Chemical Characterization of White Lupin (Lupinus albus) Flour Treated by Extrusion Cooking and Aqueous Debittering Processes.

Lupin is a very nutritious legume with high levels of protein and fiber, but it also contains quinolizidine alkaloids which, depending on the species, can accumulate to toxic levels. The objective of this work was to evaluate the white lupin chemical composition, due to the effects of different processes (aqueous debittering, extrusion cooking, and reactive extrusion), aiming at reducing total alkaloids, preserving fibers, and increasing in vitro protein digestibility. Regarding raw material, the aqueous process reduced significantly total alkaloids (-93.87%), increased dietary fiber (+22.03%), and increased protein digestibility (+6.73%), whereas the extrusion processes were inefficient to reduce alkaloids (< -3.70%) and reduced the dietary fiber content, the reduction being more severe during reactive extrusion (-75.36%). Protein digestibility was improved by extrusion cooking (+3.07%), while the reactive extrusion reduced digestibility (-12.50%). Electrophoresis and quantification of soluble proteins and aromatic amino acids confirmed the high digestibility index, staying only the γ-conglutin fraction in the digested samples evaluated by SDS-PAGE. The aqueous process proved to be the best option, as it reduces the alkaloid content to safe levels and improves the protein digestion of white lupin flour.

Artisan minas cheese of Serro: proteolysis during ripening.

The Artisan Minas Cheese (AMC) is the oldest and most traditional Brazilian cheese, it is produced in several regions of the state of Minas Gerais, such as the Serro region. The most striking features of the AMC-Serro are the use of raw milk and natural bacteria from the whey, popularly known as pingo, as well as the use of the rind washing process. The aim of the present study was to evaluate the proteolysis of the AMC-Serro from three different producers, during 60 days of maturation, and to relate the proteolysis to the producing farms, the production season and the rind washing during ripening. For this purpose, TRICINE-SDS-PAGE, proteolysis extension and depth indices, moisture, and texture (firmness) were evaluated. It was concluded that the temperature and moisture of the cheeses, that were determined by the location of the ripening room, the production season and the rind washing, were the most important factors. The degree of proteolysis also had an impact on the water loss during ripening, with effect on cheese safety. The results obtained in this study may be used to better understand the transformations during ripening of AMC-Serro and help the small traditional farmers to improve their product's quality and stability.

Influência da concentração de NaCl e pH na extração de ricina em torta de mamona (Ricinus communis L.) e sua caracterização por eletroforese / Influence of NaCl and pH concentration on the extraction of ricin in castor bean (Ricinus communis L.) and its characterization by electrophoresis

A mamoneira (Ricinus communis L.) é uma oleaginosa de alto valor econômico pelo fato de apresentar um mercado bem definido para o óleo extraído de suas sementes. A torta, que é um resíduo desta extração, se destaca pelo alto teor em proteínas. Dentre as proteínas encontradas na torta destaca-se a ricina, uma citotoxina, que inviabiliza sua utilização como fonte protéica alternativa para alimentação animal. O presente trabalho tem como objetivo identificar um melhor tratamento experimental para a extração de ricina da torta de mamona, visando futuros estudos de perda de integridade da ricina, o que garantiria a inocuidade do produto. Para tanto, buscou-se identificar a solução de maior capacidade de extração de proteínas, empregando a metodologia de superfície de resposta. Um delineamento composto central rotacional foi elaborado a fim de verificar o melhor pH e concentração de NaCl para a extração. Dos cinco diferentes valores de pH (4,0; 4,6; 6,0; 7,4; 8,0) e concentração de NaCl (0,0M; 0,3M; 1,0M; 1,7M; 2,0M) utilizados, o tratamento associando fosfato de potássio 0,2M/NaCl 1,7M pH 7,4 foi escolhido como o melhor. A concentração de proteína extraída neste tratamento chegou a valores quatro vezes maiores que o encontrado no de mínima extração de proteína. Pela evidenciação do gel de eletroforese não houve extração preferencial de ricina nos tratamentos testados, entretanto etapas de purificação usando diálise e precipitação com sulfato de amônio, permitiram uma evidenciação melhor das duas cadeias polipeptídicas de ricina.

Castor bean (Ricinus communis L.) is an oilseed crop of high economic value due to the fact of presenting a clearly defined market for the oil extracted from its seeds. Castor cake, which is a residue of oil extraction, is at the moment receiving special attention because of its high protein content. However, among the proteins found in this cake it is observed the presence of ricin, a cytotoxin, which turns this seed dangerous to be used as an alternative protein source for animal feed. The present research has the objective of identifying the best experimental treatment for extraction of ricin from castor cake, with the aim of future studies of loss of ricin integrity, which would ensure the safety of the product. With this aim, it was initiated the search for a buffer of higher capacity of proteins extraction, using the response surface methodology. A central composite design was developed in order to determine the best pH and NaCl concentration for extraction. Of the five different pH values (4.0, 4.6, 6.0, 7.4, 8.0) and NaCl (0.0M, 0.3M, 1.0M, 1.7M, 2.0M) used, the treatment containing 0.2M potassium phosphate / 1.7M NaCl pH 7.4 was chosen as the best. The amount of protein extracted in this treatment reached values four times larger than the minimum found in other treatment studied. The electrophoresis analysis showed that there was no preferential extraction of ricin in the treatments; however purification steps using dialysis and precipitation with ammonium sulfate led to a better resolution of the two polypeptide chains presents in ricin.

Perfil eletroforético de lombo suíno adicionado de proteínas não cárneas / SDS-PAGE electrophoretic pattern of pork enhanced with non-meat proteins

A legislação brasileira permite a adição intencional de proteínas não cárneas em alguns produtos cárneos; entretanto, há poucas técnicas adaptadas e próprias para controle desses ingredientes. Na presente pesquisa, empregou-se a técnica de eletroforese em gel de poliacrilamida na presença de dodecil-sulfato de sódio (SDS-PAGE) para comparar amostras de carne suína (lombo), adicionadas de 1,5 por cento de proteínas não cárneas (proteína isolada de soja e concentrado protéico de soro de leite). Mediante a padronização de dois protocolos distintos de extração (uréia 6M e Tris-HCl-SDS-mercaptoetanol) e a utilização de controles positivos e negativos, obtiveram-se perfis eletroforéticos típicos do músculo e das proteínas utilizadas. Ambas as extrações utilizadas foram adequadas para separação das proteínas do soro de leite das proteínas da carne, mas a visualização dos marcadores da soja não foi possível em razão da sobreposição de bandas.

Brazilian meat regulations allow the use of non-meat extenders in certain meat products. Thus, the need for controlling the use of these ingredients with proper analytical methods is evident, in order to avoid illegal addition. In the present research, SDS-PAGE electrophoresis has been applied to pork enhanced with 1.5 percent of soy protein isolate and whey protein concentrate, through two different methods of protein extraction (urea 6M and Tris-HCl-SDS-mercaptoethanol), in the presence of positive and negative controls. Electrophoresis has revealed typical profiles, for whole-muscle and non-meat proteins, showing to be adequate to detect the addition of whey proteins in meat products. However, the soy proteins could not be detected, due to the overlapping of bands with meat proteins.

Composiçäo química e protéico-molecular da farinha de resíduos de camaräo-sete-barbas (Xiphopenaeus kroyeri) / Chemical and proteic-molecular composition of shrimp \"ste barbas\" residues flour

Caracterizou-se a farinha de resíduos de camaräo-sete-barbas quanto aos aspectos físico-químicos e análise molecular de proteínas. O corpo do camaräo foi utilizado como parâmetro comparativo. Realizou-se estudo das proteínas pela quantificaçäo de N-total, análise colorimétrica e avaliaçäo molecular. Os resíduos apresentaram potencialem relaçäo a dois nichos alimentares: nutricional (mineral) edietético (alto teor de fibra alimentar e baixo conteúdo lipídico. Verificou-se neste resíduo de baixo teor protéico solúvel pela extraçäo e quantificaçäo em método colorimétrico. Nos extratos analisados por eletroforese em gel de poliacrilamida contendo dodecil sulfato de sódio (SDS-PAGEO) foi observada baixa diversidade protéica, devido ao menor número de cadeias polipeptídicas identificadas. A presença de uma banda de 74 kDa, resistente ao tratamento térmico, pode ser utilizadas como marcador de padräo de identidade molecular desta família