic quality of soft brine cheese made from instant whole miIk powder and from raw miIk. The chemical analysis of young and ripened (one and two month) cheese revealed similarity except for a higher salt content in the cheese made from reconstituted milk at the end of ripening . Electron microscopic studies showed distinct differences in the structure of the protein matrices in the ripened cheese samples , i .e . a very homogeneous structure in the cheese made from raw milk compared with a slightly aggregated state of the protein …

Development Of Microstructure In Set-Style Nonfat Yogurt - A Review, Miloslav Kalab, Paula Allan-Wojtas, Beverley E. Phipps-Todd

Food Structure

The development of microstructure in natural set-style nonfat yoghurt was stud i ed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition to thin-sectioning and conventional SEM described in the literature, this review illustrates gelation of milk with micrographs obtai ned by rotary shadowing of casein micelles and their clusters. The existence of void spaces occupied by lactic acid bacteria in yoghurt was con finned by cold-stage SEM of uncoa ted specimens. The microstructure of yoghurt is affected by the preheat treatment of milk, bacterial starter cultures, total solids content , and the presence of thickening agents. …

Evaluation Of Selected Properties Of Chlorinated Wheat Flours In A Lean Cake Formulation, J. Grider, E. A. Davis, J. Gordon

Food Structure

Cake flours treated with different levels of chlorine were evaluated by use in a Kissell cake formulation. Flour particle size distributions varied with chlorination level, but pH and specific gravity of the batters did not differ. Batter viscosity differences were observed at specific temperatures during heating of total batters. Temperature profiles differed positionally in the cakes, but these patterns of heat penetration were not related to level of chlorine treatment. However, water loss rates differed depending on the level of chlorine treatment indicating a more pronounced effect of chlorination level on the water loss characteristics of the cakes during the …