No description available.

Call number: LD2668 .T4 1986 O38 / Master of Science / Animal Sciences and Industry

Recent research suggests that [beta]-hydroxy-[beta]-methylbutyrate (HMB), a metabolite of leucine (Leu), increases muscle mass and attenuates muscle damage during resistance training. Although Leu acts as a potent stimulator of protein synthesis, HMB, but not Leu, has been reported to be effective in suppressing proteolysis in skeletal muscle. However, mechanisms for the effects of HMB on cell signaling pathways controlling muscle protein turnover during rest and after endurance exercise are still poorly understood. Furthermore, the effects of HMB on cell signaling pathways controlling protein synthesis and degradation under normal in vivo conditions warrant further investigation. For optimal gains in muscle mass, the appropriate type and amount of protein (PRO) is required for positive protein balance to occur in skeletal muscle. Therefore, this dissertation was designed to determine the effect of HMB, PRO and Leu, individually and in combination, on the regulation of cellular signaling pathways controlling muscle protein turnover during sedentary and post-exercise conditions. Study 1 demonstrated that, compared with HMB and PRO alone, the combination of HMB and PRO was more effective in activating the mTOR signaling pathway, which controls protein synthesis, and inhibiting FOXO3A, a major regulator of the ubiquitin-proteasome proteolytic signaling pathway. Study 2 demonstrated that, compared with its individual components, a novel HMB/PRO/Leu supplement better activated protein-synthetic signals and inhibited proteolytic signals in skeletal muscle, and these effects were better sustained. Finally, Study 3 demonstrated that adding Leu to PRO-enriched mixtures after exercise additively activated protein-synthetic signals in a fiber type-specific manner, and adding HMB clearly inhibited proteolytic signaling proteins. Furthermore, provision of an HMB/PRO/Leu supplement after exercise was found to favorably modulate signaling pathways controlling both protein synthesis and degradation. Taken together, the results of these studies suggest that a novel nutrient supplement, composed of HMB, Leu and PRO, additively enhances the intracellular signaling proteins controlling protein synthesis and attenuates signaling proteins controlling proteolysis in skeletal muscle during sedentary and post-exercise recovery. Therefore, such a supplement may be beneficial for both athletic and therapeutic purposes. / text

Six different cotton gin trash silages were studied which varied according to the rehydrating medium (water or whey) and the strain of L. plantarum, if any, used for inoculation. Silages were incubated at 34°C and analyzed at weeks 0, 1, 2, 3, 4, and 8 for counts of lactobacilli, total anaerobes, and sporeforming anaerobes. Biochemical measurements included pH, proximate analysis, volatile fatty acid analysis, and lactic acid analysis. Counts of lactobacilli and total anaerobes followed similar trends in all experimental silages with numbers greatly increasing by the end of week one and then subsequently declining. Counts of sporeforming anaerobes increased ten-fold by the end of the second week. Subsequent counts showed that the water-rehydrated silages maintained this increase whereas the whey silages decreased in numbers to their original magnitude. Whey-rehydrated silages had a significantly lower pH, higher dry matter content, a lower level of fiber, lignin, and cellulose, and a higher concentration of carbohydrate. These silages showed only traces of butyric acid and significantly higher concentrations of lactic acid. Thus the whey, as a rehydrating medium, produced silages of desirable pH and exhibited biochemical parameters indicative of good quality and feeding value. Of the three water-rehydrated silages, one was of obvious poor quality with the other two being questionable. No benefit was seen in using an inoculum of L. plantarum.

No description available.

Poly(ethylene oxide) (PEO) is known for facilitating the electrospinning of biopolymer solutions, that are otherwise not electrospinnable. The objective of this study was to investigate the mechanism by which PEO enables the formation of whey protein isolate (WPI) electrospun fibers under different pH conditions. This investigation revealed that the addition of PEO increased the viscosity of WPI/PEO (10% w/w WPI; 0.4% w/w PEO) solutions. Difference in pH levels of the polymer solutions affected electrospinnability and fiber morphology. Acidic solutions resulted in smooth fibers (700 ± 105 nm) while neutral solutions produced spheres (2.0 ± 1.0 um) linked with ultrafine fibers (138 ± 32 nm). In comparison, alkaline solutions produced fibers (191 ± 38 nm) that were embedded with spindle-like beads (1.0 ± 0.5 um). Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analyses revealed that the native globular configuration of WPI was not altered under neutral conditions. By contrast, the electrophoresis and spectrometry data indicated that WPI was denatured and hydrolyzed under acidic conditions, which facilitated the formation of smooth fibers. C13 nuclear magnetic resonance (NMR) and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopies showed that the increase random coil and a-helix secondary structures in WPI contributed to the formation of bead-less electrospun fibers. Also, C13 NMR analysis showed no evidence of chemical interaction between WPI and PEO. Scanning transmission electron microscopy coupled with energy dispersive X-rays (STEM-EDAX) revealed that WPI was uniformly distributed within WPI/PEO electrospun fibers. Observations by scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM) indicated that fibers possessed a solid core. All these findings suggested that PEO enables the formation of WPI/PEO electrospun fibers by entanglement/entrapment/deposition. Preliminary studies were conducted on hydroxypropyl methyl cellulose (HPMC). In the absence of PEO, HPMC enabled the formation of WPI electrospun fibers under acidic conditions (124 ± 46 nm). FTIR analyses indicated that there was no interaction between HPMC and WPI, suggesting that HPMC aided in the electrospinning of WPI fibers, also by entanglement/entrapment/deposition. Hence, HPMC and PEO aid in the electrospinning of WPI fibers by entanglement/entrapment/deposition, which can be manipulated by alterations in the protein configuration and solution properties. / Natural Sciences and Engineering Research Council (NSERC) of Canada and the Dairy Farmers of Ontario (DFO)

Whey Protein Concentrate (WPC) is used as a functional ingredient in many food products. To increase the applicability of WPC as well as other food proteins, it is often necessary to enhance the functional properties of the protein. Various protein modification techniques can be used for this purpose; this includes chemical, physical and enzymatic modification. In present study acid hydrolysis, a chemical modification, was investigated as a means to improve functionality of WPC, emulsifying, foaming and gelatin. Most of the previous work on WPC has been directed at enzymatic hydrolysis. / Dispersions of WPC (8%) in organic acids (0.5 N, 1 N and 1.5 N acetic acid, citric acid phosphoric acid and mixture of these acids) were subjected to acid hydrolysis (6, 18 and 48 h) and the effects of this modification on functional properties was assessed. The degrees of hydrolysis were measured and freeze-dried hydrolysates were evaluated for their foam capacity and stability, emulsifying activity and stability index and toughness. Highest foam capacity was found in the hydrolysate obtained using 0.5 N acetic acid (6 h hydrolysis, foaming capacity of 140%); acid hydrolysis increased foam stability, in general. In addition, acid hydrolysis did not affect emulsifying activity index but gave higher emulsifying stability index and toughness of prepared gels. / Results of PAGE indicated that acidic modification led to progressive decrease in the $ alpha$-lactalbumin and BSA. $ alpha$-lactalbumin was found to be the most sensitive protein with significant degradation after 6 h hydrolysis. (Abstract shortened by UMI.)

No description available.

Thesis (Ph. D.)--Victoria University (Melbourne, Vic.), 2005. / Includes bibliographical references.

A sticky coating composed of dairy proteins and bioactive peptides (caseinophosphopeptides, CPPs) to prevent dental caries was formulated. The coating consisted of 10% CPPs, 70% glycerol and 20% casein (or hydrolysate) and/or whey in ratios from 0:100 to 100:0 casein:whey. Sodium caseinate was hydrolysed with three different enzymes, Alcalase, trypsin and α-chymotrypsin, yielding three hydrolysates classified as CN-A, CN-T and CN-C, respectively. The degree of hydrolysis reached levels of 18.04, 13.63 and 11.40% for CN-A, CN-T and CN-C respectively. Degree of hydrolysis was proportional to molecular weight determined by FPLC. CN-C coatings were the stickiest based on probe-tack test and capable of withstanding up to 22.46 N of force. Attempts to correlate glass transition temperatures to stickiness of the coatings proved inconclusive. All coatings were capable of binding enough calcium to remineralise tooth enamel. Results indicated that 100:0 CN-C:whey produced the stickiest coating; however this combination also increased bacterial adhesion. / February 2016