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In Vitro Growth Of Muscle Satellite Cells Isolated From Normal And Callipyge Lambs, Beatriz T. Rodriguez

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The muscle hypertrophy of lambs expressing the Callipyge phenotype is possibly linked to characteristics of their muscle satellite cells. Therefore, characteristics (proliferation, fusion %, and protein accretion) of cultured satellite cells isolated from the longissimus muscle of Callipyge (n = 3) and normal (n = 3) lambs were compared in this study. In the first experiment, we tested whether or not the lll proliferation rates differ for satellite cells isolated from Callipyge or normal sheep when cultured in the presence of different serum types (horse, normal lamb, or Callipyge lamb). The average population doubling time (PDT, h) during log phase …

Influence Of Carbohydrate Starvation On The Culturability And Amino Acid Utilization Of Lactococcus Lactis, Mark R. Stuart

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Lactococci are widely used in the cheese industry as a starter culture. Starter cultures face carbohydrate starvation due to the absence of a fermentable carbohydrate in the cheese curd after pressing. Starvation leads to a decreased ability to synthesize ATP, generate a proton motive force, and accumulate nutrients necessary to maintain viability. The aim of this work was to investigate the culturability of lactococci grown with and without lactose in a chemically defined medium, and to define the metabolic changes that occur during carbohydrate starvation.

Lactose metabolism provided energy for logarithmic phase growth and greater cell density in L. lactis …

Studies On The Utilization Of Deboned Trout (Oncorhynchus Mykiss) Frames In Fish Snack, S. Muralidharan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Snack food development studies were conducted to iii utilize trout (Oncorhynchus mykiss) frames, a by-product of the filleting operation, using extrusion and conventional technology. Twin screw extrusion studies were conducted to study the effect of fish mince, non-fat dry milk, process temperature, and moisture content on the physicochemical properties of the extruded snack food. Response surfaces were plotted to understand the effects of the independent variables on dependent variables such as bulk density, expansion ratio, shear strength, and water absorption index. Quadratic models expressed the relationship between the dependent and independent variables.

Based on the extrusion studies, conditions …

Methanethiol And Cheddar Cheese Flavor, Benjamin Dias

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The use of slower acid-producing starter bacteria for the production of lower fat Cheddar cheese has lead to milder flavor Cheddar cheeses that lack intense Cheddar notes. The metabolism of methionine leads to the production of methanethiol, which is one of the desirable Cheddar cheese flavor compounds. The influence of NaCl and reduced pH was determined for aminopeptidase, lipase/esterase, and methanethiol-producing capability in selected lactic acid bacteria and brevibacteria in simulated cheese-like conditions. The activity of each enzyme decreased with NaCl addition and pH reduction to approximate a Cheddar cheese environment (5% NaCl and pH 5.2).

The mechanism for methanethiol …

A Study Of The Effects Of Proteolytic Adjunct Culture On The Physical And Functional Properties Of Low-Fat Mozzarella Cheese, Roxanne Stone

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As fat is removed from Mozzarella cheese, the resulting increase in protein content causes the cheese to become tough, thus decreasing the desired physical characteristics of meltability and stretch. Low-fat (6% fat) Mozzarella cheese was manufactured with the addition of several levels of a Lactococcus lactis adjunct culture that was proteinase positive and lactose deficient in an attempt to improve these physical properties. During cheese manufacture, milk was acidified to pH 6.0, then inoculated with Lactobacillus helveticus and Streptococcus thermophilus. Experimental vats were also inoculated with either 0.25, 0.50, or 1.0% of the adjunct culture. Cheeses made with the …

A Product Development Study: Rainbow Trout Bologna, Marshall Dean Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Mechanically deboned rainbow trout (Oncorhynchus mykiss) was analyzed and then used in texture studies. The meat contained a moderately low amount of fat (10% ± 2%, x ± SD). Pre-deboned meat had more calcium than deboned meat (P < 0.001). Sausages were made of fish and various non-meat ingredients including egg whites, collagen, soy protein isolate, starch, cellulose, and wheat gluten. Adhesiveness, cohesiveness, hardness, shear and springiness of the cooked sausages were measured to describe texture. The data were fit to linear and quadratic models. Adhesiveness data did not fit the model (F(6,50)=1.1, P > {F{=0.37). A combined response model predicted formulations for fish sausage that would closely duplicate the texture of commercially available processed meats. A thermal model was developed that helped verify the thermal properties of rainbow trout. Thermal conductivity was measured (k == 0.48 W/m·K) and specific heat was calculated (C_p= 3200 J/kg·K).

Influence Of Capsular And Ropy Exopolysaccharide-Producing Strepococcus Thermophilus On Mozzarella Cheese And Cheese Whey, B. L. Peterson, R. I. Dave, Donald J. Mcmahon, C. J. Oberg, Jeff Broadbent

Nutrition, Dietetics, and Food Sciences Faculty Publications

We investigated the effect of capsular and ropy exopolysaccharide-producing Streptococcus thermophilus starter bacteria on Mozzarella cheese functionality and whey viscosity. Mozzarella cheeses were manufactured with Lactobacillus helveticus LH100 paired with one of four S. thermophilus strains: MR-1C, a bacterium that produces a capsular exopolysaccharide; MTC360, a strain that secretes a ropy exopolysaccharide; TAO61, a nonexopolysaccharide-producing commercial cheese starter; and DM10, a nonencapsulated, exopolysaccharide-negative mutant of strain MR-1C. As expected, cheese moisture levels were significantly higher in Mozzarella cheeses made with exopolysaccharide-positive versus exopolysaccharide-negative streptococci, and melt properties were better in the higher moisture cheeses. Whey viscosity measurements showed that unconcentrated …

Bovine Somatotropin In Milk, Charlotte P. Brennand Phd, Clell V. Bagley Dvm

Archived Food and Health Publications

Publication discusses the controversy associated with Bovine Somatotropin in milk.

Tryptophan Catabolism By Lactobacillus Casei Andlactobacillus Helveticus Cheese Flavor Adjuncts, S. Gummalla, Jeff Broadbent

Nutrition, Dietetics, and Food Sciences Faculty Publications

Microbial degradation of Trp is thought to promote the formation of aromatic compounds that impart putrid, fecal, or unclean flavors in cheese, but pathways for their production have not been established. This study investigated Trp catabolism by Lactobacillus casei and Lactobacillus helveticus cheese flavor adjuncts under carbohydrate starvation (pH 6.5, 30 or 37°C, no sugar) and near cheese-ripening (pH 5.2, 4% NaCl, 15°C, no sugar) conditions. Enzyme assays of cell-free extracts indicated that both species of Lactobacillus catabolized Trp to indole-3-lactic acid, and micellar electrokinetic capillary chromatography of culture supernatants showed this reaction occurred via successive transamination and dehydrogenation reactions. …