Extraction des nutriments par macération enzymatique avec des pectinases

digestion characteristics. Their acceptance may depend upon public awareness to enhance health belief and industrial development to reduce preparation time. EVALUATION OF THE PIG AS A RESEARCH MODEL FOR STUDYING FERMENTATION IN THE GUT OF HUMANS. Heming*, S.E. and M. Wasilewski, Department of Nutritional Sciences, University of California, Berkeley, California 94720. This study was designed to evaluate the potential of the pig to serve as a model for studying fermentation in the gut of humans. A method was derived for collecting breath gas from the pig. The method is noninvasive, requires only a few minutes, and permits the animal to breathe in a normal manner. The concentration of hydrogen in the breath of pigs showed similar daily patterns to that of human subjects, and both species showed higher mean concentrations of hydrogen for the pectincontaining diet than for the fiber-free or corn bran-containing diets. VITAMIN RETENTION IN FOODS AFTER HOME DRYING AND STORAGE. Desrosiers*, J., G. Paquette and T.G. Smyrl, School of Food Science, Macdonald Campus of McGill University, Montreal, Quebec. An Equi Flor dehydrator system designed for the home was used to dry green peppers and peaches. The green peppers were sliced and dehydrated 7 h at 51-55° C. Peaches were scalded 2 min., cut in sections, dipped in an ascorbic acid solution and dehydrated 16 h at 32-35° C. The vitamin C content decreased significantly with time in both green peppers and peaches as determined by a microflourometric method. The presence oflight during storage had an adverse effect on the Viatamin C retention whereas severe losses were observed in the foods that were rehydrated and then drained. The percentage retention of B-carotene determined by spectophotometry was significantly reduced after the home dehydration process and during a six-months storage period. CONTRIBUTION OF BREAKFAST CEREALS TO THE DAILY INTAKE OF SOME B-VITAMINS. Hoppner*, K., and P. Verdier, Nutrition Research Division, Health Protection Branch, Health and Welfare Canada, Ottawa, Ontario KIA OL2. Breakfast cereals are an important component of the cereal food group, both nutritinally and as a nutrient delivery system. From previously determined data on the folacin, pantothenic acid and biotin content of breakfast cereals available on the Canadian market, and individually recorded daily intakes of breakfast cereals during the Nutrition Canada Dietary Survey, the contribution to the daily intake of these vitamins by different age and sex groups was calculated and will be shown. Present data indicate that breakfast cereals contribute substantially toward the intake of the above vitamins, the magnitude of the contribution depending on choice and consumption. THE CANADIAN NUTRIENT FILE. Verdier P., Nutrition Research Division, Bureau of Nutritional Sciences, Health and Welfare Canada, Ottawa, Ontario KIA OL2. Tables of the nutrient composition of foods are basic to the calculation of nutrients in foods and of all the dietary intake studies. The Canadian Nutrient File computer tape provides a data base for the nutrient content of Canadian Foods. The File is derived from the United States department of Agriculture's Handbook No. 8 series and from the Nutrition Canada Data Base. It has been designed to allow for the addition of foods and nutrients with a yearly updating. Examples of the computer file format, contents, accessibility of software programs and future development plans will be shown. BIOAVAILABILlTY OF THE ENDOGENOUS IRON OF WHEAT BRAN. Pegg*, D.L. and J. Vanderstoep, Department of Food Science, University of British Columbia, Vancouver, British Columbia V6T 2A2. The bioavailability of the endogenous iron of Hard Red wheat bran was estimated using an in vitro method. The method simulates gastrointestinal digestion and measures soluble, low molecular weight iron. The bran was incorporated into a muffin product and the influence of baking and bran particle size on the bioavailability of iron was examined. The chemical profile (elemental ferrous, ferric, soluble and complexed forms) of the endogenous iron was determined in an attempt to relate changes in the bioavailability of iron to changes in the chemistry of iron.

xviii / Affaires de I'Institut

EXTRACTION DES NUTRIMENTS PAR MACERATION ENZY_ MATIQUE AVEC DES PECTlNASES. Munsch, Marie Helene et Ronald E. Simard, Centre de Recherches en Nutrition, Universite Laval ' Quebec, Que. Au cours de I'etude des procedes de fabrication du jus de carottes I'extraction des nutriments a ete examinee. Le jus de carotles crues est plus riche en matieres azotees. Le jus de carotles blanchies est plus concentre en mineraux, en carotene, et en matieres azotees, particuliere_ ment apres maceration enzymatique. Cependant, le calcium reste fixe dans le residu de presse, et n'est libere dans le jus qu'en abaissantle pH avec de l'acide critique. PURIFICATION AND CHARACTERIZATION OF CATHESPIN C FROM ATLANTIC SQUID. Hameed*, K.S. and N.F. Haard, Department of Biochemistry, Memorial University of Newfoundland, SI. John's, Newfoundland AlB 3X9. Previous studies in our laboratory indicated that a partially purified preparation of cathepsin C (E.C. 3. -4. 14. 1) from Atlantic short finned squid (lllex illescebrousus) potentiates the formation of meaty flavour in fermented squid mantle and whole capelin. Accordingly, a study was undertaken to further purify and characterize the cathespin C from squid liver. The enzyme was isolated and partially purified by autolysis, ammonium sulfate precipitation, heat treatment and affinity chromatography. Enzyme activity was determined using two specific substrates, gIycl-L-phenylalanineamide acetate and glycyl-L-phenylalanine-f3-napthylamide. Both hydrolytic and transferase activity of the enzyme was stimulated by the thiol reagents 2-mercaptoethanol and f3-mercaptoethylamine, and an apparent absolute requirement for Cl ions was established. The enzyme was inhibited by iodoacetate. The molecular weight of the enzyme was found to be 200,000 daltons, it exists in various low molecular weight states which appear to represent associated forms of an octomer of 25,000 dalton subunits. TRYPSIN INHIBITORS OF FABA BEANS. Anderson*, M.J. and E. Hoehn, Department of Food Science, University of Manitoba, Winnipeg, Manitoba R3T 2N2. The existence of faba bean trypsin inhibitors has been well documented. Information on the level and number of inhibitors and their properties is contradictory. The purpose of this study was to optimize the extraction procedure and to isolate and characterize faba bean inhibitors. Extraction of trypsin inhibitors from faba bean protein concentrate was carried out at pH 2,3,4,5,6,7 and 8 at NaCllevels of 0, 1,2,3,4 and 5%. The optimum was found at pH3 and 2% NaC!. Affinity chromatography followed by chromatofocusing yielded seven fractions with trypsin inhibitor activity, with pI's ranging from 6,7.2,7.6,7.8,8.3, 8.6 and 9. There was evidence of trypsin inhibitor-faba bean protein interactions, thus explaining contradictory reports in the literature. INTERACTIONS OF FLAVOUR MOLECULES WITH FABABEAN PROTEINS. Ng*, P.K.W. and E. Hoehn, Department of Food Science, University of Manitoba, Winnipeg, Manitoba R3T 2N2. The capabilities of proteins to bind flavour molecules has been widely investigated. However, there is a lack of studies which are designed to correlate chemical binding studies with sensory analysis. The purpose of this study was I) to investigate mechanisms involved in vanillin-fababean protein isolate interactions and 2) to correlate binding studies with sensory analysis of vanillin-protein systems. Binding studies were carried out using a micropartition system and data were evaluated by Klotz plots. Binding forces between vanillin and fababean protein were weak and the number of binding sites increased when protein was denatured, thus indicating hydrophobic interactions. Sensory analysis revealed that these interactions resulted in a significant decrease of the perceived vanillin flavor in vanillin-protein systems. EFFET DE LA TEMPERATURE SUR L'ACTIVITE DE LA CATALSE DE CRABE ET DE MORUE. Bourassa*, Michel et Alexandre Strachan, Departement des sciences pures, Universite du Quebec a Rimouski. La presence de catalase a ete demontre chez plusieurs especes de poissons dont la morue. Des echantillons de morue (Cadhus Morrua) et de crabe (Chioneocetes opili) ont ete homogeneises (4° Cl dans I'ethanol .02% et centifuges afroid 10 minutes a 10,000 RPM. Les surnageants ont ete incubes 15 minutes ades temperatures variant de 5 a60° C. Les essais enzymatiques de catalase ont ete faits en utilisant la methode de flottaison du

J. Inst. Can. Sci. Technol. Aliment. Vo!. 16, No. 3. 1983