Food Science Commons^™

Formation Of Polycyclic Aromatic Hydrocarbons On The Surfaces Of Ultra-High Temperature Treated Meat, Michelle T. Foote

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effect of ultra-high temperature (UHT) on production of polycyclic aromatic hydrocarbons (PAHs) on the surface of beef steaks was determined. Beef steaks were treated with five treatments, raw, UHT, UHT/grill marks, UHT/grill marks/microwave, and charcoal grilled. Four PAHs, benzo[a]pyrene, benz[a]anthracene, benzo[b]fluoranthene, and benzo[k]fluoranthene, were quantified. High performance liquid chromatography (HPLC) and gas chromatography (GC) were used to purify and analyze the PAH extracts, respectively. Levels of PAH found on charcoal-grilled steaks were higher than those observed in the literature. A balanced incomplete block design was used to analyze the data. There were no significant differences among the treatments in …

A Study Of Factors Controlling Physical Properties Of Mozzarella Cheese And The Manufacture Of A Reduced Fat Mozzarella Cheese, Richard Kevin Merrill

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Variables affecting the physical properties of Mozzarella cheese were investigated. The effects of various milk-clotting enzymes were examined. The type of milk coagulating enzyme used played a significant role in determining physical properties of direct acid Mozzarella cheese. Cook color was not affected by enzyme type, but melt and stretch were significantly affected.

Proteolytic nature of starter cultures was reviewed and recommendation s were give n. Cheese made with proteinase-deficient strains had more stretch after holding for 14 and 28 d than cheese made with non-deficient strains. Cheese made with pairs or single strains of L. helveticus had the same …

Changes Over Time In Sensory Thresholds Of Individuals With Diabetes Mellitus And The Relationship To Food Preference, Marnie Ricks Spencer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effect of time on taste threshold was examined in 30 diabetics and 30 control subjects (ages 22-30) who had participated in a sensory study 14 years previously. Detection and recognition taste thresholds for sweet (sucrose), salty (sodium chloride), sour (citric acid), and bitter (quinine sulfate) were assessed using triangle testing. Food preferences related to concentration of the stimuli in model food systems were tested using a nine-point hedonic scale. Mashed potatoes were used as the carrier for different levels of salt. A beverage composed of water, sucrose, and citric acid was varied to measure preferences for sweet and sour …

The Role Of Lactose In The Age Gelation Of Ultra-High-Temperature Processed Concentrated Skim Milk, Venkatachalam Narayanaswamy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this research was to relate lactose reactivity and age gelation of UHT processed concentrated milk. Skim milk was pasteurized, diafiltered batchwise to reduce lactose concentration to less than 0.05%, and UF concentrated to 3X (one-third volume reduction). Lactose and sucrose were then each added at 3% or 6% w/v to part of the concentrate. The five samples, control (

All samples stored at 4°C and 20°C gelled after 21 weeks of storage. The viscosity changed slightly during the first 19 weeks of storage but increased suddenly (> 100 cPs) just before gelation. Samples stored at 35°C did …

Effects Of Stabilizers And Ph Adjustments On Milk Proteins In Uht-Treated Citrus Juice/Skim Milk Blend Drink, Sandra M. Newman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A UHT-processed skim milk (85%)/orange juice (15%) drink was developed. Product integrity and stability were maintained by two methods. Proper homogenization of the blend before UHT processing stabilized a drink formulation containing .25% carboxymethyl cellulose and .025% carrageenan. Adjusting the pH of the blend (pH 6.3 and 6.5) resulted in a different stabilization. After 28 days at room temperature, settling of milk solids was 5.2% of volume height in the prehomogenized sample and 86.9% of volume height in the same blend that had not been homogenized prior to UHT processing. After storage, the two treatments were analyzed to verify that …

A New Method For Measuring Macroparticulate Systems Applied To Measuring Syneresis Of Renneted Milk Gels, Jonathan R. Maynes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Syneresis is an integral part of cheese manufacture. The rate and extent of syneresis affect the properties of cheese. There are many factors that affect syneresis, but measured results vary because of inaccuracies in measuring techniques. To better control syneresis, an accurate mathematical description must be developed. Current mathematical models describing syneresis are limited because of inherent error in measuring techniques used to develop them. Developing an accurate model requires an accurate way to measure syneresis.

The curd becomes a particle in a whey suspension when the coagulum is cut. The most effective technique to measure particle size, without interference, …

Effects Of Potassium Lactate, Encapsulated Citric Acid And Storage Temperature On Microbial Growth And Shelf Life Of Pork Sticks, Yen-Kan Su

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A new product, pork sticks, was developed. Optimum shelf life and safety were major concerns associated with this product. Potassium lactate (3%) or citric acid (0.5%, 0.56%, 0.60% or 0.66%) was added to pork sticks to determine their effects on microbial growth, sensory evaluation, and shelf life when stored frozen (-20°C), refrigerated (2°C), or at room temperature (22°C). Two raw materials, pork blade meat (shoulder meat; 91% lean, 9% fat) and regular 80:20 pork trim (80% lean, 20% fat) were used. The consumer panel preferred lean pork sticks made from blade meat over high-fat pork sticks made from regular 80:20 …

Properties Of Low-Fat Yogurt Made From Ultrafiltered And Ultra-High Temperature Treated Milk, Richard Alan Dargan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Yogurts were made from intermediate-high temperature (100, 110, 120, and 130°C for 4 or 16 s), ultra-high temperature (140°C for 4 or 16 s), and vat heat (82°C for 20 min) treatments of skim milk fortified to 5% protein by either ultrafiltration or the addition of nonfat dry milk (NDM). Whey protein denaturation in heated milks increased with temperature and holding time from indirect plate heating and was highest in vat-heated milks. Whey protein denaturation and yogurt water-holding capacity increased with protein levels in the fortified milks compared to skim milk. Penetrometer gel strength and stirred viscosity in 21 day-old …

Zeta-Potential Of Casein Micelles As A Factor In Age Gelation Of Ultra-High Temperature Processed Concentrated Skim Milk, Douglas W. Olson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effect of ultra-high temperature processing by direct steam injection and room temperature storage of pH-adjusted and unadjusted 3X (volume reduction) skim milk retentate and the effect of storage at various temperatures of 3X skim milk retentate without pH adjustment on their ζ-potential, viscosity, and pH were determined. Pasteurized skim milk was concentrated to 3X by ultrafiltration. In the pH study portions of skim milk retentate were adjusted to pH 6.38 ± .02 with HCl and 6.85 ± .01 and 7.32 ± .02 with NaOH between ultrafiltration and ultra-high temperature processing. In the storage temperature study, storage temperatures used for …

Characterization Of Pigments Responsible For Red Or Pink Discoloration In Cooked Pork, Viswasrao M. Ghorpade

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The pigments responsible for pink or red discoloration in cooked vacuum-packaged meat products {bratwurst (pork and beef), ground pork, and pork roasts} were investigated. In bratwurst, this study attempted to characterize the red pigment that appears upon refrigerated storage, and to determine the effect of pH, cooking and storage temperature, and sodium lactate on incidence of red discoloration. Myoglobin was identified in the exudate of samples with red discoloration. Myoglobin levels of cooked products were significantly lower in samples of low initial pH (5.5) or cooked to higher than normal internal temperature (74°C). Red discoloration was associated with microbial growth. …

Influence Of Process Parameters In The Manufacture Of Cottage Cheese Curd From Ultrafiltered Skim Milk, Ronald Michael Raynes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A processing procedure for the manufacture of directly acidified cottage cheese curd from 16% total solids ultrafiltered retentate was developed. The effects of preacidification of skim milk before ultrafiltration and heat treatment of retentate were investigated to improve the functional and sensory qualities of retentate curd.

Retentate directly acidified with phosphoric acid and glucono-delta-lactone to pH 4.7 formed a dense, rubbery curd that could not be handled well in a vat. A heat treatment of 71.1°C for 30 min applied to the retentate resulted in a curd with acceptable handling properties. However, this heat treatment caused the curd to shift …

Estimation Of Selected Milk Protein Genetic Variants By Multi-Component Analysis Of Amino Acid Profiles, Carol M. Hollar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Cation-exchange fast protein liquid chromatography separated whole casein into β-casein A², A¹, and B, K-casein, α_s1-casein, and α_s2-casein fractions as well as γ-caseins and several unidentified peaks using a urea-acetate buffer at pH 5 and a NaCl gradient. The whole casein fractions eluted in the following order: breakdown products of β-casein and unidentified peaks; β-casein A², A^l, and B; additional breakdown products of β-casein and unidentified peaks; K-casein; α_s1-casein; and α_s2-casein. The calculated composition of the four major caseins correlated well with values obtained …

Meat Effects On Nonheme Iron Absorption, Yunji Kim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Studies were undertaken to investigate if gastric acidity and iron chelation to a meat component enhance nonheme iron absorption. Cereal meals, with and without added proteins, were gavaged into iron-deficient rats. The role of iron chelation was investigated by adding sodium phytate, an iron chelator implicated with decreased iron absorption, to the meals. The role of gastric acidity was investigated by treating the rats with cimetidine, which inhibits gastric acid production. In rats with normal acid production, beef, pork and chicken enhanced iron absorption when phytate had been added to the meals, suggesting a role for chelation in meat enhancement …

Rapid Determination Of Milk Components And Detection Of Adulteration Using Fourier Transform Infrared Technology, Ivan Von Mendenhall

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Absorption bands responding to changes in fat, protein, and lactose concentrations in milk were determined. The effects of milk fat variation and lipolysis on the infrared spectrum were studied.

Absorbances from 1283 to 1100 cm^-1 correlated with fat, protein, and lactose concentration and showed a low response to milk fat variation and lipolysis. A Fourier transform infrared spectrometer equipped with an attenuated total internal reflectance cell was calibrated using these absorption band s, partial least squares statistics, and milk samples from herds in Minnesota. When the fat, protein, and lactose concentrations in these samples were predicted, the standard deviations …

An Automated Reflectance Color Meter Instrument For Microbiological And Enzymic Assays, Tsz-Ching Yuan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The development of an automated instrument employing reflectance colorimetry was described. Several models were designed, assembled, and programmed to perform microbial and enzymic tests automatically. Samples were prepared manually or automatically by a Zymate™ II robot. These samples were incubated during the tests to maintain an optimum temperature for reactions and microbial growth. During incubation, color changes of appropriate indicator dyes in the sample/reagent mixtures were measured intermittently, recorded, and compared to previously defined end points. The computer-controlled instrument received data that related time of color changes with the initial numbers of microorganisms or the enzyme activity of the samples. …

Factors Affecting Moisture Distribution In 290-Kilogram Stirred-Curd Cheddar Cheese Blocks, Robert S. Reinbold

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this dissertation was to study factors affecting moisture distribution in 290-kilogram stirred-curd Cheddar cheese blocks cooled in stainless steel hoops. Uneven moisture distribution within blocks may create cheese with variable texture and flavor, which can be extremely costly to the producer. The effects of temperature, pH, and vacuum treatment on moisture distribution were investigated. Temperature, pH, moisture, and pressure profiles were presented. Also, comparisons were made between temperature profiles of 290- kilogram stirred-curd Cheddar cheese blocks cooled in stainless steel and in plywood hoops, as well as between temperature profiles of 66-kilogram Swiss cheese blocks cooled in …

Determining The Validity Of Methods Used In Meat Iron Analysis, Padmashri Ummadi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The validity of the Homsey method for heme iron, modified Schricker and sodium pyrophosphate extraction methods for nonheme iron and atomic absorption spectrophotometry (AAS) and ferrozine methods for total iron were determined using spikes of hemoglobin, ground beef baked to different degrees of doneness, proportional beef liver:catfish mixtures and National Institute of Science and Technology reference materials.

The mean spike recoveries of 0.01g and 0.02g Hb in raw beef and raw chicken samples were 96.7% of the heme iron for the Homsey method, 97.9% of the total iron for the ferrozine method, and 85.7% of the total iron for the …

Survival Of Lactobacillus Acidophilus And Bifidobacteria Bifidum In Ice Cream For Use As A Probiotic Food, Sharareh Hekmat

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ice cream mix (12% fat, 11% milk solids nonfat, 12.5% sugar, and 4.5% corn syrup solids) was fermented with Lactobacillus acidophilus and Bifidobacterium bifidum. Half of the mix was heat treated at 82°C for 30 minutes and cooled to 40-41°C. The other half was warmed to 40-41°C and inoculated with the starter cultures. Both were made into ice cream and stored at -29°C. Survival of L. acidophilus and B. bifidum and of ẞ-galactosidase activity were monitored during 17 weeks of frozen storage. Reinforced clostridial medium was used to enumerate culture bacteria. Colony counts, after fermentation, for both L. acidophilus …

Effects Of Heat Treatment Of Ultrafiltered Milk On Its Rennet Coagulation Time And On Whey Protein Denaturation, Bashir H. Yousif

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this research was to determine the effects of heating (including heating to ultra-high temperatures) homogenized ultrafiltered whole and skim milks on whey protein denaturation and milk's subsequent rennet coagulation properties: coagulation time, curd firmness, and microstructure.

Whole and skim milk samples were ultrafiltered using a spiral wound ultrafiltration membrane system. Samples were preheated to 72°C for 58 s, held for 8 s then heated to 72, 89, 106, 123, or 140°C for more than 97 sand held for 4 s. The milk was then cooled to 60°C and homogenized, further cooled to 30°C, packaged into 120 ml …

Purification And Immunological Reactivity Of Commercial Microbial Milk Clotting Enzyme Preparations, Chima I. Osuala

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Commercial microbial milk clotting enzyme preparations were purified by immunoaffinity chromatography using purified antibody covalently coupled to porous glass beads as the column matrix. Commercial enzyme preparation diluted in 1 mM sodium acetate buffer at pH 5.0 was then biospecifically adsorbed to the column matrix by end-over-end mixing of the glass-antibody complex in the enzyme solution for 12 h at 5°C. The antibody bound enzyme adsorbed glass beads were soaked in .2 M glycine or ethanolarnine at pH 7.0 to block uncoupled reactive sites on the matrix. Following this, the column was washed with 1 mM sodium acetate …

Chemical Evaluation And Biological Vitamin A Activity Of The Major Carotenoids In The Hybrid Carrot Beta Iii, Cynthia M. Schweitzer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Genetically enhanced high-carotene Beta III hybrid carrot was compared to a commercial carrot cultivar, Nantes Coreless, for carotene content and macronutrient composition. Beta III contained more than twice the total carotene content of Nantes Coreless, with α-carotene/β-carotene ratios higher in Beta III. Total solids from protein, lipids, and carbohydrate were greater in Beta III than in Nantes Coreless. Beta III contained about five times the amount of sucrose and one-fifth the amount of glucose and fructose than Nantes Coreless or reported literature values.

Comparison of the bioavailability of carotenes in Beta III and Nantes Coreless to purified β-carotene and retinyl …

Effect Of Proteolytic Activity Of The Lactic Cultures On Mozzarella Cheese Quality, Wen-Hsu Amos Wang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Mozzarella cheese market is growing rapidly. Major concerns with cheese meltability and color have arisen in the fast food industry. Pre starter culture was used in this study to improve the physical properties of Mozzarella cheese. Three tests (stretch test, melt test, and browning test) were modified to evaluate the quality of cheese.

A stretch test using the Brookfield helipath viscometer to stretch the cheese sample at 60°C was successful in distinguishing cheeses from different make procedures and from different proteolytic strains. A melt test using a glass tube to hold the cheese flow at 110°C for 60 min …

Plasmin In Milk: Activity Measurement, Effect Of Environmental Factors, And Correlation With Milk Coagulation, Eric D. Bastian

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Bovine plasmin activity was measured on H-D-valyl-L-leucyl-L-lysyl-4-nitroanilide by following absorbance changes at 405 nm. Steady-state kinetic parameters V_max, K_m, K_I, and K_I' were estimated. Bovine plasmin is competitively inhibited by casein and has a K_cat of .0158 ΔA₄₀₅/min/nM, K_m of .107 mM substrate, and K_I of .86 mg/ml casein. Bovine plasmin can be measured directly in bovine milk without interference from casein.

A total of 380 milk samples from nineteen Holstein (one herd) and nineteen Jersey (one herd) cows was collected monthly during one lactation period. Samples …

Influence Of Processing Parameters On Nutrient Recovery During Ultrafiltration Of Milk And Meltability Of Pasteurized Process Cheese Food Made From The Retentate, Susan Kay Fortier Collinge

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Three batches of milk were ultrafiltered to 60, 65, or 70% volume reduction before diafiltration. Starting diafiltration at 70% volume reduction took less time and water without affecting nutrient recovery.

Whole milk was heated to 60, 72, and 82°C for 16 s. Milk representing each heat treatment was divided into three batches, one unacidified (pH 6.6), the others acidified to pH 6.2 and 5.8. The milk was ultrafiltered, diafiltered, and concentrated to 5x (80% volume reduction). Retentate was inoculated with .5% lactic culture and incubated at 28°C to pH 5.1. Each lot of fermented retentate was evaporated under 76 kPa …

A Quantitative Assessment Of Minerals Of Toxicological Importance In Utah Fast Foods, Lisa R. Williams

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

X-ray flourescence (XRF) and atomic absorption spectrophotometry (AAS) measurements for manganese, iron, copper, and zinc were compared for 96 samples of 21 foods from different sources. Correlation coefficients were 0.94 for manganese, 0.99 for iron, 0.93 for copper, and 0.91 for zinc for XRF vs. AAS determinations.

Similiar comparisons were performed on 228 samples of fast foods purchased in Utah retail outlets. Correlation coefficients ranged from 0.91 for copper to 0.97 for iron and zinc. Comparisons of values generated by XRF for manganese, iron, copper, zinc, selenium, arsenic, and aluminum to values certified by the National Bureau of Standards indicated …

Proteolytic Activity Of Some Milk-Clotting Enzymes On K-Casein And K-Casein Macropeptide, Khalid M. Shammet

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This work reviews studies of bovine K-casein and specifically K-casein macropeptide. Properties of K-casein, its structure and heterogeneity, proteolytic activity of some milk clotting enzymes on K-casein, and K-casein sensitive bonds are discussed. Macropeptides of other species are also presented. The carbohydrate moieties of bovine macropeptide together with their biological and physiological functions are reviewed.

Macropeptides were produced by enzymic hydrolysis from whole casein solution using crystalline chymosin (EC 3.4.23.4). Trichloroacetic acid (final concentrations 2, 8 and 12%) was added after 5, 30 and 60 min of incubation to precipitate protein and inactivate the enzyme. The filtrate was then exhaustively …

Evaluation Of Frogurt: A New Product Prepared By Fermentation Of Ice Cream Mix, Morteza Mashayekh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ice cream mix was fermented with yogurt cultures of Streptococcus thermophilus and Lactobacillus bulgaricus to four different pH's then frozen in a batch ice cream freezer. A consumer panel of 120 people tasted samples of strawberry flavored product with pH's of 4.4, 4.7, 5.1, and 5.4 and commercial frozen yogurt as a standard. Results from the panel were used to predict a preferred pH of 4.9. Another panel of 181 people compared product at pH 4.9 with 10, 15 and 20% strawberry flavoring. There was not a statistically significant difference among levels of flavoring.

Starter culture populations and lactase activity …

Measurement Of Proteins In Milk And Dairy Products, Marie K. Walsh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to develop a short, easy procedure to measure five major proteins in milk and to detect concentrations of added protein to dairy products. Combinations of casein or whey protein with nonfat-dry milk were made with concentration ratios from 0:10 to 10:0. Similar mixtures of defatted goat milk with defatted cow milk were prepared. Samples were hydrolyzed in 6 N HCl at 145°C for 4 h and analyzed for amino acid composition. Multiple regression equations were derived to estimate the relative content of whey protein or casein added to nonfat-dry milk and goat milk added …

The Bioavailability Of Iron From Meat, Spinach, Soy Protein Isolate, Meat:Spinach And Meat:Spi Mixtures Fed To Anemic And Healthy Rats, Dejia Zhang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two Experiments were conducted to investigate the effect of iron status and iron source on iron bioavailability using the rat model. Beef was proportionally mixed with spinach (Experiment I) or soy protein isolate (Experiment II) to test if meat enhances the absorption of iron from spinach or SPI. Five diets with the iron from meat:spinach (or SPI) ratios of 100:0, 75:25, 50:50, 25:75 and 0:100 were prepared and fed to rats. FeS04 was used as a reference. Two trials of rats were used in Experiment I. In trial I, half of the rats were made severely iron deficient (Hb 6.3 …

Plasmid-Linked Maltose Utilization In Lactobacillus Spp. Isolated From Meat, Mei-Ling Liu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Five strains of Lactobacillus plantarum and four strains of Lactobacillus species isolated from fresh meat were examined for the presence of plasmid DNA. All strains examined contained between one and five plasmids ranging in molecular mass from 1.3 to 51.6 (Mdal). Plasmid-curing experiments suggest that maltose utilization is associated with a 51 Mdal plasmid in Lactobacillus sp. DB29 and 42 Mdal plasmids in Lactobacillus spp. DB27, DB28, DB31. Southern blot DNA-DNA hybridization showed homology between the maltose plasmid from Lactobacillus sp. DB29 and several plasmids from the other Lactobacillus spp.