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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

EFFECT OF DIFFERENT SPROUTING CONDITIONS ON ALPHA AMYLASE ACTIVITY, FUNCTIONAL PROPERTIES OF WHEAT FLOUR AND ON SHELF-LIFE OF BREAD SUPPLEMENTED WITH SPROUTED WHEAT

Shafqat, Saba 10 May 2013 (has links)
In this study sprouting two different wheat cultivars under various environmental conditions revealed that varietal variation is the most important factor affecting α-amylase quantity as well as quality to modify flour functionality significantly, followed by pre-soaking duration and temperature. Sprouted wheat flour post five days germination was utilized at different rates to prepare 100 g composite breads. There was an improvement in baking quality and shelf life of breads containing 1% and 5% sprouted flour resulting in a significantly increased loaf volume, better texture, and less retrogradation during 7 days post baking than the control. This study presents opportunities for industry to fortify baked products with sprouted wheat flour to yield functional whole grain products that are nutrient dense and naturally shelf-stable. / MITACS
32

Analyzing the Limits and Extent of Alpha-Amylase Catalyzed Removal of Starch-Based Filter Cake

Dharwadkar, Pavan S. 2011 December 1900 (has links)
The ability of starch to impart functions including fluid-loss control, cuttings transport, and rheological characteristics to water-based drilling fluids has led to its widespread use in the oil industry. The filter cake deposited by these drilling fluids often employs sized solid particles and starch to inhibit fluid loss into the formation. This inherently causes damage to the formation by impairing the permeability and must be removed before production. An alpha-amylase enzyme treatment was found to provide an effective approach to degrading starch in filter cake. In this work, an alpha-amylase enzyme treatment was analyzed by determining the extent of degradation of starch in filter cake using the iodine test, identifying degradants using high performance liquid chromatography, spectrophotometrically monitoring the concentration of enzyme, and measuring the cleanup efficiency of the enzyme treatment using a static filter press apparatus. The alpha-amylase enzyme used in this study was found to have a molecular weight under 30,000. The activity of the alpha-amylase enzyme was found to be sensitive to pH and temperature. The alpha-amylase enzyme was found to denature at temperatures above 165 degrees F and reversibly deactivate at pH below 4. Optimal conditions for alpha-amylase activity were found to be 150 degrees F and pH 6.5. The enzyme treatment works by hydrolyzing the interior glycosidic bonds of amylose and amylopectin residues of starch, creating soluble poly- and oligosaccharides and glucose. The enzyme treatment did not dissolve the calcium carbonate sized solids and a 5 wt. % hydrochloric acid postflush was necessary. The cleanup efficiency of the enzyme at pH 6.5 and room temperature treatment in conjunction with the postflush in a static test was 73% at 10% v/v concentration. Degradants resulting from alpha-amylase were identified chromatographically. Enzyme concentration remained steady prior to and after treatment.
33

An Investigation into Bioactive Proteins and Their Changes During Imbibition, Germination and Development of Red Kidney Bean Seeds (Phaseolus vulgaris L.)

Alizadeh, Hossein January 2011 (has links)
Red kidney bean seeds (Phaseolus vulgaris) contain a variety of bioactive proteins including lectins, enzyme inhibitors, hydrolytic enzymes and antifungal proteins. The aim of this research was to investigate activities of selected low pH and heat-stable bioactive proteins extracted from different parts of red kidney bean seed, seedling and pod as well as seed and root exudates. Crude red kidney bean seed extracts inhibited growth of Alternaria alternata as well as its protease activity, but not its amylase activity. A protein with inhibitory activity against growth of A. alternata was purified from extracts of the red kidney bean cotyledons and embryonic axis. This purified bean protein was devoid of chitinase and β-1, 3- glucanase activities. Also, it did not inhibit porcine pancreatic α-amylase, bovine trypsin, amylase and protease of A. alternata suggesting that the antifungal activity of the protein is not related to these activities. Proteinaceous extracts of red kidney bean cotyledons induced melanin and conidia formation in mycelium of A. alternata. A protein responsible for this conidiation inducing effect was shown for the first time to be a mannose-binding lectin which is also known as PvFRIL (Phaseolus vulgaris fetal liver tyrosine kinase 3-receptor interacting lectin). An unexpected finding was that extracts of the embryonic axis stimulated rather than inhibited porcine α-amylase activity. Phytohemagglutinin (PHA-L in particular), co-extracted with α-amylase inhibitor from red kidney bean seeds, was implicated as an α-amylase stimulator with the potential of greatly assisting digestion of starch. In cotyledonary extracts, amylase stimulatory activity was masked by amylase inhibitory activity that was inactivated when the extracts were boiled for 10 min. An in-gel non-denaturing electrophoretic method was used to show presence of porcine α-amylase isoinhibitors in extracts of the cotyledons and embryonic axis. All other seedling parts as well as seed and root exudates had amylase stimulatory activity. Another improved non-denaturing electrophoretic method with immobilized azoalbumin was developed for in-gel detection of isoinhibitors of bovine trypsin in seed parts. It eliminates the need for both time-consuming and labourious staining, destaining or renaturation steps used in other methods. Accumulation of most of the selected bioactive proteins during seed development in different seed parts appeared to start at 20 days after flower abscission. The activities of these proteins decreased to lower levels after 11 days of germination. Besides these observed developmental changes, under abiotic (UV-C irradiation) and biotic (seedlings co-cultured with A. alternata) stress, increased activity of some of the selected bioactive proteins were detected. In conclusion, this study has contributed to a better understanding of antifungal activity and the selected bioactive proteins in extracts of red kidney bean.
34

Structural and functional investigations of Lactobacillus reuteri glucansucrase ... with crystallographic studies on an [alpha]-amylase and a prolyl endoprotease from Aspergillus niger /

Vujičić Žagar, Andreja, January 2007 (has links)
Proefschr. Rijksuniversiteit Groningen. / Met lit. opg.-Met samenvatting in het Nederlands.
35

Onderzoekingen over microbenamylasen

Smits Van Waesberghe, Franciscus Augustinus Marie Josephus. January 1900 (has links)
Proefschrift - Delft. / Summary in Dutch and English. Includes bibliographical references.
36

Die a-Amylase @ aus Bacillus amyloliquefaciens Verbesserung der Alkaliaktivität und Steigerung der spezifischen Aktivität mittels gerichteter Evolution /

Bessler, Cornelius. Unknown Date (has links) (PDF)
Universiẗat, Diss., 2002--Stuttgart.
37

Salivary alpha-amylase reactivity during discussion of the death of a spouse in recently bereaved elders

King, Edward 13 July 2017 (has links)
In this study, bereavement-related biological and physiological stress reactivity during the discussion of a loss are evaluated by collecting saliva samples in patients aged 55 or more who have lost a spouse within the last 12 months. The concentration of salivary α-Amylase, a marker for stress, is measured. Grief symptoms are also examined in these individuals. BACKGROUND: Grief is a complex psychobiological phenomenon triggered by the loss of a loved one, and that comprises emotions (e.g., yearning, longing, intense feeling of sorrow/emotional pain), thoughts (e.g., thoughts or images about the deceased, difficulty accepting the death, guilt), and behaviors (e.g., avoidance of reminders, spending time with deceased belonging). Because bereavement is a major stressor, it has been suggested that the grief reaction is associated with increased sympathetic activity. Salivary α-Amylase levels have been proposed to be a reliable non invasive biomarker of sympathetic activity. The present study aims to examine salivary α-Amylase reactivity to discussion of the death of a spouse in older adults, and the relationship between this reactivity and grief symptom severity. METHODS: Participants were N=8 individuals who have lost a spouse within the last year (Mean(SD)age=72.8(7.5); 60% women); Mean(SD) time since death=10.6(2.5) months). Participants completed self-reported measures including the 19-item Inventory of Complicated Grief (ICG; total score ranges 0-76; Prigerson et al. 1995). The Mean(SD) ICG score was 30.5(11.5). Saliva samples were collected using cotton swabs and Salivettes at four time points during the screen: right before discussion of the loss (T1), right after discussion of the loss (T2), before screening for psychiatric disorders (T3), and at the end of the screening (T4). Salivary α-Amylase samples were frozen and assayed using a kinetic enzyme assay kit specifically designed and validated for the kinetic measurement of salivary α-Amylase activity. A repeated measure ANOVA, with α-Amylase as the dependent variable, and time as the within subject repeated factor were conducted to examine differences in α-Amylase activity across time points. Further, we examined the association between rise in α-Amylase activity (change between T1 and T2) and ICG scores. RESULTS: The ANOVA revealed a marginally significant main effect of time (F(3,20)=2.74, p=0.07), with α-Amylase activity being more elevated right after discussion of the loss (T2; Mean (SD)=194.9(79.4) µg/dL) compared to the other time points (T1: 140.00(77) µg/dL; T3: 140.5(56) µg/dL; T4: 143.0(70.3) µg/dL). Further, the rise in α-Amylase activity between T1 and T2, was marginally significantly associated with greater grief symptoms (r=0.69, p=0.08). CONCLUSION: Our preliminary findings suggest that discussion of the loss of a spouse may increase salivary α-Amylase activity, reflecting a potential increase in sympathetic activity. Targeting loss-related sympathetic reactivity might be an interesting avenue to decrease grief related distress and impairment. Limitations for this study include a small sample size and the absence of a real control condition. Future research examining sympathetic activity in grief and its relationship with persistent complex bereavement disorder pathophysiology is warranted.
38

Metabolismo germinativo de sementes de Passiflora alata Curtis tratadas com giberelinas e citocinina

Ferrari, Tainara Bortolucci [UNESP] 31 July 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-07-31Bitstream added on 2014-06-13T20:23:10Z : No. of bitstreams: 1 ferrari_tb_dr_botib.pdf: 518983 bytes, checksum: a92b144737e4cd94348b4b38f4115b5a (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O interesse pelo maracujazeiro-doce (Passiflora alata Curtis) tem crescido devido à qualidade dos frutos para consumo in natura e aos preços alcançados no mercado de frutas frescas. Iniciativas de expansão do cultivo de maracujazeiro-doce são de grande importância tanto para o mercado interno quanto para o externo. No entanto, muitos são os relatos de baixo percentual de germinação de sementes dessa espécie, o que dificulta a formação de mudas e de porta-enxertos vigorosos e, consequentemente, a formação de pomar uniforme e com boa produção. Isso sugere que trabalhos que estudem o metabolismo germinativo de sementes de maracujazeiro-doce sejam de grande importância. Sendo assim, foram instalados dois experimentos no Departamento de Botânica e um experimento no Departamento de Química e Bioquímica do Instituto de Biociências, da Unesp, Botucatu, SP com a finalidade de atingir os objetivos propostos. O primeiro experimento constou em determinar as fases da germinação das sementes de P. alata submetidas a concentrações de GA3 e GA4+7 + N-(fenilmetil)-aminopurina, enquanto que o segundo experimento estudou os efeitos desses reguladores vegetais na germinação do maracujá-doce. O delineamento experimental dos dois experimentos foi inteiramente casualizado, com 11 tratamentos e cinco repetições de 25 sementes por parcela, seguindo esquema fatorial 2x5 (reguladores x concentrações) e uma testemunha (água destilada) em comum. As concentrações utilizadas foram 100, 200, 300, 400 e 500 mg L-1 tanto para GA3 quanto para GA4+7 + N-(fenilmetil)- aminopurina. As sementes foram acondicionadas em ‘gerbox’ preto, contendo 10 mL das soluções com os reguladores vegetais e levadas à câmara de germinação, com temperatura alternada entre 20ºC por 8 h e 30ºC por 16 h. Para o experimento um foram avaliados grau de umidade das sementes, germinabilidade, velocidade e... / Interest in sweet passion fruit (Passiflora alata Curtis) has grown due to the quality of fruits for consumption in natura and prices achieved in the fresh fruit. Initiatives to expand the cultivation of sweet passion fruit are of great importance both for the domestic market and for the external. However there are many data of low percentage of seeds germination of this species. At this way, there is difficulty in the seedlings formation and vigorous rootstock and, consequently, in uniform orchard formation and with good production. This suggests that works to study the metabolism of sweet passion fruit seed germination have great importance. So, it had been installed two experiments at Department of Botany and one experiment at Department of Chemistry and Biochemistry, Bioscience Institute, in São Paulo State University, Botucatu, SP, with the aim to reach the considered purpose data. The first one had consisted of the determination of seeds germination phases subjected to concentrations of GA3 and GA4+7 + N-(phenylmethyl)-1H-purine-6-amine. The second experiment studied the effects of plant growth regulators on sweet passion-fruit germination. The experimental design had been totally randomized, with 11 treatments and five replications of 25 seeds in each plot, following factorial design 2 x 5 (regulators x concentrations), and a common control (distilled water). The seeds had been submitted to the following treatments: 100, 200, 300, 400 and 500 mg L-1, for GA3 and also for GA4+7 + N- (phenylmethyl)-1H-purine-6-amine. The seeds had been sown in black containers, containing 10 mL of solutions with plant growth regulators, and taken to the germination chamber, with temperature alternated between 20ºC for 8 hours and 30º for 16 hours. The seeds moisture degree (%), the percentage of germination, average time of germination, average speed of germination and total percentage of ... (Complete abstract click electronic access below)
39

Aproveitamento de subprodutos agroindustriais para a produção de amilases fúngicas: estudo de parâmetros fermentativos e caracterização das enzimas

Ferreira, Osania Emerenciano [UNESP] 29 July 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:27:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-07-29Bitstream added on 2014-06-13T20:56:15Z : No. of bitstreams: 1 ferreira_oe_me_jabo.pdf: 412993 bytes, checksum: aae1d57cd30b58d78f8d841727177cc0 (MD5) / A utilização de fermentação em estado sólido a partir de subprodutos agroindustriais possibilita a obtenção de várias biomoléculas de interesse industrial. As amilases são enzimas com grande aplicação nas indústrias têxtil, farmacêuticas, alimentícias e sucroalcooleira, representando aproximadamente 25% do mercado mundial. Neste trabalho foram isoladas três linhagens fúngicas (Rhizopus oryzae, Malbranchea pulchella e Chrysosporium zonatum), que apresentaram potencial amilolítico, quando cultivadas em três resíduos agroindustriais (quirera de arroz e de milho e farelo de trigo). Para a cepa que apresentou maior atividade enzimática, avaliou-se melhor substrato, tempo de cultivo, teores de umidade, fontes suplementares de nitrogênio, pH e temperatura de incubação, objetivando otimizar as condições de cultivo. Observou-se que a maior atividade enzimática foi obtida com a cepa de R. oryzae em 24 horas de fermentação, em meio de cultura contendo farelo de trigo como substrato, em temperatura de 35°C, utilizando solução de sais composta de NH4NO3 a 0,1% e MgSO4.7H2O a 0,1% como fonte de nitrogênio. Alterações de pH entre 4,0 e 6,0 não afetaram significativamente a síntese da enzima. A condições ótimas de atuação foram temperatura de 75°C e pH de 4,5. As enzima manteve-se estável a 75°C na ausência de substrato por 25 minutos / The use of fermentation in a solid state from agroindustrial byproducts permits the obtaining of several biomolecules of interest the industry, like the enzymes. The amylases are enzymes with great application on the textile, pharmaceutical and food industries, representing around 25% of the worldwide market. In this work three ungal strains (Rhizopus oryzae, Malbranchea pulchella and Chrysosporium zonatum) were isolated. They presented amylolytic potential when cultivated in three agroindustrial by products (brewers rice, corn grits and wheat bran). To the strain that presented the greatest enzyme activity, it was evaluated the best substrate, cultivation time, moisture content, additional sources of nitrogen, pH and incubation temperature, aiming the optimization of cultivation conditions. I was observed that the greatest enzyme’s activity was obtained with 24 hours of fermentation, in R. orizae in a culture medium that contained wheat bran as the substrate, at 35°C, using salt solution made with NH4NO3 0.1%, MgSO4.7h2O 0.1% and (NH4)2SO4 0.1% as nitrogen source. pH alterations between 4.0 and 6.0 didn’t change significantly the enzyme’s activity. The optimum conditions of performance of the enzyme were temperature of 75°C and pH 4.5. The enzyme kept stable in the lack of substrate for 25 minutes in 75°C
40

Determinação e caracterização de amido de cana-de-açucar e adequação de metodologia para determinação de alfa-amilase em açucar bruto / Determination and characterization on sugarcane starch and adequacy of the methodology for the residual a-amylase determination in raw sugar

Figueira, Joelise de Alencar 12 August 2018 (has links)
Orientador: Helia Harumi Sato / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-12T17:11:01Z (GMT). No. of bitstreams: 1 Figueira_JoelisedeAlencar_M.pdf: 2054069 bytes, checksum: 8eeb2cd2b576292162f4f29767ec1896 (MD5) Previous issue date: 2009 / Resumo: O presente trabalho visou à determinação da quantidade de amido em caldo de algumas variedades de cana-de-açúcar (RB86-7515, SO83-2847, RB72-454, SP80-3280 e RB85-5536) durante uma safra (período de Abril a Novembro de 2007), estudo de algumas características do amido de cana-de-açúcar e a adequação de metodologia para a determinação de atividade de a-amilase residual em açúcar bruto. A variedade de cana-de-açúcar RB86-7515 apresentou maior teor de amido durante toda safra entre as variedades analisadas. Não foi observado correlação entre o índice pluviométrico e as temperaturas da região e o teor de amido encontrado nas variedades de cana-de-açúcar. Na análise dos grânulos de amido por microscopia eletrônica de varredura (MEV) o amido de cana-de-açúcar apresentou forma esférica e diâmetro na faixa de 1-3 mm, tamanho muito inferior quando comparado ao amido de batata, mandioca e milho. Os amidos de cana-de-açúcar, milho, batata e amido solúvel complexados com iodo apresentaram maior absorção na faixa de 540 a 620 nm. O amido de cana-de-açúcar in natura mostrou maior susceptibilidade à enzima glicoamilase em relação aos amidos de milho ceroso, mandioca e batata. O amido de cana-de-açúcar mostrou susceptibilidade à enzima amilolítica desramificante pululanase que hidrolisa as ligações a-1,6 glicosídicas de modo similar ao amido de arroz ceroso, que apresenta alto teor de amilopectina. O amido de cana-de-açúcar mostrou susceptibilidade às a-amilases de Bacillus subtilis, Bacillus licheniformis e Aspergillus oryzae de modo similar aos outros amidos testados produzindo glicose; maltose; maltotriose; maltotetraose, maltopentaose e a-dextrinas limite. Para a adequação da metodologia para a determinação de a-amilase em açúcar bruto foram testados os métodos de Bernfeld baseado na determinação de açúcares redutores, método Iodométrico baseado na descoloração do complexo amido-iodo, método de Phadebas baseado na hidrólise do amido complexado com corante Cibacron Blue F3GA e o método usando-se o substrato BPNPG7 (benzylidene blocked r-nitrophenyl maltoheptaoside, Megazyme, Ireland) baseado na hidrólise do substrato e liberação do r-nitrofenol. O método de Bernfeld se mostrou mais adequado para a quantificação de a-amilase residual em açúcar bruto / Abstract: The aim of this work was to quantitatively determine sugarcane starch in five varieties of sugarcane (RB86-7515, SP83-2847, RB72-454, SP80-3280 and RB85-5536) during one harvest (May to November 2007), and study some of the characteristics of sugarcane starch. The variety RB86-7515 showed a higher starch content than the other varieties analyzed throughout the entire harvest. No correlation between the temperature, pluviometric index and starch level was found in any of the samples of sugarcane juice. The sugarcane starch granules examined under the scanning electron miscroscope showed a spherical shape with a diameter between 1-3 mm, smaller than the starch granules of maize and cassava. The sugarcane, corn, potato and soluble starches formed complexes with iodine, which showed greater absorption in the range from 540 to 620 nm. The crude sugarcane starch showed greater susceptibility to the enzyme glucoamylase than the waxy corn, cassava and potato starches. The sugarcane starch showed a susceptibility to debranching by the amylolytic enzyme pululanase, which hydrolyzed the a-1,6 glucosidic linkages in a way similar to waxy corn starch, which contains a high amount of amylopectin. The sugarcane starch showed susceptibility to the a-amylases from Bacillus subtilis, Bacillus licheniformis and Aspergillus oryzae, similar to the other starches tested, producing glucose, maltose, maltotriose, maltotetraose, maltopentaose and a-limit dextrins. This work aimed to adequate the methodologies used to determine residual a-amylase in raw sugar. The Bernfeld method is based on the determination of the reducing sugars by an iodometric method based on discoloration of the starch-iodine complex. The Phadebas method is based on the hydrolysis of the starch polymer dyed with Cibachron Blue F3GA, and the method using BPNPG7 r ¿ nitrophenyl maltoheptaoside (benzylidene blocked maltoheptaoside, Megazyme, Ireland) is based on the hydrolysis of the substrate, releasing p-nitrophenol. These three methods were tested for the determination of residual a-amylase in raw sugar, and the Bernfeld method was shown to be more adequate / Mestrado / Mestre em Ciência de Alimentos

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