74 research outputs found
Direct Compression Behavior of Low- and High-Methoxylated Pectins
The objective of this study was to evaluate possible usefulness of pectins for direct compression of tablets. The deformation behavior of pectin grades of different degree of methoxylation (DM), namely, 5%, 10%, 25%, 35%, 40%, 50%, and 60% were, examined in terms of yield pressures (YP) derived from Heckel profiles for both compression and decompression and measurements of elastic recovery after ejection. All pectin grades showed a high degree of elastic recovery. DM 60% exhibited most plastic deformation (YP 70.4Â MPa) whereas DM 5% (104.6Â MPa) and DM 10% (114.7Â MPa) least. However, DM 60% gave no coherent tablets, whereas tablet tensile strengths for DM 5% and DM 10% were comparable to Starch 1500Âź. Also, Heckel profiles were similar to Starch 1500Âź. For sieved fractions (180â250 and 90â125Â ÎŒm) of DM 25% and DM 40% originating from the very same batch, YPs were alike, indicating minor effects of particle size. These facts indicate that DM is important for the compaction behavior, and batch-to-batch variability should also be considered. Therefore, pectins of low degree of methoxylation may have a potential as direct compression excipients
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 statusâfrom 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
Dietary Pectin Increases Intestinal Crypt Stem Cell Survival following Radiation Injury
This research was performed as a project of the Intestinal Stem Cell Consortium, a collaborative research project funded by the National Institute of Diabetes and Digestive and Kidney Diseases (NIH U01 DK-085508 to CWH), and a grant from Oklahoma Center for the Advancement of Science and Technology to CWH.Gastrointestinal (GI) mucosal damage is a devastating adverse effect of radiation therapy. We have recently reported that expression of Dclk1, a Tuft cell and tumor stem cell (TSC) marker, 24h after high dose total-body gamma-IR (TBI) can be used as a surrogate marker for crypt survival. Dietary pectin has been demonstrated to possess chemopreventive properties, whereas its radioprotective property has not been studied. The aim of this study was to determine the effects of dietary pectin on ionizing radiation (IR)-induced intestinal stem cell (ISC) deletion, crypt and overall survival following lethal TBI. C57BL/6 mice received a 6% pectin diet and 0.5% pectin drinking water (pre-IR mice received pectin one week before TBI until death; post-IR mice received pectin after TBI until death). Animals were exposed to TBI (14 Gy) and euthanized at 24 and 84h post-IR to assess ISC deletion and crypt survival respectively. Animals were also subjected to overall survival studies following TBI. In pre-IR treatment group, we observed a three-fold increase in ISC/crypt survival, a two-fold increase in Dclk1+ stem cells, increased overall survival (median 10d vs. 7d), and increased expression of Dclk1, Msi1, Lgr5, Bmi1, and Notch1 (in small intestine) post-TBI in pectin treated mice compared to controls. We also observed increased survival of mice treated with pectin (post-IR) compared to controls. Dietary pectin is a radioprotective agent; prevents IR-induced deletion of potential reserve ISCs; facilitates crypt regeneration; and ultimately promotes overall survival. Given the anti-cancer activity of pectin, our data support a potential role for dietary pectin as an agent that can be administered to patients receiving radiation therapy to protect against radiation-induces mucositis.Yeshttp://www.plosone.org/static/editorial#pee
The Effect of Xyloglucans on the Degradation of Cell-Wall-Embedded Cellulose by the Combined Action of Cellobiohydrolase and Endoglucanases from Trichoderma viride.
Two endoglucanases of Trichoderma viride, endoI and endoIV, were assayed for their activity toward alkali-extracted apple xyloglucans. EndoIV was shown to have a 60-fold higher activity toward xyloglucan than endoI, whereas carboxymethyl cellulose and crystalline cellulose were better substrates for the latter. The enzymic degradation of cellulose embedded in the complex cell-wall matrix of apple fruit tissue has been studied using cellobiohydrolase (CBH) and these two different endoglucanases. A high-performance liquid chromatographic method (Aminex HPX-22H) was used to monitor the release of cellobiose and oligomeric xyloglucan fragments. Synergistic action between CBH and endoglucanases on cell-wall-embedded cellulose was, with respect to their optimal ratio, slightly different from that reported for crystalline cellulose. The combination of endoIV and CBH solubilized twice as much cellobiose compared to a combination of endoI and CBH. Apparently, the concomitant removal of the xyloglucan coating from cellulose microfibrils by endoIV is essential for an efficient degradation of cellulose in a complex matrix. Cellulose degradation slightly enhanced the solubilization of xyloglucans. These results indicate optimal degradation of cell-wall-embedded cellulose by a three-enzyme system consisting of an endoglucanase with high affinity toward cellulose (endoI), a xyloglucanase (endoIV), and CBH
Some preliminary results on the action of rhamnogalacturonase on rhamnogalacturonan oligosaccharides from beet pulp
Sugar-beet pulp was saponified and then hydrolysed with 0.1 M HCl at 80 degrees C for 72 h, and a rhamnogalacturonan fraction was isolated by ion-exchange chromatography on AG 1X8 resin. Four individual oligomers, and a mixture of oligomers with higher degrees of polymerization, were obtained by chromatography on BioGel P-4. They all presented the alpha-D-GalAp-(1[-->2)-alpha-L-Rhap-(1-->4)-alpha-D-GalAp-(1](n)-->2)-L- Rhap structure (with n greater than or equal to 2) The five fractions were submitted to hydrolysis with rhamnogalacturonase. The enzyme was active on oligomers with degrees of polymerization greater than or equal to 10, and gave as main products alpha-L-Rhap-(1-->4)-alpha-D-GalAp-(1-->2)-or-L-Rhap(1-->4)-D-GalAp and alpha-D-GalAp-(1-->2)-alpha-L-Rhap-(1-->4)-alpha-D-GalAp-(1-->2)-alpha-L -Rhap-(1-->4)-D-GalAp
- âŠ