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Full-Text Articles in Life Sciences

Characterization Of Lactose Fatty Acid Esters For Their Microbial Growth Inhibitory Activity And Emulsification Properties, Seung-Min Lee May 2018

Characterization Of Lactose Fatty Acid Esters For Their Microbial Growth Inhibitory Activity And Emulsification Properties, Seung-Min Lee

All Graduate Theses and Dissertations

Sugar esters, substances made from bonding fatty acid tails to a sugar head, can play a number of key roles in food systems from antimicrobial agents to emulsifiers. These unique and very useful properties result from their water-loving and water-avoiding ends. Lactose, a sugar found in milk, based esters are important, as they are environmentally friendly and inexpensive, however, they are not very well understood. I created four different types of lactose esters: lactose monooctanoate (LMO), lactose monodecanoate (LMD), lactose monolaurate (LML) and lactose monomyristate (LMM), and then compared them to each other to see which would be the best ...


Investigation Of Sugar/Polyols As Weakly Interacting Cosolvents And Their Influence On Hardening Of High-Protein Nutrition Bars, Sami Kadhim Hassan May 2015

Investigation Of Sugar/Polyols As Weakly Interacting Cosolvents And Their Influence On Hardening Of High-Protein Nutrition Bars, Sami Kadhim Hassan

All Graduate Theses and Dissertations

High-protein nutrition (HPN) bars (≥ 30% protein) have limited shelf life and become excessively hard during storage. Various mechanisms have been proposed to explain the hardening. The objectives of this research were to investigate the chemistry of HPN bar hardening and propose solutions for slowing it and improving bar texture.

In phase 1, HPN bars were made containing 34% whey protein isolate (WPI) or milk protein concentrate (MPC) powder, along with either sorbitol syrup or glycerol, and vegetable shortening or cocoa butter. Substituting MPC for WPI made the bars brittle and crumbly. Using glycerol initially made bars softer but accelerated hardening ...


The Effects Of High Power Ultrasonic Energy On Milk Plasmin Activity, Cindu Annandarajah Jan 2015

The Effects Of High Power Ultrasonic Energy On Milk Plasmin Activity, Cindu Annandarajah

Graduate Theses and Dissertations

The shelf life of pasteurized milk is limited by heat stable proteases that undergo depolymerization, causing age gelation and bitterness. Proteolysis of milk during storage can be attributed to both native proteases and the proteases produced by bacteria. Plasmin is the major native protease in milk. Ultra High temperature (UHT) inactivates proteases and extends shelf life up to 9 months but the sensory properties are adversely affected. Ultrasound is one emerging technology that is being applied for food processing. Since power ultrasound operates by means of mechanicals vibrations, this non-thermal technology is being explored as an alternative to pasteurization, as ...


Sonic Boom Or Bust?: Application Of High-Power Ultrasound For Fluid Milk Processing, Lily Claire Benner Jan 2015

Sonic Boom Or Bust?: Application Of High-Power Ultrasound For Fluid Milk Processing, Lily Claire Benner

Graduate Theses and Dissertations

Ultrasonication has potential application in the dairy industry for extending milk shelf life by killing bacteria and spores that survive pasteurization. However, ultrasound treatment may result in off-aromas or undesirable milk quality consequences, which increase as treatment time and intensity increase. The primary objective of this research was to determine whether short treatments of acoustic energy, in conjunction with pasteurization, increase refrigerated shelf life while producing no adverse aroma effect. Shelf life was determined by performing total aerobic counts (TAC) on skim milk that had been inoculated with Paenibacillus amylolyticus, a spore-forming, thermotolerant and psychrophilic milk contamination bacterium. Pasteurized control ...


Absorption And Utilization Of Choline And Vitamin B12 In Lactating Dairy Cows Using Different Delivery Methods, Virginia Maria Artegoitia Etcheverry Dec 2014

Absorption And Utilization Of Choline And Vitamin B12 In Lactating Dairy Cows Using Different Delivery Methods, Virginia Maria Artegoitia Etcheverry

Doctoral Dissertations

Choline and vitamin B12 are essential nutrients for growth and performances of production animals. However, both nutrients are extensively degraded during digestion in the rumen. This thesis comprised three experiments. First, four cows equipped with a rumen cannula and catheters in the portal vein and a mesenteric artery received a post-ruminal bolus of: 1) cyanocobalamin (CN-CBL) alone (0.1 g) [gram], 2) CN-CBL (0.1 g) + casein (10 g) or 3) CN-CBL (0.1 g) + whey proteins (10 g). After the bolus, blood samples were taken until 24 h [hour] post-bolus. The intestinal absorption of CN-CBL was greater when the ...


Effects Of Lipid Oxidation Initiators And Antioxidants On The Total Antioxidant Capacity Of Milk And Oxidation Products During Storage, Angelica Maria Gutierrez Jan 2014

Effects Of Lipid Oxidation Initiators And Antioxidants On The Total Antioxidant Capacity Of Milk And Oxidation Products During Storage, Angelica Maria Gutierrez

Graduate Theses and Dissertations

Oxidized flavor is a major problem currently affecting the dairy industry. The objectives of this research were to determine the effects of light (2300 Lux) and/or cupric sulfate (0, 0.5, 1 mg/kg) as pro-oxidative factors in milk during an 11-day refrigerated storage period. The effects of added vitamin A (2113 IU/L) and vitamin E (100 mg/kg milk fat) as potential inhibitors of oxidation in the presence of light (2300 Lux) and light with cupric sulfate (0.05 mg/kg) during a 7-day refrigerated storage were also investigated. The presence of pro-oxidants significantly decreased the total ...


The Effect Of Individual Milk Proteins On Bioaccessibility Of Green Tea Flavan-3-Ols, Sydney Elizabeth Moser Jan 2013

The Effect Of Individual Milk Proteins On Bioaccessibility Of Green Tea Flavan-3-Ols, Sydney Elizabeth Moser

Open Access Theses

While information regarding the impact of flavan-3-ol-protein interactions on food quality attributes (flavor, texture, and physical stability) exists, insight into the potential consequence of these interactions on bioavailability of health-promoting flavan-3-ols remains unclear. The ability of nonspecific protein interactions in flavan-3-ol rich foods and beverages to alter digestive stability and/or digestive release (bioaccessibility) of flavan-3-ols has been previously proposed but unconfirmed. The primary objective of this study was to characterize effects of individual milk proteins and the milk matrix on in vitro bioaccessibility of green tea flavan-3-ols from model beverage systems. As a secondary objective, the impact of protein ...


Oxidative Stability Evaluation Of Milk From Cows Fed Dried Distillers Grains With Solubles, By Sensory And Chemical Analysis, Gerui Li Jan 2013

Oxidative Stability Evaluation Of Milk From Cows Fed Dried Distillers Grains With Solubles, By Sensory And Chemical Analysis, Gerui Li

Graduate Theses and Dissertations

The feeding of distillers dried grains with solubles (DDGS) to dairy cows has been loosely implicated in formation of oxidized off-flavors in milk. The purpose of this study was to examine the impact of feeding DDGS to dairy cows on the oxidative quality of milk by sensory and chemical analysis. Twenty-four cows were divided into two groups, fed a total mixed ration, with three incorporation levels of DDGS (0% (control), 10%, 25%) in a two-group three-period crossover design. Each group received each of the diets, such that each cow served as her own control. Milk was collected on days 14 ...


Effects Of Thermosonication On Proteases And Characteristics Of Milk And Cream, Sakthi Vijayakumar Jan 2012

Effects Of Thermosonication On Proteases And Characteristics Of Milk And Cream, Sakthi Vijayakumar

Graduate Theses and Dissertations

Shelf-life of pasteurized milk is limited by heat-stable proteases, which cause gelation and bitterness. Ultra-high temperature processing inactivates proteases, but detrimentally affects milk quality. An adjunct to pasteurization is sought to extend milk shelf-life, while maintaining sensory properties. In this study, we evaluated the effects of combined heat and ultrasound on the activity of Staphylococcus aureus protease and total plasmin, as well as the impact on sensory properties of milk and cream. Sonication at 133 µm (p.p) for 2.5 min decreased the enzyme activity by approximately 72% in pasteurized skim and whole milk and by 92% in commercial ...


Nano-Dispersing Lipophilic Antimicrobials For Improved Food Safety, Bhavini Dipak Shah Dec 2011

Nano-Dispersing Lipophilic Antimicrobials For Improved Food Safety, Bhavini Dipak Shah

Doctoral Dissertations

Naturally occurring food antimicrobials such as plant essential oils are receiving tremendous interest as intervention systems to enhance microbiological safety and quality. Poor water solubility of essential oils makes it difficult to incorporate them in foods, impacting visual appearance, antimicrobial effectiveness, and possibly organoleptic properties. Engineered nanoscale delivery systems can principally solve these challenges, but those based on low-cost food ingredients and inexpensive and scalable processes are currently scarce. This dissertation presents a simple and scalable two-step technology to prepare nano-delivery systems. The first encapsulation step, based on emulsion-evaporation, involves preparing emulsions composed of an oil phase with thymol or ...


Assessment Of Calcium, Milk, And Non-Milk Beverage Intake Of Multiethnic Youth Aged 10 To 18 Years, J. Keith Jensen May 2004

Assessment Of Calcium, Milk, And Non-Milk Beverage Intake Of Multiethnic Youth Aged 10 To 18 Years, J. Keith Jensen

All Graduate Theses and Dissertations

Achieving and maintaining maximal peak bone mass is critical to the prevention of osteoporosis. Adequate calcium intake during youth is a major aspect of proper bone mass development. Because of the importance of calcium, a food frequency questionnaire (FFQ) that estimates calcium intake of 10- to 18-year-old Asian, Hispanic, and white youth living in the western United States was developed. This new FFQ was shown to accurately and reliably estimate calcium intake of these youth. Accuracy among Hispanics, however, was low and requires further evaluation. A second study examined intake of calcium, milk, and non-milk beverages of Hispanic and non-Hispanic ...


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 May 1996

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

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 ...


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

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 ...


Manufacture Of A Dairy Dessert From Ultra-High Temperature Milk Concentrate, Mark H. Smith May 1994

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

All Graduate Theses and Dissertations

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 ...


Properties Of Low-Fat Yogurt Made From Ultrafiltered And Ultra-High Temperature Treated Milk, Richard Alan Dargan May 1992

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

All Graduate Theses and Dissertations

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 (NOM). 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 ...


Effects Of Heat Treatment Of Ultrafiltered Milk On Its Rennet Coagulation Time And On Whey Protein Denaturation, Bashir H. Yousif May 1991

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

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 ...


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 May 1989

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

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 ...


Plasmin In Milk: Activity Measurement, Effect Of Environmental Factors, And Correlation With Milk Coagulation, Eric D. Bastian May 1989

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

All Graduate Theses and Dissertations

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 Vmax, Km, KI, and KI' were estimated. Bovine plasmin is competitively inhibited by casein and has a Kcat of .0158 ΔA405/min/nM, Km of .107 mM substrate, and KI 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 from each ...


Measurement Of Proteins In Milk And Dairy Products, Marie K. Walsh May 1988

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

All Graduate Theses and Dissertations

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 ...


Enzymic Milk Coagulation: Casein Micelle Aggregation And Curd Formation, Donald J. Mcmahon May 1983

Enzymic Milk Coagulation: Casein Micelle Aggregation And Curd Formation, Donald J. Mcmahon

All Graduate Theses and Dissertations

Enzymic milk coagulation was monitored by measuring changes in curd firmness and apparent absorbance of undiluted milk. Detection of coagulation, visually or rheologically, occurred after the milk changes from a system of aggregating particles to an extended space network. This change was observed as a shoulder in apparent absorbance plots and coagulation time was defined as the critical point in the aggregation process analogously to non-linear condensation polymerization reactions. It corresponds to the inflexion point during the period when apparent absorbance was rapidly increasing and can be calculated by fitting curd firmness data to an exponential equation.

Addition of calcium ...


Effects Of Heat Treatment And Post-Treatment Holding Time On Rennet-Clotting Properties Of Milk, Zeynep Ustunol May 1983

Effects Of Heat Treatment And Post-Treatment Holding Time On Rennet-Clotting Properties Of Milk, Zeynep Ustunol

All Graduate Theses and Dissertations

Samples of raw whole milk were heated at L5, 50 and 75 C for 0, 30, 60, llU and 240 min. After heat treatment each sample was subdivided and portions held at O C for 0, 30, 60 and 120 min. In a second experiment samples of milk were heated at 25 and 50 C for the same lengths of time as before but this time at 75 C for only 5, 10, 15 and 20 min. A constant holding time of 30 min was used after the heat treatments. Following the various heat treatments pH of each sample was ...


A Method For Separating Casein Micelles From Whey Proteins For Determining Casein In Milk, Robert N. Carpenter May 1983

A Method For Separating Casein Micelles From Whey Proteins For Determining Casein In Milk, Robert N. Carpenter

All Graduate Theses and Dissertations

The purpose of this study was to determine if size exclusion chromatography could be used to separate casein micelles from whey proteins for a rapid, direct test to measure percent casein in milk. A size exclusion chromatography column was developed for the separation having dimensions 100 by .4 cm. Packing material selected was glycophase coated porous glass supports. A Beckman DU-8B spectrophotometer monitored the casein and whey protein peaks as they eluted and a Tektronix 4052 computer accepted data points every 4 sec, storing these on tape. Absorbances and areas of each peak were used in the evaluation of samples ...


Seasonal Variation In The Ability Of Milk And Whey To Support Lactic Culture Growth, Rick Cameron Norton May 1982

Seasonal Variation In The Ability Of Milk And Whey To Support Lactic Culture Growth, Rick Cameron Norton

All Graduate Theses and Dissertations

Milk samples from two cheese plants with overlapping milk supplies were collected monthly for one year in an attempt to measure seasonal variation in the ability of milk and whey to support lactic culture growth . Treatments to control and minimize variability of milk or whey were evaluated to optimize stability in starter culture performance.

Raw milk samples were tested for somatic cell counts, activity tests (modified Horrall- Elliker), acid degree values, and total plate counts. Activity (modified Horraii-EIIiker) and inhibitory tests were also performed on pasteurized, pasteurized-vacuumized and high heat milk treatments.

Rennet whey (heated and unheated) was collected from ...


Milk Protein Analysis By Automated Ultraviolet Spectroscopy, R. Ford Wilkinson May 1975

Milk Protein Analysis By Automated Ultraviolet Spectroscopy, R. Ford Wilkinson

All Graduate Theses and Dissertations

An automated continuous flow analysis for milk protein utilizing ultraviolet spectroscopy resulted in a correlation coefficient of 0.972 and a standard estimate of error of 0.082 percent protein when 30 samples were compared with the acid orange 12 dye binding method. Milk was solubilized in 95-105 volumes of acetic acid using the Technicon Auto Analyzer II and measured for absorbance at 274 nanometers. No deviation from the standard method due to mastitis and varying milk fat concentration was observed. A theoretical model indicated a possible standard estimate of error 0.059 percent protein due to inter- and intra-breed ...


Manufacture Of Monterey Cheese From Preacidified Milk, Faisal O. Mohamed May 1974

Manufacture Of Monterey Cheese From Preacidified Milk, Faisal O. Mohamed

All Graduate Theses and Dissertations

Whole milk acidified to pH 5.3 with hydrochloric acid was used for the manufacture of Monterey cheese. The milk was inoculated with one and one-half percent lactic starter and set with 12.5 ml rennet per 1000 pounds of milk. Normal washing treatments resulted in cheese with moisture in excess of 44 percent. Moisture content was brought below 44 percent by using wash water at a temperature such that the water-curd whey mixture was 35 C. The pH of cheese made by preacidification was all between 5.21 and 5.09. No acid defects were encountered. Preacidification eliminated chance ...


Pasteurized Versus Raw Milk In Brick Cheese-Making, Z. Doyle Roundy May 1933

Pasteurized Versus Raw Milk In Brick Cheese-Making, Z. Doyle Roundy

All Graduate Theses and Dissertations

The prime object of the work undertaken in the present study has been done with the view of determining whether or not the quality and yield of brick cheese may be improved by pasteurizing the milk from which the cheese is made. An effort should be made to put brick cheese-making on a more scientific basis and at the same time produce cheese of better and more uniform quality. Since milk, containing large numbers of undesirable microorganisms thus causing objectionable flavors and odors in dairy products, is frequently delivered to cheese factories to be processed, pasteurization seems to be one ...