Iron bioavailability seems to be regulated by vitamin A (VA) but the molecular events involved in this mechanism are not well understood. It is also known that retinoids mediate most of their function via interaction with retinoid receptors, which act as ligand-activated transcription factors controlling the expression of a number of target genes. Here, we evaluated the VA effects on the modulation of the levels of mRNA encoding proteins involved in the iron bioavailability, whether in the intestinal absorption process or in the liver iron metabolism. The expression of genes involved in iron intestinal absorption (divalent metal transporter 1, duodenal cytochrome B, ferroportin 1 FPN1, and ferritin) were evaluated in vitro by treating Caco-2 cells with retinoic acid or in vivo by observing the effects of vitamin A deficiency (VAD) in BALB/C mice. Liver hepcidin and ferritin mRNA levels were upregulated by VAD; however, this condition did not promote any change on the expression of those genes that participate in the iron absorption. Moreover, data from the in vitro analysis showed that VA induced FPN1 gene expression by a hepcidin-independent manner. Therefore, the in vivo results support the idea that VAD may not affect iron absorption but would rather affect iron mobilization mechanisms. On the other hand, our results using Caco-2 cells raises the possibility that VA addition to intestinal epithelium may improve iron absorption through the induction of FPN1 gene expression.

Worldwide, the most prevalent nutritional deficiency is iron. The strategies for iron supplementation often fail due to poor adherence to supplementation methods contributed to unpleasant sensory characteristics. An alternative is the use of microencapsulated nutrients for home fortification in order to mask undesirable tastes and to allow its release in strategic sites of the gastrointestinal tract. Toward this end, pea protein concentrate was tested as a natural, edible and alternative material and the spray-drying technique was utilized for the preparation of microparticles containing ferrous sulfate. Their physical and chemical characteristics were evaluated. The microparticles had a spherical shape and grooves with an average size ranging between 2 and 3 μm. Analysis by in vitro assays tested the release of iron in simulated salivary and gastric fluids and its intestinal absorption in Caco-2 cells. No dissolution of iron occurred in the salivary medium whereas the sensory analysis showed good acceptance of a product which incorporated 5.5 mg of iron per 100 g portion of food. Thus, the effectiveness of microencapsulation was demonstrated by utilizing a plant protein as an encapsulating matrix for the controlled release of iron and capable of preserving the bioaccessibility of ferrous sulfate.

In the processing of fruits such as blueberry (Vaccinium sp), that has high levels of phenolic acid, the food industry produces tons of organic waste that causes harm to the environment. Encapsulation is a technique used to take advantage of these wastes. Several methods are used to encapsulate substances, among them ionotropic gelation proves to be a simple, precise, efficient and economical method for obtaining particles with encapsulated bioactives. In this manner, the aim of this study was to test sodium alginate as wall material to encapsulate blueberry residue by ionotropic gelation. The microbeads were characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), total phenolic compounds, antioxidant capacity and in vitro dissolution. The results showed that the microbeads had surface invagination; retention of 67.01% of the phenolic compounds after encapsulation and 68.2%, phenolic release 120 min after in vitro dissolution. The results suggest that the tested matrix was suitable for encapsulation. The produced microbeads are promising for applications in food products, once the phenolic compounds present in the blueberry residues were maintained after encapsulation.