Isolation and evaluation of quinoa (Chenopodium quinoa Willd.) protein fractions. A nutritional and bio-functional approach to the globulin fraction.

This study evaluated the solubility profiles of quinoa grain proteins and applied a complete process for the isolation of its main protein fractions, namely: albumins, globulins, prolamins and glutelins, which corresponded to 26.96%, 41.3%, 1.7% and 23.16% of the total protein content, respectively. When these fractions were digested with pepsin followed by pancreatin, the degrees of hydrolysis achieved varied between 26.62% (for unheated globulin fraction) and 38.97% (for unheated glutelin), with casein reached 33.73% hydrolysis. After heating, the globulin hydrolysis degree increased to 34.7%, not significantly differing from casein. These results reflect its good susceptibility to hydrolysis by digestive enzymes, and this observation is reinforced with assays with pepsin, trypsin and chymotrypsin tested separately. Globulins, the largest protein fraction, showed promising results in additional assays regarding the amino acid profile, with limitation only for lysine in relation to the FAO standard, and the potential for releasing bioactive peptides after digestion. Although pepsin-digested globulin inhibited only 5% of ACE activity under the conditions tested, after 24h with the addition of pancreatin, the inhibition was 100%. Antioxidant activity (DPPH assay) also indicated very similar results, when hydrolysis with pepsin was inefficient in releasing antioxidant peptides, while hydrolysis by pancreatin led to 35 times greater results.

Physicochemical characteristics, antioxidant activity, and acceptability of strawberry-enriched ketchup sauces.

The addition of strawberry pulp to ketchup sauces may be an alternative to attend the consumers' demand for innovative products with functional appeal. Sauces were made using different tomato/strawberry pulp ratios (100:0; 75:25; 50:50; 25:75; 0:100) and characterized for the physicochemical characteristics, bioactive compounds, antioxidant activity, and consumers' acceptance. The strawberry-enriched ketchup sauces presented higher phenolics, total flavonoids, antioxidant activity, and increased fluidity, and lower browning index, hue angle, chroma, pH, and Bostwick consistency. The antioxidant activities (ABTS and DPPH) were positively correlated with phenolics (r = 0.96 and 0.91) and flavonoids (r = 0.92 and 0.89) contents, respectively. The replacement of up to 50% tomato pulp by strawberry pulp did not change the acidity, flavor, and overall acceptance of the samples. The strawberry pulp has proven to be an effective alternative to increase the concentrations of bioactive compounds while reducing the amount of sugar used in traditional ketchup formulations.

Biotechnological Applications of Proteases in Food Technology.

This review presents some of the hottest topics in biotechnological applications: proteases in biocatalysis. Obviously, one of the most relevant areas of application is in the hydrolysis of proteins in food technology, and that has led to a massive use on proteomics. The aim is to identify via peptide maps the different proteins obtained after a specific protease hydrolysis. However, concepts like degradomics are also taking on a more relevant importance in the use and study of proteases and will also be discussed. Other protease applications, as seem in cleaning (detergent development), the pharmaceutical industry, and in fine chemistry, will be analyzed. This review progresses from basic areas such as protease classification to a discussion of the preparation of protease-immobilized biocatalysts, considering the different problems raised by the use of immobilized proteases due to the peculiar features of the substrates, usually large macromolecules. Production of bioactive peptides via limited hydrolysis of proteins will occupy an important place in this review.

In vitro versus in vivo protein digestibility techniques for calculating PDCAAS (protein digestibility-corrected amino acid score) applied to chickpea fractions.

Seven different in vitro methods to determine the protein digestibility for chickpea proteins were considered and also the application of these methodologies for calculating PDCAAS (protein digestibility-corrected amino acid score), seeking their correlations with the in vivo methodology. In vitro digestibility of raw and heated samples were determined using pepsin-pancreatin hydrolysis, considering soluble nitrogen via Kjeldahl (ppKJ) and hydrolysed peptide linkages using trinitrobenzenesulfonic acid and o-phthaldialdehyde. In vitro digestibility was also determined using trypsin, chymotrypsin and peptidase (3-Enz) or trypsin, chymotrypsin, peptidase and pronase solution (4-Enz). None of the correlations between in vitro and in vivo digestibilities were significant (at p<0.0500), but, strong correlations were observed between PDCAAS calculated by in vitro and in vivo results. PDCAAS-ppKJ, PDCAAS-3-Enz and PDCAAS-4-Enz presented the highest correlations with in vivo method, r=0.9316, 0.9442 and 0.9649 (p<0.0500), respectively. The use of in vitro methods for calculating PDCAAS may be promising and deserves more discussions.

Use of different spices as potential natural antioxidant additives on cooked beans (Phaseolus vulgaris). Increase of DPPH radical scavenging activity and total phenolic content.

Herbs and spices, excellent sources of phenolic compounds, can be considered potential antioxidant additives. The use of spices must strike a balance between their potential antioxidant capabilities during preparation and the flavor acceptance, in order to avoid rejection of the food. The aimed of this study is to evaluate the influence of different spices and their concentrations on cooked common beans, focusing its potential as antioxidant additives. Onion, parsley, spring onion, laurel and coriander increased the antioxidant activity of preparation when used at 7.96 g of onion, 1.06 g parsley, 3.43 g spring onion, 0.25 g laurel (dry leaves), and 0.43 g coriander/100 g of cooked beans. Besides, these spices concentrations enhance total phenolics and alter the mixture protein digestibility minimally. For garlic samples it was not possible to establish a concentration that increases the antioxidant activity of cooked beans.

Baixa digestibilidade proteica e presença de antinutricionais em produtos tipo mix de cereais / Low protein digestibility and anti-nutritional factors in cereal mix like products

Products composed of cereal mixes and other ingredients such as guarana, gelatin and cocoa powders; yeast; and soybean, flaxseed and sesame extracts have presented increased sales while receiving ever-growing criticism. Amongst the ingredients that could compose this cereal mix, most are of vegetable origin, wholegrain and not thermally processed. Therefore, they may present anti-nutritional factors, which are recognized to harm the bioavailability of nutrients, such as proteins. In this study, we aimed to evaluate the protein quality of these products, sold in the municipality of Uberaba, Brazil. The protein digestibility, tannins and trypsin inhibitors of the 14 samples were assessed. All samples showed trypsin inhibition activity and tannins. These results suggest that those products present low potential for nutrient utilization, especially with regards to proteins.

Productos compuestos por mezclas de cereales y otros ingredientes, como guaraná en polvo, gelatina en polvo, cacao en polvo, levadura de cerveza, extracto de soja, linaza y ajonjolí, presentan creciente comercialización, al mismo tiempo que aumentan los cuestionamientos al respecto. Estos productos están compuestos de variados ingredientes, la mayoría de origen vegetal, integral y sin procesamiento térmico previo, y podrían presentar antinutricionales, reconocidamente capaces de perjudicar la biodisponibilidad de nutrientes, tales como las proteínas. Este estudio evaluó la calidad proteica de productos listos para el consumo, compuestos por mezclas de cereales y otros componentes, comercializados en la ciudad de Uberaba-MG, determinando sus niveles antinutricionales y su digestibilidad proteica in vitro. Todas las muestras analizadas presentaron inhibición en la actividad de tripsina y de taninos. Las muestras presentaron muy claramente bajos valores de digestibilidad proteica in vitro. Los resultados sugieren que estos productos presentan bajo potencial de utilización de sus nutrientes, muy especialmente con respecto a sus proteínas.

Misturas de cereais e outros ingredientes, como guaraná em pó, gelatina em pó, cacau em pó, levedo de cerveja, extrato de soja, linhaça e gergelim, vêm apresentando crescente comercialização, concomitantemente com crescentes questionamentos a seu respeito. Dentre os ingredientes variados que podem compor estes produtos, a maioria é de origem vegetal, integral e sem processamento térmico prévio, e poderiam apresentar antinutricionais, reconhecidamente capazes de prejudicar a biodisponibilidade de nutrientes, como proteínas. Este trabalho buscou avaliar a qualidade proteica de produtos prontos para o consumo, compostos por misturas de cereais e outros componentes, comercializados no município de Uberaba-MG, determinando seus teores de antinutricionais e sua digestibilidade proteica in vitro. Todas as amostras analisadas apresentaram atividade de inibição de tripsina e teores de taninos, e baixa digestibilidade in vitro.

Produção de glicose e frutose por invertase de Saccharomyces cerevisiae imobilizada em suporte MANAE-Agarose / Glucose and Fructose Production by Saccharomyces cerevisiae Invertase Immobilized on MANAE-Agarose Support

Invertase from Saccharomyces cerevisiae was immobilized on agarose beads, activated with various groups (glyoxyl, MANAE or glutaraldehyde), and on some commercial epoxy supports (Eupergit and Sepabeads). Very active and stable invertase derivatives were produced by the adsorption of the enzyme on MANAE-agarose, MANAE-agarose treated with glutaraldhyde and glutaraldehyde-agarose supports. At pH 5.0, these derivatives retained full activity after 24h at 40 ºC and 50 ºC. When assayed at 40 °C and 50 °C, with the pH adjusted to 7.0, the invertase-MANAE-agarose derivative treated with glutaraldehyde retained 80% of the initial activity. Recovered activities of the derivatives produced with MANAE, MANAE treated with glutaraldehyde and glutaraldehyde alone were 73.5%, 44.4% and 36.8%, respectively. These three preparations were successfully employed to produce glucose and fructose in 3 cycles of sucrose hydrolysis.

Invertase de Saccharomyces cerevisiae foi imobilizada em agarose ativada com diferentes grupos (glioxil, MANAE ou glutaraldeído) e suportes epóxidos comerciais (Eupergit e Sepabeads). Derivados de invertase ativos e estabilizados foram produzidos pela adsorção da enzima em suportes MANAE-agarose, MANAE-agarose tratado com glutaraldeído e glutaraldeído-agarose. Em pH 5,0 estes derivados retiveram total atividade até 24h a 40 ºC e 50 ºC. Quando os ensaios foram a 40 °C e 50 °C com o pH alterado para 7,0, o derivado invertase-MANAE-agarose tratado com glutaraldeído apresentou 80% da atividade inicial. As atividades recuperadas dos derivados foram 73,5%, 44,4% e 36,8%, respectivamente para MANAE, MANAE tratado com glutaraldeído e glutaraldeído. Essas três preparações foram empregadas com sucesso em 3 ciclos de hidrólise da sacarose para produzir glicose e frutose.

Presença de inibidores de proteases em amostras comerciais de “faseolaminas” utilizadas como bloqueadores de carboidratos e os riscos à saúde / Occurrence of proteases inhibitors in commercial samples of “phaseolamins” used as carbohydrate blockers and the health risks

Foi investigada a veiculação de inibidores de proteases, concomitante ao consumo de “faseolamina”, cuja ingestão diária e de maneira prolongada poderia estar associada ao risco no desenvolvimento de alterações morfológicas e metabólicas de pâncreas. Dez amostras foram obtidas em farmácias de manipulação no município de Uberaba – MG, as quais são comercializadas na forma de cápsulas como “faseolamina”e uma como “farinha de feijão branco”, além de amostra de farinha preparada a partir da trituração de feijões brancos (Phaseolus vulgaris) obtidos comercialmente, sem qualquer processamento. Estas amostras foram analisadas efetuando-se a determinação de atividade de inibidores de tripsina, a determinação de proteínas totais e de atividade de inibição de amilase. Todas as amostras estudadas apresentaram atividades de inibição de tripsina, porém com baixa ou mesmo inexistente inibição de amilase; e em algumas amostras foi detectada concentração de proteínas muito inferior ao esperado. Uma vez observada a presença de atividade de inibição de tripsina em todas as amostras estudadas, e pela inexistência de níveis seguros de consumo estabelecidos para o ser humano, e ainda baseando-se nos trabalhos sobre associação de ingestão prolongada destes inibidores com alterações de atividade pancreática, o consumo destes “bloqueadores de carboidratos” deveria ser melhor controlado.

This study aimed at verifying the risk in developing the metabolic and morphological changes inpancreas, owing to the use of daily and prolonged consumption of protease inhibitors in conjunctionwith “phaseolamine”. Ten samples were obtained from drugstores in the city of Uberaba – MG, soldas “phaseolamine” and one known as “white bean flour”, and also one flour sample produced fromcommercial white beans (Phaseolus vulgaris) without any processing. These samples were analyzedby determining the activity of trypsin inhibitors, the total protein and the amylase inhibition activity.Trypsin inhibition activity was found in all of analyzed samples; however, the amylase inhibition activitywas low, and in some samples the protein concentration was much lower than expected. Seeing that thetrypsin inhibitory activity was detected in all of analyzed samples, and considering that the prolongedingestion of these inhibitors might cause activity changes in pancreas, the consumption of these types of“carbohydrate blockers” should be deeply discussed, since the safe amounts of these compounds have notbeen established for humans consumption yet.

Cyclodextrin glycosyltransferase production by new Bacillus sp. strains isolated from brazilian soil / Produção de ciclodextrina glicosiltransferase por novas cepas de Bacillus sp. isoladas de solo brasileiro

Three strains of Bacillus sp. (BACRP, BACNC-1 and BACAR) were isolated from soil adhered to cassava husk. CGTase specific activity for the three isolated strains was higher when cultivated at 40¨¬C. Potato starch, cassava starch, maltodextrin and glucose were used as carbon source and growth temperatures varied from 25 to 55¨¬C. The three isolates presented higher CGTase specific activity when cultivated with potato starch at 40¨¬C. Isolated BACRP and BACAR presented specific activity of 4.0x10-3 and 2.2x10-3 U/mg prot at pH 7.0, respectively, when cultivated in mediums added with NaCl 2 percent; at pH 10,0 their activities were of 3.4x10-3 and 3.0x10-3 U/mg prot, respectively, in the same concentration of NaCl. On the other hand, the isolated BACNC-1 presented activity specific of 2.4x10-3 U/mg prot when cultivated at pH 7.0 added of NaCl 1 percent, and at pH 10.0 the specific activity was of 3.4x10-3 U/mg prot without NaCl addition. This work also showed the presence of cyclodextrins formed during fermentation process and that precipitation with acetone or lyophilization followed by dialysis was efficient at removing CDs (cyclodextrins), thus, eliminating interference in the activity assays. The enzyme produced by the BACAR strain was partially purified and ¥â-CD was liberated as a reaction product.

Três linhagens de Bacillus sp (BACRP, BACNC- 1 e BACAR) foram isoladas a partir de solo aderido em casca de mandioca. Foram utilizados amido de batata, amido de mandioca, maltodextrina e glicose como fonte de carbono, e temperaturas de crescimento de 25-55¨¬C, sendo que os três isolados apresentaram maior atividade específica de CGTase quando cultivados com amido de batata a 40¨¬C. Em pH 7,0 os isolados BACRP e BACAR apresentaram atividade específica de 4,0x 10-3 e 2,2x10-3 U/mg prot, respectivamente, quando cultivados em meios acrescidos de 2 por cento de NaCl; em pH 10,0 suas atividades foram de 3,4x10-3 e 3,0x10-3 U/mg prot na mesma concentração de NaCl. Por outro lado, o isolado de BACNC-1 apresentou atividade específica 2,4x10-3 U/mg prot quando cultivado em pH 7,0 acrescido de 1 por cento de NaCl, e em pH 10,0 sua atividade específica foi de 3,4x10-3 U/mg prot sem adição de NaCl. Também foi demonstrada neste trabalho que ciclodextrinas são formadas durante o processo fermentativo, e que a precipitação com acetona ou liofilização seguida de diálise foram eficientes na remoção destas CDs, eliminando sua interferência nos ensaios enzimáticos. A enzima produzida pela cepa BACAR foi purificada parcialmente liberando b-CD como produto da reação.

Nutritional responses of rats to diets based on chickpea ( Cicer arietinum L.) seed meal or its protein fractions.

The aim of this study was to isolate the protein fractions from chickpea, var. IAC-Marrocos, as well as to evaluate its in vivo nutritional protein quality. Among the proteins, albumins showed better nutritional value in the in vivo assays and amino acid contents, despite their higher trypsin inhibitor contents. Trypsin inhibitors were found to be heat labile in all samples, but the digestibility results for unheated and heated flour and albumins suggest that their contents are not very decisive. The PER values for casein (not supplemented) were very similar to those of heated flour and unheated or heated albumin and total globulins. The albumin and glutelin fractions showed the best results for PDCAAS, however, lower than those of casein. Despite the high digestibility of the globulin the very low essential amino acid content lowered its PDCAAS, and it had the lowest values.

Cyclodextrin glycosyltransferase production by new Bacillus sp. strains isolated from brazilian soil.

Three strains of Bacillus sp. (BACRP, BACNC-1 and BACAR) were isolated from soil adhered to cassava husk. CGTase specific activity for the three isolated strains was higher when cultivated at 40°C. Potato starch, cassava starch, maltodextrin and glucose were used as carbon source and growth temperatures varied from 25 to 55°C. The three isolates presented higher CGTase specific activity when cultivated with potato starch at 40°C. Isolated BACRP and BACAR presented specific activity of 4.0×10(-3) and 2.2×10(-3) U/mg prot at pH 7.0, respectively, when cultivated in mediums added with NaCl 2%; at pH 10,0 their activities were of 3.4×10(-3) and 3.0×10(-3) U/mg prot, respectively, in the same concentration of NaCl. On the other hand, the isolated BACNC-1 presented activity specific of 2.4×10(-3) U/mg prot when cultivated at pH 7.0 added of NaCl 1%, and at pH 10.0 the specific activity was of 3.4×10(-3) U/mg prot without NaCl addition. This work also showed the presence of cyclodextrins formed during fermentation process and that precipitation with acetone or lyophilization followed by dialysis was efficient at removing CDs (cyclodextrins), thus, eliminating interference in the activity assays. The enzyme produced by the BACAR strain was partially purified and ß-CD was liberated as a reaction product.