49 research outputs found
An overview of the recent developments on fructooligosaccharide production and applications
Over the past years, many researchers have suggested
that deficiencies in the diet can lead to disease states
and that some diseases can be avoided through an adequate
intake of relevant dietary components. Recently, a great interest
in dietary modulation of the human gut has been registered.
Prebiotics, such as fructooligosaccharides (FOS), play a key
role in the improvement of gut microbiota balance and in
individual health. FOS are generally used as components of
functional foods, are generally regarded as safe (generally
recognized as safe status—from the Food and Drug Administration,
USA), and worth about 150€ per kilogram. Due to
their nutrition- and health-relevant properties, such as moderate
sweetness, low carcinogenicity, low calorimetric value,
and low glycemic index, FOS have been increasingly used
by the food industry. Conventionally, FOS are produced
through a two-stage process that requires an enzyme production
and purification step in order to proceed with the chemical
reaction itself. Several studies have been conducted on the
production of FOS, aiming its optimization toward the development
of more efficient production processes and their potential
as food ingredients. The improvement of FOS yield and
productivity can be achieved by the use of different fermentative
methods and different microbial sources of FOS producing
enzymes and the optimization of nutritional and
culture parameter; therefore, this review focuses on the latest
progresses in FOS research such as its production, functional
properties, and market data.Agencia de Inovacao (AdI)-Project BIOLIFE reference PRIME 03/347. Ana Dominguez acknowledges Fundacao para a Ciencia e a Tecnologia, Portugal, for her PhD grant reference SFRH/BD/23083/2005
Unravelling the secret of seedbased gels in water: the nanoscale 3D network formation
Chia (Salvia hispanica) and basil (Ocimum basilicum) seeds have the intrinsic ability to form a hydrogel concomitant with moisture-retention, slow releasing capability and proposed health benefits such as curbing diabetes and obesity by delaying digestion process. However, the underlying mode of gelation at nanoscopic level is not clearly explained or explored. The present study elucidates and corroborates the hypothesis that the gelling behavior of such seeds is due to their nanoscale 3D-network formation. The preliminary study revealed the influence of several conditions like polarity, pH and hydrophilicity/ hydrophobicity on fiber extrusion from the seeds which leads to gelation. Optical microscopic analysis clearly demonstrated bundles of fibers emanating from the seed coat while in contact with water, and live growth of fibers to form 3D network. Scanning electron microscope (SEM) and transmission electron microscope (TEM) studies confirmed 3D network formation with fiber diameters ranging from 20 to 50 nm
Highly Diastereoselective Synthesis of the 1,1'-Binaphthol Unit on a Bile Acid Template
The use of 7-deoxycholic acid as a chiral template in the asymmetric syntheses of 1,1'-binaphthyl-2,2'-diol derivatives is reported. Intramolecular coupling of compounds 7 and 11 have been carried out with Mn(acac)(3) in CH3CN to afford coupled binaphthol products 8 and 12 with 65% and >99% diastereoselectivity, respectively. In both cases the predominant formation of the (S) isomers were predicted by computer modeling studies. This was confirmed in the case of compound 12
Novel cationic and neutral analogues of bile acids: Synthesis and preliminary study of their aggregation properties
Novel cationic and neutral analogues of bile acids (1-6) were synthesized and their aggregation properties studied. Cations 1 and 2 formed thermoreversible gels in aqueous salt solutions, whereas neutral 4 formed gels in water in the presence of organic solvents such as ethanol, methanol, DMSO, and DMF. The gels derived from 1 and 4 have been investigated by SEM and with pyrene as a fluorescent probe
Helical aggregates from a chiral organogelator
A new class of pyrene based organogelators has been discovered, and a chiral gelator of this type has been shown to form helical aggregates upon gelation
Ammonium lithocholate nanotubes:stability and copper metallization
Ammonium lithocholate nanotubes have been prepared in alkaline ammonia solutions and exhibited remarka ble monodisperse cross-sectional dimensions (external diameter = 52 nm) as shown by cryo-transmission electron microscopy measurements. A classical electroless metallic replication method was used with a single poly(ethylene-imine) PEI layer coating the negatively charged nanotubes. Short copper rods (external diameter 80 nm) were observed by scanning electron microscopy that corresponded to the original organic templates. The results obtained in acidic conditions are analyzed in terms of the lifetime of the self-assembled structures and formation of bundles of tubes. Dynamic light scattering measurements and optical observations show that the system in the presence of controlled amounts of hydrochloric acid is stable enough to account for a metallic replication in acidic conditions. An average apparent diffusion coefficient of the organic assemblies is extracted in homogeneous suspensions where bundles have been dispersed by the acidic additions