Viviane Silva - Academia.edu (original) (raw)

Papers by Viviane Silva

The International Journal of the Arts in Society: Annual Review, 2011

Artshots-Art and Multimedia Communication Labs is an annual event organized by LAB: ACM-Laborator... more Artshots-Art and Multimedia Communication Labs is an annual event organized by LAB: ACM-Laboratory of Art and Multimedia Communication within the Polytechnic Institute of Beja, in Portugal. The event promotes several workshops lead by students from two BA Courses, Art and Multimedia, and Education and Multimedia Communication. The main goal of ArtShots is to actively integrate the current students on the training process and to approach teachers and students of Secondary School with the knowledge and practice of Higher Education. The purpose of using a methodology based on working laboratories is to acknowledge conceptual and technical aspects of artistic practice and content mediatisation. This article presents the event as a successful case study, regarding the increase of affluence and interest by the program and the BA Courses on a national scale, which has been contributed positively to minimize the inland depopulation of south of Portugal and also to reinforce the role of the arts on this context. Since the first edition, in 2005, we have been able to frame a critical thinking on the models and practices that allow the improvement of training strategies and gather useful information about our current and future students. For this purpose we developed a study focused on obtaining results about the impact of applicant students in our institution. Furthermore, this study intends to analyse the students experience as a trainee, namely its significance on their education and professional integration.

Acta científica venezolana, 2004

In this work, the second derivative spectrophotometry (SDS), a fast, simple and relatively low-co... more In this work, the second derivative spectrophotometry (SDS), a fast, simple and relatively low-cost method,-was used to characterize aromatic amino acids at two pH values (7 and 13) and to evaluate the exposition rate of Phe in casein hydrolysates prepared with papain. The results indicate that at 37 degrees C, pH 7.5 and an enzyme:substrate ratio of 4:100, for hydrolyzing casein by papain, the highest Phe exposition was observed. Therefore these are the most appropriate conditions for Phe removal and preparation of supplements for phenylketonurics. The use of SDS at pH 13.0 gives a good resolution of Tyr and Trp peaks. A similarity among SDS spectra of aromatic amino acids and protein hydrolysates, was also observed.

Publicatio UEPG - Ciencias Exatas e da Terra, Agrarias e Engenharias, 2012

Enzymatic hydrolysis of proteins increases the use of whey. In this study, a B. licheniformis pro... more Enzymatic hydrolysis of proteins increases the use of whey. In this study, a B. licheniformis protease was used to evaluate the extent of hydrolysis of a whey protein concentrate (WPC) as well as the size distribution of the peptides. Four methods were used to determine the extent of hydrolysis: formol titration, soluble protein content, OPA (orthophytalaldehyde) and osmometry. The fractionation of peptides was performed by size-exclusion high performance liquid chromatography. The soluble protein content method produced the highest value for extent of hydrolysis of the WPC (44.7%) and the formaldehyde method was considered to be the most suitable for evaluating this parameter. A signifi cant amount of dipeptides and tripeptides (8.79%) were produced. A positive and signifi cant correlation was observed between the methods of formaldehyde with OPA (r = 0.9891; p = 0.0014) and OPA with soluble protein content (r = 0.8974; p = 0.0388). The same type of correlation was observed between the extent of hydrolysis obtained by all the four methods with the levels of dipeptides and tripeptides

Pesquisa Agropecuária Tropical, 2011

A utilização de hidrolisados proteicos, em formulações específicas, é uma área de crescente inter... more A utilização de hidrolisados proteicos, em formulações específicas, é uma área de crescente interesse. Estes hidrolisados vêm sendo empregados na fabricação de alimentos especiais, para diversos grupos, tais como recém-nascidos prematuros, crianças com diarreia, gastroenterite, má-absorção e fenilcetonúria e pessoas com alergia a proteínas (Frei-ABSTRACT RESUMO tas et al. 1993, Akyiama et al. 2006). Além disto, estes preparados enzimáticos podem ser úteis na suplementação dietética de idosos, pacientes portadores de HIV/AIDS e na nutrição de esportistas, bem como em dietas para controle de peso (Frøkjaer 1994). Porém, a maior parte dos hidrolisados proteicos existentes no mercado nacional são obtidos a partir da caseína e do concentrado proteico do soro de leite, que são fontes proteicas importadas e de preço elevado. Por

LWT - Food Science and Technology, 2003

... Viviane DM Silva and Marialice PC Silvestre Corresponding Author Contact Information , E-mail... more ... Viviane DM Silva and Marialice PC Silvestre Corresponding Author Contact Information , E-mail The Corresponding Author. ... in the same laboratory as this work concerning the functional properties of proteins like casein and bovine globin ([Duarte, Carreira, Junqueira, Coelho, &amp; ...

Journal of Food Science and Technology, 2013

ABSTRACT Enzymatic hydrolysis of whey protein concentrate was used to prepare hydrolysates with a... more ABSTRACT Enzymatic hydrolysis of whey protein concentrate was used to prepare hydrolysates with appropriate peptide profiles for use in the development of dietary supplements. Effects of the type of enzyme (pancreatin and proteases from Bacillus licheniformis, Aspergillus oryzae and Aspergillus sojae) and enzyme:substrate ratio (0.5:100, 1:100, 2:100, 3:100, 4:100 and 8:100) were evaluated. Twenty-four hydrolysates were prepared, and their peptide profiles were characterized by chain length using size exclusion liquid chromatography fractionation, followed by a rapid Correct Fraction Area method for quantifying the peptide and amino acid contents. The use of a protease from Bacillus licheniformis (E:S 8:100) and a pancreatin (E:S 2:100, 3:100, 4:100 and 8:100) yielded preparations of hydrolysates with the highest sums of di- and tripeptide and free amino acid contents (9.99 and 11.28 % for the protease from Bacillus licheniformis and pancreatin, respectively) as well as the lowest amount of large peptides (44.61 and 44.13 %, respectively).

Journal of Food Biochemistry, 2013

ABSTRACT The effects of proteolytic enzyme type (including pancreatin and proteases from Bacillus... more ABSTRACT The effects of proteolytic enzyme type (including pancreatin and proteases from Bacillus licheniformis, Aspergillus oryzae and A. sojae) and enzyme : substrate ratio (E : S = 0.5:100, 1:100, 2:100, 3:100, 4:100 and 8:100) were evaluated in this work with the aim of obtaining whey protein concentrate hydrolysates with inhibitory activity toward angiotensin‐converting enzyme. Twenty‐four hydrolysates were prepared, and their inhibitory activities (IA) were evaluated in vitro, resulting in inhibition rates ranging from 2.02 to 96.66%. Eleven samples had IAs that were very high (>80%). The hydrolysates obtained using the B. licheniformis protease had the highest IA values at all tested E : S ratios. In some cases, lowering the E : S ratio produced a higher IA value. This was observed for the B. licheniformis protease when the ratio was lowered from 2:100 to 1:100, as well as for the A. oryzae protease when lowered from 3:100 to 2:100 and from 2:100 to 1:100.

International Journal of Food Science & Technology, 2012

The action of various proteases was tested for preparing whey protein concentrate (WPC) hydrolysa... more The action of various proteases was tested for preparing whey protein concentrate (WPC) hydrolysates with high degree of hydrolysis (DH), appropriate peptide profiles and reduced phenylalanine (Phe) content. The peptide profile analysis included the fractionation of hydrolysates by size-exclusion HPLC. The rapid correct fraction area method was used to quantify the components of the chromatographic fractions. Activated carbon (AC) was used to remove Phe, and its efficiency was evaluated by measuring the amount of Phe by second-derivative spectrophotometry. The results showed that the DH of WPC hydrolysates increased and that the protease from Aspergillus oryzae yielded the highest DH value. This protease also produced the best peptide profile, that is, the highest di-and tripeptide content (16.14%), the highest amounts of free amino acids (18.43%) and the lowest amount of large peptides (18.76%). The proteases from both A. oryzae and Bacillus subtilis produced the highest Phe removals (79.0 and 77.8%, respectively).

International Journal of Food Properties, 2014

ABSTRACT

International Journal of Food Engineering, 2013

In this work, the influence of some reactional parameters in the hydrolysis of whey protein conce... more In this work, the influence of some reactional parameters in the hydrolysis of whey protein concentrate (WPC) was evaluated, in terms of the nutritional quality of peptide profiles of the hydrolysates as well as the reduction of costs for scaling-up the process. Two enzymes (subtilisin and pancreatin) were used for preparing 18 hydrolysates, using different E:S ratios and reaction times, and the distribution of peptides according to chain length was analyzed by size-exclusion chromatography. The studied parameters affected the peptide profiles of WPC hydrolysates and the best result was similar for subtilisin and pancreatin, both using an E:S ratio of 4:100, after 5 h and 10 h, respectively. In these conditions, these enzymes gave rise to the smallest large peptide contents (12.28% and 12.34%, respectively) and one of the highest amount of di- and tripeptides (13.34% and 13.00%, respectively) as well as of free amino acids (45.56% and 47.26%, respectively). However, in terms of numb...

International Journal of Food Engineering, 2009

The free use of rice in the phenylketonurics diet needs the reduction of phenylalanine (Phe) cont... more The free use of rice in the phenylketonurics diet needs the reduction of phenylalanine (Phe) content from its proteins. This procedure involves protein extraction and hydrolysis followed by Phe removal. Enzymatic processes were then used for extracting and hydrolyzing rice proteins. In the former, a protease from Bacillus licheniformis was used while for the second case, six different enzymes were tested (pancreatin, papain, proteases from Aspergillus sojae, Bacillus stearothermophilus and two from Bacillus subtilis). Also, the activated carbon (AC) was employed as the adsorptive medium for removing Phe. The efficiency of Phe removal was evaluated by second derivative spectrophotometry. The hydrolysate prepared with papain showed the highest Phe removal (94.1%), using an E:S ratio of 4:100, a protein:AC ratio of 1:88 and three different meshes of AC simultaneously.

Revista Brasileira de Ciências Farmacêuticas, 2004

Sete hidrolisados de leite em pó desnatado foram preparados, visando à produção de hidrolisados p... more Sete hidrolisados de leite em pó desnatado foram preparados, visando à produção de hidrolisados protéicos, como suplemento dietético para fenilcetonúricos. Para isso, utilizaram-se uma protease do Aspergillus oryzae (AO), a papaína (PA) e a pepsina (PE), isoladamente ou em associação, em diferentes relações enzima:substrato (E:S), sendo o tempo total de reação de 5 h e a temperatura de 50 ºC. Adotou-se como critério para a avaliação nutricional dos hidrolisados, o estudo da distribuição dos peptídeos nas amostras, de acordo com o tamanho da cadeia. Inicialmente, os hidrolisados foram fracionados por cromatografia líqüida de alta eficiência de exclusão molecular (SE-HPLC) e, para a quantificação dos componentes das frações cromatográficas, empregou-se o método rápido da Área Corrigida da Fração (ACF). Os resultados indicaram que, de modo geral, a ação isolada das três enzimas foi mais vantajosa em relação ao perfil peptídico em comparação com as associações estudadas. Entre todas as preparações testadas, a ação isolada de AO e de PA, e a associação destas enzimas (relação E:S de 1% e 2%, respectivamente) produziram hidrolisados com perfis peptídicos semelhantes, mais adequados nutricionalmente, ou seja, com maior teor de die tripeptídeos e menor proporção de aminoácidos livres.