Raising agents strongly influence acrylamide and HMF formation in cookies and conditions for asparaginase activity in dough

The impact of raising agents on formation of heat-induced contaminants, acrylamide and 5-hydroxymethylfurfural (HMF), with focus on the efficiency of enzyme asparaginase as a potent tool for acrylamide reduction was investigated in the model system of cereal products. Acrylamide formation was strongly supported by ammonium hydrogen carbonate (NH₄HCO₃), observing 6 times higher level in comparison with control sample without raising agents, and was suppressed effectively by sodium hydrogen carbonate (NaHCO₃) up to 52 %. Sodium pyrophosphate (Na₄P₂O₇) had no influence on the final acrylamide content. The level of HMF remained untouched by NH₄HCO₃ contrary to sodium raising agents that both diminished HMF concentration up to 95 % using NaHCO₃. Furthermore, enzyme asparaginase eliminated acrylamide formation in the range from 23 to 75 % depending mainly on pH value of dough and time of enzyme incubation (15, 30 and 60 min). The optimum pH value for asparaginase action was in neutrality. Na₄P₂O₇ shifted pH value of dough to the optimum in comparison with control (from 5.82 to 6.78). NH₄HCO₃ and NaHCO₃ changed pH value out of optimum up to 7.82 and 8.10, respectively. The longer the enzyme treatment, the higher the acrylamide elimination was observed, with the main importance in cases of pH shifting by raising agents. These findings indicate that a product-specific optimization of the conditions for enzymatic treatment is still challenging in terms of achieving desired quality parameters with improved safety, although acrylamide mitigation by means of asparaginase was proved to be a very effective tool especially in cereal-based products.     

In vitro study of partially hydrolyzed poly(2-ethyl-2-oxazolines) as materials for biomedical applications

Polymers based on 2-oxazoline, such as poly(2-ethyl-2-oxazolines) (PETOx), are considered to be a type of ‘pseudopeptide’ with the ability to form novel biomaterials. The hydrolysis of PETOx was carried out to evaluate its use in biomedical applications. In the present work, PETOx samples with a range of molar masses were prepared by living cationic polymerization. Hydrolysis was carried out at time intervals ranging from 15 to 180 min to prepare copolymers with different amounts of ethylene imine units. ¹H NMR spectroscopy was used to identify the structure of the hydrolyzed polymers. The dependence of in vitro cell viability on the degree of hydrolysis was determined using three different model cell lines, namely, mouse embryonic 3T3 fibroblasts, pancreatic βTC3 cells, and mouse lymphoid macrophages P388.D1. It was demonstrated that increasing the degree of hydrolysis decreased cell viability for all cell types. Fibroblast cells displayed the highest tolerance; additionally, the effect of polymer size showed no observable significance. Macrophage cells, immune system representatives, displayed the highest sensitivity to contact with hydrolyzed PETOx. The effect of polymer hydrolysis, polymer concentration and the incubation time on cell viability was experimentally observed. Confocal laser-scanning microscopy provided evidence of cellular uptake of pyrene-labeled (co)polymers.     

Green synthesis of silver nanoparticles and biopolymer nanocomposites: a comparative study on physico-chemical,antimicrobial and anticancer activity

The current report was intended towards comparative study of green-synthesized biogenic Rhubarb silver nanoparticles (RS-AgNPs) and chitosan crosslinked silver nanocomposites (CSHD-AgNCs). The physico-chemical characterization was done by UV–visible, FTIR, scanning electron microscopy (SEM), transmission electron microscopy (TEM), EDX, TGA, XRD and zeta potential (\(\zeta \)). The analysis and spectroscopic characterization was done by SEM and TEM and their results reveal that the nanoparticles are spherical in shape, with average size ranges from 5 to 50 nm, and was gathered by face centered cubic (FCC) structure throughout the polymer matrix and stable without any protecting or capping reagents over 450 days. The antimicrobial property of RS-AgNPs and CSHD-AgNCs (\(\zeta = +29.6\) and \(+\)32.8 mV) was evaluated against E. coli and S. aureus and showed an effective inhibitory property. The RS-AgNPs and CSHD-AgNCs were assessed for their anticancer activity against HeLa cell line by MTT method, and it reveals a dose–response activity, time and cell line-dependent cytotoxicity. Based on the results obtained, the RS-AgNPs exhibited higher toxicity over CSHD-AgNCs after 24 h incubation of HeLa cells with different concentrations and is negligible for the aqueous Rhubarb extract. It was concluded that the changes in anticancer activity towards HeLa cells due to biological activity of silver nanoparticles depend on their method of biosynthesis and their physico-chemical nature.     

Impact of oregano and virgin olive oil phenolic compounds on acrylamide content in a model system and fresh potatoes

In this study the effect of olive oil and oregano phenolic compounds on antioxidant activity (AOA) and acrylamide formation in a model system and fresh potatoes was evaluated. The addition of oregano phenolic extract in the model system resulted in an increase of AOA and in a reduction of acrylamide content, up to 49%, after heating. On the contrary, addition of olive oil extract resulted in AOA reduction and a concentration-dependent effect on acrylamide formation was observed with a reduction up to 15% (p < 0.05) followed by an increase up to 48%. The same trend, in acrylamide formation, was observed in fresh potatoes but to a lower extent. Finally, addition of tyrosol, oleuropein and p-hydroxyphenylacetic acid in the model system resulted in acrylamide reduction up to 50%. The discrepancy in acrylamide formation, caused by phenolic compounds, is ascribed to their structure and related to their terminal functional hydroxyl and aldehydic groups.     

Effect of Moisture on the Insulation Condition of Twisted Coils

Method IEEE 841 is used to test endurance of insulation system of stators to 100% humidity at 40 ℃ for168 h. Insulation resistance after this test between phases or between phase and frame has not been lover as 5 × 10^6 Ohm. Some producers of motors use this method for determining quality of impregation resin. On such test insulation resistance between phases was lover as between phase and frame. Because between phases is only wire insulation impregnating resins on insulation resistance of insulation system an impregnating resin we observe influence of type of wires and after humidity test. With diagnostic of insulation, the state is dealt. We compare our impregnation resin with competitive impregnation resin. We made test on twisted coils prepared after STN IEC from two parallel wires. In this test, we succeed in demonstrating that the main influence on insulation resistance of insulation system wire and impregnation resin has insulation of wire. Impregnation resin has influenced on data dispersion.     

A study of the interaction of mechanically generated polypropylene radicals with phenolic antioxidant in the presence of oxygen by EPR spectroscopy

Isotactic polypropylene (iPP) was mechanically degraded in the absence and presence of a phenolic antioxidant at liquid nitrogen temperature in the presence of oxygen. The interaction of the primarily formed iPP macroradicals with oxygen and phenol was studied by EPR spectroscopy in the temperature region between 77 and 303 K at antioxidant concentrations of 0.1, 0.5, and 3.0 wt%. It was found that iPP macroradicals react at low temperature with oxygen, yielding peroxy radicals, and with antioxidant, with a simultaneous formation of phenoxy radicals. The development and decay of all kinds of radicals was studied. The rate constants for peroxy radical decay were determined and the apparent activation energies for the regions of slow and fast decay were calculated. © 1993 John Wiley & Sons, Inc.