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22. The Alpha-amylase Inhibitory Activity of Proteins of Phaseolus Beans
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*fid bacterium longum ATCC 19708; Lactobacillus acidophilus f"'c~, 4022; L. bulgaricus 5089; L.cas~i var. rhamnos~s 4008; L. 1IeI ticus L-89; Streptococcus cremons 2487; S. lactls 2432; S. . ve ophilus 12. The phagocytic activity of the pulmonary al~ macrophages was measured after 3,5 and 8 days of feeding, ~ 7 days after the feeding of fermented milk was stopped. On 8th day, the phagocytic index for mice fed with B. longum and L e acidophilus fermented milks was almost twice that of the •ntrol. This suggests that the animals feeding on such fermented ~kS could enhance the host defense mechanisms against infections.
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1 COMPARISON OF THREE METHODS FOR MEASUREMENT I. OF DEGREE OF HYDROLYSIS OF ENZYMATICALLY MODIFIED MILK PROTEINS. S. L. Turgeon*, C. Bard and S.F. Gautbier, Groupe de recherche-STELA, Departement de sciences ·et technologie des aliments, Universite Laval, Quebec, P.Q. GIK 7P4. The O-phthaldialdehyde (OPA), trinitrobenzene sulphonic acid (TNBS) and pH-stat methods were compared for the determination of degree of hydrolysis (D.H.) as a measure of the extent of proteolysis of milk proteins by trypsin and chymotrypsin. Compared to the OPA method, TNBS method resulted in lower values of D.H. For whole proteins and higher values for ultrafiltered hydrolysates due to an interference wi!h lactose. The pH-stat method gave D.H. values slightly higher ( 10,70) than those obtained by OPA method. The OPA method is rapid, simple, sensitive, do not interfere with lactose and can be performed during the hydrolysis process. 18. INDIVIDUAL VARIATION IN THE DEGREE OF GLYCOSYLATION OF K-CASEIN IN THE MILK OF HOLSTEIN COWS. G. Robitaille*, M. Legare, K.F. Ng-KwaiHang and H. Monardes, Department of Animal Science, Macdonald College of McGill University, Ste. Anne de Bellevue, P.Q. H9X ICO. In milk, K-casein is the major glycoprotein. Shorts oligosaccharides, which contain a N-acetylneuraminic acid as terminal carbohydrate, are O-linked to threonines located in the caseinomacropeptide region of the protein. The aim of this study was to determine the individual variation in the glycosylation extent of K-casein. The milk of 15 Holstein cows were collected twice a month and the sugar content of K-casein was estimated by an assay specific for N-acetylneuraminic acid on the casein pellet obtained by precipitation at pH 4.6. The milk was also analysed for protein, casein serum protein, fat and somatic cell count using standar methods. The relative proportion of as-, (3- and K-casein were determined by a densitometric analysis after electrophoresis of casein fraction on urea gel. The N-acetylneuraminic acid content of K-casein varied between 30 and 80 Hg/mg of K-casein. The concentration of N-acetylneuraminic acid in the milk ranged between 60 and 180 Ilg/ml with an average of 991lg/ml of milk. The variation during the lactation period and the possible link between the sugar content of K-casein and the level of production will be discussed. Supported by NSERC Strategic grant. 19. SOLID FAT CONTENT AND OTHER PHYSICAL PROPER. TIES OF MARGARINES. E. Postmus, J.M. deMan and L. deMan, Department of Food Science, University of Guelph, Guelph, Ont. NIG 2Wl. Solid fat content in Canadian and U.S. stick margarines was estimated by pulsed NMR at 10° and 22°C. The solid fat content of the isolated fats was measured using IUPAC and AOCS tempering procedures. When using the IUPAC methods the SFC values at 10°C for the fat were 130,70 higher than the values obtained with the margarine. At 22°C the values were 2.50,70 higher. With the AOCS method the SFC values at 10°C for the fat were 4.20,70 higher than the values for the margarine. At 22°C these values were 0.70,70 lower. Softening points and DSC melting and crystallization data were obtained. 20. PECTINESTERASE NATIVE ET PECTINASE AJOUTEE DANS LA FABRICATION DU JUS DE CAROTTES. M. H. Munsch et R.E. Simard, Departement de sciences et technologie des aliments, Universite Laval, Quebec, P.Q. GIK 7P4. Con. Inst. Food Sci. Technol. J. Vol. 22. No. 4, 1989
Le blanchiment a I'eau des carottes entieres (3 a 1I min) pour empecher le brunissement, a pour effet cl'activer la pectinesterase native. S'il y a un delai (10 a 30 min) avant I'extraction du jus, nous observons une augmentation de matiece seche, de carotene et de methanol dans le jus. Cet effet est cependant beaucoup moins important que I'effet de la maceration enzymatique par une pectinase commerciale. 21. TEXTURAL AND ENZYMATIC STUDIES OF THE EFFECTS OF CHILLING TEMPERATURES ON THE RIPENING PROCESS IN MATURE GREEN TOMATO FRUIT. A.G. Marangoni, R.L. Jackman and D.W. Stanley, Department of Food Science, University of Guelph, Guelph, Ont. NIG 2WI. The effects of cold temperatures on the ripening of mature green tomato fruit (Lycopersicon esculentum vaT. Caruso) was studied. Peroxidase activity increased due to chilling (p < 0.05) but did not vary during the ripening period. Pectinmethylesterase activity increased dramatically due to chilling (p < 0.001) and dropped during ripening, reaching values similar to those of controls. Total polygalacturonase (PG) and polygalacturonase 1 (PG I) activity increased more for chilled fruit during the ripening period than for control fruits (p <0.001). The coefficient of elasticity (k = Maximum Force/Maximum Deformation), as determined by two plate compression (TPC), constant area compression (CAC) and puncture (P) for tomato pericarp tissue during ripening, proved to be the most sensitive textural parameter for assessment of structural alterations in tomato tissue. The coefficient of elasticity for all textural measurements was highly correlated with PG and PG activities (0.7 < r < 0.9; p < 0.01), depicting closely the ripening process. 22. THE ALPHA-AMYLASE INHIBITORY ACTIVITY OF PROTEINS OF Phaseolus BEANS. Z. Li*, I. Alii and S. Kermasha, Department of Food Science and Agricultural Chemistry, Macdonald College of McGiII University, Ste. Anne de Bellevue, P.Q. H9X ICO. Protein isolates which show bipyramidal crystalline, spheroidal and amorphous microstructures were prepared by acidic and by alkaline extractions of Phaseolus vulgaris (white kidney, navy) and Phaseolus lunatus (baby lima, large lima). Evaluation of the protein isolates for x-amylase inhibitory activity indicated that all isolated proteins were inhibitory towards x-amylase hydrolysis of starch. X-amylase inhibitory activity ranged from 40 to 260 units/g protein; this represented 0,70 inhibition ranging from 20.80,70 to 60.40,70. There was no relationship between the X-amylase activity and the microstructures of the isolated proteins. The bipyramidal crystalline protein of white kidney bean showed the highest xamylase inhibitory activity (260 units/g protein). 23. PURIFICATION AND CHARACTERIZATION OF LIPOXYGENASE OF CANOLA SEED (Brassica sp.). A. Khalyfa*, S. Kermasha and I. Alii, Department of Food Science and Agricultural Chemistry, Macdonald College of McGill University, Ste. Anne de Bellevue, P.Q. H9X ICO. Canola lipoxygenase was extracted and partially purified by precipitation with solid ammonium sulfate at 20-500,70 of saturation. Further purification of the enzyme extract was performed by ion-exchange chromatography on DEAE-cellulose. The purified enzyme demonstrated the presence of a major and two minor isozymes similar to those obtained by the analysis of a commercial soybeanlipoxygenase. Preparative purification of the enzyme was also performed by liquid chromatography on Sepharose 6B and resulted in a single major peak. Preparative ion exchange fast protein liquid chromatography (FPLC) on Mono Q HR resulted in a major and two minor isozymes. The pH for optimum activity was 7.5. The effect of cyanide on the enzyme activity was investigated. The substrate selectivity of canola lipoxygenase was also determined. 24. PURIFICATION AND CHARACTERIZATION OF TRANS· AMINASES OF FRENCH BEANS (Phaseolus vulgaris) SEED. S. Kermasha, I. Alii and M. Metche, Department of Food Science and Agricultural Chemistry, Macdonald College of McGill University, Ste. Anne de Bellevue, P.Q. H9X ICO; and Laboratoire de
Abstract / 405
*fid bacterium longum ATCC 19708; Lactobacillus acidophilus f"'c~, 4022; L. bulgaricus 5089; L.cas~i var. rhamnos~s 4008; L. 1IeI ticus L-89; Streptococcus cremons 2487; S. lactls 2432; S. . ve ophilus 12. The phagocytic activity of the pulmonary al~ macrophages was measured after 3,5 and 8 days of feeding, ~ 7 days after the feeding of fermented milk was stopped. On 8th day, the phagocytic index for mice fed with B. longum and L e acidophilus fermented milks was almost twice that of the •ntrol. This suggests that the animals feeding on such fermented ~kS could enhance the host defense mechanisms against infections.
=
1 COMPARISON OF THREE METHODS FOR MEASUREMENT I. OF DEGREE OF HYDROLYSIS OF ENZYMATICALLY MODIFIED MILK PROTEINS. S. L. Turgeon*, C. Bard and S.F. Gautbier, Groupe de recherche-STELA, Departement de sciences ·et technologie des aliments, Universite Laval, Quebec, P.Q. GIK 7P4. The O-phthaldialdehyde (OPA), trinitrobenzene sulphonic acid (TNBS) and pH-stat methods were compared for the determination of degree of hydrolysis (D.H.) as a measure of the extent of proteolysis of milk proteins by trypsin and chymotrypsin. Compared to the OPA method, TNBS method resulted in lower values of D.H. For whole proteins and higher values for ultrafiltered hydrolysates due to an interference wi!h lactose. The pH-stat method gave D.H. values slightly higher ( 10,70) than those obtained by OPA method. The OPA method is rapid, simple, sensitive, do not interfere with lactose and can be performed during the hydrolysis process. 18. INDIVIDUAL VARIATION IN THE DEGREE OF GLYCOSYLATION OF K-CASEIN IN THE MILK OF HOLSTEIN COWS. G. Robitaille*, M. Legare, K.F. Ng-KwaiHang and H. Monardes, Department of Animal Science, Macdonald College of McGill University, Ste. Anne de Bellevue, P.Q. H9X ICO. In milk, K-casein is the major glycoprotein. Shorts oligosaccharides, which contain a N-acetylneuraminic acid as terminal carbohydrate, are O-linked to threonines located in the caseinomacropeptide region of the protein. The aim of this study was to determine the individual variation in the glycosylation extent of K-casein. The milk of 15 Holstein cows were collected twice a month and the sugar content of K-casein was estimated by an assay specific for N-acetylneuraminic acid on the casein pellet obtained by precipitation at pH 4.6. The milk was also analysed for protein, casein serum protein, fat and somatic cell count using standar methods. The relative proportion of as-, (3- and K-casein were determined by a densitometric analysis after electrophoresis of casein fraction on urea gel. The N-acetylneuraminic acid content of K-casein varied between 30 and 80 Hg/mg of K-casein. The concentration of N-acetylneuraminic acid in the milk ranged between 60 and 180 Ilg/ml with an average of 991lg/ml of milk. The variation during the lactation period and the possible link between the sugar content of K-casein and the level of production will be discussed. Supported by NSERC Strategic grant. 19. SOLID FAT CONTENT AND OTHER PHYSICAL PROPER. TIES OF MARGARINES. E. Postmus, J.M. deMan and L. deMan, Department of Food Science, University of Guelph, Guelph, Ont. NIG 2Wl. Solid fat content in Canadian and U.S. stick margarines was estimated by pulsed NMR at 10° and 22°C. The solid fat content of the isolated fats was measured using IUPAC and AOCS tempering procedures. When using the IUPAC methods the SFC values at 10°C for the fat were 130,70 higher than the values obtained with the margarine. At 22°C the values were 2.50,70 higher. With the AOCS method the SFC values at 10°C for the fat were 4.20,70 higher than the values for the margarine. At 22°C these values were 0.70,70 lower. Softening points and DSC melting and crystallization data were obtained. 20. PECTINESTERASE NATIVE ET PECTINASE AJOUTEE DANS LA FABRICATION DU JUS DE CAROTTES. M. H. Munsch et R.E. Simard, Departement de sciences et technologie des aliments, Universite Laval, Quebec, P.Q. GIK 7P4. Con. Inst. Food Sci. Technol. J. Vol. 22. No. 4, 1989
Le blanchiment a I'eau des carottes entieres (3 a 1I min) pour empecher le brunissement, a pour effet cl'activer la pectinesterase native. S'il y a un delai (10 a 30 min) avant I'extraction du jus, nous observons une augmentation de matiece seche, de carotene et de methanol dans le jus. Cet effet est cependant beaucoup moins important que I'effet de la maceration enzymatique par une pectinase commerciale. 21. TEXTURAL AND ENZYMATIC STUDIES OF THE EFFECTS OF CHILLING TEMPERATURES ON THE RIPENING PROCESS IN MATURE GREEN TOMATO FRUIT. A.G. Marangoni, R.L. Jackman and D.W. Stanley, Department of Food Science, University of Guelph, Guelph, Ont. NIG 2WI. The effects of cold temperatures on the ripening of mature green tomato fruit (Lycopersicon esculentum vaT. Caruso) was studied. Peroxidase activity increased due to chilling (p < 0.05) but did not vary during the ripening period. Pectinmethylesterase activity increased dramatically due to chilling (p < 0.001) and dropped during ripening, reaching values similar to those of controls. Total polygalacturonase (PG) and polygalacturonase 1 (PG I) activity increased more for chilled fruit during the ripening period than for control fruits (p <0.001). The coefficient of elasticity (k = Maximum Force/Maximum Deformation), as determined by two plate compression (TPC), constant area compression (CAC) and puncture (P) for tomato pericarp tissue during ripening, proved to be the most sensitive textural parameter for assessment of structural alterations in tomato tissue. The coefficient of elasticity for all textural measurements was highly correlated with PG and PG activities (0.7 < r < 0.9; p < 0.01), depicting closely the ripening process. 22. THE ALPHA-AMYLASE INHIBITORY ACTIVITY OF PROTEINS OF Phaseolus BEANS. Z. Li*, I. Alii and S. Kermasha, Department of Food Science and Agricultural Chemistry, Macdonald College of McGiII University, Ste. Anne de Bellevue, P.Q. H9X ICO. Protein isolates which show bipyramidal crystalline, spheroidal and amorphous microstructures were prepared by acidic and by alkaline extractions of Phaseolus vulgaris (white kidney, navy) and Phaseolus lunatus (baby lima, large lima). Evaluation of the protein isolates for x-amylase inhibitory activity indicated that all isolated proteins were inhibitory towards x-amylase hydrolysis of starch. X-amylase inhibitory activity ranged from 40 to 260 units/g protein; this represented 0,70 inhibition ranging from 20.80,70 to 60.40,70. There was no relationship between the X-amylase activity and the microstructures of the isolated proteins. The bipyramidal crystalline protein of white kidney bean showed the highest xamylase inhibitory activity (260 units/g protein). 23. PURIFICATION AND CHARACTERIZATION OF LIPOXYGENASE OF CANOLA SEED (Brassica sp.). A. Khalyfa*, S. Kermasha and I. Alii, Department of Food Science and Agricultural Chemistry, Macdonald College of McGill University, Ste. Anne de Bellevue, P.Q. H9X ICO. Canola lipoxygenase was extracted and partially purified by precipitation with solid ammonium sulfate at 20-500,70 of saturation. Further purification of the enzyme extract was performed by ion-exchange chromatography on DEAE-cellulose. The purified enzyme demonstrated the presence of a major and two minor isozymes similar to those obtained by the analysis of a commercial soybeanlipoxygenase. Preparative purification of the enzyme was also performed by liquid chromatography on Sepharose 6B and resulted in a single major peak. Preparative ion exchange fast protein liquid chromatography (FPLC) on Mono Q HR resulted in a major and two minor isozymes. The pH for optimum activity was 7.5. The effect of cyanide on the enzyme activity was investigated. The substrate selectivity of canola lipoxygenase was also determined. 24. PURIFICATION AND CHARACTERIZATION OF TRANS· AMINASES OF FRENCH BEANS (Phaseolus vulgaris) SEED. S. Kermasha, I. Alii and M. Metche, Department of Food Science and Agricultural Chemistry, Macdonald College of McGill University, Ste. Anne de Bellevue, P.Q. H9X ICO; and Laboratoire de
Abstract / 405