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URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11847
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Item Hydrolysis of galacto-oligosaccharides in soy molasses by α -galactosidases and invertase from Aspergillus terreus(Brazilian Archives of Biology and Technology, 2010-05) Reis, Angélica Pataro; Guimarães, Valéria Monteze; Ferreira, Joana Gasperazzo; Queiroz, José Humberto de; Oliveira, Maria Goreti Almeida; Falkoski, Daniel Luciano; Almeida, Maíra Nicolau de; Rezende, Sebastião Tavares deTwo α -galactosidase (P1 and P2) and one invertase present in the culture of Aspergillus terreus grown on wheat straw for 168 h at 28ºC were partially purified by gel filtration and hydrophobic interaction chromatographies. Optimum pH and temperatures for P1, P2 and invertase preparations were 4.5-5.0, 5.5 and 4.0 and 60, 55 and 65ºC, respectively. The KM app for ρ -nitrophenyl-α -D-galactopyranoside were 1.32 mM and 0.72 mM for P1 and P2, respectively, while the KM app value for invertase, using sacarose as a substrate was 15.66 mM. Enzyme preparations P1 and P2 maintained their activities after pre-incubation for 3 h at 50ºC and invertase maintained about 90% after 6 h at 55 ºC. P1 and P2 presented different inhibition sensitivities by Ag+, D-galactose, and SDS. All enzyme preparations hydrolyzed galacto-ologosaccharides present in soymolasses.Item Treatment of soy milk with Debaryomyces hansenii cells immobilised in alginate(Food Chemistry, 2009-05-15) Souza Júnior, Waldeck Campanha de; Rezende, Sebastião Tavares de; Viana, Pollyanna Amaral; Falkoski, Daniel Luciano; Reis, Angélica Pataro; Machado, Solimar Gonçalves; Barros, Everaldo Gonçalves de; Guimarães, Valéria MontezeWhole cells of Debaryomyces hansenii UFV-1 were permeabilised with ethanol and immobilised in calcium alginate hydrogel. The optimum pH and temperature for α-galactosidase activities of permeabilised free (PFC) and permeabilised immobilised cells (PIC) were 4.5 and 60 °C; and 4.0 and 70 °C, respectively. PIC α-galactosidase was more stable than that of PFC. The incubation of PIC at 60 and 70 °C promoted an increase in α-galactosidase activity. The α-galactosidase activity was maintained when PIC was used in three repeated batches. The Km values for PIC and PFC α-galactosidases, with ρNPαGal, were 0.82 mM and 0.30 mM, respectively. Soy milk treatment with PIC for 6 h at 60 °C promoted 100% hydrolysis of raffinose oligosaccharides.Item Characterization and biotechnological application of an acid α-galactosidase from Tachigali multijuga Benth. seeds(Phytochemistry, 2008-10-02) Fialho, Lílian da Silva; Guimarães, Valéria Monteze; Callegari, Carina Marin; Reis, Angélica Pataro; Barbosa, Daianny Silveira; Borges, Eduardo Euclydes de Lima; Moreira, Maurilio Alves; Rezende, Sebastião Tavares deTachigali multijuga Benth. seeds were found to contain protein (364 mg g−1 dwt), lipids (24 mg g−1 dwt), ash (35 mg g−1 dwt), and carbohydrates (577 mg g−1 dwt). Sucrose, raffinose, and stachyose concentrations were 8.3, 3.0, and 11.6 mg g−1 dwt, respectively. α-Galactosidase activity increased during seed germination and reached a maximum level at 108 h after seed imbibition. The α-galactosidase purified from germinating seeds had an Mr of 38,000 and maximal activity at pH 5.0–5.5 and 50 °C. The enzyme was stable at 35 °C and 40 °C, but lost 79% of its activity after 30 min at 50 °C. The activation energy (Ea) values for p-nitrophenyl-α-d-galactopyranoside (pNPGal) and raffinose were 13.86 and 4.75 kcal mol−1, respectively. The Km values for pNPGal, melibiose, raffinose, and stachyose were 0.45, 5.37, 39.62 and 48.80 mM, respectively. The enzyme was sensitive to inhibition by HgCl2, SDS, AgNO3, CuSO4, and melibiose. d-Galactose was a competitive inhibitor (Ki = 2.74 mM). In addition to its ability to hydrolyze raffinose and stachyose, the enzyme also hydrolyzed galactomannan.Item Purification and characterization of Aspergillus terreus α-Galactosidases and their use for hydrolysis of Soymilk Oligosaccharides(Applied Biochemistry and Biotechnology, 2011-02-18) Ferreira, Joana Gasperazzo; Reis, Angélica Pataro; Guimarães, Valéria Monteze; Falkoski, Daniel Luciano; Silva Fialho, Lílian da; Rezende, Sebastião Tavares deα-Galactosidases has the potential to hydrolyze α-1-6 linkages in raffinose family oligosaccharides (RFO). Aspergillus terreus cells cultivated on wheat bran produced three extracellular forms of α-galactosidases (E1, E2, and E3). E1 and E2 α-galactosidases presented maximal activities at pH 5, while E3 α-galactosidase was more active at pH 5.5. The E1 and E2 enzymes showed stability for 6 h at pH 4–7. Maximal activities were determined at 60, 55, and 50°C, for E1, E2, and E3 α-galactosidase, respectively. E2 α-galactosidase retained 90% of its initial activity after 70 h at 50°C. The enzymes hydrolyzed ρNPGal, melibiose, raffinose and stachyose, and E1 and E2 enzymes were able to hydrolyze guar gum and locust bean gum substrates. E1 and E3 α-galactosidases were completely inhibited by Hg2+, Ag+, and Cu2+. The treatment of RFO present in soy milk with the enzymes showed that E1 α-galactosidase reduced the stachyose content to zero after 12 h of reaction, while E2 promoted total hydrolysis of raffinose. The complete removal of the oligosaccharides in soy milk could be reached by synergistic action of both enzymes