101 documents found, page 1 of 11
Separation of Bioactive Compounds in Olive Leaf with a Pyridyl-Functionalized A...
Bilalov, Elchin; Martins, Cláudia Filipa; Costa, Mário Rui; Dias, RolandoThe separation of different types of bioactive compounds in olive leaf is demonstrated with a tailored adsorbent functionalized with pyridyl moieties and sorption−desorption processes developed to use only hydroalcoholic solvents. The competitive binding isotherms of mixtures of vanillic acid, oleuropein, quercetin, maslinic, and oleanolic acids in water/ethanol solvents, with the composition ranging from 50/50...
Reaction routes with glycidyl methacrylate for the incorporation of oleic acid ...
Gomes, Catarina; Costa, Mário Rui; Dias, RolandoThis research focused on assessing different reaction routes for synthesizing amphiphilic block copolymers, with the hydrophobic part built using glycidyl methacrylate and oleic acid and the hydrophilic segment made from 2(dimethylamino)ethyl methacrylate. The main objectives of this study were to identify reaction routes leading to low-impact branching and/or crosslinking mechanisms involving epoxides and olei...
Pyridyl-functionalized and surface molecularly imprinted cellulose particles to...
Almeida, Ayssata Patrícia da Costa Leocádia Vaz; Gaspar, Rita M.; Ferreira-Dias, Suzana; Costa, Mário Rui; Dias, RolandoHybrid particles consisting of a cellulose core and a 4-vinylpyridine-based cross-linked shell were synthesized inthe presence of the quercetin imprinting template by surface initiated atom transfer radical polymerization (ATRP). The modification of cellulose with the introduction of pyridyl moieties was demonstrated by FTIR, SEM, surface area measurement and quantification of nitrogen in the hybrid particles b...
Fractionation of flavonols and anthocyanins in winemaking residues using molecu...
Gomes, Catarina P.; Dias, Rolando; Costa, Mário RuiHybrid cellulose-synthetic particles with surface active pyridyl moieties and molecularly imprinted cavities for quercetin were prepared via atom transfer radical polymerization. The functionalization of the materials with pyridyl groups was confirmed by FTIR and the SEM micrographs of the hybrid particles demonstrate a clear surface modification compared with the pristine cellulose. Competitive sorption/desorp...
Purification of stilbenes from grape stems in a continuous process based on pho...
Bzainia, Amir; Igrejas, Getúlio; Pereira, Maria João; Costa, Mário Rui; Dias, RolandoThis study presents a sustainable method to purify stilbenes from residual grape stem biomass. This approach was experimentally validated through the use of a pilot size fixed-bed adsorption prototype for the automation of the purification process. Molecularly imprinted polymers, synthesized through photopolymerization at room temperature and incorporating the 4-vinylpyridine monomer, serve as adsorbents. The p...
Competitive Adsorption of Phenolic Acids, Secoiridoids, and Flavonoids in Querc...
Almeida, Ayssata; Martins, Ana Filipa; Dias, Rolando; Costa, Mário RuiThe competitive adsorption of phenolic acids, secoiridoids, and flavonoids in a molecularly imprinted polymer (MIP) functionalized with 4-vinylpiridine (4VP) moieties is analyzed here considering vanillic acid, oleuropein, and quercetin as reference molecules. Measured adsorption isotherms highlight a much stronger binding capacity of the quercetin-MIP particles toward quercetin as compared with vanillic acid a...
Scale-up of a sorption process working with molecularly imprinted adsorbents fo...
Gomes, Catarina; Duarte, Cristina N.; Martins, Cláudia D.; Amaral, Joana S.; Igrejas, Getúlio; Pereira, Maria João; Costa, Mário Rui; Dias, RolandoThis work presents the scale-up of a sorption process for the fractionation and enrichment of bioactive compounds in winemaking residues using molecularly imprinted adsorbents. The process works with hydroalcoholic solvents and the improvement of the bioactivity of the produced fractions, comparatively to the raw extracts, is demonstrated. The proposed approach was experimentally validated through the designing...
Surface molecularly imprinted cellulose-synthetic hybrid particles prepared via...
Gomes, Catarina; Dias, Rolando; Costa, Mário RuiSurface molecularly imprinted cellulose-synthetic hybrid particles are prepared via atom transfer radical polymerization (ATRP). The two-step process involves the immobilization of alpha-bromoisobutyryl bromide in the pristine microcrystalline cellulose, to generate ATRP macroinitiator particles, and then the creation of a crosslinked-imprinted shell in the particles surface considering ATRP of 4-vinylpyridine ...
Functionalization of polymer networks to target trans-resveratrol in winemaking...
Bzainia, Amir; Dias, Rolando; Costa, Mário RuiThe present work aims to produce functionalized polymer networks to target the bioactive molecule trans-resveratrol found in winemaking residues, specifically at grape stems. The synergistic choice of photoinitiation, polymerization composition, and molecular imprinting approach allows the functionalization of these materials. Experimental design is applied to methodically perform the syntheses. The amount of c...
Molecular imprinting and surface grafting of glycoprotein fragments in polymeri...
Bzainia, Amir; Gomes, Catarina P.; Dias, Rolando; Costa, Mário RuiGlycoproteins and glycans are widely found in eukaryotes, prokaryotes, archaea, and viruses. Many fundamental biological mechanisms, such as molecular recognition, signal transduction, cell adhesion, and immune response are regulated with the intervention of glycoproteins, glycans, and monosaccharides. Several diseases are a result of anomalous changes affecting the structure of these molecules or their abnorma...