Paulo Rodrigo Stival Bittencourt

Subcritical Extraction of Salvia hispanica L. Oil with N-Propane: Composition, Purity and Oxidation Stability as Compared to the Oils Obtained by Conventional Solvent Extraction Methods

This study evaluated the Chia (Salvia hispanica L.) oil composition in terms of fatty acids (FA), sterols, acylglycerols and oxidative stability obtained via subcritical n-propane fluid extraction (SubFE-propane), in different temperatures and pressure conditions, as compared to Bligh & Dyer (BD), Soxhlet (SE) and Folch (FLS) extractions. Total lipid varied from 23.25 to 30.21% and the best yield was obtained by both SubFE-propane extraction at 45 oC and 12 MPa (A). α-Linolenic acid (18:3n-3) was the most abundant FA and SubFE-propane extraction provided the best results for the sum of n-3 and PUFA. All oil samples were similar in regard to triacylglycerols (TAG) profiles as measured via direct electrospray ionization mass spectrometry (ESI-MS) analysis. The total amounts of stigmasterol, β-tocopherol and tocopherol total were highest in the Chia oil obtained by BD, campesterol and sitosterol by SE and γ-tocopherol by SubFE-propane extraction. The SubFE-propane oil also presented the best (2 to 5 times) oxidation stability. SubFE-propane was the most efficient extraction method for Chia oil, providing the highest extraction yields, purity, oxidation stability and diverse profile of sterols.

Using chemometric techniques to characterize gluten-free cookies containing the whole flour of a new quinoa cultivar

Celiac disease is defined as intolerance to the gluten proteins present in certain cereals used to prepare foodstuffs. We developed and performed physico-chemical, sensory, and nutritional assessments of three formulations of gluten-free cookies containing Linum usitatissimum L. and different levels of whole Chenopodium quinoa BRS Piabiru flour. No gluten was detected in the prepared cookie formulations. The crude protein and total lipid contents ranged from 85.58 to 97.55 and 121.69 to 166.19 g per kg of sample, respectively. The polyunsaturated/saturated and n-6:n-3 fatty acid ratios ranged from 0.85:1 to 0.92:1 and 3.08:1 to 4.38:1, respectively. Formulation C had the best alpha-linolenic acid content, lipid fraction nutritional indices and mineral content per portion, with excellent sensory characteristics. Multivariate analysis highlighted the effect of the concentration of quinoa on the nutritional and sensory qualities of the product.

Cellophane and filter paper as cellulosic support for silver nanoparticles and its thermal decomposition catalysis.

Silver nanoparticles (AgNPs) have attracted great attention due to its optical, electrical and thermal properties. Cellulosic supports for these nanoparticles are of particular interest because of its availability, flexibility and biocompatibility. In this work, AgNPs were synthesized using two cellulosic materials, cellophane (CP) and filter paper (FP), as matrix support. Cellulosic materials were immersed in an aqueous solution of silver nitrate containing polyvinylpyrrolidone (PVP) and then reduced with hydroxylamine. The obtained nanocomposites (CP-AgNPs and FP-AgNPs) were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (DRX) and scanning electron microscopy (SEM). AgNPs of near 15nm anchored onto cellulosic surfaces were detected. The thermal properties of these materials were investigated through thermogravimetry (TG). Their kinetic of thermal decomposition was studied by the Vyasovkin method of dynamic isoconvertion, which indicated a catalytic effect of AgNPs in the cellulose thermal decomposition reaction.

Photocatalytic degradation of H2S in the gas-phase using a continuous flow reactor coated with TiO2-based acrylic paint

ABSTRACT For the photocatalytic degradation of the hydrogen sulphide (H2S) in the gas-phase it was developed a rectangular reactor, coated with acrylic paint supported on fiber cement material. The surface formed by the paint coverage was characterized structural and morphologically by scanning electron microscopy with energy dispersive X-ray and X-ray diffraction analysis. The flow rate and the inlet concentration of H2S were evaluated as operational performance parameters of the reactor. Removal efficiencies of up to 94% were obtained at a flow rate of 2 L min−1 (residence time of 115 s) and inlet concentration of 31 ppm of H2S. In addition, the H2S degradation kinetics was modelled according to the Langmuir–Hinshelwood (L–H) model for the inlet concentrations of 8–23 ppm of H2S. The results suggest that flow rate has a more important influence on photocatalytic degradation than the inlet concentration. It is assumed that H2S has been oxidized to , a condition that led to a deactivation of the photocatalyst after 193 min of semi-continuous use.

EFEITO DA INCORPORAÇÃO DE MACA PERUANA (Lepidium meyenii) NO VOLUME ESPECÍFICO E DUREZA DE PÃES SEM GLÚTEN

O glúten é essencial na produção de produtos panificados, devido a sua propriedade de formar com a água e ação mecânica, uma substância viscoelástica, insolúvel em água, responsável pela textura dos mais diversos tipos de pães. No processamento de pães sem glúten, um dos desafios é aliar qualidade sensorial, o volume específico e a dureza, com a adição de farinhas que contribuam com o aumento de nutrientes na formulação. A farinha de maca peruana (Lepidium meyenii), um tubérculo nativo da região Andina, possui as seguintes propriedades relatadas na literatura: a prevenção da osteoporose, câncer de próstata, infertilidade, depressão, fadiga e anemia ferropriva. Assim, o presente estudo objetivou avaliar a influência da maca peruana nos parâmetros: volume específico e dureza dos pães isentos de glúten. Foi aplicado um planejamento de misturas nas formulações que continham como base a farinha mista composta por farinha de arroz (fixo = 75,4 g), amido de batata (Formulação A = 34,8 g; B = 17,8 g; C = 52,2 g), e maca peruana (Formulação A = 34,8 g; B = 52,2 g; C = 17,4 g). Os demais ingredientes foram 15,0 g de açúcar; 1,5 g de sal; 2,5 g de fermento biológico seco; hidroxipropilmetilcelulose 0,875 g; 2,5 g de goma xantana; 50,0 g de água; 18,75 g de óleo de girassol e 50,0 g de ovos. Os pães foram misturados em batedeira planetária, assados em fôrmas de alumínio, no forno convencional a 180°C por 20 minutos. O volume específico (mL g) foi obtido pelo método de deslocamento das sementes de painço 1 hora após serem assados, e a dureza através do perfil de textura avaliado no Texturômetro TA-XT2i (Stable Micro Syste). Os volumes específicos foram 1,95, 1,90 e 1,93 mL g, respectivamente, nas formulações A (0,50:0,50, maca e batata), B (0,75:0,25, maca e batata) e C (0,25:0,75, maca e batata). A dureza das formulações A (4452,32) e B (4134,26) não diferiram, o mesmo perfil foi verificado nestes pães. No pão C com 0,25 de maca peruana e 0,75 de amido de batata, mostrou-se o pão com volume intermediário e com menor dureza (3341,89). A incorporação de farinha de maca peruana permitiu obter pães com um bom volume específico e uma maior dureza, quando adicionado uma fração superior a 25% na porção de farinha mista (69,6 g) que foi modelada. Esse efeito pode ser explicado, uma vez que a maca peruana, possui alta quantidade de sacarose, o que contribuiu no aumento da fermentação, consequente retenção do dióxido de carbono no gel formado com as gomas e aumento no volume da massa. Palavras-chave: Planejamento de misturas; pão sem glúten; maca peruana.