Search results for "acrylamide"
showing 10 items of 485 documents
Influence of the addition ofHelianthus tuberosusL. fermented with different lactobacilli on acrylamide content in biscuits
2014
Summary The aim of the study was to investigate the effect of the addition of Helianthus tuberosus L. fermented with different lactobacilli (Lactobacillus sakei KTU05-6, Pediococcus acidilactici KTU05-7 and Pediococcus pentosaceus KTU05-9) on acrylamide content in biscuits. Results of study indicated that submerged fermented Helianthus tuberosus L. tubers had the significantly (P ≤ 0.05) lower pH, higher total titratable acidity and from 1.2 to 1.3 times higher protease and from 1.2 to 2.0 higher alpha-amylase activities compared with treated by solid-state fermentation. The acrylamide content in all biscuit samples enriched with submerged fermented Helianthus tuberosus L. was measured lowe…
Effect of fermented Helianthus tuberosus L. tubers on acrylamide formation and quality properties of wheat bread
2013
Abstract The main focus in this study was to investigate the effects on wheat bread safety and quality due to addition of Helianthus tuberosus L. (JA) tubers, fermented by different lactic acid bacteria (LAB) strains (Pediococcus acidilactici KTU05-7, Pediococcus pentosaceus KTU05-8, P. pentosaceus KTU05-9, Lactobacillus sakei KTU05-6, P. pentosaceus KTU05-10). We found experimentally that JA tubers fermented with LAB contained more L(+) than D(−) lactic acid, which resulted in safer products than by spontaneous treatment. The concentrations of biogenic amines in all analysed fermented JA products were far below levels causing a health risk, while the products fermented with LAB contained l…
Novel acrylamido monomers with higher hydrophilicity and improved hydrolytic stability: I. Synthetic route and product characterization.
1996
The novel acrylamido monomer reported by our group (N-acryloylaminoethoxyethanol, AAEE; Chiari et al., Electrophoresis 1994, 15, 177-186), found to combine high hydrophilicity with extraordinary resistance to alkaline hydrolysis, has come under closer scrutiny due to unexpected and random autopolymerization while stored as a 1/1 v/v water solution at 4 degrees C (possibly due to a greater oxidability of the ether group). We have additionally found a unique degradation pathway of the monomer, called "1-6 H-transfer", by which the C1 (on the double bond site), by constantly ramming against the C6, next to the ether oxygen (O7, which in fact favors the transfer of the hydrogen atom by C1), pro…
The guanidinium group as a key part of water-soluble polymer carriers for siRNA complexation and protection against degradation.
2014
Here, the preparation of a novel block copolymer consisting of a statistical copolymer N-(2-hydroxypropyl) methacrylamide-s-N-(3-aminopropyl) methacrylamide and a short terminal 3-guanidinopropyl methacrylamide block is reported. This polymer structure forms neutral but water-soluble nanosized complexes with siRNA. The siRNA block copolymer complexes are first analyzed using agarose gel electrophoresis and their size is determined with fluorescence correlation spectroscopy. The protective properties of the polymer against RNA degradation are investigated by treating the siRNA block copolymer complexes with RNase V1. Heparin competition assays confirm the efficient release of the cargo in vi…
Synthesis of CO2-responsive polymers by post-polymerization modification
2014
Abstract We describe a general method to synthesize a double responsive polymer, exhibiting a temperature and CO 2 responsive behavior. The polymer derived from a controlled radical polymerization technique of pentafluorophenyl acrylate (PFPA), followed by a sequential post-polymerization modification of a CO 2 responsive- and thermo-responsive amines. Utilizing this approach three double responsive copolymers were synthesized, poly(3- N′,N′ -dimethylaminopropyl acrylamide- co - N -isopropyl acrylamide) (poly(DMPA- co -NIPAM)), poly( L -Arginine methyl ester acrylamide- co - N -isopropyl acrylamide) (poly(AME- co -NIPAM)) and poly( L -Arginine methyl ester acrylamide- co - N -cyclopropyl ac…
Stabilization of anti-leukemic enzyme l-asparaginase by immobilization on polysaccharide levan
2001
Abstract Biologically active fructose polymer levan from Zymomonas mobilis of different molecular mass (75 and 2000 kDa) was covalently coupled to anti-leukemic enzyme Erwinia carotovora l -asparaginase. The method used for the immobilization of the enzyme involved periodate oxidation of the polysaccharide, followed by reductive alkylation. A gentle periodate oxidation of levan (oxidation degree ≤24%) resulted in the highest residual enzyme activity (≥55%). The K m(app.) of glycoconjugates was higher than the K m of native l -asparaginase. The conjugation of l -asparaginase widened the optimum pH range of the enzyme. The electrophoretic mobility in polyacrylamide gel of glycoconjugates obta…
Radioactive labeling of defined HPMA-based polymeric structures using [18F]FETos for in vivo imaging by positron emission tomography.
2009
During the last decades polymer-based nanomedicine has turned out to be a promising tool in modern pharmaceutics. The following article describes the synthesis of well-defined random and block copolymers by RAFT polymerization with potential medical application. The polymers have been labeled with the positron-emitting nuclide fluorine-18. The polymeric structures are based on the biocompatible N-(2-hydroxypropyl)-methacrylamide (HPMA). To achieve these structures, functional reactive ester polymers with a molecular weight within the range of 25,000-110,000 g/mol were aminolyzed by 2-hydroxypropylamine and tyramine (3%) to form (18)F-labelable HPMA-polymer precursors. The labeling procedure…
Long-term biodistribution study of HPMA- ran -LMA copolymers in vivo by means of 131 I-labeling
2018
Abstract Background For the evaluation of macromolecular drug delivery systems suitable pre-clinical monitoring of potential nanocarrier systems is needed. In this regard, both short-term as well as long-term in vivo tracking is crucial to understand structure-property relationships of polymer carrier systems and their resulting pharmacokinetic profile. Based on former studies revealing favorable in vivo characteristics for 18 F–labeled random (ran) copolymers consisting of N-(2-hydroxypropyl)methacrylamide (HPMA) and lauryl methacrylate (LMA) – including prolonged plasma half-life as well as enhanced tumor accumulation – the presented work focuses on their long-term investigation in the li…
Interaction of pHPMA–pLMA Copolymers with Human Blood Serum and Its Components
2013
Immediately after administration, polymer therapeutics are exposed to complex biological media like blood which may influence and alter their physicochemical properties due to interactions with proteins or serum components. Among such interactions those leading to larger sized aggregates can be sensitively detected by dynamic light scattering (DLS) as a pre in vivo screening method. Random copolymers from N-(2-hydroxypropyl)methacrylamide and lauryl methacrylate p(HPMA-co-LMA) and copolymers loaded with the model drug domperidone were characterized by DLS in isotonic salt solution and in blood serum. The bare amphiphilic copolymer micelles (Rh=30 nm in isotonic salt solution) formed large a…
Enantioselektive Trifluoracetylierung mit Hilfe chiraler Polyamide
1980
(S)-Poly(2-aminobutyric acid) (1) [(S)-poly(imino-1-methyl-3-oxotrimethylene)] was transformed into its N-trifluoroacetyl derivative 4. The IR spectra and the circular dichroism of both substances were compared. In addition, (S)-poly[N-(1-phenylethyl)acrylamide] (2) ((S)-poly-[1-(1-phenylethylaminocarbonyl)ethylene]) was trifluoroacetylated leading to polymer 5. 4 was found to react as trifluoroacetylating agent with L-1-phenylethylamine (L-3) twice as fast as it reacts with D-3. Accordingly, the reaction of 4 with D,L-3 leads preferentially to the L-form of N-(1-phenylethyl)trifluoroacetamide with optical yields up to 6%. The reaction of 5 with D,L-3 affords the D-form of N-(1-phenylethyl)…