Edmilson Antonio Canesin

Polyelectrolyte complexes based on alginate/tanfloc: Optimization, characterization and medical application

Hydrogels based on alginate and tanfloc (a cationic biopolymer obtained from natural condensed tannins) were successfully prepared. Tanfloc (TN) presents high aqueous solubility at pHs lower than 10; it contains substituted amino sites and molar weight of ca. 600,000gmol-1. A factorial design (22) was used to optimize the yield of alginate/tanfloc polyelectrolyte complexes (PECs). Dialysis recovered the overplus of alginate (AG) no complexed with TN. These materials were characterized by thermal analyses (TGA/DTG and DSC), zeta potential, and FTIR, while SEM technique depicted a rough surface on AG/TN complex, containing non-homogeneous pores. Indeed, the AG and TN were tailored to elicit scaffold materials with outstanding cytocompatibility, mainly upon mouse preosteoblastic cells because of reconstruction of bone tissues (119% at 10days). The AG/TN complex also displayed antioxidant and bactericidal activities against Staphylococcus aureus (S. aureus). Besides, the pristine TN fostered bacteriostatic and bactericidal performances towards S. aureus and Escherichia coli. However, for our best knowledge, no studies were still carried out on TN and TN-based materials for medical purpose.

Incorporation of conjugated fatty acids into Nile tilapia (Oreochromis niloticus)

BACKGROUND The aim of this work was to improve the nutritional quality of Nile tilapia meat through enriched diets with conjugated isomers of linolenic acid from tung oil. The transfer process of conjugated fatty acids (CFAs) into fish muscle tissue was evaluated by gas chromatography-flame ionization detection (GC-FID) and easy ambient sonic-spray ionization mass spectrometry (EASI-MS). RESULTS The results showed that conjugated fatty acids were transferred from enriched diet for muscle tissue of Nile tilapia. Conjugated linoleic acids biosynthesis from conjugated linolenic acids was also observed after 10 days. Other important fatty acids such as docosahexaenoic (DHA), eicosapentaenoic (EPA) and arachidonic (AA) acids were also identified over time; however, DHA showed the highest concentration when compared with EPA and AA compounds. CONCLUSION Therefore, the nutritional quality of Nile tilapia was improved through feeding with enriched diets. The ingestion of these fish may contribute to reaching adequate levels of daily CFA consumption. Furthermore, other important substances which play an important role in human metabolism, such as EPA, DHA and AA, can also be ingested together with CFA.

Influence of the extracts of senna leaves, blackberries and hibiscus flowers in the oxidation reaction of commercial biodiesel

ABSTRACT Biodiesel is being increasingly used as an alternative energy source to reduce the dependence on derived petroleum fuels. However, sources of raw material for its production may contain substances susceptible to oxidation that are incorporated into biodiesel. As an alternative to minimize and even inhibit the oxidation reaction, antioxidant extracts from senna leaves, blackberries and hibiscus flowers were added to biodiesel, which present in their composition (structures) phenolic compounds capable of inhibiting the formation of free radicals in the reaction medium. The efficiency of the extracts was evaluated by the induction period determined using the Rancimat® method at temperatures of 110, 115, 120 and 125°C. The best results were obtained in the tests with large proportions of hibiscus flower extract. The mixture design provides predictive equations for all temperatures. Furthermore, in all the assays the values of the induction period were higher than in the control sample, thus demonstrating that the extracts of leaves of senna, blackberries and hibiscus flowers were efficient in protecting the biodiesel against the oxidation reaction. The multiresponse optimization proposed an optimal mixture containing 80% hibiscus flower and 20% senna leaves extract.