The mammary gland of lactating transgenic animals has several advantages for production of heterologous proteins including a high cell density that results in high concentrations of secreted protein and the ability to perform several types of post-translational modifications. Transgenes were constructed from the 4.1 kbp murine Whey Acidic Protein promoter (mWAP) and the three cDNAs coding for the Aα, Bβ and γ fibrinogen chains to evaluate the requirements of the transgenic murine mammary gland for high level secretion of fully assembled human fibrinogen. After introducing the constructs into the murine zygotes by microinjection, secretion of fully assembled fibrinogen into milk was measured at concentrations between 10 ug/ml to 200 ug/ml. In one line of mice the total secretion of fibrinogen and unassembled subunits approached 700 ug/ml in milk. The level of assembled fibrinogen was proportional to the lowest amount of subunit produced where both the Bβ and γ chains were rate limiting. Also, the subunit complexes γ₂, Aαγ₂ and the individual subunits Aα, Bβ and γ were found as secretion products. This is the first time that secretion of individual Bβ-subunits by any cell type has been reported and suggests the organization of the secretion pathway in mammary epithelia is different from that in liver. Glycosylated forms of individual Bβ-chain contained a complex saccharide with low mannose. Glycosylation of the γ-chain was also observed. These results suggest the 4.1 mWAP promoter can drive expression of fibrinogen cDNAs to high levels and that the amount of fully assembled fibrinogen secreted is equal to the level of the lowest expressing chain. / Master of Science

No description available.

No description available.

Wheyruit slush formulas were evaluated prior to consumer testing of pre-selected formulated beverages. Varying ingredients were prepared in accordance to a factorial design of maximum use of whey and minimum use of additional ingredients. Whey was obtained from the Mississippi State University Dairy Processing Plant and evaporated. The evaporated sweet whey was combined with blueberries, cherry concentrate, Splenda®, water and ice. Sensory tests were conducted to evaluate appearance, flavor and overall acceptability of formulations. Panelists were asked to participate in a survey to elaborate personal perceptions of the products. Formulation of 125mL whey and 30g blueberries had the higher acceptability score, but was not different from the beverage with 150mL whey and 30g blueberries. These two formulas were tested for chemical analysis. Adequate levels of antioxidants, total phenolics and neutral pH were observed. Results from proximate analysis showed minimal caloric levels with low presence of protein and carbohydrate.

No description available.

No description available.

No description available.

With the increased utilization of whey powders in food products there is a need to investigate the storage stability of whey powders. The objectives were to determine the effects that compositional factors of whey powders had on the Maillard reaction during storage. The Maillard reaction is the major deteriorative reaction limiting the shelf-life of whey powders. Eight commercial whey powders were stored at accelerated storage conditions (35°C) and at five different water activities, a_ws, (0.32, 0.44, 0.52, 0.63, and 0.74) for up to 120 days. Small quantities of the hydrolyzates of lactose- glucose and galactose (less than 2% dry wt.) caused a sizable increase in the relative rates of the Maillard reaction in whey powders. The relative rate of the Maillard reaction rate was determined by measuring brown pigment formation at 420 nm. Increasing the amount of nonprotein nitrogen (NPN) significantly increased the relative rates of the Maillard reaction in the whey powders. Increasing ash content had a positive but statistically insignificant effect on the Maillard reaction. The influence of water activity on the storage stability of whey powders was also investigated. Increasing the protein content of the whey powders increased the a_w, where the maximum rate of brown pigment formation was observed. In the highest protein whey powders (46% and 82%) however, the browning rate maxima shifted to lower a_ws. The loss in protein quality of the whey powders was determined by examining the loss of available lysine using the dye-binding method. Intermediate protein whey powders (31-40% protein) and unprocessed sweet dried wheys lost the greatest relative percentages of available lysine during the storage period. / Master of Science

Master of Science / Food Science Institute / Jayendra Amamcharla / Greek yogurt is one of the largest-growing sectors in the dairy industry accounting for over 25% of yogurt sales in the United States. Greek yogurt is produced by removing a portion of water and water soluble components from yogurt. Consequently, a large quantity of Greek yogurt whey (GYW) is being produced as a co-product. GYW is compositionally different from cheese whey, and thus poses economic and environmental challenges to the dairy industry. The objective of the present study was to evaluate two physical treatments as alternative methods for separating valuable GYW components: magnetic fluid treatment (MFT) and the addition of sepiolite, a clay mineral. A MFT chamber was designed using four pairs of neodymium magnets arranged to produce a magnetic field strength of 0.6 Tesla. Three batches of GYW each from two manufacturers were procured. A 2×3 factorial design was used with MFT or without MFT and the addition of zero, two, or four grams of sepiolite per 100g of GYW. The pH of GYW was adjusted to 7.2 using 5N NaOH solution, and the GYW was pumped at a rate of 7.5 L/min through the MFT system with or without MFT chamber attached. The sample was split into three sub-samples, heated to 80°C, and sepiolite was added as per the experimental design. The samples were centrifuged at 1,000g for five minutes. The top aqueous layer was separated and analyzed for total solids, ash, lactose, protein, calcium, phosphates, and sodium content along with color. MFT did not influence the analyzed whey components (P > 0.05) except for lactose. However, addition of sepiolite influenced protein content and a* and b* color values for the top aqueous layers (P < 0.05). Both levels of sepiolite addition resulted in about a 50% decrease in protein compared to original GYW. Adding two grams of Sepiolite per 100g of GYW from manufacturer 1 resulted in b* decreasing from 25.99 to 8.16 compared to treated GYW with no sepiolite. Sepiolite was found to have possible applications in the removal of proteins and color pigments in GYW.

A whey product has been formulated for use as a lactic starter medium. Phosphate-treated whey medium (PWM) has been shown to support growth of lactic cultures and prevent phage proliferation. Comparisons were made of a commercial phage inhibitory medium (PIM), reconstituted non-fat dry milk (NDM) and PWM. PWM inhibited all phages tested and stimulated starter growth. PWM was not as stimulating as PIM but was better than NDM. Good Cheddar cheese has been made using PWM. PWM is more economical than PIM but NDM is the most economical one if cheese yield is considered.