The wort from the malted barley used in the Scotch Malt Whisky process must be obtained solely from the activity of enzymes associated with the malted barley. Little or no detailed studies have been reported on the complex mixtures of enzymes found in malted barley, nor their subsequent activity and fate within the Scotch Malt Whisky process. The aims of this study were to determine assay procedures for a total of 17 enzymes, ascertain their suitability within the heterogeneous mixture of a malted barley extract and then establish the enzyme activity levels within the production process. Method development of the assay procedures gave rise to specific assays for 13 enzymes. Especially important were those for a-amylase, using the Phadebas substrate, and the I!-nitrophenyl-maltopentaose substrate for β-amylase. Both assays were found to be specific within the complex mixture of malted barley wort, with all other carbohydrase enzymes active. Enzyme activities between malted barley varieties were studied and compared. This suggested that differences occurred between the enzyme levels of varieties, as well as within a single variety. These may be due to malting conditions or to geographical, environmental and/or climatic factors associated with barley cultivation. The activities and fate of the enzymes were followed during the production process. Although the distillery where the study was carried out employed an infusion mashing system, the results obtained may also be valid in the semi-Iauter/lauter type systems used within the industry. Malted barley enzymes were active during the initial stages of fermentation, but thereafter other enzyme systems were evident. These were most likely associated with yeast and bacteria.

The possibililty of using the simple technologies of malting and fermentation to modify endogenously the sorghum grain components, to alleviate the grittiness, dryness and high crumb firmness caused by the inclusion of sorghum flour in composite bread, was investigated. The most suitable grain and the optimal malting time for sorghum for bread¬making, were selected by malting five sorghum cultivars, up to 8 days, and evaluating them for the highest protein modification and lowest dry matter losses. On that basis, a 6¬days malt of Local White, a relatively high protein sorghum (10.7%), was selected. Sorghum malt flour potentially suitable for bread-making was produced by boiling the selected malt, rather than drying it at high temperatures, stewing or steaming. Boiling was most effective in inactivating the amylases and in increasing the pasting viscosity of sorghum malt. The bread made with boiled malt flour (30%) had an improved crumb structure and water-holding capacity, a softer crumb and increased resistance to staling, compared to bread made with sorghum grain flour (30%). Bread-making with reconstituted flours from flour and bran fractions of whole sorghum grain and whole boiled sorghum malt indicated that the bread improving effect of malting and boiling was due to dextrinization and gelatinization of starch, and to the increase of total and water-soluble pentosans, and crude fiber. Dextrinization and gelatinization of starch decreased the gelatinization temperature and the rate of starch retrogradation, thus decreasing the crumb firmness and firming rate of sorghum and wheat composite bread. However, high levels of gelatinized starch decreased dough strength and bread volume. The increase of total pentosans and crude fiber of sorghum malts, caused by germinating grains roots and shoots growth, and the increase of water-soluble pentosans, due to hydrolysis of the non-starch polyssacharides during malting, significantly increased flour and dough water-holding capacity. Thus, crumb structure was improved and crumb firmness and crumb-firming rate decreased. Treatment of sorghum flour with endo-(l-4)-β-xylanase to determine whether endoxylanases could solubilize sorghum pentosans, increased the water-soluble pentosans slightly, indicating the potential of endoxylanases to improve the bread-making quality of sorghum flour. However, heating the endoxylanase treated flour to inactivate the enzyme, so as to determine its specific effect, gelatinized the starch and decreased the bread volume. A natural lactic acid fermentation of sorghum flour, followed by drying at 60°C, decreased the pH of sorghum flour from 6.2 to 3.4 and slightly increased the gelatinized starch and the pasting viscosity of sorghum flour. Apparently, the low pH caused higher loaf volume and improved crumb structure and softness by suppressing the amylases and by increasing the viscosity of dough, and hence increasing its gas-holding capacity. Adding wet fermented sorghum flour directly to wheat flour (sourdough process), as an alternative to drying, further increased the volume and decreased the crumb firmness. Fermentation and drying also improved the protein digestibility of sorghum composite bread. Consumer panel members liked the bread made with boiled sorghum malt flour most, apparently because it was softer, more moist and had a fine malt flavor. They liked the bread made with fern1ented and dried sorghum flour less, apparently because it had a pronounced sour taste. Malting and fermentation can be successfully used to produce acceptable sorghum and wheat composite bread. Fermentation is probably the most suitable technology for poor developing countries because it is simple and effective. Steaming the malt and adding the endoxylanases directly when mixing the dough, to eliminate the flour drying step and to reduce starch gelatinization, should be looked at further. / Thesis (PhD (Food Science))--University of Pretoria, 2005. / Food Science / unrestricted

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-09-13T13:08:07Z No. of bitstreams: 1 2016 - Glenda Ribeiro de Oliveira.pdf: 12901294 bytes, checksum: 80c7709c3b1f78480862304148029e9c (MD5) / Made available in DSpace on 2017-09-13T13:08:07Z (GMT). No. of bitstreams: 1 2016 - Glenda Ribeiro de Oliveira.pdf: 12901294 bytes, checksum: 80c7709c3b1f78480862304148029e9c (MD5) Previous issue date: 2016-08-30 / Four outbreaks of a neurological disease affecting dairy cattle which consumed malted barley waste contaminated with Aspergillus clavatus in the municipalities of Valen?a, Paty do Alferes, and Barra Mansa, in the state of Rio de Janeiro, are described. In all farms, stored malted barley waste exhibited visible fungal contamination and only the animals that ingested the by-product got sick. Animals exhibited muscle tremors, hyperesthesia, ataxia, progressive paresis and paralysis, and marked weight loss. Affected animals were walking with knuckling of hindlimb fetlocks, and some would assume a sitting-dog position. When forced to move around, falls were frequent. There was marked decrease in milk production, even though appetite and thirst remained normal up to the moment of death or euthanasia. Clinical evolution varied from 1 to 16 days. From the animals that recovered, four remained with mild locomotor system sequelae. Morbidity varied between 41.42% and 73.08%, mortality between 33.33% and 69.23%, and lethality between 51.11% and 94.73%. Macroscopic alterations included focal pale areas on the myocardium, semitendinosus, semimembranosus, adductor, pectineus, and Longissimus dorsi muscles. Histopathology was characterized by degenerative-necrotic alterations, tumefaction, vacuolation, and chromatolysis of neurons of cerebellar peduncle nuclei, base of the brain, medulla oblongata, and grey matter of the medulla (the H shape). At histology, muscular lesions were characterized by degeneration and coagulative necrosis, at times with incipient mineralization. In one of the bovines, there was also coagulative necrosis of the myocardium , and presumably, myoglobinuric nephrosis. Fungal culture of samples of malted brewer waste resulted in isolation and identification of A. clavatus. The clinical pathological picture was reproduced experimentally in sheep which consumed 40g/kg of malted brewer waste per day, which was collected from the two investigated farms; these animals developed clinical signs and microscopic lesions similar to those observed in bovines. We conclude that even though brewery by-products have a reasonable cost/benefit ratio for bovine feeding, there is a need to observe steps to avoid eventual poisoning and consequent economical losses / Descrevem-se quatro surtos de uma doen?a neurol?gica que afetou bovinos de aptid?o leiteira que consumiam ?cevada? (baga?o de malte) contaminada por Aspergillus clavatus nos munic?pios de Valen?a, Paty do Alferes e Barra Mansa, no Estado do Rio de Janeiro. Em todas as propriedades, a cevada estocada apresentou vis?vel contamina??o f?ngica e somente os animais que ingeriram o subproduto adoeceram. A morbidade variou entre 41,42% e 73,08%, a mortalidade entre 33,33% e 69,23% e a letalidade entre 51,11% e 94,73%. Os animais evidenciaram tremores musculares, hiperestesia, ataxia, paresia e paralisia progressivas e marcada perda de peso. Os mais afetados caminhavam com apoio sobre os boletos flexionados e alguns assumiam a posi??o de "c?o sentado". Quando os animais eram for?ados a movimentarem-se, as quedas eram frequentes. Houve acentuada queda na produ??o leiteira, embora o apetite e a dipsia tenham se mantido normais at? pr?ximo ? morte ou ? eutan?sia. A evolu??o cl?nica variou de 1 a 16 dias. Dos animais que se recuperaram, quatro permaneceram com sequelas locomotoras leves. As altera??es macrosc?picas inclu?ram ?reas p?lidas focais na musculatura card?aca, m?sculos semitend?neo, semimembran?ceo, adutor, pect?neo e Longissimus dorsi. O quadro histopatol?gico caracterizou-se por altera??es degenerativo-necr?ticas, tumefa??o, vacuoliza??o e cromat?lise nos neur?nios dos n?cleos dos ped?nculos cerebelares, da base do c?rebro, da medula oblonga e do ?H? medular. Histologicamente, as les?es musculares caracterizaram-se por degenera??o e necrose coagulativa, com mineraliza??o, por vezes, incipiente. Em um bovino havia, adicionalmente, necrose coagulativa no mioc?rdio e nefrose mioglobin?rica. O cultivo micol?gico das amostras de cevada resultou no isolamento e identifica??o do fungo A. clavatus. O quadro cl?nico patol?gico foi reproduzido experimentalmente em ovinos que consumiram 40g/kg de cevada por dia, coletada de duas das propriedades investigadas; esses animais desenvolveram sinais cl?nicos e les?es microsc?picas, em grande parte, similares ?s observadas nos bovinos. Conclui-se que embora os res?duos da ind?stria cervejeira tenham razo?vel rela??o custo-benef?cio na alimenta??o de bovinos, ? necess?rio que se observem alguns cuidados para evitar eventuais intoxica??es e consequentes preju?zos econ?micos.

La souche Carnobacterium maltaromaticum LMA 28, isolée d’un fromage à pâte molle, possède des propriétés physiologiques non conventionnelles pour une bactérie lactique. Sa croissance en TSB-YE et en lait traduisent son exigence nutritionnelle en facteurs de croissance facilement assimilables et sa faible vitesse de production d’acide lactique à partir de glucose, lactose, fructose et saccharose. Le galactose n’est pas métabolisé et lors de l’hydrolyse du lactose n’est pas excrété dans le milieu de culture. Les caillés lactiques sont obtenus après des durées d’incubation non compatibles avec les cadences industrielles. De plus, ils présentent une texture très friable. La numération et l’identification de cette souche, en vue de suivre son comportement dans une matrice fromagère, ont été optimisées par la mise au point du milieu de culture sélectif CM, à l’aide de plan d’expériences, et par la technique de PCR. Le comportement de C. maltaromaticum LMA 28 a été comparé à ceux de deux souches lactiques d’intérêt technologique Lc. lactis DSM 20481 et S. thermophilus INRA 302, dans une large gamme de températures (3 à 37 °C) et de pH (5,2- 8,0). Des essais en co-culture, associant cette souche avec Lc. lactis DSM 20481 ou avec S. thermophilus INRA 302, ont montré que la production d’acide lactique était due à la croissance de la souche lactique traditionnelle. Cependant C. maltaromaticum LMA 28, souche lente, n’est pas inhibée par cette acidification. L’aptitude fromagère de C. maltaromaticum LMA 28 a été testée lors de deux fabrications de fromages à pâte molle. Inoculée à différents niveaux de population, elle a été mise en évidence à tous les stades de la fabrication. Présente à une concentration très faible dans le lait de fabrication, elle devient une flore lactique dominante après l’affinage et le stockage en réfrigération. Cette aptitude technologique est en relation avec son caractère psychrotrophe et sa faculté à se développer activement à des pH alcalins. Son « alimentarité », testée par la production d’amines biogènes, a montré des niveaux nuls ou très faibles en tyramine et en histamine, comme avec S. thermophilus INRA 302 et avec Lc. lactis DSM 20481. L’optimisation de sa production de flaveurs maltées a été abordée sur milieu TSB-YE et sur lait, supplémentés avec de la leucine, de l’isoleucine ou de la valine. La production de 3-méthylbutanal est la plus importante. Les analyses sensorielles des fromages contenant des niveaux de population importants (108-109 ufc.g-1) de C. maltaromaticum LMA 28 n’ont pas permis de mettre en évidence cet arôme. Présente dans de nombreux fromages français AOC ou non AOC, cette espèce opportuniste, de statut GRAS, pourrait être considérée comme un auxiliaire de fabrication intéressant, car elle permet un ralentissement du vieillissement des fromages, en évitant notamment l’apparition de flaveurs désagréables. Cette flore lactique psychrotrophe pourrait être retenue comme flore bactérienne d’affinage / The C. maltaromaticum LMA 28 bacteria strain, isolated from soft cheese, was observed to possess non conventional lactic bacteria physiological properties. Its growth in TSB YE medium and milk was found to be characterised by the requirements for easily assimilated growth nutrients and a low kinetic rate of lactic acid production from glucose, lactose, fructose and sucrose. In addition, it was found to not metabolise galactose or not excrete it during the hydrolysis of lactose. In the process of milk fermentation, it not only took an unusually long duration but produced products of fragile texture. In order to eventually determine the behaviour of this strain in the process of cheese-making, a selective culture medium CM was developed using an experimental design and PCR techniques for its isolation and identification. The behaviour of C. maltaromaticum LMA 28 was compared with that of two strains of lactic bacteria of technological interest namely Lc. lactis DSM 20481 and S. thermophilus INRA 302, within a wide temperature range (3 to 37°C) and of pH (5.2 – 8.0). Tests carried out in co-culture associating this strain with Lc. lactis DSM 20481 or with S. thermophilus INRA 302 showed that the lactic acid production was due mainly to the growth of the traditional lactic strain. In the process, the C. maltaromaticum LMA 28 slow strain was observed not to be inhibited by acidification. The cheese-making potential of C. maltaromaticum LMA 28 was evaluated in the process of two soft cheese manufactures. Inoculated at various levels of population, it was observed to be present at all manufacturing stages. Generally present at very weak concentrations in the starting milk, it becomes a dominant lactic flora following ripening and refrigeration storage. This technological aptitude is in relation with its psychrotrophic character and its ability to actively develop in alkaline medium. Its “alimentarity”, tested by its ability to produce biogenic amines, showed zero or very low levels in tyramine and histamine, as in the case of S. thermophilus INRA 302 and Lc. lactis DSM 20481. The optimization of its malted flavour production capacity was carried out on a TSB-YE medium and on milk supplemented with leucine, isoleucine or valine. In this process the production of 3-méthylbutanal was observed to be the most abundant product while cheese containing high levels (108-109 ufc.g-1) of C. maltaromaticum LMA 28 did not exhibit this flavour. This notwithstanding, the presence of this species of GRAS status in many French AOC and non AOC cheeses could be considered as an interesting auxiliary in cheese manufacturing process since it tends to slow down the aging process and thereby retard the development of unpleasant flavours. In this respect this strain of psychotrophic lactic bacteria could be retained as a flora for cheese ripening process