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All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

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A Comparative Study Of The Oxygen Uptake Between Nonmotorized And Motorized Treadmills, Michael S. Wood May 1996

A Comparative Study Of The Oxygen Uptake Between Nonmotorized And Motorized Treadmills, Michael S. Wood

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to determine the effects of nonmotorized treadmill walking and motorized treadmill walking on VO2 results, measured in ml•kg-1•min-1, of males and females, ages 20-30 at Utah State University, Logan, Utah, USA. The participants were required to walk at a pace of 3 miles per hour and 13% grade for a total exercise time of 9 minutes. The exercise time was broken up with 3-minute recovery periods. Oxygen uptake was measured continuously using a metabolic measurement cart. The data obtained from the metabolic cart were correlated for each treadmill to …


An Ecological History Of Tintic Valley, Juab County, Utah, Jeffrey A. Creque May 1996

An Ecological History Of Tintic Valley, Juab County, Utah, Jeffrey A. Creque

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This work was a case study of historical ecological change in Tintic Valley, Juab County, Utah, an area historically impacted by mining and ranching activities common to much of the American West. The temporal framework for the study was approximately 120 years, the period of direct Euroamerican influence. In recognition of the ecological implications of cultural change, however, the impacts of prehistoric and protohistoric human activity on study area landscape patterns and processes were also explicitly addressed.

The study included a narrative description of historic land uses and ecological change in Tintic Valley, and examined the changes in landscape patterns …


Livestock As Seed Disseminators For Reseeding Degraded Rangelands: The Role Of Dung In Gap Formation And Plant Establishment, Brian S. Auman May 1996

Livestock As Seed Disseminators For Reseeding Degraded Rangelands: The Role Of Dung In Gap Formation And Plant Establishment, Brian S. Auman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Livestock (cattle and sheep) were examined as seed disseminators for reseeding degraded Intermountain rangelands. "Hycrest" crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult. X A. cristatum (L.) Gaert.] seed was fed to yearling Holstein steers and Suffolk ewes. Dung was collected from each animal type and deposited on plots of high and low densities of an annual [cheatgrass (Bromus tectorum L.)] and perennial [squirreltail (Sitanion hystrix Nutt.)] grass species. The experiment evaluated the ability of the dung to suppress the resident vegetation, and the recruitment and establishment of Hycrest seedlings emerging from the dung.

Sheep dung had …


Growth Responses Of Great Basin Plant Species To Variation In Nitrogen Availability, Carol J. Bilbrough May 1996

Growth Responses Of Great Basin Plant Species To Variation In Nitrogen Availability, Carol J. Bilbrough

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

For this dissertation, I examined the ability of field-grown plants to capture N presented in enriched patches or in whole-plant pulses. I assessed root proliferation in N-enriched patches when Agropyron desertorum plants had been previously fertilized or shaded. All plants responded with increased root growth rates in N-enriched patches. However, root proliferation by shaded plants was 50% less than unshaded plants. Unexpectedly, plants with higher N status had greater root growth rates in enriched patches than plants that had not received N supplement. I concluded that plants already under competitive pressure above ground for light and below ground for nutrients …


Effects Of Graded Levels Of Dietary Lasalocid On Performance Of Holstein Cows During Early Lactation, Dennis E. Christensen May 1995

Effects Of Graded Levels Of Dietary Lasalocid On Performance Of Holstein Cows During Early Lactation, Dennis E. Christensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Thirty-six multiparous Holstein cows were assigned to one of three dietary levels of lasalocid· 0, 180, or 360 mg/hd/d in a completely randomized design Cows were assigned to treatments 1 wk postcalving and remained on treatment until 11 wk postcalving Basal diets were composed of ground corn, alfalfa hay, alfalfa haylage, corn silage, and soybean meal, fortified with vitamins and minerals as needed. All ingredients were ground and fed as a total mixed ration Daily rations were fed in two equal portions at 0500 and I 700 h at a rate to allow a 5- 10% refusal. Daily measurements included …


Evaluation Of Milk Production In Western Whiteface And Navajo-Churro Ewes, Marla Faye Brindley May 1995

Evaluation Of Milk Production In Western Whiteface And Navajo-Churro Ewes, Marla Faye Brindley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Western Whiteface and Navajo-Churro Ewes, two types of sheep present in the Intermountain West, were compared for their milk production ability. Amount of milk produced per individual and the group milk composition were analyzed for butterfat, lactose, somatic cell count, protein, calcium, and phosphorous.

Ewes were fed ad libitum alfalfa hay and had access to free-choice grain while in the milking parlor. Lambs were weaned at 35 d of age and removed to another holding area and placed on creep feed . Ewes were milked for 90 d following the weaning of the lambs.

Western Whiteface ewes had a much …


The Effects Of Feeding Chelated Metal Proteinates On Milk Production And Reproductive Performance In Holstein Dairy Cows, Ben James Hardcastle May 1995

The Effects Of Feeding Chelated Metal Proteinates On Milk Production And Reproductive Performance In Holstein Dairy Cows, Ben James Hardcastle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Twenty-two primiparous Holstein heifers were allocated to one of two treatments. Treatments consisted of: 1) basal ration plus 226.8 g inorganic mineral supplement (control); and 2) basal ration plus 226.8 g inorganic mineral and metal proteinate supplement (50:50). Individual heifer performance was measured during the final 10 weeks of the prepartum period. Feed intake and refusals were recorded daily. Individual heifer body weights recorded weekly did not differ significantly. Blood samples taken at 4-week intervals did not differ in plasma concentration between treatments. Calf birth weights for control heifers were not significantly higher than calves from the treatment heifers.

The …


Effects Of Antioxidants On Development Of In Vitro Fertilized Bovine Embryos, Bret L. Anderson May 1995

Effects Of Antioxidants On Development Of In Vitro Fertilized Bovine Embryos, Bret L. Anderson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Free radicals are short-lived molecules that can cause decreased embryonic development in vitro. Antioxidants are molecules that block free radical formation or guard against their harmful effects. Many studies have linked exposure of media to light and culturing of embryos in high (20%) oxygen concentrations to free radical production. Some of the antioxidants used in culture media are superoxide dismutase (SOD), catalase, zinc (II), ethylenedinitrilo tetraacetic acid (EDTA), mannitol, vitamin E, dimethyl sulfide, and taurine. Most research involving antioxidants and embryonic development has been conducted on non-farm animals, particularly mouse and rabbit. Studies have shown that antioxidants in vitro culture …


The Efficacy Of A Self-Administered Cognitive Behavioral Treatment Program For Body Image Dissatisfaction In Women With Subclinical Bulimia Nervosa, Ellen N. Emerson May 1995

The Efficacy Of A Self-Administered Cognitive Behavioral Treatment Program For Body Image Dissatisfaction In Women With Subclinical Bulimia Nervosa, Ellen N. Emerson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Subjects for this study were 40 women (N = 40) with subclinical bulimia nervosa who were randomly assigned to either a Cognitive Behavioral Treatment group (CBT) or to a waiting list control group. Treatment was provided for 8 weeks in an individual, self-administered format, using an audio-taped treatment package for Body Image Dissatisfaction (BID). Cognitive behavioral treatment focused on changing negative thoughts and feelings about one's body. No specific treatment focused on changing eating symptomatology or concomitant symptoms, although these were assessed. The waiting list control condition received assessment, followed by 8 weeks of no treatment. Treatment outcome measures …


Effects Of Homogenization And Ultra-High Temperature Processing On The Properties Of Whole Milk Concentrated By A Multiple-Membrane Separation System, Chien-Ti Chang May 1995

Effects Of Homogenization And Ultra-High Temperature Processing On The Properties Of Whole Milk Concentrated By A Multiple-Membrane Separation System, Chien-Ti Chang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Three different concentrated whole milks (2.5x, 2.75x, and 3.0x) were produced by mixing equal parts of ultrafiltration retentate of whole milk and reverse osmosis retentate of the UF milk permeate. The concentrated whole milks were ultra-high temperature processed by direct steam injection (140.6°C) followed by flash cooling and two-stage homogenization pressures (2500/500 psi, 3500/700 psi, or 4500/900 psi). The milk concentrates were packaged aseptically and stored at room temperature. On the other hand, the milk concentrates produced by the RO single membrane system with the same concentration levels served as the control. Physicochemical properties of the milks were surveyed every …


Muscle Fiber Types, Dna:Rna:Protein Ratios, And Measures Of Tenderness In Various Muscles Of Normal And Callipyge Lambs, Owen D. Rice May 1995

Muscle Fiber Types, Dna:Rna:Protein Ratios, And Measures Of Tenderness In Various Muscles Of Normal And Callipyge Lambs, Owen D. Rice

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An inherited muscle hypertrophy in sheep is caused by the callipyge gene (CLPG) located on ovine chromosome 18. It has been suggested that this gene is a single autosomal dominant gene. Animals expressing the callipyge gene show increased muscling in the pelvic and torso regions of the body and, thus, have been given the phenotype- descriptive name callipyge (from Greek calli-beautiful; pyge-buttocks). In this study 21 wether lambs, the offspring of callipyge rams (genotype CLPG /clpg) and normal Rambouillet ewes (genotype clpg/clpg), were used to determine the differences in muscle fiber type percentages, composition, and tenderness between normal …


Improved Control Of Cheese Manufacture Through Continuous Vat Monitoring Of Coagulation Parameters Using The Hot Wire Method, Michael John Lefevre May 1995

Improved Control Of Cheese Manufacture Through Continuous Vat Monitoring Of Coagulation Parameters Using The Hot Wire Method, Michael John Lefevre

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The hot wire method, with pH and temperature sensors, was evaluated to determine its usefulness and application for cheese production automation. Coagulation of milk substrate was measured with the hot wire instrument and by four other methods: Formagraph, Brookfield®, vixcometer, Omnispec™ bioactivity monitor, and Sommer and Matsen rolling bottle method. The hot wire, using the time at maximum slope, detected coagulation before methods that measure resistance to shear, and after methods that measure light reflectance. Coagulation time was not significantly different from the industry standard rolling bottle method used by Sommer and Matsen. the hot wire instrument was also used …


Effects Of Iron Fortification On Microbiological, Physical, Chemical, And Organoleptic Properties Of Yogurt, Sharareh Hekmat May 1995

Effects Of Iron Fortification On Microbiological, Physical, Chemical, And Organoleptic Properties Of Yogurt, Sharareh Hekmat

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

It has been shown that iron binds strongly to the proteins in milk, and our aim was to determine whether or not this binding was affected by lowering pH in the manufacture of yogurt. Iron-protein complexing was studied using two different techniques. 1) Skim milk was fortified with 10 mg iron/100 ml and the pH of the milk was adjusted to 6.7, 6.2, 5.8, 5.3, 4.5, and 4.0. The milk was fractionated by ultracentrifugation at 52,000 x g for 60 minutes. The pellets and serum were then analyzed for iron, calcium, and phosphorus content by inductively coupled plasma spectroscopy. SDS-PAGE …


The Effect Of Iron Fortification On The Chemical, Physical, And Sensory Properties Of Mozzarella Cheese, Wendy Haws Rice May 1995

The Effect Of Iron Fortification On The Chemical, Physical, And Sensory Properties Of Mozzarella Cheese, Wendy Haws Rice

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Mozzarella cheese was made from milk fortified with iron so that the cheese contained 25 and 50 ppm iron. Iron was added to the milk in three ways: (1) complexed to casein (ferric-casein), (2) complexed to whey protein (ferric-whey protein), and (3) ferric chloride (FeCl3·6H20) added directly to milk. Cheese quality was determined by chemical, physical, and sensory characteristics and compared with a control cheese.

Chemical oxidation, during 28 days storage, was determined by absorbance of malondialdehyde at 535 nm using the thiobarbituric acid assay (TBA). Physical properties were assessed by the Arnott test for melt, helical viscometer for stretch, …


Conjunctival Impression Cytology Assessment Of Vitamin A Status Of Migrant Children, Laura Nihan May 1995

Conjunctival Impression Cytology Assessment Of Vitamin A Status Of Migrant Children, Laura Nihan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Subclinical vitamin A deficiency was assessed in 65 Hispanic children attending four migrant Head Start programs in Utah. Subjects aged 2 to 6 years (median 3 years 10 months) were examined for evidence of vitamin A deficiency by conjunctival impression cytology. Biochemical indices for serum vitamin A, retinol-binding protein, zinc, and iron were performed.

Of eight children (12.5%) with subclinical vitamin A deficiency, one child had a marginal serum vitamin A of 11 μg/dl. Retinol-binding protein concentrations were significantly lower in two subjects with abnormal conjunctival impression cytology. Serum zinc, which when low can mimic signs of ocular vitamin …


Membrane Protein As A Basis Of Nacl Tolerance In Alfalfa, Husni N. Sabah May 1995

Membrane Protein As A Basis Of Nacl Tolerance In Alfalfa, Husni N. Sabah

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study sought to determine whether NaCl altered the plasma membrane proteins in alfalfa exhibiting differential NaCl concentrations, and whether CaSO4 modified the responses. Two alfalfa cultivars, Centurion and Condor, were grown in 0.5 strength Hoagland solution in a greenhouse. The cultivars were exposed to 0, 88, and 132 mM of NaCl alone and mixed with CaSO4 ⋅ H2O at 7 and 14 Mm CaSO4 for 3, 9, and 60 days.

In experiment 1, roots were dried to determine their Na, Ca, K, and Mg concentration. The results were similar to previous reports in which …


Cytological And Molecular Analyses Of The Ns Genome In Russian Wildrye, Psathyrostachys Juncea (Fisch.), Junzhi Wei May 1995

Cytological And Molecular Analyses Of The Ns Genome In Russian Wildrye, Psathyrostachys Juncea (Fisch.), Junzhi Wei

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Russian wildrye (Psathyrostachys juncea Fisch. 2n=2x=14, NsNs) is an important forage grass and a potentially useful germplasm in wheat improvement. A standard C-banding karyotype of Ps. juncea has been developed based on the C-bands of chromosomes in geographically diverse materials. Although there are C-banding polymorph isms, the seven pairs of chromosomes can be distinguished from each other according to their basic banding patterns. Based on C-banded karyotype, one deletion-translocation heterozygote, four primary trisomies, one double-deletion trisomic, and two tertiary trisomies were identified. These cytogenetic stocks will be useful in genetic studies of Russian wildrye.

Genetic variations in Russian wildrye were …


Behavioral Characteristics Affect Habitat Selection Of Domestic Ruminants, Cody B. Scott May 1995

Behavioral Characteristics Affect Habitat Selection Of Domestic Ruminants, Cody B. Scott

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

I evaluated some of the factors affecting livestock distribution by conducting experimental (Chapters II and III) and observational (Chapter IV) studies. In Chapter II, I described the effect of locations of familiar foods and social interactions on choice of feeding location by lambs. Lambs were exposed to a pasture as subgroups of strangers and companions with different dietary habits (i.e., three lambs that preferred milo with three lambs that preferred wheat). Milo was placed on one end and wheat on the other, about 100 m apart. Strangers typically fed in different locations, reflecting dietary preferences. Conversely, companions fed in both …


Consumption Of Iron-Fortified Cheese And Lipid Peroxidation In Females, Gene Joseph Giunti May 1994

Consumption Of Iron-Fortified Cheese And Lipid Peroxidation In Females, Gene Joseph Giunti

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Dairy products are important sources of calcium and other nutrients but are a poor source of dietary iron. Cheese comprises a substantial portion of dairy food consumption and has been determined an appropriate medium for iron-fortification. However, iron may promote the potentially harmful process in food and biological systems known as lipid peroxidation. Therefore, the safety of consuming iron-fortified cheese was examined.

Commercial-scale batches of Cheddar cheese were iron-fortified to a level of two milligrams of iron per ounce with either ferric chloride, ferric-casein complex, or ferric-whey protein complex. Fifty-four premenopausal females were divided into three treatment groups and supplemented …


Officially Reported Characteristics Of Spouse Abuse Victims Seeking Assistance In Utah, 1992, Kevin D. Thompson May 1994

Officially Reported Characteristics Of Spouse Abuse Victims Seeking Assistance In Utah, 1992, Kevin D. Thompson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Spouse abuse is a significant social problem that has recently received considerable attention by family researchers. National studies have estimated the incidence of spouse abuse in the United States, but few studies have been conducted at the state or local level.

Data were obtained from the Utah Division of Family Services Domestic Violence Client Record (Form 741-S) reporting system. A total of 1,363 primary victims of spouse abuse was identified for the calendar year 1992.

It is posited that victims of low socioeconomic status and victims of severe physical abuse are more likely to return to their own home after …


Transcervical Versus Laparoscopic Insemination In Nulliparous And Multiparous Ewes After Estradiol Cypionate Treatment, Tami L. Gage May 1994

Transcervical Versus Laparoscopic Insemination In Nulliparous And Multiparous Ewes After Estradiol Cypionate Treatment, Tami L. Gage

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The only practical method for artificially breeding ewes with frozen semen is laparoscopic insemination into the lumen of the uterine horn. Like all surgical procedures, however, laparoscopic artificial inseminatiom has limitations. The procedure requires surgical skill and costly equipment. Repeated passage of the laparoscope through the abdominal wall causes adhesions. Depositing frozen/thawed semen at the os cervix results in low conception rates. The inability to pass an insemination pipette through the cervix has prevented artificial insemination in sheep from becoming a standard breeding method as in the cattle industry. This study compared laparoscopic and transcervical methods of insemination in nulliparous …


Molecular Toxicology Of Pyrrolizidine Alkaloids, Hea-Young Kim May 1994

Molecular Toxicology Of Pyrrolizidine Alkaloids, Hea-Young Kim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Pyrrolizidine alkaloids are cytotoxic, carcinogenic, and anti-carcinogenic in vivo and in vitro, and they produce many hazardous effects in humans and animals. Pyrrolizidine alkaloids (PAs) also cross-link with DNA and/or protein. However, whether such cross-linking is important to the toxic action of PAs is not known. In addition, the exact mechanism underlying these DNA cross-links or cytotoxicity is also not clear.

In three separate studies, I characterized the nature of PA-induced DNA cross-links and the relationships between PA structures and cross-linking potency. In the first study (Chapter II), I found that cross-linking potency of PA congeners coincided with their …


Agribusiness Management In Utah Dairies, Rick L. Hirschi May 1994

Agribusiness Management In Utah Dairies, Rick L. Hirschi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis outlines the theoretical factors impacting dairy profitability. The theoretical portion includes: a general review of production and profit maximization theory, a review of related studies, and an outline of the variables impacting dairy profitability.

An empirical study follows using data gathered from three applied technology centers in Utah in conjunction with dairy herd improvement production records for the farms where these data were available. The empirical section includes a synopsis of the methods and procedures used to collect and analyze the data. Regression analysis was used to determine the significant production and financial factors influencing returns per cow; …


Do Prospective Ratings Correct Retrospective Distortions Based On Negative Social Stereotypes Of Premenstrual Syndrome?, Mary L. Stone May 1994

Do Prospective Ratings Correct Retrospective Distortions Based On Negative Social Stereotypes Of Premenstrual Syndrome?, Mary L. Stone

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Daily Assessment Form (OAF) retrospectively assessed symptoms of late luteal phase dysphoric disorder (LLPDD), both at the beginning and at the end of a 2-month time interval. Ninety-four women between the ages of 18 and 45 entered the study. Half of the subjects viewed a negative-case, stereotypic presentation of LLPDD prior to the pretest. sixty-eight subjects qualified on the pretest to complete the study. Half of the remaining no-case subjects and half of the remaining negative-case subjects completed 8 weeks' prospective ratings via the OAF. Forty-eight subjects remained to complete the posttest at the end of that time interval. …


Factor Analytic Study Of Spatial Abilities In Second-Grade, English-Speaking Navajo And Non-Navajo Children, Laurie Sullivan-Sakaeda May 1994

Factor Analytic Study Of Spatial Abilities In Second-Grade, English-Speaking Navajo And Non-Navajo Children, Laurie Sullivan-Sakaeda

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study was conducted to continue the investigation of apparent differences in cognitive abilities between Navajo Indian children and non-Navajo children. Subjects were 248 second-grade students, ranging from 7 to 9 years old. The Navajo sample lived in the Shiprock, New Mexico, area of the Navajo Indian Reservation, and the non-Navajo sample lived on the east side of Salt Lake City, Utah. Data were collected using six tests designed to measure spatial abilities in primary grade children. Results indicated that the non-Navajo children scored significantly higher on two individual tests and on the total test score under timed conditions, with …


Differential Parental Participation In A Comprehensive Early Intervention Project: Is More Active Better?, Gary Percival May 1994

Differential Parental Participation In A Comprehensive Early Intervention Project: Is More Active Better?, Gary Percival

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The current study examined the level of participation by families who have been involved between 1 and 3 years with the Community-Family Partnership (CFP) project. The CFP project is 1 of 34 Comprehensive Child Development Projects funded by the Administration for Children, Youth, and Families through the Head Start Bureau. The CFP makes available comprehensive, on-going services to enrolled families. Twenty-six families were identified as the Low Participation Group. Twenty-three families were identified as the High Participation Group. Children from each group were tested using the Battelle Developmental Inventory on a yearly basis. Results of a repeated measures ANOVA indicated …


Influences Of Nitrogen Supply And Elevated Co2 On Nitrogen Consumption, Nitrogen Loss, Tissue Nitrogen Concentration, And Yield Of Hydroponic Wheat, Karl B. Ritchie May 1994

Influences Of Nitrogen Supply And Elevated Co2 On Nitrogen Consumption, Nitrogen Loss, Tissue Nitrogen Concentration, And Yield Of Hydroponic Wheat, Karl B. Ritchie

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wheat was grown hydroponically for 23 days (early boot stage) in a controlled environment at NO3- concentrations of 100 and 1000 μmol and CO2 levels of 360 and 1200 μmol mo1-1. Nitrogen consumption and transpiration were measured daily. Tissue nitrogen concentration, total biomass, and percent root mass were measured at harvest. Nitrogen recovery and nitrogen use efficiency were calculated. Elevated CO2 increased nitrogen consumption of the 100 μmol NO3- treatment by 13.6% and the 1000 μmol NO3- treatment by 21.3%. These increases were particularly evident during …


Effects Of Soluble Calcium-To-Protein Ratio On Age Gelation Of Ultra, Je Hong Ryue May 1994

Effects Of Soluble Calcium-To-Protein Ratio On Age Gelation Of Ultra, Je Hong Ryue

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Reverse osmosis (RO) and ultrafiltration (UF) retentates were ultra-high temperature (UHT) processed and compared for storage life at room temperature. Viscosity studies indicated that UHT-treated, RO retentate delayed age gelation longer than UF retentate at the same total solids level (26% TS). When compared at 6.4% protein level (2x RO vs 2.7x UF where x=ratio of the feed volume to concentrate volume), the storage life for both RO and UF retentates was about 6 to 8 months.

Sodium hexametaphosphate (SHMP) and disodium phosphate (DSP) at 1, 3, 5, 10, and 20 mM concentrations were incorporated prior to UHT processing …


Pantothenate-P-Nitroanilide As A Substrate For Pantetheinase Assay, Robert T. Davidson May 1994

Pantothenate-P-Nitroanilide As A Substrate For Pantetheinase Assay, Robert T. Davidson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Pantothenate-p-nitroanilide has been synthesized for use as a substrate in a continuous spectrophotometric assay of pantetheinase activity monitoring absorbance at 410 nm. Pantothenate-p-nitroanilide is a crystalline compound with a molecular weight of 338.0 and a melting point of 146-149°C. Use of this substrate in the described assay is suitable for enzyme activity determination in high protein content media such as blood serum. Serum pantetheinase activity was determined for rats of varying pantothenate nutriture. Rats with mildly (but significantly, p < 0.05) lower serum pantothenate levels had significantly higher serum pantetheinase activities than the control group (6.24 nmol/min/ml ± 0.72 and 16. 16 nmol/min/ml ± 4. 14, respectively, p=0.0005).


Microstructural Changes In Casein Micelles During Acidification Of Skim Milk, Hongwen Du May 1994

Microstructural Changes In Casein Micelles During Acidification Of Skim Milk, Hongwen Du

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Pasteurized skim milk was acidified using glucono-δ-lactone (GDL) at 10, 20, 30, and 40°C or with 1.2% freeze-dried yogurt starter culture at 40°C. Milk coagulation was followed by measuring turbidity, curd firmness, particle size, and casein micelle microstructural changes using transmission electron microscopy .

The pH of milk was gradually lowered during acidification with GDL or starter culture. Acidification rate showed greater influence on turbidity change at 10°C than at 20, 30, or 40°C.

Average casein micelle size increased with decreasing temperature. The patterns of average micelle size versus pH were not affected by temperature. No great variation of average …