Food Science Commons^™

Characterization Of The Proteolytic System In Lactococcus Lactis Starter Cultures, Christina Beer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The proteolytic system of Lactococcus lactis starter cultures influences both flavor and the characteristic body and texture of cheese. The ability to further understand and control how different components of this proteolytic system work together to hydrolyze milk proteins would be of immense importance to the dairy industry.

The goal of this research was to characterize Lactococcus lactis subsp. lactis starter bacteria with varying prt operon compositions by proteinase specificity, aminopeptidase and lipase activities, growth, and influence on cheese flavor. By using a cheese slurry system, a statistical model to predict milk protein hydrolysis patterns was developed.

Lactococcus lactis subsp. …

Expression And Iron Loading Of Recombinant Ferritin Homopolymers, Jia-Hsin Guo

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ferritin is an iron storage protein consisting of H and L chains to form a 24-subunit heropolymer. Ceruloplamin oxidizes Fe(II) and then loads the iron into ferritin. This research was conducted to determine which ferritin subunit is involved and whether a proposed iron-loading channel is required for iron loading by ceruloplasmin.

Recombinant rat liver H and L chain ferritin homopolymers, designated as rH-Ft and rL-Ft, respectively, were produced using insect cell-baculovirus and Escherichia coli expression systems. The expressed rH-Ft strongly suppressed the growth of the host. The rH-Ft expressed in the E. coli contained approximately 150 iron atoms/ferritin and was …

A Study Of The Interactions Between Milk Proteins And Soy Proteins, Venkatachalam Narayanaswamy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research investigates the protein interactions that occur when soy protein is added to milk and subjected to renneting or heating. Milk was fortified with 20% soy protein and enzymic coagulation studied at 35°C at various pH's and CaCl₂ levels. The first part deals with the interaction between milk and soy proteins during rennet-induced milk coagulation. The first goal was to determine how soy proteins affected milk coagulation. The effects of native versus heat-denatured soy proteins on rennet coagulation time and curd firmness were compared. lmmunogold labeling along with transmission electron microscopy was used to identify and localfze soy …

Effect Of Ph, Fat Level, And Various Browning Agents On Composition, Color, Texture, And Sensory Characteristics Of Dark-Cutting Beef Patties, Igor V. Moiseev

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Extra lean (3.3% fat) and lean (20.0% fat) hamburgers in three pH groups (≤ 6.0; 6.01-6.49; 6.50-6.92) were evaluated for cooking-temperature profile, total process lethality, and physical properties after cooking to 71°C by double-side frying on an electric grill. Neither cooking-temperature profile nor cooking time was affected by hamburger fat content or pH. Double-side frying to 71.1°C internal temperature was adequate for more than 6-log destruction of viable E. coli O157:H7 and Salmonella at the geometrical center of extra lean and lean hamburgers. The coldest spot was on the circumferential surface, as indicated by the presence of a red ring …

Isolation And Biochemical Characterization Of Acid- And Bile- Tolerant Strains Of Lactobacillus Acidophilus And Bifidobacterium Bifidum, Lan-Szu Chou

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Lactic acid bacteria have been reported to be used as a health adjunct in food for u many years. However, these health benefits have not been proven. and how these bacteria pass through the digestion process and remain viable in the human intestinal tract is still not clear. The aim of this work was to isolate mutants from Lactobacillus acidophilus or Bifidobacterium bifidum that could tolerate the conditions of the digestion process (low pH and bile conduction) and to characterize these isolated mutants.

Acid- and bile-tolerant mutants of L. acidophilus were isolated from parental strains successfully using natural selection techniques. …

Evaluation Of Methods Used In Meat Iron Analyses And Iron Content Of Raw, Cooked, And Cured Meats, Eldred Merlyn Clark

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research project was divided into three parts. In the first part, heme, nonheme, and total iron methodologies for meats were evaluated. The accuracy, precision, and specificity of each method were determined by spike recoveries of heme and nonheme iron, and by analysis of National Institute of Science and Technology standard reference materials. The most reliable and practical methods were then used to determine the total, nonheme, and heme iron contents of various meats before and after cooking. The meats analyzed were beef, pork, lamb, chicken, and turkey. The wet-ashing technique was a novel procedure in which nitric acid was …

A Quantitative Analysis Of Potassium Loss As A Result Of Different Processing Methods, Patricia M. Klefbeck

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Compliance with the strict dietary regimen for the dialysis patient can be very challenging. Many foods are limited from the diet of a renal patient because of the high potassium content. The physiological consequences of failure to follow a diet prescription can be fatal for the dialysis patient. In an effort to improve patient compliance with nutritional protocols, several potato cooking methods and centrifugation of tomato sauce were investigated for their effects in reducing potassium content.

All methods with a 24-hour soak were found to be significant in reducing potassium content of potatoes (P < 0.05). However, some of the methods in which the potatoes were not soaked were also found to be effective in reducing potassium content. Slice thickness and volume of cooking water used were found to be two important factors in determining potassium loss. The 4-mm sliced potatoes, which had a mean potassium value of 84 mg/100 g, lost more potassium than the 8-mm potatoes with a mean potassium value of 182 mg/100 g (P < 0.05). Furthermore, the potatoes cooked in 10 times the amount of water lost more potassium (124 mg/100 g) than those cooked in only 5 times the amount of water (148 mg/100 g) (P < .005). Soaking in cold versus hot water, agitation of the soak water, or the addition of chemical chelators to the soak water were not shown to be any more effective in reducing the potassium content than the other methods. Sensory data indicated that participants did not have a strong taste preference for potatoes cooked by any one particular method (P < 0.05).

Centrifugation of …

Quantitation Of Bovine Serum Albumin In Cow's-Milk-Based Infant Formulas And Removal Of Bovine Serum Albumin From Cow's Milk And Whey Protein Isolates, Patricia Z. Marincic

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Early introduction of cow's-milk-based infant formulas, in particular the ABBOS epitope of bovine serum albumin (BSA), has been implicated as an autoimmune trigger in the pathogenesis of insulin dependent diabetes mellitus (IDDM). A direct enzyme-linked immunosorbant assay (ELISA), using polyclonal anti-BSA antibodies, was developed to determine the BSA content of cow's milk and 15 infant formulas. Powdered high-whey (60%) formulas averaged 41 mg BSA/100 ml; 2% milk contained 52 mg BSA/100 ml; and the high-casein formulas averaged 13 mg/100 ml. BSA content of powdered polymeric formulas and cow's milk varied directly with the whey protein concentration (correlation coefficient = 0.8445, …

Survival Of Microorganisms On Meat Surfaces Treated With Ultra-High Temperatures, Bret Max Mattinson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Sterile ceramic plates and the surface of beef steaks were inoculated with the pathogenic microorganisms Listeria monocytogenes, Campylobacter jejuni, Escherichia coli and Salmonella typhimurium. Samples were also inoculated with nonpathogenic microorganisms Clostridium sporogenes ATCC 7955, Pseudomonas aeruginosa, and Bacillus stearothermophilus. Concentrations of organisms in the pure culture used to inoculate the samples were selected within the range of 10⁶ to 10⁸ colony forming units/ml (CFU/ml). Samples were treated with ultra-high temperature (UHT), and· the surviving organisms were recovered and counted. Meat samples were exposed to 1100°C for 22 seconds.

Beef steaks inoculated with pathogenic microorganisms had …

Acceptability And Proximate Composition Of Meat-Vegetable Sticks Versus All-Meat Sticks Adjusted To Ph 4.6 Or 5.2 With Citric Or Lactic Acids, Ronnald Dean Quinton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A new innovative product, stewsticks, made with beef, pork, spices, and dehydrated vegetables, was developed as a nutritious snack. Lactic or citric acid was added at pH 5.2 or 4.6 to both meatsticks and stewsticks. Meatsticks and stewsticks were prepared by mixing ingredients until a cohesive mass was obtained. This mixture was then extruded into sticks that were cooked to about 50% of original weight. Sticks were then cut to desired length, packaged, and stored. Then meatsticks (beef, pork, and spices) were compared to stewsticks for appearance, texture, flavor, and overall acceptability.

The stewsticks had excellent shelf life due to …

Fats And Iron In The Rat Colon: Effects On Lipid Peroxidation, Ji Jenny Chin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Preliminary studies were undertaken to investigate whether or not added iron (0, 35, 880 ppm of iron as ferrous fumarate) and fat type (corn oil, beef tallow, or menhaden oil) influenced the oxidation of the rat diet during storage. Iron level affected thiobarbituric acid (TBA) values only in the menhaden oil diets. Storage for 4 d did not affect TBA values of the diets. Neither food intake nor body weight of the rats was affected by the different diets, suggesting all diets were equally acceptable to rats.

The effects of iron supplementation and fat type on in vivo lipid peroxidation …

Microbiological And Sensory Effects Of Milk Processed For Extended Shelf Life And The Development Of Rapid Methods To Quantitate Spores And Lipase Activity, Michael R. Blake

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The initial aim of this work was to evaluate processing conditions for extended shelf life (ESL) milk to have a shelf life at refrigeration temperature of 60 d. Milk was processed on a pilot-scale ultra-high-temperature processing plant and evaluated for microbial and sensory quality over 60 d at 7°C storage. Results of this study showed that lower process temperatures were preferable to minimize cooked flavors and that the minimum safe processing temperature was 134°C for 4 s as determined by the destruction of bacterial spores in the processed milk.

Consumer preference panel results indicated that consumers preferred milk processed at …

Manufacture, Shelf Stability, And Acceptability Of Aseptically Packaged, Unripened Soft Cheese Produced By Post-Ultra-High Temperature Acidulant Injection Of Ultrafiltered Milk Concentrate, Elena S. Moiseeva

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study investigated the manufacturing procedures and texture attributes of direct acid set of an unripened, shelf-stable cheese variety produced by the combined technologies of ultrafiltration and ultra-high temperature processing. Product evaluation included physical and chemical properties such as gel strength, syneresis, pH, moisture, protein, and fat. Whole milk was concentrated by ultrafiltration to 30, 35, and 40% total solids. Milk retentate was ultra-high temperature-processed by preheating to 65 or 77°C, sterilized at 141°C for 4 s by direct steam injection, flash cooled to approximately 62 or 72°C, homogenized in two stages at either 13.8/2.1 or 27.6/4.1 MPa, cooled to …

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

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

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 …

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, …

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 …

Effects Of Nonfat Dry Milk, Whey Protein Concentrate, And Calcium Caseinate On Color And Texture Of Turkey Rolls, Brent Neeley Dobson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two studies were conducted to evaluate the effects of milk solids on restructured and emulsified turkey rolls. the milk solids used were nonfat dry milk (NFDM), whey protein concentrate (WPC), and calcium caseinate (CC). Turkey rolls consisted of 100% breast meat or 90:10 or 70:30 breast-to-thigh, salt (1%), water (10%), internal or cluster fat (10%), and 3% of various milk solids (WPC, NFDM, CC).

The objectives of these studies were to 1) determine which ratio between light and dark meat is preferred; 2) determine which of milk solids evaluated will permit the highest level of dark meat incorporation into evaluated …

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 …

A Response Surface Study Of Extruded Corn Starch/Skim Milk Powder Blends, Sachin Singh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Skim milk was ultrafiltered to three lactose/protein ratios and spray dried. The skim milk powder was extruded with pearled corn starch at different moisture contents, protein contents, lactose/protein ratios, and feed rates (control variables). Response surface methodology and a central composite in cube experimental design were used. This design required 30 experimental runs with 16 factorial points, 8 axial points, and 6 center points for replication. The physical and functional properties evaluated were expansion ratio, product temperature, bulk density, color, shear stress, viscosity, and water absorption index (response variables). Scanning electron microscopy was done to evaluate the microstructural attributes of …

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 …

Influence Of Ultra-High Temperature Process Parameters On Age Gelation Of Mille Concentrate, Mohamed A. Elhilaly

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this research was to investigate the effect of ultra-high temperature process parameters on age gelation of milk concentrate. Skim milk was concentrated to 2X (volume reduction) using reverse osmosis. The milk concentrate was preheated at 75 or 90°C for 20 or 50 s and UHT-processed at 138 or 145°C for 4 or 16 s. Sterilizing methods used were direct steam injection and indirect plate heat exchanger. The samples were aseptically collected in presterilized plastic containers and stored at 15 or 35°C. At 15°C storage temperature, the steam-injected samples gelled in 5 months when 4 s UHT time …

Fate Of Β-Lactoglobulin, Α-Lactalbumin, And Casein Proteins In Ultrafiltered Concentrated Milk After Ultra-High Temperature Processing, Mark Christopher Alleyne

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The problem of age gelation in ultra-high temperature (UHT) sterilized milk retentate (ultrafiltered 3x concentrated) is investigated in this work. Transmission electron microscopy (TEM), utilizing the microcube encapsulation technique and protocols for immunolocalization of milk proteins, provides insight into the phenomenon of age gelation of UHT-sterilized, ultrafiltered (UF) milk retentate. Primary antibodies (specific for the native as well as the complexed forms of milk proteins) and secondary antibodies (conjugated to gold probes) are used to elucidate the positions of the milk proteins in various samples of milk from the stage of milking through UHT sterilization and storage for 12 months, …

Effects Of Whey Protein Concentrate, Phosphate, And Sodium Hydroxide On Texture And Acceptability Of Turkey And Beef Rolls, Igor V. Moiseev

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Processed turkey rolls were prepared with 1 or 3% whey protein concentrates WPC-50 (pH=5.80), WPC-60 (pH=4.53) and WPC-75 (pH=6.85} containing 50, 60 and 75% protein along with controls (phosphate and no phosphate). Control rolls made with 0.5% phosphate had the highest bind strength, and sensory evaluation scores. Only WPC-75 (1%) was acceptable as a binding agent and flavor enhancer. WPC-60 reduced pink discoloration of rolls, but flavor, bind and cohesiveness scores were unacceptably low. WPC-50 was not an effective binding agent. In general, rolls made with 3% WPC had lower scores for intensity of turkey flavor.

Bind strength and sensory …

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 …

Manufacture Of A Dairy Dessert From Ultra-High Temperature Milk Concentrate, Mark H. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this project was to initiate development of a nonrefrigerated dairy dessert product. Milk was concentrated by pressure-driven filtration and then sterilized using ultra-high temperature (UHT) processing. Following sterilization, samples were aseptically inoculated with rennet to coagulate the milk, which was then stored at room temperature. These processing steps produced a dairy dessert that did not require refrigeration. I investigated the influence of total solids, milk fat, rennet dosage, storage temperature, and storage time on curd firmness and syneresis. I investigated the effect on curd firmness and syneresis of giving the concentrate a heat treatment prior to UHT …

The Contribution Of Meats To Energy And Essential Nutrient Intakes Of Women In The United States, C. Dian Martin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study used the 1987-88 USDA Nationwide Food Consumption Survey to investigate the contribution meat products make to intakes of nutrients at risk of inadequate or excessive consumption by women. The study is unique in that meat nutrients were extracted from mixed dishes, providing a more accurate picture of consumption. Cluster analysis was used to classify nonpregnant, nonlactating women 19 years and older based on their consumption patterns of total meat and individual meats (beef, poultry, processed meats, pork and seafoods) as percent of caloric intake.

Total fat and SFA intakes exceeded National Research Council (NRC) goals regardless of meat …

Anaerobic Treatment Of Whey Permeate Using Upflow Sludge Blanket Bioreactors, Seokhwan Hwang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Whey permeate was anaerobically digested in laboratory scale upflow anaerobic sludge blanket reactors. Nine hydraulic retention times between 5 and 0.2 days were examined with a fixed influent concentration of 10.6 ± 0.2 g COD/L.

Chemical oxygen demand removal efficiency ranged from 99.0 to 18.9% and maximum production rate of methane gas was 2.67 L/L/day at a hydraulic loading rate of 12.97 kg COD/m³/day. About 70% of the chemical oxygen demand removed was converted to methane.

Both the nonlinear least square method with 95% confidence interval and linear regression were used to evaluate kinetic coefficients. The maximum substrate …

Sensory And Functional Properties Of Wheat Stored Under Home Conditions, Marilyn M. Shumway

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Samples of wheat that had been stored in homes up to 48 years were collected with information about age and storage conditions. Germination, weight per bushel, protein, moisture, grade, and aroma were investigated. Volumes of gluten balls and bread made from ground whole wheat samples were measured. Sensory attributes of bread were evaluated by Quantitative Descriptive Analysis (QDA) for eight flavor and seven texture characteristics. Because of the tremendous variation in samples, generalizations on cause and effect are difficult to make. No one criterion was a perfect indicator of quality. A high percentage of germination was one of the better …