Survey of aflatoxins in tomato products

Tomatoes are highly susceptible to fungi contamination in the field, during transportation, processing, and storage. Aspergillus flavus and Aspergillus parasiticus have been isolated from tomatoes and tomato products, and both fungi species can produce aflatoxin, mycotoxin with hepatotoxic, carcinogenic, teratogenic, and mutagenic effects on all animal species tested so far. In order to verify a possible aflatoxin contamination of tomato products commercialized in Brazil, 63 samples of tomato products (pulp, paste, purée, ketchup, dehydrated tomatoes, and dried tomatoes preserved in oil) produced in 5 Brazilian states and 1 imported sample (ketchup), totalizing 29 brands, were analyzed by thin layer chromatography. The analytical method showed an average recovery of 86% for all aflatoxins at two spiking levels. The limits of detection for the aflatoxins B1, B2, G1, and G2 varied with the type of the product ranging from 2 to 7 µg/kg. Aflatoxins were not detected in any evaluated sample indicating that they did not pose a risk to human health since there was no invasion of raw materials by toxigenic fungi or no conditions for toxin production.

Obtention and characterization of gluten-free baked products

This work had as objective the development of gluten-free breads and muffins using rice flour and maize and cassava starches. From seven samples resulting from a Simplex-Centroid design, the sensory and instrumental analyses of specific volume, elasticity, and firmness were performed. For the sensory analysis, the optimized formulation contained 50% of rice flour and 50% of cassava starch, and for the instrumental evaluation, the optimal simultaneous point for the three conducted analyses were 20% of rice flour, 30% of cassava starch, and 50% of maize starch. A comparative analysis of specific volume, elasticity, firmness, and triangular test was performed with pre-baked, baked, and frozen bread. Physicochemical, nutritional, and microbiological analyses were performed for both bread and muffin according to the Brazilian legislation.

Application of Response Surface Methodology to study the effect of different calcium sources in fish muscle-alginate restructured products

Sodium alginate needs the presence of calcium ions to gelify. For this reason, the contribution of the calcium source in a fish muscle mince added by sodium alginate, makes gelification possible, resulting a restructured fish product. The three different calcium sources considered were: Calcium Chloride (CC); Calcium Caseinate (CCa); and Calcium lactate (CLa). Several physical properties were analyzed, including mechanical properties, colour and cooking loss. Response Surface Methodology (RSM) was used to determine the contribution of different calcium sources to a restructured fish muscle. The calcium source that modifies the system the most is CC. A combination of CC and sodium alginate weakened mechanical properties as reflected in the negative linear contribution of sodium alginate. Moreover, CC by itself increased lightness and cooking loss. The mechanical properties of restructured fish muscle elaborated were enhanced by using CCa and sodium alginate, as reflected in the negative linear contribution of sodium alginate. Also, CCa increased cooking loss. The role of CLa combined with sodium alginate was not so pronounced in the system discussed here.

Culture alternative medium for the growth of extreme halophilic bacteria in fish products

Halotolerant or halophilic (Archaeabacteria) microorganisms can be found in salted and ripening fish products that are not affected by salt. They can be moderate or extremely halophilic bacteria. The extremely halophilic bacteria require between 15-30% of NaCl for growth. The extremely halophilic archaeobacteria may be selectively isolated in different media. The aim of this work was to determine the effectiveness of the Salt-Agar-Milk medium, a medium modified in our laboratory through the addition of MgSO4 and KCl - named SAMm, and its effect on the bacterial growth by means of comparison with other media, with and without milk, determining time of incubation and counting. Two samples of salted fish from local fish salting factories and two laboratory strains were used. The factory samples were matured anchovy and anchovy fillets in oil, and the laboratory strains were: Haloarcula spp. (proteolytic) and Halococcus spp. (non-proteolytic). The following media were alternatively used for the isolation of extremely halophilic bacteria: IRAM; Formulation of Gibbons and collaborators, Cod Milk agar, and SAMm. IRAM and Gibbons were also used enriched with milk. In the SAMm medium, there were obtained count values similar or higher than the ones of the traditional media; besides the simplicity of its elaboration, the possibility to obtain positive results two or three days earlier also added to its benefit. Consequently, it can be considered an alternative to the media traditionally used for the studied halophilic bacteria.

Partial chemical and functional characterization of milk whey products obtained by different processes

Whey protein samples (S-1 to S-5) were tested in vivo and in vitro for nutritional properties and selected bioactivities. Weanling male Wistar rats fed modified AIN-93G (12 g protein.100 g-1) diets for 21 days were used the in vivo studies. The nutritional parameters did not differ among the protein diets tested. Erythrocyte glutathione content was considered high and was higher for S-3, but liver glutathione was the same for all dietary groups. For S-3, cytokine secretion (IL-10 and TNF-α) by human peripheral blood mononuclear cells (in RPMI-1640 medium) was higher in the absence of antigen than in the presence of BCG antigen. Interleukin-4 secretion was repressed in all treatments. The IC50, whey protein concentration required to inhibit 50% of the melanoma cell proliferation, was 2.68 mg.mL-1 of culture medium for the S-3 sample and 3.66 mg.mL-1 for the S-2 sample. Based on these results, it was concluded that S-3 (whey protein concentrate enriched with TGF-β and lactoferrin) produced better nutritional and immunological responses than the other products tested.

Modeling of allergen proteins found in sea food products

Shellfish are a source of food allergens, and their consumption is the cause of severe allergic reactions in humans. Tropomyosins, a family of muscle proteins, have been identified as the major allergens in shellfish and mollusks species. Nevertheless, few experimentally determined three-dimensional structures are available in the Protein Data Base (PDB). In this study, 3D models of several homologous of tropomyosins present in marine shellfish and mollusk species (Chaf 1, Met e1, Hom a1, Per v1, and Pen a1) were constructed, validated, and their immunoglobulin E binding epitopes were identified using bioinformatics tools. All protein models for these allergens consisted of long alpha-helices. Chaf 1, Met e1, and Hom a1 had six conserved regions with sequence similarities to known epitopes, whereas Per v1 and Pen a1 contained only one. Lipophilic potentials of identified epitopes revealed a high propensity of hydrophobic amino acids in the immunoglobulin E binding site. This information could be useful to design tropomyosin-specific immunotherapy for sea food allergies.