Sebastião César Cardoso Brandão

ATP-bioluminescence assay as an alternative for hygiene-monitoring procedures of stainless steel milk contact surfaces

A tecnica do ATP-bioluminescencia avaliou os procedimentos de higienizacao de superficies em aco inoxidavel dos tanques de transporte de leite cru, de estocagem de leite cru resfriado, de equilibrio de um pasteurizador, de estocagem de leite pasteurizado e para embalagem de leite pasteurizado e, ainda, a superficie interna de uma centrifuga de leite quanto a determinacao de Unidades Relativas de Luz (URL) e da contagem de mesofilos aerobios (UFC.cm-2). Nao houve diferenca significativa (p>0.05) na medida de URL nas superficies antes e depois do procedimento de higienizacao. Tambem, nao houve diferenca significativa (p>0.05) no numero de UFC.cm-2 nas superficies antes da higienizacao. No entanto, contagens bacterianas diferentes foram constatadas apos este procedimento. As superficies da centrifuga e dos tanques de leite resfriado e para embalagem de leite apresentaram as maiores contagens apos a higienizacao, atingindo 2,21, 2,18, e 1,21 log10, respectivamente. Os resultados mostram que nao ha concordância entre os metodos na classificacao das condicoes higienicas das superficies, indicando que nao ha relacao direta entre RLU e UFC.cm-2. A tecnica do ATP-bioluminescencia indicou que 100% das superficies estavam em condicoes higienicas inadequadas, enquanto a contagem bacteriana indicou apenas 50% de acordo com as recomendacoes da APHA e 33% de acordo com OMS. Variacoes elevadas nas medidas de URL sugerem a necessidade de se realizar mais de uma analise na mesma superficie. A tecnica do ATP-bioluminescencia nao deve simplesmente substituir os testes microbiologicos mas ser usada para se obter informacoes complementares para avaliar as condicoes higienicas das superficies para o processamento de leite.

Efeito da Suplementação de Lipídios na Ração sobre a Produção de Ácido Linoléico Conjugado (CLA) e a Composição da Gordura do Leite de Vacas

The objective of this work was to verify the effects of lipid sources (ground soybean and soybean oil) added to the diet on the fatty acids profile of milk fat, specially in the increasing of CLA. Six multiparus 7/8 Holstein-Zebu cows, 30 days after calving, with average body weight of 500 kg and average milk production of 20 kg/day, were used. The animals were divided in three groups in order to receive isoprotein and isocaloric diets (treatments), in which control diet had 3% ether extract in total dry matter and the others 7%. Comparing to the control one, the treatments containing supplementar lipids, decreased the percentage of short chain fatty acids and decreased the content of butyric, caproic, caprilic, capric, lauric, miristic and the percentage of saturated fatty acids. There was still a trend for reduction in the content of palmitic and palmitoleic acids and a trend for increasing the percentage of unsaturated fatty acids and long chain fatty acids. Supplementar lipids increased stearic acid and tended to increase oleic acid and CLA. Soybean oil, compared to ground soybean, decreased the content of linoleic and linolenic acids and increased CLA, tended to increase the content of undentified fatty acids and tended to decrease the saturated fatty acids. In conclusion, adding soybean oil and not crushed soybean in the diet increased the content of CLA in milk fat.

ATP - bioluminescence as a technique to evaluate the microbiological quality of water in food industry

ATP-bioluminescence was used to evaluate the microbiological quality of water samples collected from the water supply, the water treatment system and from a dairy plant, including ammonia-cooling water and industrial water. For industrial water, there was relation between the ATP-bioluminescence technique and microbial count. There were no differences (p>0.05) between water supply and ammonia-cooling water samples for total and free ATP concentrations nor for the microbial counts. Different microbial ATP concentrations were found for these water samples. The results suggested that the physical chemical quality of ammonia cooling water decreased the RLU measurements slightly. It could be concluded that the total ATP concentration was the most effective technique to evaluate the microbiological quality of water used in the food indsutry by ATP-bioluminescence.

Otimização de método para análise de folatos em hortaliças folhosas por cromatografia líquida de alta eficiência com detecção por fluorescência

We optimized a method for the determination of three main folate isoforms in leafy vegetables. Analysis was carried out by HPLC, using gradient of elution and fluorescence detection. Limits of quantification were 2 ng/mL; 2 ng/mL and 28 ng/mL for tetrahydrofolate (THF), 5-methyltetrahydrofolate (5-MTHF) and 5-formyltetrahydrofolate (5-FTHF), respectively. Recovery rates of THF, 5-MTHF and 5-FTHF varied from 87.86 to 100.64%; 88.12-94.22% and 89.82-106.69%, respectively. Test of repeatability showed relative standard deviation for peak areas lower than 10%. Tests for linearity showed high coefficients of determination. The results showed advances in folates extraction and analysis in raw and cooked leafy vegetables.

Evaluation of total carotenoids, alpha- and beta-carotene in carrots (Daucus carota L.) during home processing

This study aims to analyze the influence of dehydration and different preparation methods during home processing related toa-carotene, b-carotene and total carotenoids stability in carrots. Vitamin A values were evaluated after different treatments. Thus, carrots were submitted to steam cooking, water cooking with and without pressure, moist/dry cooking and conventional dehydration. Determination of a- and b-carotenes was made by High-Performance Liquid Chromatography (HPLC) (conditions were developed by us) using spectrophotometric detection visible-UV at 470 nm; a RP-18 column and methanol: acetonitrile: ethyl acetate (80: 10: 10) as mobile phase. Total carotenoids quantification was made by 449 nm spectrophotometer. The retention of the analyzed carotenoids ranged from 60.13 to 85.64%. Water cooking without pressure promoted higher retention levels of a- and b-carotene and vitamin A values, while water cooking with pressure promoted higher retention levels of total carotenoids. Dehydration promoted the highest carotenoid losses. The results showed that, among the routinely utilized methods under domestic condition, cooking without pressure, if performed under controlled time and temperature, is the best method as it reduces losses in the amount of a- and b-carotene, the main carotenoids present in the carrots. Despite the significant carotenoid losses, carrots prepared through domestic methods, remain a rich source of provitamin A.

Development and validation of the high performance liquid chromatography-ion exclusion method for detection of lactic acid in milk

The present work reports the development and validation of an analytical method for lactic acid quantification in milk by ion exclusion-HPLC with UV detection. This method showed good precision (variation coefficient <7.0%) and good accuracy (97.6-99.6%). Calibration curves were linear (R(2)>0.996) at the tested range of 5.0-25.0mmolL(-1); and the detection and quantification limits were 0.5 and 1.0mmolL(-1), respectively. Analysis of lactic acid in fermented milk (FM) or NaOH neutralised fermented milk (FNM) was performed using samples obtained during 9h of fermentation. An ANOVA analysis combined with the Tukey test was used to show that the method was insensitive to the differences between FM and FNM. The proposed method therefore proved to be a useful quality control tool in laboratories because it was able to determine milk acidity even in adulterated samples.

Produção e composição do leite de vacas submetidas a dietas contendo diferentes níveis e formas de suplementação de lipídios

The objective of this work was to verify the effect of lipids sources (whole soybean meal - WSM; and soybean oil - SBO) added to the diet on changes in milk production and its physical-chemical characteristics. Six multiparous 7/8 Holstein-Zebu cows, averaging 30 days post calving, 500 kg body weight and daily milk production of 20 l were used. The animals were divided into three groups and received three isoproteic and isocaloric diets (treatments): control (3% ether extract), WSM (7% ether extract) and SBO (7% ether extract). There were no treatment effects on any measured parameters. The results on the physical-chemical analysis of the milk were within the range of allowed values by Brazilian regulation of industrial inspection and sanity of products of animal origin.

Determinação de ácido benzóico e ácido sórbico em iogurtes comerciais

Quinze amostras de iogurtes comerciais foram analisadas quanto ao teor de acido benzoico e sorbico, por meio de cromatografia liquida de alta performance de acordo com Ito et al. (1983). O teor de acido sorbico em todas as amostras encontrava-se dentro dos limites estabelecidos por lei. O rotulo de tres amostras nao continham a especificacao (P.IV). O acido benzoico foi encontrado em todas as amostras. Devido a fermentacao latica, nenhuma amostra declarava a adicao do acido benzoico no rotulo.