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| Neves,Valdir Augusto. |
| Soluble, ionically bound peroxidase (POD) and polyphenoloxidase (PPO) were extracted from the pulp of peach fruit during ripening at 20°C. Ionically bound form was purified 6.1-fold by DEAE-cellulose and Sephadex G-100 chromatography. The purified enzyme showed only one peak of activity on Sephadex G-100 and PAGE revealed that the enzyme was purified by the procedures adopted. The purified enzyme showed a molecular weight of 29000 Da, maximum activity at pH 5.0 and at 40ºC. The calculated apparent activation energy (Ea) for the reaction was10.04 kcal/mol. The enzyme was heat-labile in the temperature range of 60 to 75ºC with a fast inactivation at 75ºC. Measurement of residual activity showed a stabilizing effect of sucrose at various temperature/sugar... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Peach peroxidases; Ripening; Purification; Kinetics; Heat stability. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132002000100002 |
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| Neves,Valdir Augusto; Picchi,Douglas Gatte; Silva,Maraiza Aparecida da. |
| Polyphenoloxidase (PPO; EC 1.14.18.1) extracted from Mentha arvensis leaves was isolated by (NH4)2SO4 precipitation and extensive dialysis. Its optimum pH and temperature varied with the substrate. The PPO showed activity with various diphenols. Km values were found 0.825, 0.928 and 7.41mM for caffeic acid, 4-methylcatechol and catechol, respectively. On heat-inactivation, half of the activity was lost after 60 and 15 sec at 70 and 75ºC, respectively. Measuring of residual activity showed a stabilizing effect of sucrose at various temperatures with activation energy (Ea) for inactivation increasing with sucrose concentration from 0 to 40% (w/w). Ea values of 78.13; 80.37; 82.79 and 81.00 kJ/Mol were found for 0, 15; 30 and 40% sucrose, respectively. PPO... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Polyphenoloxidase; Mentha arvensis; Characterization; Heat inactivation; Inhibitors. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132009000400025 |
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| Neves,Valdir Augusto; Lourenço,E. J.. |
| Peroxidase from peach fruit was purified 28.9-fold by DEAE-cellulose, Sephadex G-100 and hydroxylapatite chromatography. The purified enzyme showed only one peak of activity with an optimum pH of 5.0 and temperature of 40ºC. The calculated activation energy (Ea) for the reaction was 7.97 kcal/mol. The enzyme was heat-labile in the temperature range of 60 to 80ºC with a fast inactivation at 80ºC. PAGE of the inactivation course at 70ºC showed only one band of activity. Different sugars increased the heat stability of the activity in the following order: sucrose>lactose>glucose>fructose. Measurement of residual activity showed a stabilizing effect of sucrose at various temperature/sugar concentrations (10 to 40%, w/w) with the Ea for inactivation... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Peach peroxidase; Purification; Heat stability; Regeneration. |
| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89131998000200002 |
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| Neves,Valdir Augusto; Silva Jr.,Sinézio Inácio; Silva,Maraiza Aparecida da. |
| Os objetivos do trabalho foram isolar, purificar e estudar algumas propriedades da fração globulina majoritária de tremoço-doce, var. Multolupa; assim como avaliar as características de digestibilidade da farinha e frações isoladas. As frações protéicas foram separadas por fracionamento diferencial com uso de diferentes solventes. A globulina majoritária de tremoço-doce foi isolada, purificada por cromatografia em Q-Sepharose, revelando um único pico de proteína. Apresentou um peso molecular de 162,5 ± 10,0 kDa, determinado por cromatografia em Sephacryl S-300, e subunidades entre 20-70 kDa em PAGE-SDS. A solubilidade em função do pH e concentrações de NaCl revelaram curva típica dessa fração. A digestibilidade da proteína da farinha e das frações... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Lupinus albus; Frações protéicas; Globulina principal; Digestibilidade in vitro e in vivo; Ensaio biológico. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612006000400019 |
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| Guimarães,Rita de Cássia Avellaneda; Favaro,Simone Palma; Viana,Antonio Camilo Arguelho; Braga Neto,José Antônio; Neves,Valdir Augusto; Honer,Michael Robin. |
| Baru (Dipteryx alata Vog.) is an abundant legume in the Brazilian Savanna. Its nuts can be exploited sustainably using its protein and lipid fractions. This study aimed to analyze the proteins of the nuts present in the defatted flour and protein concentrate in terms of their functional properties, the profile of their fractions, and the in vitro digestibility. The flour was defatted with hexane and extracted at the pH of higher protein solubility to obtain the protein concentrate. The electrophoretic profile of the protein fractions was evaluated in SDS-PAGE gel. The functional properties of the proteins indicate the possibility of their use in various foods, like soybeans providing water absorption capacity, oil absorption capacity, emulsifying... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Dipteryx alata; Protein fractions; Functional properties; Solubility; In vitro digestibility. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612012000300007 |
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| Fontanari,Gustavo Guadagnucci; Jacon,Mônica Cristina; Pastre,Ieda Aparecida; Fertonani,Fernando Luis; Neves,Valdir Augusto; Batistuti,José Paschoal. |
| Isolados protéicos (IPs) foram obtidos a partir da farinha da semente de goiaba (Psidium guajava) por extração a diferentes pHs seguido de precipitação isoelétrica (pI 4,5). As condições para o preparo do IP foram definidas a partir da curva de solubilidade, em pH 10,0 e 11,5, na ausência de NaCl e em temperatura de 25 ± 3 ºC. Essas condições levaram a um rendimento na extração de 45,19 e 66,23%, e teor protéico de 96,4 e 93,5% para IP 10,0 e 11,5, respectivamente. Capacidade de absorção de água e óleo de 1,05 ± 0,07 e 2,30 ± 0,01 mL.g-1 proteína e 1,65 ± 0,07 e 1,70 ± 0,07 mL.g-1 proteína foram obtidos, respectivamente, para IP 10,0 e IP 11,5. Não foram observadas diferenças entre os IPs quanto à atividade e estabilidade de emulsão, atingindo valores... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Psidium guajava; Semente de goiaba; Propriedades funcionais; Isolado protéico (IP). |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612007000500013 |
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