Otniel Freitas Silva

Influência da calagem, da época de colheita e da secagem na incidência de fungos e aflatoxinas em grãos de amendoim armazenados

The objective of this work was to evaluate the effect of the storage on the potential of aflatoxin production by isolates from Aspergillus flavus group in peanut (Arachis hypogaea L.). These kernels were obtained from a field experiment with two areas (with or without lime), three times of harvest (104, 114 and 124 days after planting) and two types of dryer conditions (ambient and chamber with forced air). After 12 and 18 months of storage, the kernels were treated with sodium hypochloride and incubated in a PDA at 20oC during five days. The isolates from Aspergillus flavus group were identified after incubation in ADM culture medium. The toxigenic potential was analyzed by thin layer chromatography. The genera detected were Aspergillus, Penicillium and Fusarium. The kernels from the first harvest, showed higher contamination by the Aspergillus flavus group, but the small proportion with toxigen potential.

Efeito da calagem, da colheita e da secagem na qualidade sanitária de amendoim na seca

Abstract – The objective of this work was to evaluate the effect of liming, harvest period and dryingmethod on the sanitary quality of peanut ( Arachis hypogaea L.) cv. Botutatu, cultivated in the field inthe dry season. The experimental design was a split split plot replicated four times in completelyrandomized blocks. Lime levels (0.0 and 1.8 ton/ha) were applied in the plots, four different harvestingperiods starting at 104 days after planting were assigned to the split plots and two conditions of drying(forced air oven at 30 o C and ambient at 24 o C and 60% of relative humidity) were attributed to the splitsplit plots. Populations of soil fungus and fungus associated to the seeds and to the pods and aflatoxinproduction potential were evaluated at each harvest. There was no effect of liming on the Aspergillus spp.population in soil as well as on the pods and seeds. The delay at the time of harvest provides contami-nation increase of Aspergillus flavus in the pods and in G1 and G2 aflatoxin production; the dryingconditions in ambient propitiate larger incidence for

Characterization of Aspergillus species on Brazil nut from the Brazilian Amazonian region and development of a PCR assay for identification at the genus level.

BackgroundBrazil nut is a protein-rich extractivist tree crop in the Amazon region. Fungal contamination of shells and kernel material frequently includes the presence of aflatoxigenic Aspergillus species from the section Flavi. Aflatoxins are polyketide secondary metabolites, which are hepatotoxic carcinogens in mammals. The objectives of this study were to identify Aspergillus species occurring on Brazil nut grown in different states in the Brazilian Amazon region and develop a specific PCR method for collective identification of member species of the genus Aspergillus.ResultsPolyphasic identification of 137 Aspergillus strains isolated from Brazil nut shell material from cooperatives across the Brazilian Amazon states of Acre, Amapá and Amazonas revealed five species, with Aspergillus section Flavi species A. nomius and A. flavus the most abundant. PCR primers ASP_GEN_MTSSU_F1 and ASP_GEN_MTSSU_R1 were designed for the genus Aspergillus, targeting a portion of the mitochondrial small subunit ribosomal RNA gene. Primer specificity was validated through both electronic PCR against target gene sequences at Genbank and in PCR reactions against DNA from Aspergillus species and other fungal genera common on Brazil nut. Collective differentiation of the observed section Flavi species A. flavus, A. nomius and A. tamarii from other Aspergillus species was possible on the basis of RFLP polymorphism.ConclusionsGiven the abundance of Aspergillus section Flavi species A. nomius and A. flavus observed on Brazil nut, and associated risk of mycotoxin accumulation, simple identification methods for such mycotoxigenic species are of importance for Hazard Analysis Critical Control Point system implementation. The assay for the genus Aspergillus represents progress towards specific PCR identification and detection of mycotoxigenic species.

Crescimento in vitro de fungos (Colletotrichum gloeosporioides e Cladosporium cladosporioides) isolados de frutos do mamoeiro, sob atmosfera controlada e refrigeração

ABSTRACT - The use of these combined technologies in tropical fruits does not present satisfactory results yet, most of the time because o fthe fruits injury by chilling. This injury could be intensified under atmospheric control conditions. There are evidences that the controlledatmosphere has fungistatic effect. Therefore, the objective of this work was verifying , in vitro , the influence of controlled atmosphere andtemperature on the two pathogenic fungi from papaya fruit: Colletotrichum gloeosporioides and Cladosporium cladosporioides . Thesefungi had been storage under two temperatures, atmospheres and period of incubation patterns (10oC and 25oC; ambient and contro lled - 3%O 2 and 6% CO 2 ; 7 or 14 days. After this period of storage, the contaminated plates had been incubated at 25oC under environment atmospherefor seven days more. It was verified a small growth of Colletotrichum gloeosporioides under refrigeration, also after additional period at 25oC.At 25 o C, the growth of this fungus was also reduced when stored under controlled atmosphere. On the other hand, it was not verifiedsignificant inhibitor effect of the controlled atmosphere at 10oC on the growth of

Compostos Organofosforados e seu Papel na Agricultura

A necessidade agropecuaria de maior producao de alimentos em espacos cada vez menores levou a busca de tecnologias capazes de proporcionar maior rendimento por area, o que disseminou o uso de defensivos agricolas. Alem disso, o ataque por microrganismos como fungos, bacterias e virus, e provavelmente uma das causas mais serias de perdas pos-colheitas de frutas e hortalicas. Dentre os produtos utilizados como defensivos, os compostos organofosforados (OFs) foram e ainda sao importantes para as atividades agricolas em todo o mundo, constituindo uma familia muito diversificada de produtos quimicos orgânicos. Os OFs foram banidos da agricultura em varios paises devido sua alta toxicidade, pois podem ser inibidores da enzima acetilcolinesterase (AChE), que desempenha um papel critico no bom funcionamento das celulas nervosas. No entanto, a toxicidade esta relacionada a estrutura da molecula. Desta forma, tem-se estudado uma nova geracao de OFs, nao inibidores da AChE e com maior atividade biologica.

COMPATIBILITY AMONG PATOGENIC INDICATOR MICRORGANISM STRAINS USED IN DECONTAMINATION TESTS OF ASSAI BERRIES

Valeria Saldanha Bezerra (valeria.bezerra@embrapa.br); Izabela Alves Gomes; Eduardo Henrique Miranda Walter; Otniel Freitas-Silva; Lourdes Maria Correa Cabral 1 Embrapa Amapá, Macapá, Brazil 2 PPGCAL/Institute of Chemistry Federal University of Rio de Janeiro (UFRJ), Brazil 3 Food and Nutrition Graduate Program (PPGAN) – Federal University of Rio de Janeiro State (UNIRIO), Brazil 4 Embrapa Food Technology, Rio de Janeiro, Brazil

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.

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.