RESUMO
The aim of this work was to evaluate the suitability of incorporating Fe3O4 (magnetite, M) NPs into water kefir (wKef) beverages. Magnetite NPs were synthesized and coated with pectins (cM), and incorporated into wKef beverages obtained by fermentation of a muscovado sugar solution with wKef grains. FeSO4, usually employed as fortifier, was used as a control. Four different beverages were analyzed: wKef, wKef-cM, wKef-M, wKef-FeSO4, indicating wKef beverages fortified with cM, M or FeSO4, respectively. Their stability was assessed by determining the viability of total lactic acid bacteria and yeasts, and the composition of saccharides along storage at 4 °C for up to 30 days. The toxicity of M and cM was evaluated in an in vivo model of Artemia salina. The absorption of iron was quantified by determining ferritin values on intestinal Caco-2/TC7 cells, and its internalization mechanisms, by employing inhibitors of endocytic pathways and quantifying ferritin. M and cM were non-toxic on Artemia salina up to 500 µg/mL, a toxicity even lower than that of FeSO4, which showed a LD50 of 304.08 µg/mL. After 30 days of storage, no significant decrease on yeasts viability was observed, and bacteria viability was above 6 log CFU/mL for the four beverages. In turn, sucrose decreased to undetectable values, concomitantly to an increase in the concentrations of glucose and fructose. Both wKef-M and wKef-cM led to a significant increase in the ferritin values (up to 2 folds) with regard to the basal state. The internalization of M NPs occurred via clathrins and caveolin pathways, whereas that of cM, by macropinocytosis. Safely incorporating M and cM NPs into wKef beverages appear as an innovative strategy for providing bioavailable iron aiming to ameliorate the nutritional status of populations at risk of iron deficiency (e.g., vegans).
Assuntos
Kefir , Nanopartículas de Magnetita , Células CACO-2 , Humanos , Ferro , ÁguaRESUMO
A bathochromic shift for both Soret and Q bands in the polyCo(III)PP were indicative of Co(III) oxidation state in film. The presence of an isosbestic point indicates a chemical equilibrium between polyCo(III)PP (band I) in polyCo(III)PP with water as axial neutral ligand (band II). Concentration levels of iodide of 10(-1) M showed irreversible broadening of Soret band with a maximum shift from 400 nm to 380 nm attributed to film reduction. The thiocyanate anion shows a remarkable effect on polyCo(III)PP spectra. The degree of configuration interaction for Q and B transitions is nearly constant in air and water for Ni(II)PP, Cu(II)PP and Zn(II)PP films. The poly[Co(III)-protoporphyrin IX] showed strong deviation from the pattern. This result indicates that the Co atom does not present a planar conformation in polyCo(III)PP which is consistent with the less packed structure of this film. The apparent diffusion coefficients (D') were calculated for electroactive species using the polyNi(II)PP chemically modified electrode, with an experiment short enough to avoid preconcentration. D' was compared with D (diffusion coefficient), obtained with the bare working electrode. Apparent diffusion coefficients (D') changed regularly with molecular volume indicating certain molecular sieving effect.