Cristiana Pedrosa

Comparison of α-tocopherol microparticles produced with different wall materials: pea protein a new interesting alternative

α-Tocopherol is a radical chain breaking antioxidant that can protect the integrity of tissues and play an important role in life process. Microparticles containing α-tocopherol were produced by spray drying technique using pea protein (PP), carboxymethylcellulose(CMC) and mixtures of these materials with maltodextrin (PP-M and CMC-M) as wall materials. The microparticles produced were characterised as regards the core retention (high performance liquid chromatography), the morphology (scanning electron microscopy) and size distribution (laser diffraction). The retention of α-tocopherol within all microparticles was above 77%. They showed a spherical shape and roughness at varied degrees. Their mean particles size remained below 7 µm, and the smallest sizes were found in PP and CMC-M microparticles. The results obtained in this work show that the pea protein use for α-tocopherol microencapsulation is a promising system for further application in food.

Vitamin A modulates the expression of genes involved in iron bioavailability.

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.

Effective stabilization of CLA by microencapsulation in pea protein.

CLA was microencapsulated by spray drying in ten varied wall systems (WS) consisting of pea protein isolate or pea protein concentrate (PPC) alone at varied core:WS ratios (1:2; 1:3 and 1:4), or blended with maltodextrin (M) and carboxymethylcellulose at a pea protein:carbohydrate ratio of 3:1. The physical-chemical properties of the CLA microparticles were characterised by core retention, microencapsulation efficiency (ME), particle size and moisture. CLA:M:PPC (1:1:3) showed the most promising results, thus we evaluated the effect of M addition in the WS on other physical-chemical characteristics and oxidative stability (CLA isomer profile, quantification of CLA and volatile compounds by SPME coupled with CG-MS) during two months of storage at room temperature, CLA:PPC (1:4) was selected for comparisons. CLA:M:PPC (1:1:3) microparticles demonstrated better morphology, solubility, dispersibility and higher glass-transition temperature values. M addition did not influence the oxidative stability of CLA, however its presence improved physical-chemical characteristics necessary for food applications.

Aceitabilidade de feijão preto (Phaseolus vulgaris L.), fortificado com micropartículas de ferro

Este trabalho teve como objetivo avaliar a aceitabilidade de feijao preto (Phaseolus vulgaris L.), fortificado com microparticulas de ferro, para que seja posteriormente utilizado na prevencao e controle da anemia ferropriva. Foram preparadas tres amostras de feijao preto cozido, sendo uma sem adicao de microparticulas de ferro (controle); a segunda foi adicionada quantidade equivalente a 5 mg de ferro, para cada concha media de feijao, e, a ultima amostra, 10 mg de ferro para cada concha media. Utilizou-se escala hedonica de cinco pontos para avaliacao dos atributos. Com base nos resultados obtidos, as amostras controle e 5 mg/porcao foram as mais aceitas; houve, porem, pouca diferenca em relacao a amostra com 10 mg/porcao. A boa aceitacao do alimento pelos provadores mostra ser viavel a fortificacao de feijao preto com ferro microencapsulado, podendo ser usado na prevencao e controle da anemia ferropriva.