RESUMO

Esters of 3-monochloropropane-1,2-diol (3-MCPD) and glycidol are reported vegetable fats and oils contaminants formed during processing. During digestion, esterified forms are hydrolyzed making the free forms, with high toxicity to human health, possibly available in the digestive system, which could depend, among other factors, on the phase condition stablished in the gastrointestinal tract between contaminants and lipids. Therefore, this work was aimed at evaluating the solid-liquid equilibrium (SLE) of binary and pseudobinary mixtures of fatty acids (palmitic, oleic and stearic), triacylglycerols (tripalmitin, triolein and tristearin) and a partial acylglycerols, with 3-MCPD and glycidol, by differential scanning calorimetry (DSC) and thermodynamic modeling with Margules 2 and 3 suffixes, UNIFAC and ideal models. Melting properties of the contaminants were determined by DSC thermograms, with microstructure micrographs and compared to some predictive group contribution models (GC). 14 complete SLE phase diagrams could be determined. Results showed that the lipid compounds had high affinity with the free contaminants with probably the formation of liquid crystalline structures and/or solid solutions. The Margules 3 suffixes model showed the best fit with the lowest average relative deviations, no higher than 1%, although the parameters probably incorporated the non-ideality promoted by the crystalline phase behavior. The formation of mesophases and/or solid solutions with very high melting temperature probably means a difficulty of separating the contaminants from the lipid matrix in which, on the other hand, could avoid separation process or affect (probably decreasing) their absorption during digestion.

Assuntos

alfa-Cloridrina , alfa-Cloridrina/química , Compostos de Epóxi , Óleos , Propanóis

RESUMO

BACKGROUND: Intestinal parasites' eggs, larvae, or cysts can be carried in public transport buses, and contribute to the increased incidence of diseases. This study aimed to detect biological forms of intestinal parasites in samples from public buses in the town of Diamantina, Minas Gerais, in order to know the local situation and propose interventions to improve public health. MATERIALS AND METHODS: In November 2014, six samples were obtained in buses of the two stations by using Graham method, in duplicate, by affixing a 6×5 cm clear tape, six times on each collection site of the bus, in an area of ~30 cm2. Then, each tape was positioned longitudinally on a slide microscope, and the identification of the biological forms of the parasites was performed with the aid of a 40× objective optical microscope. RESULTS: A total of 216 slides were analyzed, of which 86 (39.8%) were positive for at least one intestinal parasite. Cysts of Entamoeba coli were the most frequently found in this study (52.1%), followed by Endolimax nana cysts (30.7%), Iodamoeba butschlii (6.5%), helminth larvae (4.7%), Giardia lamblia cysts (3.6%), Hymenolepis nana eggs (1.2%), Enterobius vermicularis eggs (0.6%), and Entamoeba histolytica cysts (0.6%). Top right handrails and right stanchions had the highest occurrence of biological forms, with 18.3% and 14.8%, respectively. CONCLUSION: The results indicated the need for better cleaning of the buses and better personal hygiene by users, since pathogenic and non-pathogenic intestinal parasites were found, suggesting fecal contamination of these sites, representing a risk to public health.