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Full-Text Articles in Life Sciences

Combination Of Natural Variability Estimation With Real Time Measurement For Mushroom Shelf Life Assessment., Leixuri Aguirre Jan 2008

Combination Of Natural Variability Estimation With Real Time Measurement For Mushroom Shelf Life Assessment., Leixuri Aguirre

Doctoral

The shelf life of mushrooms (Agaricus bisporus) is affected by the natural variability of the produce which influences the perishable vegetable quality. One of the main causes of this variability is non-homogeneity in the product maturity at harvest, resulting in each vegetable batch being at a different stage of senescence. The present work aims to study a new approach to improve the assessment of the shelf life of mushrooms (Agaricus bisporus) taking into account this variability. The study of variability involved the: i) study of the shelf life, quality parameters and variability of the mushrooms and modelling these experimental laboratory ...


Characterisation Of The Aldo Keto Reductase From Helicbacter Pylori., Denise Cornally Apr 2007

Characterisation Of The Aldo Keto Reductase From Helicbacter Pylori., Denise Cornally

Doctoral

Aldo keto reductases reversibly reduce toxic aldehydes to their corresponding alcohol products. The aldo-keto reductase from Helicobacter pylori (HpAKR) was cloned and expressed in Escherichia coli as a His-tag fusion protein and purified using nickel chelate chromatography. The enzyme is a monomer with a molecular mass of approximately 39 kDa. It reduces a broad range of aldehyde substrates with a high catalytic efficiency and exhibits dual co-factor specificity for both NADH and NADPH. HpAKR can function over a broad pH range (pH 4-9) with a pH optimum of 5.5. Inhibition of AKR activity was observed with sodium valproate. Generation ...


Sequential Extraction Processing: Alternate Technology For Corn Wet Milling , Milagros P. Hojilla-Evangelista Jan 1990

Sequential Extraction Processing: Alternate Technology For Corn Wet Milling , Milagros P. Hojilla-Evangelista

Retrospective Theses and Dissertations

A radical new approach to fractionating dried, flaked, whole corn was studied. The countercurrent process involved sequential extraction of crude oil and simultaneous dehydration of ethanol. Protein was extracted by using a mixture of alkali and ethanol. The procedure provided a means of recycling the alcohol from cornstarch fermentation to upstream steps of extraction. Ethanol was able to extract oil in quantities significantly greater than the 72% obtained by conventional prepress hexane extraction methods in industry. The water adsorption capacity of the flaked whole corn (at an initial moisture content of <2%) was 26 g/kg corn which was sufficient to dry 35 g of 95% ethanol/100 g corn (2.5 gal/bu) to about 99% ethanol. The mixture of 45% ethanol:55% 0.100 M NaOH extracted 64-72% of the available protein. The protein concentrate contained 72.5% crude protein (db). Neither sonication nor homogenization improved protein yields.


Effect Of Porcine Somatotropin And Stress Susceptibility On The Sensory, Physical And Chemical Properties Of Porcine Skeletal Muscle , Jane Ann Boles Jan 1990

Effect Of Porcine Somatotropin And Stress Susceptibility On The Sensory, Physical And Chemical Properties Of Porcine Skeletal Muscle , Jane Ann Boles

Retrospective Theses and Dissertations

Forty-eight pigs of three genetically defined phenotypes (stress positive, stress carrier and stress negative) were injected daily with recombinant porcine somatotropin (PST) (4 mg/day) or placebo, and the effects of PST along with stress susceptibility on the sensory, physical, chemical and processing characteristics of pork longissimus and semimembranosus (SM) muscle were observed. Two end-point temperatures (71° and 77°C) were used for sensory analysis of broiled pork chops;PST treatment significantly lowered panel scores for tenderness, juiciness and flavor of broiled pork chops, while stress susceptibility decreased panel scores for tenderness only. PST treatment reduced intramuscular fat and increased ...


Flavor Development In Lactic Fermentation Of Ultrafiltered Cottage Cheese Whey , Anand Rao Jan 1990

Flavor Development In Lactic Fermentation Of Ultrafiltered Cottage Cheese Whey , Anand Rao

Retrospective Theses and Dissertations

Fermented dairy products based on ultrafiltered proteins often seem lacking in flavor particularly if the protein is washed by diafiltration. A model system based on protein collected from cottage cheese whey was used to investigate this phenomenon;The whey proteins were concentrated 10-fold by ultrafiltration through a membrane with 30,000 MW cutoff, diluted 1:1 with water and reconcentrated to a final concentration of 6-7% of the initial whey volume. This resulted in approximately 15-fold concentration of whey. The whey protein concentrate was diluted to 3.5% protein, various constituents were added, and the mixtures fermented with Leuconostoc dextranicum ...


Effects Of Amylose And Amylopectin On The Functional Properties Of Starch, Jen-Fang Chen Jan 1990

Effects Of Amylose And Amylopectin On The Functional Properties Of Starch, Jen-Fang Chen

Retrospective Theses and Dissertations

No abstract provided.


Gelation Properties Of Porcine Muscle Proteins , Juan Pedro Camou Arriola Jan 1989

Gelation Properties Of Porcine Muscle Proteins , Juan Pedro Camou Arriola

Retrospective Theses and Dissertations

The effects of linearly increasing heating rates (17, 38 and 85°C/hr) and protein concentration (10, 20, 30, 40 and 50 mg/mL) on thermally induced gels made of extracted salt-soluble proteins were evaluated. Gel strength analyses indicated that the force needed to compress muscle protein gels decreased when heating rate was increased. A greater water loss from compressed gels occurred at protein concentrations of 10 and 20 mg/mL than at 30 to 50 mg/mL. Above 30 mg/mL, water loss tended to be relatively constant. Protein loss in the expelled water, after compression, was less for ...


Properties Of Soybean-Corn Mixtures Processed By Low-Cost Extrusion , Gabriel Jaime Guzman Jan 1989

Properties Of Soybean-Corn Mixtures Processed By Low-Cost Extrusion , Gabriel Jaime Guzman

Retrospective Theses and Dissertations

An examination of the effects of low-cost extrusion on some nutritional and sensory properties of whole soybean/whole corn mixtures was carried out;Ground soybeans and corn at ratios 60:40, 70:30, 80:20, and 100:0 soybean:corn were processed with an Insta Pro 600 extruder cooker. Extruder exit temperatures were 127, 138, 149, and 160°C. Soybean trypsin inhibitor activity was destroyed 48.9 to 98.8% as exit temperature increased. Extrusion had no major effect on the tocopherol isomers. Lipoxygenase was completely inactivated by extrusion. In vitro protein digestibilities of samples extruded at 127°C were ...


Isolation And Characterization Of Plasmid Dna From Propionibacterium , Thomas G. Rehberger Jan 1989

Isolation And Characterization Of Plasmid Dna From Propionibacterium , Thomas G. Rehberger

Retrospective Theses and Dissertations

A simple and rapid method was developed for the isolation of plasmid DNA from propionibacteria. Effective cellular lysis was achieved in all species when cells were treated with a high concentration of lysozyme. Purification by acid phenol extraction or cesium chloride-density gradient centrifugation was required to remove contaminating chromosomal and open circular DNA and to obtain complete endonuclease digestions. With this method, 119 strains representing all species of the classical propionibacteria were screened for the presence of plasmid DNA. Twenty strains were found to contain plasmids ranging in size from 4.4 to greater than 119 megadaltons (Mdal);Restriction endonucleases ...


Role Of Peroxisomes In Lipid Metabolism Of The Oleaginous Yeast Apiotrichum Curvatum , Wan Soo Park Jan 1989

Role Of Peroxisomes In Lipid Metabolism Of The Oleaginous Yeast Apiotrichum Curvatum , Wan Soo Park

Retrospective Theses and Dissertations

Apiotrichum curvatum ATCC 20509 (formerly Candida curvata D) is an oleaginous yeast that can accumulate large amounts of intracellular lipid when grown with excess carbon. Cells were incubated in nitrogen-limited, balanced, and carbon-free media, and cell composition, lipid metabolism, and activity of catalase as a marker enzyme for peroxisomes were measured in whole cells or in cell-free extracts. The organism accumulated 54% of its dry weight as intracellular lipid when grown under nitrogen limitation, and accumulated no more than half that amount when grown in balanced medium. When starved for carbon, cells utilized endogenous lipid and carbohydrate as carbon and ...


Effects Of Polyphosphates And Heat On Selected Gram-Positive Bacteria Important In Foods , Stephen John Knabel Jan 1989

Effects Of Polyphosphates And Heat On Selected Gram-Positive Bacteria Important In Foods , Stephen John Knabel

Retrospective Theses and Dissertations

In one series of studies, a simple well-plate technique was utilized to determine the effect of various metals on the growth of microorganisms in media containing different polyphosphates. Aspergillus flavus and four Gram-positive bacteria were almost completely inhibited by media containing 1% of various alkaline polyphosphates, whereas four Gram-negative bacteria were not. Significant differences were observed between the type of polyphosphate added, the type of metal added, and the species of Gram-positive bacterium inhibited. A method for determining the amount of calcium and magnesium in water was modified to detect free Mg[superscript]2+ by replacing EDTA with phosphate. The ...


The Effects Of Phosphate Blends On The Microbiology Of A Cooked Meat System , John Allen Marcy Jan 1987

The Effects Of Phosphate Blends On The Microbiology Of A Cooked Meat System , John Allen Marcy

Retrospective Theses and Dissertations

Tetrasodium pyrophosphate and sodium acid pyrophosphate were examined first separately or in combinations at a level of 0.4% of meat weight. Sodium acid pyrophosphate inhibited streptococci during storage of the cooked, vacuum-packaged sausage for 48 hours at 20-22(DEGREES)C, whereas tetrasodium pyrophosphate did not. Neither phosphate had a significant antimicrobial effect during 21 days of refrigerated storage at 5(DEGREES)C;Combinations of sodium acid pyrophosphate and trisodium pyrophosphate, a pH-neutral pyrophosphate, were used in a second study in cooked pork sausage also at a level of 0.4% of meat weight. Sausages without phosphate had lower bacterial ...


A Kinetic Study On The Lime-Heat Treatment Of Corn For Masa Production , Yung-Ho Chang Jan 1987

A Kinetic Study On The Lime-Heat Treatment Of Corn For Masa Production , Yung-Ho Chang

Retrospective Theses and Dissertations

An objective method to predict the optimum cooking time of corn for tortilla production does not exist. Since nixtamalization (lime-heat treatment) is the most important step in the preparation of tortillas, the changes in the corn kernel during this period should be analyzed for the development of an optimal tortilla-making process. This study presents a mathematical model for quantitatively analyzing the kinetics of water diffusion and starch gelatinization during the nixtamalization process;Corn was cooked with and without calcium hydroxide, according to traditional processing steps. The temperature of the cooking solution, the amount of water absorbed by the corn, and ...


Effect Of Low-Dose (1 Kgy) Gamma Radiation And Selected Phosphates On The Microflora Of Vacuum-Packaged Ground Pork , Robson M. Ehioba Jan 1987

Effect Of Low-Dose (1 Kgy) Gamma Radiation And Selected Phosphates On The Microflora Of Vacuum-Packaged Ground Pork , Robson M. Ehioba

Retrospective Theses and Dissertations

The effects of low-dose (1 kGy) gamma radiation and selected phosphates on the microbiology of refrigerated, vacuum-packaged ground pork were studied. Low-dose gamma radiation reduced (P 0.05) pH differences between irradiated and nonirradiated treatments, and irradiation treatment did not significantly (P > 0.05) increase lipid oxidation. Lipid oxidation was also not affected by phosphates. Pseudomonas was the major bacterial genus constituting the nonirradiated refrigerated (5(DEGREES)C), vacuum-packaged ground pork microflora. Pseudomonas predominated in nonirradiated samples in four of five sampling times. There was a decrease in the incidence of Pseudomonas as storage time increased. Irradiation greatly decreased the ...


Microbiological Effects On Poly- And Pyrophosphates Added To Meat And Meat Products , Ricardo A. Molins Jan 1985

Microbiological Effects On Poly- And Pyrophosphates Added To Meat And Meat Products , Ricardo A. Molins

Retrospective Theses and Dissertations

The microbiological effects of 0.5% poly- and pyrophosphates were studied in laboratory media and in fresh or cooked, vacuum packaged bratwurst-type sausage held under refrigeration (5(DEGREES)C) and subsequent elevated temperatures (24-25(DEGREES)C). Tetrasodium pyrophosphate (TSPP), heated or unheated, was most inhibitory to selected bacteria in laboratory media, while sodium tripolyphosphate (STPP) and sodium polyphosphate glassy (SPG) lost their antimicrobial properties upon heating and sodium acid pyrophosphate (SAPP) was ineffective. Although phosphate addition consistently resulted in lower bacterial numbers, none of the phosphates exhibited significant (P 0.05) antibacterial effects in frozen beef patties held 90 days ...


The Quantification Of Carbonyl Compounds Produced From Linoleic And Linolenic Acid Hydroperoxides: Thermal, Metal Ions And Antioxidant Effects , Bouali Saaidia Jan 1985

The Quantification Of Carbonyl Compounds Produced From Linoleic And Linolenic Acid Hydroperoxides: Thermal, Metal Ions And Antioxidant Effects , Bouali Saaidia

Retrospective Theses and Dissertations

The decomposition of fatty acid hydroperoxides leads to the formation of various carbonyl compounds in different yields. A method for the quantification of carbonyl compounds in oxidized fat by gas chromatography of the trichlorophenylhydrazones was adapted for the quantification of carbonyls produced from the decomposition of pure linoleic acid and linolenic acid hydroperoxides produced by autoxidation or enzymatically by soybean lipoxygenase or potato lipoxygenase. The hydroperoxides were dissolved in dodecane and decomposed anaerobically under different conditions: temperature, metal ions, and antioxidants;Both linoleic acid 9- and 13-hydroperoxides produced hexanal and 2,4-decadienal at higher temperatures (80(DEGREES)C, 160(DEGREES ...


The Analysis Of Volatiles In Moldy Corn And Their Correlation To Mold Presence And Mycotoxin Production , Walter Gaylord Hyde Jan 1985

The Analysis Of Volatiles In Moldy Corn And Their Correlation To Mold Presence And Mycotoxin Production , Walter Gaylord Hyde

Retrospective Theses and Dissertations

This study consisted of three parts: (1) the development of analytical techniques for the collection, separation, identification, and quantitation of volatile organic components commonly reported to be associated with moldy feeds and feed components; (2) to develop a controlled laboratory model for growing molds on grain and collecting any volatiles produced; and (3) to test the correlation, if any, between volatiles found and molds or mold toxins present;Several analytical gas chromatographic techniques were investigated for the analysis of headspace volatiles, including organic compound adsorption onto Tenax('RM) resin with subsequent thermal desorption onto packed column GLC, capillary GLC, mega-bore ...


The Effect Of Calcium Activated Protease (Caf) And Cathepsin D On Bovine Muscle Myofibrils Under Varying Conditions Of Ph And Temperature , Michael George Zeece Jan 1984

The Effect Of Calcium Activated Protease (Caf) And Cathepsin D On Bovine Muscle Myofibrils Under Varying Conditions Of Ph And Temperature , Michael George Zeece

Retrospective Theses and Dissertations

This study examined effects of purified CAF and cathepsin D on bovine skeletal myofibrillar proteins and structure when incubated under postmortem-like conditions of pH and temperature;When CAF (purified from bovine cardiac muscle) was incubated with isolated myofibrils under near optimal conditions (pH 7.5 and 25(DEGREES)C), a rapid and significant release of soluble protein, including intact alpha-actinin, from the myofibrils was observed. SDS-PAGE analysis of treated sedimented myofibrils showed CAF digestion had degraded titin and, at least partly, tropomyosin, and troponins T and I. A trio of bands in the 30,000-dalton region appeared in the gels ...


Influence Of Soybean Variety And Method Of Processing On Tofu Manufacturing, Quality And Consumer Acceptability , Lamar Daniel Johnson Jan 1984

Influence Of Soybean Variety And Method Of Processing On Tofu Manufacturing, Quality And Consumer Acceptability , Lamar Daniel Johnson

Retrospective Theses and Dissertations

The purpose of this study is two-fold: 1) to determine if soybean variety and the method of processing are important factors in influencing tofu quality and 2) to determine American preferences for this traditional Oriental product.


Alterations In Bovine Skeletal Muscle Desmin And The Cytoskeleton Induced By Temperature And Electrical Stimulation , Lenard Edward Kasang Jan 1983

Alterations In Bovine Skeletal Muscle Desmin And The Cytoskeleton Induced By Temperature And Electrical Stimulation , Lenard Edward Kasang

Retrospective Theses and Dissertations

Alterations in the myofibrillar integrating cytoskeleton and its constituent protein, desmin, were assessed in bovine skeletal muscle at 1, 24 and 168 hours of postmortem storage. Changes assessed over post-mortem storage in muscle subjected to usual (control) storage conditions (2(DEGREES)C) were compared to changes in tissue subjected to either of two conditions known to increase meat tenderness, i.e. high temperature (25(DEGREES)C) storage or electrical stimulation. Quantities of desmin extractable at the selected intervals were determined in part by densitometric scanning of the desmin band in polyacrylamide tube gels of desmin-enriched fractions. Alterations in the protein ...


Effect Of Postmortem Storage On Degradation Of The Recently Discovered Myofibrillar Protein Titin In Bovine Longissimus Muscle, Mary Lee Gragg Lusby Jan 1983

Effect Of Postmortem Storage On Degradation Of The Recently Discovered Myofibrillar Protein Titin In Bovine Longissimus Muscle, Mary Lee Gragg Lusby

Retrospective Theses and Dissertations

The high molecular weight (M(,r) (TURN) 1 x 10('6)) protein titin was isolated from purified bovine longissimus muscle myofibrils by gel filtration column chromatography in the presence of sodium dodecyl sulfate (SDS). Purified bovine, rabbit and chicken skeletal muscle titins were closely related or homologous in that they yielded similar column elution profiles and had similar amino acid compositions. Titin purified from rabbit and bovine skeletal muscles also comigrated in SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and cross-reacted with antibodies specific for titin. Indirect immunofluorescence localization demonstrated that titin is preferentially localized in the A-I junctional area with some diffuse ...


Effect Of Method Of Freezing, Processing And Packaging Variables On Microbiological And Other Quality Characteristics Of Beef And Poultry , Kuruganti Venkatakrishna Reddy Jan 1981

Effect Of Method Of Freezing, Processing And Packaging Variables On Microbiological And Other Quality Characteristics Of Beef And Poultry , Kuruganti Venkatakrishna Reddy

Retrospective Theses and Dissertations

Various aspects of freezing preservation and packaging methods were studied for feasibility of use for beef and poultry in practical applications;Investigations on the effects of combining fresh and frozen beef in different proportions showed that a 50:50 ratio of fresh to frozen beef produced higher bacterial numbers than observed when other proportions were combined and held in frozen storage. No health hazard was evident from any of the different combinations of fresh or frozen beef or from liquid nitrogen or liquid CO(,2) freezing and frozen storage. Changes in bacterial flora as a result of freezing and frozen ...


Effect Of Randomization On The Oxidation Products Of Corn Oil , Flora Yu-Man Lau Jan 1981

Effect Of Randomization On The Oxidation Products Of Corn Oil , Flora Yu-Man Lau

Retrospective Theses and Dissertations

Randomization of fat usually causes an increase in its rate of autoxidation. The reason for this is unclear. To study this, natural and randomized corn oil were purified by passage through alumina and oxidized to peroxide values of 30 to 40 at 28 C. The hydroperoxides were reduced to alcohols with iodide. Two major bands of oxidized products were separated from the unoxidized triglycerides by thin-layer chromatography on Silica gel G. The lower band was a triglyceride containing one hydroxyacyl group. The upper band was a triglyceride containing an azelaic semialdehyde or methyl azelaic group. This band also contained an ...


A Rapid Method For Stereospecific Glyceride Analysis And Its Application To Soybean And Oat Varieties , Wenchi Peter Pan Jan 1981

A Rapid Method For Stereospecific Glyceride Analysis And Its Application To Soybean And Oat Varieties , Wenchi Peter Pan

Retrospective Theses and Dissertations

Rapid methods for the analysis of glyceride structure were explored so they could be applied to the determination of the extent of variation in glyceride structure of oilseed crops and possible use in oil crop breeding. For analysis of the sn-2-position of glycerol and the generation of diglycerides for stereospecific analysis, a method was adopted in which pancreatic lipase hydrolysis of the triglycerides and subsequent separation of the mono- and diglycerides was achieved on one thin layer silica gel plate;Attempts to phosphorylate diglycerides for stereospecific analysis of the glycerides on thin layer plates either with the enzyme diglyceride kinase ...


Quality Changes In Vacuum Packaged Fresh Pork , William Joseph Lulves Jan 1981

Quality Changes In Vacuum Packaged Fresh Pork , William Joseph Lulves

Retrospective Theses and Dissertations

This study was concerned with effects of different commercial practices on quality of vacuum packaged pork chops. Variables included type of packaging film (high or low barrier to oxygen), presence or absence of bone in the packaged pork chops, length of loin storage time prior to cutting into chops, method of cutting into chops, and length of storage period of packaged chops prior to retail display. The microflora of the pork chops was characterized with regard to numbers of microorganisms, types present, and changes in numbers and types over time. Vacuum packaged pork chops were also tested with regard to ...


The Quantification Of Carbonyl Compounds In Oxidized Fat By Gas Chromatography Of The Trichlorophenylhydrazones , Pamela June White Jan 1981

The Quantification Of Carbonyl Compounds In Oxidized Fat By Gas Chromatography Of The Trichlorophenylhydrazones , Pamela June White

Retrospective Theses and Dissertations

A rapid, reliable determination of the carbonyl flavor compounds in oxidized fats and oils has proved elusive, especially because of the ease with which hydroperoxides can generate additional carbonyl compounds during isolation procedures. Carbonyl compounds can be converted to trichlorophenylhydrazones (TCPH's) and isolated from fat in a simple two-column procedure. A solution of fat in cyclohexane:ether (99:1) is passed through a Florisil column and nonvolatile hydrocarbons, which interfere with later stages of the analysis, are eluted. The remaining lipid constituents including carbonyls are eluted with 100% ether, reacted with TCPH using a Florisil catalyst, and packed on ...


Effect Of Processing Variables On The Canned Quality Of Fava Beans , Basima Sa'di Abou-Dheir Jan 1980

Effect Of Processing Variables On The Canned Quality Of Fava Beans , Basima Sa'di Abou-Dheir

Retrospective Theses and Dissertations

No abstract provided.


Distribution, Production, Analysis And Effects Of Aflatoxin In Animal Tissues And Effects Of Scirpene Toxins On Chicken Embryos , Iheanyichukwu Wilfred Obioha Jan 1979

Distribution, Production, Analysis And Effects Of Aflatoxin In Animal Tissues And Effects Of Scirpene Toxins On Chicken Embryos , Iheanyichukwu Wilfred Obioha

Retrospective Theses and Dissertations

No abstract provided.


Lipoxygenase Activity And Protein Solubility In Extracts From Soybeans Treated With Heat And Ethanol, Manoochehr Borhan Jan 1979

Lipoxygenase Activity And Protein Solubility In Extracts From Soybeans Treated With Heat And Ethanol, Manoochehr Borhan

Retrospective Theses and Dissertations

No abstract provided.


Microscopy Of Soybean Seeds: Cellular And Subcellular Structure During Germination, Development And Processing With Emphasis On Lipid Bodies , Craig William Bair Jan 1979

Microscopy Of Soybean Seeds: Cellular And Subcellular Structure During Germination, Development And Processing With Emphasis On Lipid Bodies , Craig William Bair

Retrospective Theses and Dissertations

No abstract provided.