Food Science Commons^™

Galactose Transport In Streptococcus Thermophilus, Robert W. Hutkins, Howard A. Morris, Larry L. Mckay

Department of Food Science and Technology: Faculty Publications

Although Streptococcus thermophilus accumulated [¹⁴C]lactose in the absence of an endogenous energy source, galactose-fermenting (Gal⁺) cells were unable to accumulate [¹⁴C]galactose unless an additional energy source was added to the test system. Both Gal⁺ and galactose-nonfermenting (Gal^-) strains transported galactose when preincubated with sucrose. Accumulation was inhibited 50 or 95% when 10 niM sodium fluoride or 1.0 mM iodoacetic acid, respectively, was added to sucrose-treated cells, indicating that ATP was required for galactose transport activity. Proton-conducting ionophores also inhibited galactose uptake, although N,N'-dicyclohexyl carbodiimide had no effect. The results suggest …

Galactokinase Activity In Streptococcus Thermophilus, Robert W. Hutkins, Howard A. Morris, Larry L. Mckay

Department of Food Science and Technology: Faculty Publications

ATP-dependent phosphorylation of [¹⁴Cigalactose by 11 strains of Streptococcus thermophilus indicated that these organisms possessed the Leloir enzyme, galactokinase (galK). Activities were 10 times higher in fully induced, galactose-fermenting (Gal⁺) strains than in galactose-nonfermenting (Gal-) strains. Lactose-grown, Gal^- cells released free galactose into the medium and were unable to utilize residual galactose or to induce galK above basal levels. Gal⁺ S. thermophilus 19258 also released galactose into the medium, but when lactose was depleted growth on galactose commenced, and galK increased from 0.025 to 0.22 μmol of galactose phosphorylated per min per mg of …

Soymilk Process, Charles W. Deyoe, William J. Hoover, Lawrence A. Johnson

Lawrence A. Johnson

Process for making a soybean-based milk analog or soymilk and food products prepared therefrom. The process involves the comminuting of whole soybeans having the hulls thereon; forming a slurry of the comminuted soybeans; simultaneously initiating the inactivation of trypsin inhibitor and lipoxygenase without fixing protein bodies or substantially denaturing the soybean protein; confining the heated slurry until the trypsin inhibitor activity is reduced to a desired value; cooling the slurry; and separating the hulls from the slurry to recover the desired product. The resulting soymilk is an aqueous preparation of the soybean which exhibits minimal destruction of essential amino acids, …

Soybean Oil Is Not Allergenic To Soybean-Sensitive Individuals, Robert K. Bush, Steve L. Taylor, Julie A. Nordlee, William W. Busse

Department of Food Science and Technology: Faculty Publications

We have previously demonstrated that peanut oil is not allergenic to peanut-sensitive individuals. Seven soybean-sensitive patients were enrolled in a double-blind crossover study to determine whether ingestion of soybean oil can induce adverse reactions in such patients. All subjects had histories of systemic allergic reactions (urticaria, angioedema, wheezing, dyspnea, and/or vomiting) after soybean ingestion and had positive puncture skin tests with a 1:20 w/v glycerinated-saline whole soybean extract. Sera from six of the seven subjects were tested by RAST assay for the presence of specific IgE antibodies to soybean allergens. All patients had elevated levels of serum IgE antibodies to …

Effects Of Bulk Starter Media And Proteolytic Lactic Streptococci On Protein Loss In Cheddar Curd Manufacture, Steven A. Winkel

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effects of whey-based and milk-based starter media, and low concentrations (0.02% each) of citrate, phosphate and calcium upon various milk coagulation properties were measured. Samples inoculated with milk-based starter medium had shorter coagulation times, faster rate of curd formation, and greater final curd firmness than those inoculated with externally neutralized whey-based starter. Starter medium treatment was statistically interacted with calcium for coagulation time and rate of curd formation. Citrate addition caused longer coagulation times, slower rates of curd formation, and weaker final coagula. Citrate interacted with calcium and phosphate for several of the parameters measured. Addition of phosphate did …

Modifying Lamb/Mutton Flavors In Processed Meat Products By Smoking, Curing, Spicing, Starter Cultures And Fat Modifications. Investigating The Use Of The Technicon Infraalyzer 400r As A Rapid Method For Proximate Analysis, Chima I. Osuala

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Mutton meat was tested in different products in order to obtain prototype products in which mutton can effectively be used without the objectionable mutton off flavor. Mutton flavor reduction was achieved in the processed meat products by: (a) lowering mutton fat to a level of 10% or less, (b) using spices, smoking and/or curing, (c) substituting fat from beef or pork for mutton fat, and (d) the action of microbial starter cultures. Four taste panel sessions were set up to rate these products against an all beef or all pork control for consumer acceptability. Taste panel results indicate that flavor …

Effect Of Iron On Residual Nitrite Level In Ground Pork And Model Systems, Changmin Kim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effects of iron, temperature, and presence of botulinal spores or sodium ascorbate on depletion of nitrite level were determined in meat and model systems. Higher temperature and presence of botulinal spores definitely increased nitrite depletion in a meat system. Added hemoglobin also significantly increased nitrite depletion, while ferrous iron and ferric iron did not significantly decrease nitrite level in a meat system. High temperature and presence of sodium ascorbate increased nitrite depletion in a model system. Only ferrous iron significantly decreased nitrite level in the absence of ascorbate, while ferric iron, heme iron, and ferritin iron did not decrease …

Effect Of Proteolytic Activity Of Streptococcus Cremoris On Cottage Cheese Yield, Gary W. Stoddard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Using proteinase negative variants of Streptococcus cremoris UC310 or UC320 to manufacture cottage cheese, theoretical yields were increased 1.97% and 1.56% respectively when compared to the theoretical yields of the proteinase positive parents. Yield differences were strain dependent and differences between positive and negative variants were not manifest with strains of UC73 and UC97. It was necessary to produce bulk culture using pH control and to add sufficient nitrogenous stimulant to provide carry-over stimulant into the cheese milk. All cultures examined developed normally even when the bulk medium contained a blend of 5% yeast extract and casein hydrolysate. It was …

Iron Requirement Of Clostridium Botulinum Type A And Characterization Of Iron-Sulfur Proteins In Nitrite Treated And Untreated Botulinal Cells, Divya Shree A. Reddy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effect of added iron on the growth of Clostridium botulinum type A in a chemically defined medium was studied. Growth of C. botulinum was supported by an iron level of 0.05 ug/ml with maximum growth observed at a level of 3 ug iron/ml.

Electron paramagnetic resonance (EPR) studies were conducted to detect the presence of iron-sulfur centers and iron-nitric oxide complexes in untreated and nitrite treated cell-free extracts of C. botulinum type A. Untreated extracts of C. botulinum exhibited EPR signals in the oxidized and reduced states characteristic of a "HiPiP-type" iron-sulfur center (g=2.02) in the oxidized state and …

Reduction Of Sodium Nitrite And Sodium Chloride In A Cured Meat Product By Using Acid Development To Inhibit Botulinal Toxin Formation, Angsana Assamongkorn

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Pediococcus acidilactici as a lactic acid producer, and sucrose were added to breakfast strip products in order to reduce added levels of sodium nitrite and sodium chloride and yet limit the growth of Clostridium botulinum and inhibit toxin production. Sucrose at 0.4 or 0.9% with P. acidilactici at 1.0 x 10⁸ cells/g were added during preparation of breakfast strip products prepared with combinations of 40 or 80 ppm sodium nitrite and 1.0 or 2.0% sodium chloride. Other ingredients were added at levels normally used in cured meat products. C. botulinum types A and B at 1,000 spores/g were inoculated …

The Influence Of Dietary Intake On Hypertension And/Or Erythrocyte Na+, K+- Atpase Activity, Gloria A. Gaskin

Masters Theses

Normotensive (11) and medicated hypertensive (6) female subjects ages 23 to 58 participated in blood pressure measurements, blood sampling (2 days) following a 10-hour fast, for the determination of maximum ouabain binding, and dietary assessment using 7-day records and/or food frequency forms. Maximum ouabain binding, an index of Na⁺,K⁺-ATPase activity, was measured using a tritiated ouabain binding technique in which the number of ouabain binding sites per cell are determined. The number of enzyme units (Na⁺,K⁺-ATPase units) was calculated from the number of binding sites per cell because the two are directly …

Soymilk Process, Charles W. Deyoe, William J. Hoover, Lawrence A. Johnson

Lawrence A. Johnson

Process for making a soybeanbased milk analog or soymilk and food products prepared therefrom. The process involves the comminuting of whole soybeans having the hulls thereon; forming a slurry of the comminuted soybeans; simultaneously initiating the inactivation of trypsin inhibitor and lipoxygenase without fixing protein bodies or substantially denaturing the soybean protein; confining the heated slurry until the trypsin inhibitor activity is reduced to a desired value; cooling the slurry; and separating the hulls from the slurry to recover the desired product. The resulting soymilk is an aqueous preparation of the soybean which exhibits minimal destruction of essential amino acids, …

Potential For Development Of Tolerance By Penicillium Digitatum And Penicillium Italicum After Repeated Exposure To Potassium Sorbate, Lisa L. Schroeder, Lloyd B. Bullerman

Department of Food Science and Technology: Faculty Publications

Two strains of Penicillium digitatum and one strain of Penicillium italicum were exposed to various levels of sorbic acid and potassium sorbate, and the MICs were determined. Selected strains of the molds were then repeatedly exposed to subinhibitory levels of the compounds to determine whether increased tolerance might develop. The MIC of sorbic acid (pH 4.75) to P. digitatum was between 0.02 and 0.025%. The MIC of sorbate (pH 5.5) to two strains of P. digitatum and P. italicum was found to be between 0.06 and 0.08%. Increasing levels of sorbate resulted in increasing growth suppression of the molds. Populations …

Estimates Of Soil Solution Ionic Strength And The Determination Of Ph In West Australian Soils, P. J. Dolling, G. S.P. Ritchie

Food Science and Nutrition

The average ionic strength of 20 West Australian soils was found to be 0.0048. The effects of three electrolytes (deionized water, CaCl₂ and KNO₃), three ionic strengths (0.03, 0.005 and soil ionic strength at field capacity, I_s) and two soil liquid ratios (1:5 and 1:10) on the pH of 15 soils were investigated. pH measurements in solutions of ionic strength 0.005 differed the least from measurements made at I_s. The differences that occurred in comparisons with distilled water or CaCl₂ of ionic strength 0.03 (0.01 M) were much greater (≥0.4 pH …

The Role Of Organic Matter In Soil Acidification, G. S.P. Ritchie, P. J. Dolling

Food Science and Nutrition

The pH and buffer capacity of two soils increased or remained constant after incubation with different amounts of plant material (lucerne cham at field capacity and when air dry. For both soils, the pH changes were greater at field capacity, whereas the buffer capacities were independent of the water treatments. The pH changes observed could be explained in terms of the organic anion concentration of the plant material. The results indicate that the initial soil pH and the anion concentration (i.e. the per cent dissociation of soluble organic acids when released into the soil) determine the acidifying effect of organic …

The Application Of Light And Scanning Electron Microscopy During Flour Milling And Wheat Processing, R. Moss

Food Structure

Light and scanning electron microscopy have been employed as part of an on-going study on the effect of the milling system on flour composition and quality. Examples are given of some areas where microscopy has been particularly useful in understanding the functional changes that take place during milling or the subsequent processing of the flour . The use of heavy reduction roll pressures was shown to modify gluten protein quality as well as produce the desired increase in starch damage. The use of in-line impact machines not only disrupted flaked flour particles but also fragmented wheat germ and allowed it …

Ultrastructural Study Of Yam Tuber As Related To Postharvest Hardness, L. Sealy, S. Renaudin, D. J. Gallant, B. Bouchet, J. M. Brillouet

Food Structure

Usually, parenchyma cell walls of monocotyledons do not develop secondary walls; however a few days after harvesting, the yam tuber of Dioscorea dumetorum starts to harden. Two or three weeks Iater, hardness is so pronounced that the tubers cannot be eaten, even after a long cooking time.

Cytochemical studies using autofluorescence or some fluorescent dyes, such as phloroglucinol hydrochloride showed that the thin, and flexible cell walls of parenchyma tubers very quickly became fully lignified after harvesting. Ultrastructura 1 stud ies of the hardened ce 11 wa 11 s showed very thick secondary wa 11 s and very deep pit …

Ultrastructural Studies On The Cultivation Processes And Growth And Development Of The Cultivated Mushroom Agaricus Bisporus, D. A. Wood, G. D. Craig, P. T. Atkey, R. J. Newsam, K. Gull

Food Structure

Scanning electron microscopy (SEM) , transmission electron microscopy and light microscopy have been used to study various processes in the cultivation of the edible mushroom Agaricus bisporus . Mushrooms are cultured on composted wheat straw. The microbial degradation processes during composting have been visualised by TEM and SEM and correlated with microbiological studies . Various modes of attack by the microorganisms on the plant cell walls can be seen. Most rapid degradation occurred on the cuticle and phloem and spread to other cell types. Microbial attack was found to be nonuniform between tissue types and individual cells. The mycelium of …

Observations On The Air-Serum Interface Of Milk Foams, B. E. Brooker

Food Structure

A new rapid method for the preparation of milk foams for transmission electron microscopy is described . The air-serum interface of foams made from skimmed milk consists of a uniform electron dense layer (5 nm thick) to which casein micelles become secondarily attached . Changes in bubble volume lead to the formation of folds of excess interfacial material which project into the aqueous phase. Using collapsed bubble ghosts to study the attachment of micelles to the airserum interface it was concluded that neither disulphide bridge formation nor hydrophobic interactions were of major importance. Similar preparations of interfacial material but without …

Rheological And Ultrastructural Studies Of Wheat Kernel Behaviour Under Compression As A Function Of Water Content, A. Al Saleh, D. J. Gallant

Food Structure

The rhea logical behaviour of two wheat varieties (Triticum durum), cultivated at different sites, was studied by INSTRON* as a function of water content. Patterns of crushed grains were investigated by scanning electron microscopy . The apparent modulus of elasticity of the wheat grains was apparently re 1 a ted to their vitreosity. The mealy grain generally had an apparent modulus of elasticity lower than that of the vitreous one and the modulus appeared to be related to the air spaces in mealy endosperm. Humidification favoured the conversion of vitreous endosperm to the mealy state. Grain morphology and particularly the …

Structure Formation In Acid Milk Gels, I. Heertje, J. Visser, P. Smits

Food Structure

The structure formation in acid milk gels is influenced by many factors such as heat, salt system, pH, culture and thickening agents. Understanding of the mechanism of structure formation is important in order to be able to influence the final texture of these products.

In the present study the network formation in acid milk gels during acidification is monitored by freeze-fracture electron microscopy. Network formation appears to be a much more complex process than just an aggregation of the original milk casein micelles; it is accompanied by subtle dissociation and association phenomena of the milk caseins. The observed sequence of …

Ultrastructural And Biochemical Investigations Of Mature Human Milk, Robert J. Carroll, Jay J. Basch, John G. Phillips, Harold M. Farrell Jr.

Food Structure

The casein complexes (casein micelles) of human skim milk were evaluated by electron microscopy. Fourteen samples of human milk were obtained from seven donors whose stage of lactation varied from 1 to 23 months. Compositional and biochemical parameters were measured to evaluate the nature of these samples. For mature human milks, 2-13 months of lactation, average percentage of solids-notfat was found to be 8.32 ± 0.16. Protein compositions of the skim milks were studied by the Coomassie blue dye binding method and by SDS-gel electrophoresis; total protein and casein were found to be 0.62 ± 0.18 and 0.29 ± 0.02 …

Proceedings From The 22nd Annual Marschall Invitational, Various Authors

Cheese Industry Conference

No abstract provided.

Sulfite Residues In Maraschino Cherries, Julie A. Nordlee, Laura B. Martin, Steve L. Taylor

Department of Food Science and Technology: Faculty Publications

A survey of 53 samples of maraschino cherries from 14 different processors revealed that total sulfite residues averaged 52.3 ± 44.7 ppm. However, 58.5% of the samples had less than 40 ppm total SO₂, while only 7.6% had greater than 120 ppm total SO₂ indicating that the distribution was skewed in the direction of lower residue levels. Free sulfite residues in the 53 samples were considerably lower, averaging 14.2 ± 7.1 ppm. With free SO₂ levels, 35.8% of the samples had less than 10 ppm free SO₂, while only 5.7% had greater than 30 …

The Size Distribution Of Bovine Casein Micelles: A Review, C. Holt

Food Structure

This review considers the average size and size distribution of bovine casein micelles as measured by electron microscopy, light scattering and controlled pore glass chromatography, and the origin and biological function of the size distribution.

Recent work by electron microscopy has given average sizes in reasonable agreement with measurements on the same milk sample by light scattering . It is suggested that natural variations in averaqe micelle size and overestimation of micelle radii by light scattering methods as well as deficiencies in electron microscopical methodology were responsible for past discrepancies.

Electron microscopy and controlled pore glass chromatography provide evidence that …

Seed Structure And Composition Of Potential New Crops, D. W. Irving, R. Beckler

Food Structure

Prosopis , Ol neya , and Amaranthus have potenti a l economic value as food or feed crops fo r a rid /semi- arid r egions. Ma ture seeds of these genera we r e examined using scanning e l ec tron and fluoresce nce microscopy to define a natomy and localize s t or age s truc tures in cells . Pro t ein bodies, some co nt a ini ng phytin inc lu sions , were l oca li zed in the embryos of five Prosopi s s peci es . Prosopis chilensis wa s the only one …

The Combined Effects Of The Calcium Activated Factor And Cathepsin D On Skeletal Muscle, E. A. Elgasim, M. Koohmaraie, A. F. Anglemier, W. H. Kennick, E. A. Elkhalifa

Food Structure

Myofibrils were isolated from atdeath ovin elongissimus muscles and incubated with crude calcium activated factor prepared from the same muscle and with purified cathepsin D. Myofibrils we reincubated with these enzymes separately (first incubation) and successively (second incubation). The major changes induced by cathepsin D first incubation include degradation of myofibrillar proteins with molecular weight > 200 K, myosin, actin, troponin- T and troponin 1. Also new bands appeared at the 140- 160 K, 80 K, 68 K and 30 K regions. Similar changes were obtained 1v hen myofibrils were incubated first with CAF then with cathepsin D (second incubation). On …

A Fluorescence Microscopic Study Of Cheese, S. H. Yiu

Food Structure

Fluorescence techniques were used to study the microstructure of several varieties of cheese. The size and distribution of fat globules in various cheeses were demonstrated by fluorescent staining using Nile Blue A as a marker. Acridine Orange was used as a dye to detect structural differences between casein matrices of various cheese varieties. Differences between the ripe and the less- ripe zones of Ca membert cheese were detected by staining the cheese sections with Acridine Orange and Nile Blue A separately, and then comparing the re sults of the stainings. The Nile Blue A stain ing s howed that fat …

The Microstructure Of Wheat: Its Development And Conversion Into Bread, D, B. Bechtel

Food Structure

Wheat endosperm development has been studied in numerous laboratories. The genera 1 i zed scheme of protein body formation assembled from these data indicates that storage proteins are initially formed in the rough endoplasmic reticulum (RER). The storage proteins in RER may be processed via the Golgi apparatus into vesicles that enlarge by several mechanisms into membrane-bounded protein bodies. The prote in bodies are transported through the cytoplasm to the vacuole where they fuse with the tonoplast and deposit the protein granules into the vacuoles. The protein granules fuse with one another, lose water, and eventually become transformed into the …

Comparison Of The Microstructure Of Firm And Stem-End Softened Cucumber Pickles Preserved By Brine Fermentation, W. M. Walter Jr., H. P. Fleming, R. N. Trigiano

Food Structure

Soft and firm stem end tissues of cucumbers fermented at a low concentration of sodium chloride were examined by a combination of light microscopy {LM), transmission electron microscopy { TEM), and scanning electron microscopy { SEM) . When compared to firm tissue, softened tissue cell walls were swollen and striated, and the middle lamellae were poorly stained by the uranyl acetate-1 ead citrate used in TEM . When the tissue was penetrated by a circu l ar punch {1.5 mm diameter), cells in soft tissue tore along the middle l arne ll ae rather than across cell walls, as did …