Edna Maria Morais Oliveira

Production of L-asparaginase by filamentous fungi

L-asparaginase production was investigated in the filamentous fungi Aspergillus tamarii and Aspergillus terreus. The fungi were cultivated in medium containing different nitrogen sources. A. terreus showed the highest L-asparaginase (activity) production level (58 U/L) when cultivated in a 2% proline medium. Both fungi presented the lowest level of L-asparaginase production in the presence of glutamine and urea as nitrogen sources. These results suggest that L-asparaginase production by of filamentous fungi is under nitrogen regulation.

Using Real-Time PCR as a tool for monitoring the authenticity of commercial coffees.

Coffee is one of the main food products commercialized in the world. Its considerable market value among food products makes it susceptible to adulteration, especially with cereals. Therefore, the objective of this study was to develop a method based on Real-Time Polymerase Chain Reaction (PCR) for detection of cereals in commercial ground roast and soluble coffees. After comparison with standard curves obtained by serial dilution of DNA extracted from barley, corn and rice, the method was sensitive and specific to quantify down to 0.6 pg, 14 pg and 16 pg of barley, corn and rice DNA, respectively. To verify the applicability of the method, 30 commercial samples obtained in different countries were evaluated and those classified as gourmets or superior did not present the tested cereals DNA. However, barley was detected in various traditional (cheaper) samples from South America. In addition, corn and rice were also detected in different samples. Real-Time PCR showed to be suitable for detection of food adulterants in commercial ground roast and soluble coffees.

Influence of the body mass and visceral adiposity on glucose metabolism in obese women with Pro12Pro genotype in PPARgamma2 gene

INTRODUCTION Glucose metabolism may be altered in obesity and genotype for PPAR 2 can influence this variable. OBJECTIVE To evaluate the influence of body mass (BM) and visceral adiposity (VA) in glucose metabolism in morbid obese women with Pro12Pro genotype. METHODS Were selected 25 morbidly obese women. Groups were formed according to body mass index (BMI) [G1: 40-45 kg/m² (n = 17); G2: > 45 kg/m² (n = 8)]. Anthropometric, glycemia and insulinemia assessments (fasting, 60 and 120 minutes after high polyunsaturated fatty acids meal) were carried out. The insulin resistance (IR) and insulin sensitivity (IS) were assessed by HOMA-IR and QUICKI respectively. RESULTS G2 had higher BMI and waist circumference, compared to G1, impaired fasting glucose, low IS and higher IR. The postprandial glucose was normal, but there was a higher insulin peak one hour after the meal in G2. CONCLUSION Increased BM and VA were associated with worse glucose metabolism suggesting metabolic differences between morbid obese with Pro12Pro genotype.

Aplicabilidade da metodologia de reação de polimerase em cadeia em tempo real na determinação do percentual de organismos geneticamente modificados em alimentos

Detection of genetically modified organisms in the food chain is an important issue for all subjects involved in raw material control, food industry and distribution. Both labeling and traceability of genetically modified organisms are current issues that are considered for trade and regulation. Currently, labeling of genetically modified foods containing detectable transgenic material is required by the Brazilian legislation. The Brazilian government published the Decree no 4.680 in April 2003, which requires labeling for all foods or food ingredients, with a stricter labeling threshold of 1%. Although polymerase chain reaction technology has some limitations, the high sensitivity and specificity explain why it has been the first choice of most analytical laboratories interested in detection of genetically modified organisms and their derived products. Among the currently available methods, polymerase chain reaction-based methods are accepted, considering the sensitivity and reliability for detection of genetically modified-derived material in routine analysis. In this paper, a review of currently available polymerase chain reaction methods for screening and quantifying genetically modified-derived ingredients is presented, discussing their applicability and limitations.Detection of genetically modified organisms in the food chain is an important issue for all subjects involved in raw material control, food industry and distribution. Both labeling and traceability of genetically modified organisms are current issues that are considered for trade and regulation. Currently, labeling of genetically modified foods containing detectable transgenic material is required by the Brazilian legislation. The Brazilian government published the Decree no 4.680 in April 2003, which requires labeling for all foods or food ingredients, with a stricter labeling threshold of 1%. Although polymerase chain reaction technology has some limitations, the high sensitivity and specificity explain why it has been the first choice of most analytical laboratories interested in detection of genetically modified organisms and their derived products. Among the currently available methods, polymerase chain reaction-based methods are accepted, considering the sensitivity and reliability for detection of genetically modified-derived material in routine analysis. In this paper, a review of currently available polymerase chain reaction methods for screening and quantifying genetically modified-derived ingredients is presented, discussing their applicability and limitations.

Coffea arabica and C. canephora discrimination in roasted and ground coffee from reference material candidates by real-time PCR

To produce specific desirable coffee blends, Coffea arabica and C. canephora are mixed each other, in some cases to suit consumer preference, but in others to reduce production costs. In this scenario, the aim of this work was to evaluate standard candidate reference materials (RMc) for analysis of different blends of roasted and ground coffee. For this purpose, we analyzed different percentages of C. arabica and C. canephora (100:0; 50:50; 25:75; and 0:100, respectively). These RMc samples were developed in a previous study with green coffee beans submitted to medium roasting. In this work, coffee species differentiation (C. arabica and C. canephora) was analyzed by real-time PCR, using specific primers previously developed, called ARA primers. The RMc material with 100% C. canephora did not present amplification, in contrast with the samples containing C. arabica, which all presented amplification. These results indicate the specificity of ARA primers for C. arabica and that the detection system assay can be used as a promising molecular tool to identify and quantify percentages of C. arabica in different coffee blends.

OBTENÇÃO E CARACTERIZAÇÃO DE MATERIAL DE REFERÊNCIA EM BLENDS DE COFFEA. ARABICA E C. CANEPHORA

Não há no Brasil uma legislação para características mínimas de qualidade e autenticidade para blends de Coffea arabica e C. canephora robusta torrados e moídos. A fim de obter padrão de identidade para rotulagem, faz-se necessária a elaboração de material de referência (MR) que permita a identificação e ratificação da composição percentual dos blends de café, para dar suporte a uma possível legislação. Atualmente os MR disponíveis para comercialização que utilizam o café como matriz, foram desenvolvidos para identificação de alguns analitos, tais como, ocratoxina A, cafeína, acrilamida, entre outros. No entanto, ainda não existe nenhum MR de C. arabica e C. canephora para verificação dos teores dessas espécies nos blends. O objetivo do trabalho foi elaborar e caracterizar um candidato a MR de C. arabica, C. canephora e mesclas das duas espécies. O café verde foi torrado a 240 °C por 14 minutos, moído e peneirado na granulometria < 600 μm. O MR consistiu dos percentuais: 100:0; 95:5; 75:25; 50:50, 25:75, 5:95 e 0:100 de C. arabica e C. canephora, respectivamente. Foram avaliados a perda de massa durante a torra, a cor instrumental, o tamanho e a distribuição de partículas por difratometria laser. Os resultados indicaram que o MR apresentou homogeneidade quanto ao tamanho e a distribuição de partícula e perda de massa. A análise de cor instrumental mostrou maior luminosidade para espécie C. canephora comparado ao C. arabica, segundo o parâmetro CIEL*. O MR apresentou tendência ao amarelo conforme aumentava a proporção de C. canephora no blend, de acordo com o parâmetro CIEb* e o ângulo Hue, e uma tendência a tonalidade vermelha, segundo os valores de CIEa*. Concluiu-se que as condições estabelecidas para a produção do MR de blend de café apresentou uniformidade e homogeneidade adequadas e podem ser utilizadas como parâmetro para novos MR que utilizam café torrado e moído, bem como contribuir para avaliação da garantia de qualidade e identidade do produto e para fins de rotulagem onde constem os percentuais de C. arabica e C. canephora no blend.

Overview of Currently Applied Techniques for Detection of Adulterants in Coffee and Potential Use of DNA-Based Methods as Promising New Analytical Tools

Reports on coffee adulteration with cheaper materials date from over a century. Along with this illicit practice, a number of methods have been developed for the analysis of coffees authenticity. Among the most commonly applied techniques for this purpose are optical and electronic microscopy, liquid and gas chromatography, spectroscopy, and, most recently, molecular biology. This chapter presents a brief overview on the methods proposed in the literature for detection of adulterants in coffee, with emphasis on molecular biology, which is known as the most sensitive and specific method among all the existing ones. The authors hope to provide reference material to support the development of significant future works.

Qualitative and quantitative assessment of genetically modified soy in enteral nutrition formulas by polymerase chain reaction based methods

OBJECTIVE: The aim of this work was to investigate the occurrence of Roundup Ready soybean in enteral nutrition formulas sold in Brazil. METHODS: A duplex Polymerase Chain Reaction based on the amplification of the lectin gene and the construction of the recombinant deoxyribonucleic acid of transgenic glyphosate-tolerant soybean (35S promoter and chloroplast transit peptide gene) was performed in order to analyze the deoxyribonucleic acid obtained from nine soy protein isolate-containing formulas. RESULTS: Despite the highly processed nature of the food matrices, amplifiable deoxyribonucleic acid templates were obtained from all tested samples, as judged by the amplification of the lectin gene sequence. However, amplicons relative to the presence of Roundup Ready soybean were restricted to one of the nine enteral nutrition formulas analyzed as well as to the soybean reference powder, as expected. Quantitative analysis of the genetically modified formula by real-time Polymerase Chain Reaction showed a content of approximately 0.3% (w/w) of recombinant deoxyribonucleic acid from the Roundup Ready soybean. CONCLUSION: The results show that one of the formulas contained genetically modified soy, pointing to the need of regulating the use of transgenic substances and of specific labeling in this product category.