Cléia Batista Dias Ornellas

Atitude do consumidor frente à irradiação de alimentos

Fatores economicos e sociais como custo, disponibilidade e habitos alimentares tem, tradicionalmente, influencia sobre a escolha do consumidor. Atualmente, outros fatores como legislacao, aumento da quantidade de refeicoes realizadas fora de casa e o emprego de novas tecnologias tem sido, tambem, parâmetros de decisao. Neste sentido, esclarecimentos a respeito da irradiacao, proposta como uma alternativa na conservacao de alimentos se faz necessaria, uma vez que seu uso comercial tem sido lento em funcao de interpretacoes erroneas por parte dos consumidores. Sendo assim, o presente trabalho teve como objetivo realizar um levantamento do nivel de conhecimento e aceitacao da irradiacao de alimentos, na cidade de Belo Horizonte (MG), bem como esclarecer ao consumidor o real conceito da irradiacao de alimentos. Os resultados indicaram que 59,6% dos entrevistados nao sabiam que a irradiacao e um metodo de conservacao de alimentos e nao souberam responder se consumiriam produtos irradiados, 16% acreditam que alimentos irradiados significam o mesmo que alimentos radioativos. Alem disto, 89% dos entrevistados consumiriam alimentos irradiados se soubessem que a irradiacao aumenta a seguranca alimentar.

Diagnóstico do complexo teníase-cisticercose bovina em São João Evangelista, Minas Gerais, Brasil

Com o objetivo de diagnosticar a situacao do complexo teniase-cisticercose bovina em Minas Gerais, Brasil, foi selecionado o municipio de Sao Joao Evangelista, onde foram coletadas amostras de sangue de 339 bovinos em 15 propriedades rurais, sorteadas aleatoriamente. Em cada propriedade, foi aplicado um questionario socioeconomico para a analise de fatores que favorecem a manutencao do complexo teniase-cisticercose bovina. Foi realizado tambem o diagnostico de teniase humana por meio de exame coproparasitologico dos habitantes das propriedades. Encontrou-se a prevalencia de 4,1% para cisticercose bovina e a frequencia de 2,94% para teniase humana. Entre os fatores de risco para a manutencao do complexo teniase-cisticercose analisados, foi observada uma relacao estatisticamente significativa (P=0,042) entre a ocorrencia de cisticercose bovina e a ingestao de carne malpassada pelos entrevistados. Concluiu-se que a cisticercose bovina esta presente no municipio de Sao Joao Evangelista, MG, em indices considerados endemicos, sendo o consumo de carne malpassada e nao inspecionada o principal fator de risco para a manutencao do complexo teniase-cisticercose, o que reforca a necessidade da adocao de medidas de controle com continua vigilância epidemiologica e sanitaria.

Efeito da adição de NaCl sobre as propriedades funcionais do plasma bovino e de seus hidrolisados trípticos

The effect of the NaCl addition, in a 0.035 mol/L concentration, on some functional properties of plasma and its tryptic hydrolysates was studied in two pH values (5.0 and 6.0). In that way, protein solubility, hydrophobicity, emulsifying capacity (EC), emulsifying activity index (EAI) and emulsion stability (ES) were determined. The results showed that, in the two pH values studied, the addition of NaCl produced a significant reduction of solubility, hydrophobicity and EC of plasma and of some of its tryptic hydrolysates. On the other hand, this procedure increased the EAI of plasma, in pH 5.0 as well as of the most of its tryptic hydrolysates. Concerning ES , this treatment had no effect on plasma but influenced positively some of its tryptic hydrolysates, especially in pH 5.0.

Desenvolvimento, caracterização e análise sensorial de formulações alimentares com proteínas do soro de leite ou albumina para crianças

O presente trabalho visou verificar a elaboracao, a caracterizacao e a avaliacao da aceitacao de duas formulacoes alimentares achocolatadas (uma contendo albumina e a outra, concentrado proteico de soro de leite - WPC) para criancas de 7 a 10 anos. O desenvolvimento das formulacoes baseou-se nas recomendacoes nutricionais para a faixa etaria. Foram avaliados os seguintes parâmetros fisico-quimicos: composicao quimica, estabilidade, pH, viscosidade e fluidez. A analise sensorial englobou as escalas hedonica de atitude, intencao de consumo e docura e foi realizada por um grupo de 142 julgadores de um centro universitario, com media de 24,5 ± 7,3 anos de idade e 66,2% do sexo feminino. Todos os dados obtidos foram submetidos a analise estatistica, adotando-se p 0,05). Observaram-se 3,88 (albumina) e 4,79 (WPC) vezes mais proteinas em 100 mL de amostra do que em bebidas comerciais. A primeira formulacao mostrou-se mais viscosa (137,33 cP versus 22,33 cP da formulacao com WPC) e menos fluida (percorreu 40 mL em 69 segundosversus 29 segundos da formulacao com WPC). Quanto ao pH, o produto com albumina apresentou caracteristica alcalina (8,60) e o com WPC acida (6,28). Ambas as formulacoes permaneceram estaveis e homogeneas apos 24 horas de visualizacao. A analise sensorial mostrou que as formulacoes foram similares em todos os testes aplicados (p > 0,05), sendo que as caracteristicas mais bem avaliadas foram o sabor, a textura e a docura, para ambas. Houve boa aceitacao das formulacoes, com nota mediana de 7 e valores acima de 80% para a soma das respostas positivas nos testes. Conclui-se que as formulacoes alimentares analisadas apresentaram boas caracteristicas fisico-quimicas e mostraram-se equilibradas nutricionalmente, com potencial para comercializacao.

Efeito da precipitação pelo ácido tricloroacético (TCA) e da ultrafiltração sobre o perfil peptídico de hidrolisados de caseína

Neste trabalho, estudou-se a influencia da ultrafiltracao e da precipitacao pelo acido tricloroacetico (TCA) sobre o perfil peptidico de hidrolisados de caseina. Apos esses tratamentos, os hidrolisados foram fracionados pela CLAE-EM (cromatografia liquida de alta eficiencia - exclusao molecular), seguida da quantificacao dos peptideos nas fracoes cromatograficas pelo metodo rapido da Area Corrigida da Fracao (ACF). Observou-se que esses tratamentos alteraram o perfil peptidico, tendo reduzido os teores de di- e tripeptideos da maioria das preparacoes enzimaticas. Algumas consideracoes relacionadas as condicoes operacionais e a influencia da hidrofobicidade dos peptideos foram feitas, no intuito de explicar os resultados obtidos.

Caracterização química e funcional do caseinato de sódio e da globina bovina

With the aim of finding an industrial utilization for proteins from bovine blood, two methodologies for globin extraction were tested. Also, the chemical composition of this protein and the effect of the addition of NaCl on some functional properties were evaluated. The results were compared to those obtained for commercial sodium caseinate. The extraction method using acidified acetone showed a better yield and protein recuperation when compared to the carboxymethyl cellulose method. However, the former is not recommended for food use, due to the presence of organic solvent residues in the protein. Moreover, the extraction procedure influenced the chemical composition of bovine globin. The addition of NaCl produced varied effects on the functional properties of the studied proteins like a reduction of the solubility, emulsifying capacity (EC) and emulsifying activity index (EAI), which was higher for a salt concentration close to that used in meat products (0.25mol/L). In the case of sodium caseinate this level of salt had a negative effect on all functional properties studied, except the ES. The use of a 10 fold lower NaCl concentration improved both EAI and ES.

Influence of cutting room temperature on the microbiological quality of chicken breast meat

The temperature control in the processing room is one of the major factors associated with the production of safe food with a satisfactory microbiological quality. A total of 288 samples of skinless chicken breast meat were placed in a cutting room, subjected to four different temperatures (12oC, 14oC, 16oC and 18oC) and collected to evaluate the influence of the room temperature on the microbiological quality during the cutting and boning of chicken breasts. Aerobic mesophilic microorganisms were counted to evaluate the environmental contamination. In addition, coliforms at 35oC and 45oC and Staphylococcus spp. were counted, and an analysis for the presence of staphylococcal enterotoxins and Salmonella spp. was performed to determine the microbiological quality of the meat. The results showed an increase in environmental contamination (P=0.01) with an increase in room temperature. However, no significant differences (P˃0.05) were observed in the meat cuts regarding the counts of coliforms at 35oC and 45oC, the count of Staphylococcus spp. and the presence of Salmonella spp. Moreover, no staphylococcal enterotoxins were detected in the samples analyzed. Thus, despite increasing the environmental contamination, the increase in the cutting room temperature did not affect the microbiological quality of the final product.

Avaliação da qualidade interna de ovos de consumo pela pesquisa do teor de aminas bioativas

In order to evaluate the quality of commercial eggs by searching the bioactive amine levels, 224 samples of eggs from the five regions of Minas Gerais State were collected during one year by the official inspection service. The biogenic amines (putrescine, cadaverine, phenylethylamine, histamine and tyramine) and the polyamines (spermidine and spermine) were determined by high performance liquid chromatography with ultraviolet detection (HPLC/UV) and pre-column derivatization with dansyl chloride. The results demonstrated the presence of putrescine in all samples of yolk and albumen, but in low concentrations. The other amines were also detected, however, with a lower frequency, and spermine was found only in one sample of albumen. It was concluded that the commercial eggs produced in Minas Gerais State are not a considerable source of polyamines, important for growth and cell proliferation; and low levels of biogenic amine, formed by decarboxylation of amino acids by bacterial enzymes, do not represent risks to consumer health, indicating that it has good quality, based on the bioactive amine criterion.

Validation of an HPLC-UV method for the identification and quantification of bioactive amines in chicken meat

A high-performance liquid chromatography with ultraviolet detection (HPLC-UV) method was validated for the study of bioactive amines in chicken meat. A gradient elution system with an ultraviolet detector was used after extraction with trichloroacetic acid and pre-column derivatization with dansyl chloride. Putrescine, cadaverine, histamine, tyramine, spermidine, and spermine standards were used for the evaluation of the following performance parameters: selectivity, linearity, precision, recovery, limits of detection, limits of quantification and ruggedness. The results indicated excellent selectivity, separation of all amines, a coefficient of determination greater than 0.99 and recovery from 92.25 to 102.25% at the concentration of 47.2mg.kg-1, with a limit of detection at 0.3mg.kg-1 and a limit of quantification at 0.9mg.kg-1 for all amines, with the exception of histamine, which exhibited the limit of quantification, of 1mg.kg-1. In conclusion, the performance parameters demonstrated adequacy of the method for the detection and quantification of bioactive amines in chicken meat.

Efeito da hidrólise tríptica e do pH sobre as propriedades funcionais do plasma bovino

Aiming to use of the bovine plasma as functional agent of foods, we studied its solubility, hidrophobicity and ability to form and to stabilize emulsions, in the range of pH from 3.0 to 8.0. Emulsifying capacity (EC), the emulsifying activity index (EAI) and the stability of the emulsion (ES) were determinated. The effect of the trypsin on these properties was also studied and five enzymatic hydrolysates were prepared. The results showed that hydrophobicity and EAI presented a maximum value at pH 3.0 and 7.0, respectively, while the other properties practically were not influenced by the pH variation. The tryptic hydrolysis produced a reduction of the solubility and EC, it showed no effect on EAI and ES and improved only the hidrophobicity in some periods of reaction.