Encontrados 15 documentos, a visualizar página 1 de 2
Lipossomas
Conceição, Ana Isabel F. S.; Matos, Carla M.; Moutinho, Carla G.; Balcão, Victor M.Os lipossomas são microsistemas constituídos por uma ou mais bicamadas lipídicas dispostas esfericamente, separadas por fases aquosas, cujo cerne é um compartimento aquoso. Tais estruturas esféricas fechadas, cujo diâmetro varia tipicamente entre os 50 nm e os 5 mm, formam-se espontaneamente quando alguns lípidos são colocados em solução aquosa. Logo após a sua descoberta, na década de sessenta, surgiu a ideia ...
Changes in the pool of free fatty acids in ovine, bovine and caprine milk fats,...
Regado, Mafalda A.; Cristovão, Betina M.; Tavaria, Freni K.; Ferreira, João Paulo; Moutinho, Carla G.; Balcão, Victor M.; Malcata, F. XavierLipolysis catalysed by lipases, native or released by natural microflora in milk, plays a key role in development of aroma and flavour throughout cheese ripening. This research effort was aimed at a deeper understanding of the action of two wild strains used in traditional ewe’s milk cheesemaking in Portugal, viz. Lactococcus lactis and Debaryomyces vanrijiae. They were both tested as viable cells and cellfree ...
Flavour development via lipolysis of milkfats: changes in free fatty acid pool
Regado, Mafalda A.; Cristóvão, Betina M.; Moutinho, Carla G.; Balcão, Victor M.; Aires-Barros, Raquel; Ferreira, João Paulo M.; Malcata, F. XavierUnder the trade name lipolysed milkfat (LMF), concentrated cheese flavours obtained via enzymatic treatments of cheese (or other dairy substrates) have been made available in increasing numbers. In this research effort, (anhydrous) milkfats from cows, ewes and goats were used as substrates for production of cheesy flavours. Those milkfats were subjected to modifications brought about by ten different (commercia...
Hydrolysis of α-lactalbumin by cardosin A immobilized on highly activated supports
Barros, Rui M.; Extremina, Clara I.; Gonçalves, Inês C.; Braga, Beatriz O.; Balcão, Victor M.; Malcata, F. XavierIn the present research effort, production of derivatives of cardosin A (a plant protease) encompassing full stabilization of its dimeric structure has been achieved, via covalent, multi-subunit immobilization onto highly activated agarose-glutaraldehyde supports. Boiling such enzyme derivatives in the presence of sodium dodecyl sulfate and β-mercaptoethanol did not lead to leaching of enzyme, thus providing ev...
Coimmobilization of L-asparaginase and glutamate dehydrogenase onto highly acti...
Balcão, Victor M.; Mateo, Cesar; Fernández-Lafuente, R.; Malcata, F. Xavier; Guisán, José M.In the present research work, production of coimmobilized derivatives of L-asparaginase and glutamate dehydrogenase was attempted. Comparison of immobilization of each enzyme independently with coimmobilization of the two enzymes unfolded important advantages of the latter, namely a decrease in the induction period (time before the maximum reaction rate is virtually achieved) and an increase in the maximum reac...
Hydrolysis of whey proteins by proteases extracted from Cynara cardunculus and ...
Lamasa, Estela M.; Barrosa, Rui M.; Balcão, Victor M.; Malcata, F. XavierBlends of cardosins A and B, enzymes present in aqueous extracts of the flowers of the thistle (Cynara cardunculus L.), have for long been used as rennets by the cheesemaking industry in the Iberian Peninsula. These dimeric proteases are present in the stigmæ and stylets of said flowers, and are thought to play a role in sexual reproduction of the plant. In the present research effort, production of cardosin de...
Maximisation of the yield of final product on substrate in the case of sequenti...
Celayeta, Jesus F.; Silva, André H.; Balcão, Victor M.; Malcata, Xavier F.A theoretical procedure is reported, which aims at finding the best molar distribution of two enzymes (considered equivalent and mutually exclusive in terms of occupancy of immobilisation sites), coimmobilised in a slab-shaped porous bead, that catalyse two sequential irreversible reactions (involving an initial reactant species, an intermediate species and a final product species, at 1:1:1 stoichiometry) follo...
Kinetics and mechanisms of reactions catalyzed by immobilized lipases
Paiva, Ana L.; Balcão, Victor M.; Malcata, F. XThis review focuses on the kinetics of several modes of immobilization of lipases, on the mechanisms of reactions of activation of immobilized lipases, and on the kinetics and mechanisms of reactions catalyzed by immobilized lipases. A comprehensive overview of the state of the art pertaining to structural features of lipases is provided as an aid to understand immobilization, interfacial activation, and cataly...
Interesterification and acidolysis of butterfat with oleic acid by Mucor javani...
Balcão, Victor M.; Malcata, F. X.Lipases have become powerful tools in the manufacture of structured fats either via randomization of their glyceride composition or incorporation of externally supplied fatty acid residues in such glycerides. The present communication reports on changes that occurred in the fatty acid pool of anhydrous butterfat subject to interesterification and to acidolysis with oleic acid catalyzed by a commercial lipase im...
Lipase catalyzed modification of milkfat
Balcão, Victor M.; Malcata, F. XavierDecreasing consumption of high fat milk and dairy products is driving the dairy industry to seek other uses for increasing surplus of milkfat. Enzyme catalyzed modification of milkfat using lipases is receiving particular attention. This review examines lipase-mediated modification of milkfat. Especial attention is given to industrial applications of lipases for producing structured and modified milkfat for imp...
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