Thesis (MScAgric)--University of Stellenbosch, 2007. / Bibliography. Also available via the Internet.

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Lipoxygenase was extracted from Canola seeds (Brassica napus cv, Westar) and partially purified by precipitated with ammonium sulfate at 20-50% of saturation. The optimum pH for the enzyme activity was 7.5 and its K$ sb{ rm m}$ value was 2.0 $ times$ 10$ sp{-4}$ M. The activity of the enzyme extract was considerably greater on linoleic acid than on its ester or on linolenic acid. The effect of cyanide on the enzyme activity was also investigated. / Further purification of the enzyme extract was performed by successive chromatography on ion-exchange and gel filtration, using FPLC system. Four lipoxygenase isozymes (I, IIA, IIB and III) were separated. The homogeneity of each isozyme was demonstrated by the presence of a single protein band on SDS-PAGE gel electophoresis. The molecular weights of isozymes I, IIA, IIB and III were, respectively, 72,000, 106,000, 78,000 and 62,000. The optimum pH for lipoxygenase activity was 6.5 for isozyme I and 6.0 for isozymes IIA, IIB and III.

Two experiments were conducted to determine the apparent (ATTD), standardized (STTD) and true total tract digestibility (TTTD) of phosphorus (P) and ATTD of calcium (Ca) in Brassica napus black (BNB) and Brassica juncea yellow (BJY) canola meal (CM) fed to growing pigs. In Experiment 1, eight semi-purified diets containing graded levels of P i.e., 0.8, 1.6, 2.4 and 3.3 g/kg of DM, from either BNB or BJY, were fed to growing pigs with an initial BW of 19.9 ± 0.22 kg (mean ± SEM) in a randomized complete block design. The total and basal EPL estimated with the regression analysis and P-free diet methods were 665 ± 0.03 and 209 ± 96 mg/kg of DMI, respectively. The TTTD and STTD of P were determined to be 33.3 and 31.0% for BNB and 32.0 and 28.3% for BJY, respectively. In Experiment 2, the effect of high level of phytase supplementation on the ATTD of P and Ca and STTD of P in growing pigs was studied. Forty-two growing pigs with an initial BW of 19.8 ± 1.22 kg (mean ± SEM) were randomly allocated to 7 dietary treatments with 6 pigs per treatment according to a completely randomised design in a factorial arrangement with the factors being: 1) 2 types of CM (BNB and BJY) and 2) 3 levels of phytase (i. e., 0, 500 and 2,500 U/kg). The ATTD of P increased from 39.1 to 69.3, and 78.0% in BNB and from 46.0 to 71.4, and 78.0% in BJY as phytase levels were added at 0, 500 and 2,500 U/kg, respectively. The STTD of P increased from 40.0 to 70.0, and 78.3% in BNB, and from 46.3 to 72.1, and 78.5% in BJY as phytase levels were added at 0, 500 and 2,500 U/kg. The basal EPL estimate was 117 ± 23.4 mg/kg DMI. Fecal P excretion in BNB and BJY were reduced by average value of 50.3 and 61.0% with the addition of both 500 and 2,500 FTU phytase II respectively. Results from these two experiments show that the values obtained for STTD and TTTD of P in BNB and BJY were similar.

The presence of mucilaginous material in the seed coat of canola cv. Candle has been associated with storage and mold infestation problems. This study examined the yield of mucilage from canola cv. Candle and some of its chemical and physical properties. Canola seeds were extracted for 16 hours with water using a seed:water ratio of 1:18 or heat-treated prior to water extraction using a seed:water ratio of 1:7. The mucilage was precipitated with 4 volumes of 95% ethanol and recovered by centrifugation at 3500 x g and 23 C for 10 minutes. A twofold increase in the yield of mucilage (1.33%) was obtained for the heat-treated seeds compared to (0.69-0.72%) for the unheated canola seeds. The heat-treated canola seeds were subjected to different extraction times from 4 to 16 hours using a seed:water ratio of 1:7. Approximately 63.8% of the total extractable rnucilage was obtained after the first 4 hours. No significant differences (P<0.05) were observed in the yield of mucilage between 4 hour extraction intervals. A significant difference (P<0.05) however, was evident in the yield of mucilage between 8 and 12 hour extraction intervals. The total yield of mucilage obtained at the end of the 16 hour extraction period was 1.16% Proximate analysis of canola mucilage showed it contained moisture (8.2%), protein (18.2%), carbohydrate (30.6%), ash (29.4%) with the remainder (13.6%) unidentified. No significant differences (P<0.05) were observed in either the protein or carbohydrate content of mucilage throughout the 16 hour extraction period. This suggested the mucilage was homogeneous with respect to protein and carbohydrate content. Analysis of the carbohydrate composition by gas chromatography showed that with the exception of rhamnose, no significant (P<0.05) differences between the individual monosaccharides over the different extraction intervals. The monosaccharide composition of canola mucilage was galactose (31.7%) rarabinose (28.9%), glucose (14.9%), mannose (9.7%), rhamnose (4.5%), xylose (3.7%) with the remaining 7.1% unidentified . Purification of mucilage was accompanied by a two and threefold increase in rhamnose and unidentified fractions respectively. A marked decrease in the other monosaccharides was observed for the purified material. The flow curve of a 0.5% solution of canola mucilage exhibited a shear thickening property. Canola mucilage was non-Newtonian in behaviour up to a shear rate corresponding to 350 rpm while at higher rate of shear it was Newtonian. The viscosity of a 0.5% solution of canola mucilage within the Newtonian range was 4 cp. Canola mucilage reduced surface tension and interfacial tension of a corn oil:water system . The interfacial tension value using canola mucilage was 9.5 dynes/crn which was similar to mustard mucilage (8.5 dynes/cm). The ability of canola mucilage to reduce interfacial tension was responsible for the formation of a stable salad dressing incorporating canola mucilage as emulsifier.

The metabolic syndrome is characterized by obesity, insulin resistance, hypertension and dyslipidemia. It has also been suggested that hepatic steatosis and inflammation should be added to the classical components of the metabolic syndrome. Previous research on obesity and insulin resistance has examined the effects of many different fats and oils, however, the effects of canola oil on metabolic syndrome parameters have yet to be investigated. It is hypothesized that in a diet induced obese (DIO) rodent model, the combination of canola and flax oils will reduce the severity of metabolic syndrome parameters and favorably alter hepatic phospholipid (PL) and triacylglycerol fatty acid composition. The objective of the study was to investigate the biological effects of a 12 week dietary intervention with high fat diets based on various vegetable oils (high oleic canola, canola, canola/flax (3:1; C/F), safflower and soybean) and lard in 6 week old obese prone rats with regards to obesity, insulin resistance, lipidemia, hypertension, inflammation, hepatic steatosis, hepatic fatty acid composition and markers of hepatic fatty acid oxidation and synthesis. Overall the C/F diet attenuated more of the components of the metabolic syndrome, including obesity, glycemia, lipidemia, inflammation and hepatic steatosis, than the other high fat diets in DIO rats. However, each of the dietary treatments attenuated various components of the metabolic syndrome suggesting that all dietary fats and oils have their role in the prevention of different components of the metabolic syndrome. Additionally, the C/F diet led to increased eicosapentaenoic acid and docosahexaenoic acid concentrations in hepatic PL suggesting that α-linolenic acid can be efficiently converted to its very long chain derivatives in DIO rats. Thus, the addition of flax oil to conventional canola oil, in the C/F diet, appeared to enhance the beneficial effects of canola oil on metabolic syndrome parameters.

Two experiments were conducted to determine the apparent (ATTD), standardized (STTD) and true total tract digestibility (TTTD) of phosphorus (P) and ATTD of calcium (Ca) in Brassica napus black (BNB) and Brassica juncea yellow (BJY) canola meal (CM) fed to growing pigs. In Experiment 1, eight semi-purified diets containing graded levels of P i.e., 0.8, 1.6, 2.4 and 3.3 g/kg of DM, from either BNB or BJY, were fed to growing pigs with an initial BW of 19.9 ± 0.22 kg (mean ± SEM) in a randomized complete block design. The total and basal EPL estimated with the regression analysis and P-free diet methods were 665 ± 0.03 and 209 ± 96 mg/kg of DMI, respectively. The TTTD and STTD of P were determined to be 33.3 and 31.0% for BNB and 32.0 and 28.3% for BJY, respectively. In Experiment 2, the effect of high level of phytase supplementation on the ATTD of P and Ca and STTD of P in growing pigs was studied. Forty-two growing pigs with an initial BW of 19.8 ± 1.22 kg (mean ± SEM) were randomly allocated to 7 dietary treatments with 6 pigs per treatment according to a completely randomised design in a factorial arrangement with the factors being: 1) 2 types of CM (BNB and BJY) and 2) 3 levels of phytase (i. e., 0, 500 and 2,500 U/kg). The ATTD of P increased from 39.1 to 69.3, and 78.0% in BNB and from 46.0 to 71.4, and 78.0% in BJY as phytase levels were added at 0, 500 and 2,500 U/kg, respectively. The STTD of P increased from 40.0 to 70.0, and 78.3% in BNB, and from 46.3 to 72.1, and 78.5% in BJY as phytase levels were added at 0, 500 and 2,500 U/kg. The basal EPL estimate was 117 ± 23.4 mg/kg DMI. Fecal P excretion in BNB and BJY were reduced by average value of 50.3 and 61.0% with the addition of both 500 and 2,500 FTU phytase II respectively. Results from these two experiments show that the values obtained for STTD and TTTD of P in BNB and BJY were similar.

The presence of mucilaginous material in the seed coat of canola cv. Candle has been associated with storage and mold infestation problems. This study examined the yield of mucilage from canola cv. Candle and some of its chemical and physical properties. Canola seeds were extracted for 16 hours with water using a seed:water ratio of 1:18 or heat-treated prior to water extraction using a seed:water ratio of 1:7. The mucilage was precipitated with 4 volumes of 95% ethanol and recovered by centrifugation at 3500 x g and 23 C for 10 minutes. A twofold increase in the yield of mucilage (1.33%) was obtained for the heat-treated seeds compared to (0.69-0.72%) for the unheated canola seeds. The heat-treated canola seeds were subjected to different extraction times from 4 to 16 hours using a seed:water ratio of 1:7. Approximately 63.8% of the total extractable rnucilage was obtained after the first 4 hours. No significant differences (P<0.05) were observed in the yield of mucilage between 4 hour extraction intervals. A significant difference (P<0.05) however, was evident in the yield of mucilage between 8 and 12 hour extraction intervals. The total yield of mucilage obtained at the end of the 16 hour extraction period was 1.16% Proximate analysis of canola mucilage showed it contained moisture (8.2%), protein (18.2%), carbohydrate (30.6%), ash (29.4%) with the remainder (13.6%) unidentified. No significant differences (P<0.05) were observed in either the protein or carbohydrate content of mucilage throughout the 16 hour extraction period. This suggested the mucilage was homogeneous with respect to protein and carbohydrate content. Analysis of the carbohydrate composition by gas chromatography showed that with the exception of rhamnose, no significant (P<0.05) differences between the individual monosaccharides over the different extraction intervals. The monosaccharide composition of canola mucilage was galactose (31.7%) rarabinose (28.9%), glucose (14.9%), mannose (9.7%), rhamnose (4.5%), xylose (3.7%) with the remaining 7.1% unidentified . Purification of mucilage was accompanied by a two and threefold increase in rhamnose and unidentified fractions respectively. A marked decrease in the other monosaccharides was observed for the purified material. The flow curve of a 0.5% solution of canola mucilage exhibited a shear thickening property. Canola mucilage was non-Newtonian in behaviour up to a shear rate corresponding to 350 rpm while at higher rate of shear it was Newtonian. The viscosity of a 0.5% solution of canola mucilage within the Newtonian range was 4 cp. Canola mucilage reduced surface tension and interfacial tension of a corn oil:water system . The interfacial tension value using canola mucilage was 9.5 dynes/crn which was similar to mustard mucilage (8.5 dynes/cm). The ability of canola mucilage to reduce interfacial tension was responsible for the formation of a stable salad dressing incorporating canola mucilage as emulsifier.

The metabolic syndrome is characterized by obesity, insulin resistance, hypertension and dyslipidemia. It has also been suggested that hepatic steatosis and inflammation should be added to the classical components of the metabolic syndrome. Previous research on obesity and insulin resistance has examined the effects of many different fats and oils, however, the effects of canola oil on metabolic syndrome parameters have yet to be investigated. It is hypothesized that in a diet induced obese (DIO) rodent model, the combination of canola and flax oils will reduce the severity of metabolic syndrome parameters and favorably alter hepatic phospholipid (PL) and triacylglycerol fatty acid composition. The objective of the study was to investigate the biological effects of a 12 week dietary intervention with high fat diets based on various vegetable oils (high oleic canola, canola, canola/flax (3:1; C/F), safflower and soybean) and lard in 6 week old obese prone rats with regards to obesity, insulin resistance, lipidemia, hypertension, inflammation, hepatic steatosis, hepatic fatty acid composition and markers of hepatic fatty acid oxidation and synthesis. Overall the C/F diet attenuated more of the components of the metabolic syndrome, including obesity, glycemia, lipidemia, inflammation and hepatic steatosis, than the other high fat diets in DIO rats. However, each of the dietary treatments attenuated various components of the metabolic syndrome suggesting that all dietary fats and oils have their role in the prevention of different components of the metabolic syndrome. Additionally, the C/F diet led to increased eicosapentaenoic acid and docosahexaenoic acid concentrations in hepatic PL suggesting that α-linolenic acid can be efficiently converted to its very long chain derivatives in DIO rats. Thus, the addition of flax oil to conventional canola oil, in the C/F diet, appeared to enhance the beneficial effects of canola oil on metabolic syndrome parameters.

Thesis (M. Sc.)--University of Alberta, 2009. / Title from pdf file main screen (viewed on Jan. 7, 2010). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Animal Science, Department of Agricultural, Food and Nutritional Science, University of Alberta." Includes bibliographical references.