Life Sciences Commons^™

Influence Of External Ph And Organic Acids On Internal Ph And Acid Anion Accumulation In Listeria Monocytogenes And Escherichia Coli, Savannah R. Branson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Listeria monocytogenes and Escherichia coli are both among the most common microbial pathogens that cause foodborne illnesses and death. They both are capable of growing over a wide range of conditions. Organic acids are widely employed in the food industry to control growth of these pathogens to help prevent foodborne illnesses. There is substantial evidence that intracellular accumulation of organic acid anions is a major inhibitor to cell growth, and that many bacteria may combat anion accumulation by lowering their intracellular pH (pH_i). In this study, we followed the accumulation of acid anion into the cell pellet and …

Injection Of Iodoacetic Acid Into Pre-Rigor Bovine Muscle Simulates Dark Cutting Conditions, Jared Forrest Buhler

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Following the harvest of an animal, muscle will continue to produce energy in an attempt to stay alive, primarily through the pathway of glycolysis. This occurs in the form of anaerobic (oxygen-free) metabolism of glucose and glycogen, which causes the meat to acidify. This acidification process is important for proper meat quality development and when insufficient glycolysis occurs it can cause a meat defect known as dark cutting. This defect causes the color of the muscle to become very dark, increases the water-holding capacity of the meat, and causes it to feel firm and dry on the surface because the …

Influence Of Sodium Chloride, Calcium, Moisture, And Ph On The Structure And Functionality Of Nonfat Directly Acidified Mozzarella Cheese, Brian M. Paulson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Experiment A explored the influence of sodium on direct acid, nonfat Mozzarella cheese. Cheeses with differing salt levels were obtained by varying dry salt applications (none, 0.5%, and 1.0% NaCl w/w) and hot brine stretching (0%, 5%, and 10% NaCl wt/v). Salt application and salt content influenced cheese moisture, meltability, expressible serum, micro- and ultra-structure, and color. Moisture was highest when cheese was salted before stretching (P = 0.03). Melt was lowest in cheeses that were unsalted (P = 0.05). Cheeses stretched in salt brine had < 1% of the amount of expressible serum found in unsalted cheese (P < 0.0001). Unsalted cheeses had a more open structure with pockets of serum distributed throughout the protein matrix giving it an opaque, white appearance. Salted cheeses had a more homogeneous protein matrix lacking light scattering surfaces, resulting in a translucent cheese. Neither salt concentration nor method of salting affected the calcium content of the cheeses (P > 0.05).

Experiment B explored the influence of calcium, moisture, and …

Effects Of Ph And Calcium Level On Extrusion-Textured Whey Protein Products, Andrea B. Hale

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effects of altering pH and calcium level during whey protein extrusion were assessed by measuring the protein solubility and WHC of the textured whey protein (TWP). TWP samples were produced by extruding dry mixtures of 2/3 WPC 80 (80% protein) and 1/3 cornstarch using screw speed of 200 rpms, feed rate of 23 g/min, water flow rate of 11 g/min, and product temperature of 150°C. The levels of acid and base were adjusted by adding concentrated HCl or NaOH, respectively, to the water source. Calcium was added to the raw mix in the form of calcium chloride dihydrate before …

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 …

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 …

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 …

The Effect Of Various Levels Of Bicarbonate, Phosphorus, And Ph On The Translocation Of Iron In Plants, Ronald Conrad Doney

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Line-induced chlorosis is a nutritional disease affecting many fruit trees, berries, ornamental shrubs, and flowers in Utah and the western United States. In fact, this disease is of wide distribution on calcareous soils throughout the world. Lime-induced chlorosis has contributed to untold economic loss and has challenged the technical ingenuity of plant and soil scientists throughout the world. As yet the exact cause of chlorosis has not been determined; consequently, no permanent cures have been found.

The first symptoms of this disease are characterized by an interveinal yellowing of younger leaves, with the veins remaining green. In more severe cases …