The control of milk protein production was investigated utilising two different approaches. The first model is one of intravenous infusion of atropine. Atropine, which decreases milk protein yield, has been theorised to act either by decreasing blood somatotropin (ST) concentration or by decreasing blood amino acid (AA) concentration. Thus, the first experiment was designed to test which mechanism, or both, is responsible for the effects on milk protein yield. Five lactating dairy cows were assigned to the following treatments which were administered intravenously: Saline (CONT), atropine (ATR), ATR + ST, ATR + AAs, and ATR + ST + AAs. Atropine treatment failed to decrease plasma ST concentration but did decrease plasma alpha-amino nitrogen concentration. Atropine treatment decreased milk protein yield but neither ST, AAs, nor ST + AAs were able to maintain milk protein yield at the CONT level when infused with ATR. It is clear that the treatments tested are not directly responsible for the decrease in milk protein yield due to ATR. Therefore, neither ST, AAs, nor ST + AAs appear to have direct control of milk protein production. Plasma insulin (INS) concentration was decreased and plasma IGF-I concentration was not decreased by ATR treatment. Insulin, therefore, presents itself as a candidate for direct control over milk protein synthesis. The second model is one of monitoring endocrine response to abomasal infusion of AAs mimicking the profile of milk protein with selective deletion of certain AAs. Six lactating dairy cows were subjected to the following treatments: Saline (negative control, NC), AAs (positive control, PC), PC minus methionine (PC-Met), PC minus lysine (PC-Lys), PC minus histidine (PC-His), and PC minus the branched-chain AAs (PC-BCAAs). All endocrine factors studied (ST, INS, glucagon & IGF-I) were affected by treatment. Plasma IGF-I concentration responded similarly, except for the PC-Met treatment, to milk protein yield (Weekes and Cant, 200

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Commercial food proteins were used in order to study the relationship between hydrophobicity and two functional properties: emulsification and foaming. Hydrophobicity determined by sodium dodecyl sulfate (SDS) binding method and the cis-parinaric acid (CPA) fluorescence probe method gave poor statistical correlation with foaming and emulsification. The SDS binding method gave higher hydrophobicity and higher correlation values with foaming and emulsifying, than the fluorescence probe CPA method. / Fourier Transform Infrared (FTIR) spectroscopy was used to study the secondary structures, of the commercial food proteins. Infrared spectra of the protein samples with or without denaturing agents (SDS, urea, and guanidine) in the region of the amide I and II bands were determined in deuterium oxide (D$ sb{2}$O) buffer. Fourier self-deconvolution was used to study infrared band positions. BSA was an $ alpha$-helix protein, and in the presence of SDS, due to protein unfolding, exhibited a random coil structure. By correlating their infrared spectra to predetermined peak positions in the protein samples, it was shown that the legume proteins contained $ beta$-structure, and as SDS was added, exhibited non-ordered structures. The spectra of gluten samples were obtained only in the presence of SDS, showing either random coil, or non-ordered structures.

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The formation of gas hydrates in the oil and gas industry causes numerous problems that require costly solutions and operation downtime. A great deal of hydrate research has focused on their prevention either through kinetic or thermodynamic inhibitors. Recently, antifreeze proteins (AFPs) produced by cold adapted organisms have been found to have a kinetic inhibitory effect on clathrate hydrates. / Kinetic experiments were conducted on the methane-water system in the presence of AFPs by measuring the gas uptake during the formation of methane hydrate in a 610 cc high pressure crystallizer. These experiments were performed at temperatures ranging from 277.15 K to 280.65 K, pressures of 5800 KPa to 8100 KPa and at an AFP concentration of 0.01 mM. / The results of these experiments showed that the presence of AFPs affect methane hydrate formation in multiple ways. They were shown to increase the nucleation time, reduce the initial growth rate of methane hydrate at the time of nucleation and there was evidence to suggest that they also have an anti-agglomerating effect on hydrate crystals.

Bipyramidal crystalline, spheroidal crystalline and amorphous proteins were prepared from following four seeds: white kidney, navy (Phaseolus vulgaris) beans; baby lima, large lima (Phaseolus lunatus) beans. A study of the biological properties of the proteins which exhibit the different microstructures, was carried out. The nature of tryptic inhibitory activity and alpha-amylase inhibitory activity were investigated. All protein showed both trypsin inhibitory and alpha-amylase activities; the kinetics of the alpha-amylase revealed non-competitive mechanism. The crystalline isolates showed lower trypsin inhibitory (TI) and alpha-amylase inhibitory (AI) activities than the amorphous isolates. The extents of tryptic hydrolysis (in vitro) were not related to TI indicating involvement of some other factors, in addition to trypsin inhibitory activity. Electropherograms of SDS-PAGE indicated that the major proteins of P. lunatus beans were more resistant to tryptic hydrolysis than the major fractions of the P. vulgaris. Phytate was found to have an effect on trypsin inhibition as well as on alpha-amylase inhibition; in the latter case, however, phytate complexed to protein was required for the inhibitory effect. There were no relationships between tannin content of the proteins and biological activity. Fractionation of bipyramidal crystalline and amorphous proteins by size exclusion chromatography showed that each isolate contained three fractions having approximate MW of 443,000, 200,000 and 150,000 daltons. The 200,000 MW fraction was a principal fraction. The fraction of 150,000 contained most of the trypsin inhibitory activity, alpha-amylase inhibitory activity was not detected in any of the fractions.

Spring barley (Hordeum vulgare L.) is an important cereal crop in Quebec, where it is used as a crop for swine and poultry. Since barley is a better source of energy than protein, a protein supplement must be added to the feed. Consequently, the production of barley with high protein concentration in the grain (GPC) is desirable. Studies on intensive cereal management (ICM) practices in other countries have shown that high yields can be combined with a high GPC. From 1987 to 1990 three field experiments were conducted to evaluate the effects of ICM on the yields and GPC of six-rowed spring barley in Quebec. Our results describe the effects of individual ICM components (N fertilizer application, fungicide, and plant growth regulator) on the development of yield components and on GPC. In general, N had little effect on main stem yield spike$ sp{-1}$ and on tiller spikes m$ sp{-2}$. Possibly, plant density or environmental conditions may have imposed greater limitations on yield rather than N. Nitrogen treatments increased GPC generally by increasing the amount of protein grain$ sp{-1}$. Nitrogen treatments which increased the amount of protein grain$ sp{-1}$ increased the lysine and cyst(e)ine concentrations of the grain but decreased their concentration in the grain protein. The plant growth regulator ethephon increased GPC by increasing the amount of protein grain$ sp{-1}$, by decreasing the nonprotein content grain$ sp{-1}$, or by altering final grain size distribution. Ethephon often had damaging effects on yield. Large genotypic variation was observed for GPC, but could not be related to genotypic differences in N harvest index, total N accumulation, protein yield or post-anthesis N uptake and assimilation. Grain yield was weakly correlated with GPC. Examination of the cultivars grown from 1910 to 1988 showed that increases in grain yield were accompanied by increases in harvest index, total dry matter, and lodging resistance. Plant height was reduced over tim