João Andrade da Silva

AVALIAÇÃO MICROBIOLÓGICA DA CARNE-DE-SOL ELABORADA COM BAIXOS TEORES DE CLORETO DE SÓDIO

A total of 96 samples of sun meat were analyzed, 48 of them were collected in inspected establishments and the other 48 in establishments without inspection. This work was developed in order to evaluate the hygienic-sanitary conditions of these products during their processing and marketing. The incidence of mesophilic bacterias, molds, yeasts, Staphylococcus aureus, fecal coliforms and Escherichia coli was investigated. Also, some physical-chemical parameters as water activity and sodium chloride were analyzed. In both groups the results obtained in microbial analysis were quite high. In the samples of the inspected establishments the averages of mesophylic counts bacterias, molds and yeasts, Staphylococcus spp and fecal coliforms were 6,2Log UFC/g, 3,8Log UFC/g, 7,4Log UFC/g and 1,34Log NMP/g respectively and, in the samples without inspection, the averages were 7,41Log UFC/g, 4,44Log UFC/g, 6,78Log UFC/g and 2,6Log NMP/g, respectively. The microbial results suggest errors in the processing and manipulation of both samples, and the fecal contamination was much higher in the samples collected in establishments without inspection. The variation of the sodium chloride content and water activity of the sample indicated lack of standardization during sun dried meat processing. There is the need tho establish microbiological and physical-chemical legal parameters capable of offering safe food to the consumer.

Nature of the antimicrobial activity of Lactobacillus caseiBifidobacterium bifidum and Bifidobacterium animalis against foodborne pathogenic and spoilage microorganisms

The antimicrobial activities as well as the nature of the inhibitory compounds obtained from Lactobacillus casei, Bifidobacterium bifidum and Bifidobacterium animalis strains were assayed on foodborne pathogenic - Staphyloccoccus aureus subsp. aureus (CCUG ATCC® 25926™) and Escherichia coli (ATCC® 25922™) - and spoilage microorganisms - Pseudomonas aeruginosa (ATCC® 27853™). Test producer strains showed inhibitory effect on all indicator microorganisms in diffusion of cell-free concentrated supernatant by agar in well methods (10.0-22.5 mm) in periods of 24, 48 and 72 h. Inhibitory compounds showed no sensitivity to the action of proteolytic enzyme trypsin and were completely inactivated by adjusting the pH of the cell-free 20 × concentrated supernatant to 7.0. The results demonstrated that antimicrobial substances do not have proteinaceous nature and are caused by the action of organic acids with decreasing medium pH.The antimicrobial activities as well as the nature of the inhibitory compounds obtained from Lactobacillus casei, Bifidobacterium bifidum and Bifidobacterium animalis strains were assayed on foodborne pathogenic – Staphyloccoccus aureus subsp. aureus (CCUG ATCC® 25926™) and Escherichia coli (ATCC® 25922™) – and spoilage microorganisms – Pseudomonas aeruginosa (ATCC® 27853™). Test producer strains showed inhibitory effect on all indicator microorganisms in diffusion of cell-free concentrated supernatant by agar in well methods (10.0–22.5 mm) in periods of 24, 48 and 72 h. Inhibitory compounds showed no sensitivity to the action of proteolytic enzyme trypsin and were completely inactivated by adjusting the pH of the cell-free 20 × concentrated supernatant to 7.0. The results demonstrated that antimicrobial substances do not have proteinaceous nature and are caused by the action of organic acids with decreasing medium pH.

Flour production from shrimp by-products and sensory evaluation of flour-based products

The objective of this work was to evaluate the production of flour using by‑products (cephalothorax) obtained from the shrimp (Litopenaeus vannamei) industry, and to perform a sensory analysis of shrimp flour‑based products. Physicochemical and microbiological analyses on fresh cephalothorax and on manufactured flour were performed, as well as the determination of cholesterol content of this flour, and the sensorial evaluation of soup and pastry made with this flour. By the microbiological analyses, no pathogenic microorganism was detected in the samples. Physicochemical analyses of flour showed high levels of protein (50.05%) and minerals (20.97%). Shrimp cephalothorax flour showed high levels of cholesterol. The sensory evaluation indicated a good acceptance of the products, with satisfactory acceptability index (81% for soup, and 83% for pastry), which indicates that shrimp cephalothorax in the form of flour has a potential for developing new products.

Metabolites of interest for food technology produced by microalgae from the Northeast Brazil

There is an increasing demand for bioprospection focusing on microalgae isolated from the northeastern region of Brazil with potential importance for food industries. To attend that need, we evaluated the characteristics of 12 regional species of microalgae grown under controlled cultivation conditions (temperature = 24 ± 1 oC, illumination 150 µmol photons m-2 s-1, photoperiod of 12 h) in terms of their nutritional quality and lipid profiles. Significant differences in growth characteristics and chemical compositions were observed among the species investigated. High carbohydrate contents (> 25 g 100 g-1) were recorded in various strains of Chlorococcum and the marine microalga Amphidinium carterae; high protein contents (> 35 g 100 g-1) were observed in Scenedesmus acuminatus and Pediastrum tetras; and high lipid contents (> 25 g 100 g-1) in A. carterae and some strains of Chlorococcum sp. (cf. hypnosporum). Chlamydomonas sp. demonstrated the greatest production of carotenoids (64.92 mg g-1), chlorophyll-a (234.74 mg g-1), and chlorophyll-b (59.34 mg g-1). The lipid profiles of Chlorella cf. minutissima, four strains of Chlorococcum sp. (cf. hypnosporum), P. tetras, Planktothrix isothrix, and S. acuminatus indicated the presence of palmitic, oleic (ω-9), linoleic (ω-6) and α-linolenic (ω-3) acids, with more than 50% omegas in the total composition of their fatty acids. In terms of chemical nutrients, the microalgae cited were found to be potential sources of omegas, carotenoids, and chlorophylls that could be used in food industries.

Caracterização físico-química e microscópica de ovos desidratados de avestruz

Approximately 20% of ostrich eggs are infertile and can be consumed by humans, however, its high volume and perishability indicate the need of appropriate technological processes. Thus, this study aimed to determine the chemical composition of in natura ostrich eggs, as well as physical, chemical and microscopic parameters of ostrich egg products after dehydration. The chemical composition of in natura ostrich and chicken eggs was determined. Ostrich egg whites, yolks and whole eggs were fermented and dried in mini spray-dryer. After dehydration, yield, composition and particle diameter of egg products collected in the cyclone and spray-dryer chamber were evaluated. In natura ostrich egg white and yolk showed higher protein (respectively 15.21% and 11.54%) and fat (respectively 38.48% and 0.34%) contents, when compared to chicken eggs. Samples collected from the cyclone showed a lower moisture content and better particle diameter uniformity. The ostrich egg products presented satisfactory yield, uniformity and nutritional value, demonstrating that the spray-dryer technique is another alternative for conservation and use of this food for human consumption.