Life Sciences Commons^™

Selection And Preparation Of Lactic Culture Starters For Manufacture Of Cheddar Cheese, Aly Youssef Gamay

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A Spiral Plater and a Microtiter system were used to isolate and evaluate cultures for a paired strain culture program. Bacteriophage and temperature sensitivity data of 43 Streptococcus cremoris strains were introduced into a computer cluster program to pair the least similar strains.

Selected pairs were challenged with phage. Resistant mutants were developed.

Characteristics of proteinase positive and proteinase negative variants were examined. Proteinase positive isolates produced more changes in pH, cell mass and more generations in milk than their counter-parts. Paired proteinase negative cultures produced more change in pH and cell mass and more generations in milk than single …

The Effect Of Heat Treatment On Meat Heme And Nonheme Iron Bioavailability For The Anemic Rat, Oranong Jansuittivechakul

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Three separate experiments were conducted to investigate the effects of heat treatment on meat heme and nonheme iron bioavailability in anemic rats. Male weanling Sprague-Drawley rats were first made anemic, then subsequently fed with experimental diets. In the first experiment, dietary iron sources were raw or autoclaved meat mixed with ferrous sulfate to give the ratios of iron from meat and ferrous sulfate equal to 100:0, 75:25, 50:50, 25:75, and 0:100 respectively. For the second experiment, the dietary iron sources were raw or autoclaved meat mixed with bovine hemoglobin (HB) to give dietary iron ratios as described for experiment 1. …

Effects Of Heat Treatment And Post-Treatment Holding Time On Rennet-Clotting Properties Of Milk, Zeynep Ustunol

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Samples of raw whole milk were heated at L5, 50 and 75 C for 0, 30, 60, llU and 240 min. After heat treatment each sample was subdivided and portions held at 0 C for 0, 30, 60 and 120 min. In a second experiment samples of milk were heated at 25 and 50 C for the same lengths of time as before but this time at 75 C for only 5, 10, 15 and 20 min. A constant holding time of 30 min was used after the heat treatments. Following the various heat treatments pH of each sample was …

A Study Of The Action Of Bovine Cathepsin D On Intramuscular Connective Tissue, Elimosaria Elikalia Maeda

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Cathepsin D has been postulated to play a role in the tenderization of meat with ageing. Meat toughness has been related to connective tissue content and degree of myofibrillar shortening. This investigation was undertaken to determine the activity of cathepsin D on bovine intramuscular connective tissue.

Highly purified cathepsin D preparations from bovine spleen and bovine sternomandibularis muscle were obtained by ammonium sulfate fractionation followed by affinity chromatography on pepstatin coupled to controlled pore size alkyl amine glass beads. Maximum proteolytic activity using hemoglobin as substrate was obtained at pH 3.5 and 3.8 for bovine spleen and muscle cathepsin D, …

Enzymic Milk Coagulation: Casein Micelle Aggregation And Curd Formation, Donald J. Mcmahon

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Enzymic milk coagulation was monitored by measuring changes in curd firmness and apparent absorbance of undiluted milk. Detection of coagulation, visually or rheologically, occurred after the milk changes from a system of aggregating particles to an extended space network. This change was observed as a shoulder in apparent absorbance plots and coagulation time was defined as the critical point in the aggregation process analogously to non-linear condensation polymerization reactions. It corresponds to the inflexion point during the period when apparent absorbance was rapidly increasing and can be calculated by fitting curd firmness data to an exponential equation.

Addition of calcium …

A Method For Separating Casein Micelles From Whey Proteins For Determining Casein In Milk, Robert N. Carpenter

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to determine if size exclusion chromatography could be used to separate casein micelles from whey proteins for a rapid, direct test to measure percent casein in milk. A size exclusion chromatography column was developed for the separation having dimensions 100 by .4 cm. Packing material selected was glycophase coated porous glass supports. A Beckman DU-8B spectrophotometer monitored the casein and whey protein peaks as they eluted and a Tektronix 4052 computer accepted data points every 4 sec, storing these on tape. Absorbances and areas of each peak were used in the evaluation of samples. …

The Effect Of Long Term Storage Of Nonfat Dry Milk On Sensory Quality And On The Development Of Oxidative Derivatives Of Sterols, Nancy R. Driscoll

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nonfat dry milk (NOM) was evaluated to determine the effect of long term storage on its sensory quality, its solubility index and on the development of oxidative derivatives of sterols. Storage variables included the form of the milk, the atmosphere in the storage container, the type of package and the storage temperature. A trained taste panel evaluated the milk for the development of cooked, metallic, and oxidized/stale flavors, mouthfeel and overall acceptability. Gas chromatography was used to determine cholesterol content and the quantity of oxidative derivatives of cholesterol present in the samples.

Although long term storage of NOM did not …

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 …

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 …

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 …

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.

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 …

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 …

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 …

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

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

Ultrafiltration Of Skim Milk Prior To Cottage Cheese Making, Izhar H. Athar

Electronic Theses and Dissertations

Cottage cheese has the largest sales volume potential of all cultured dairy products in the United States today. Moreover, it can be a highly profitable product if proper control is exercised during its manufacturing (46). Commercial production of cottage cheese utilizes a significant portion of the total fluid milk produced in the U. S.A. After the 1955's, yearly per capita consumption of cottage cheese increased from 1. 7 7 kg (3.9 lb) to a high of 2. 45 kg (5.4 lb) in 1972 (67) . Consumer demand for lower fat dairy products gradually increased, which put more pricing emphasis on …

Significance Of Residual Organisms In Foods After Substerilizing Doses Of Gamma Radiation: A Review, R. B. Maxcy

Department of Food Science and Technology: Faculty Publications

The nature of the flora surviving substerilizing irradiation of foods is dependent on the dose applied and the conditions of applications as well as the microenvi¬ronment of the food. At a dose level low enough to preserve acceptable sensory properties of fresh food, few if any of the common contaminants of public health significance survive irradiation. Survivors are weakened and present no unique problem of acquired resistance through recycling. Those bacteria surviving a low dose treatment of a relatively contaminated product like ground beef can grow under normal storage conditions and cause obvious sensory spoilage. Thus, low dose irradiation extends …

Recipe Design And Management In A Nutritional Data Base System, Robert G. Trenary

Masters Theses

The Nutritional Data Base System (NDBS) is an interactive information system which provides the user the ability to create and process menus, recipes and food items. Three primary program modules are thus indicated along with modules to translate user requests and process file and directory information. A discussion of standard data base concepts and an application of these concepts to the processing of recipes in the NDBS system is presented. Future possible expansions are suggested and other similar information systems are discussed.

The Mexicans' And Mexican-Americans' Contribution To The Development Of The Lower Rio Grande Valley Of Texas And Its Citrus Industry, Camilo A. Martinez Jr.

Theses and Dissertations - UTB/UTPA

The little-discussed Mexican and Mexican-American contribution to the development of the Lower Rio Grande Valley of Texas into the great citrus producing area that it is today is exposed in general terms in this thesis. Due credit has been given to the Burgos, Tamaulipas, residents who came to the Valley during and after the Mexican Revolution in search of stability and better wages. In spite of the abuses they suffered, some of them decided to stay. Their children (now Mexican-Americans), are still contributing to the citrus industry today, although not in the strenuous way their parents did.

The Valley owes …

Feeding And Food Selection In The Japanese Oyster Crassostrea Gigas, Rickey D. Moore

Dissertations and Theses

The Japanese oyster Crassostrea gigas is commercially grown in bays and estuaries of the Pacific Northwest. The oyster's complex, ciliated, plicate gill is responsible for removing particles from surrounding waters for ingestion. In order to determine how this is accomplished, structural interrelationships of gill components were investigated using scanning electron microscopy and light microscopy. Particle movement was observed directly on both isolated gill sections and intact gills. Feeding data were obtained by comparing initial to final concentration and size of algal particles in a Coulter counter.