Quality attributes and functional properties of whole wheat bread baked from frozen dough with the addition of enzymes and hydrocolloids.

BACKGROUND: The increased demand for healthy and standardized bread has led to a demand for an efficient and promising dough improver, of natural origin, to reduce the deterioration of whole wheat bread baked from frozen dough caused by the high levels of dietary fiber and by freezing treatment. In this study, the combined effects of xylanase (XYL), lipase (LIP), and xanthan gum (XAN) on the quality attributes and functional properties of whole wheat bread baked from frozen dough were evaluated. RESULTS: The optimal combination, which contained XYL (0.12 g kg-1 ), LIP (0.25 g kg-1 ), and XAN (3.1 g kg-1 ), was obtained using response surface methodology (RSM). The addition of the optimal combination endowed frozen dough bread with a higher specific volume, softer texture, better brown crumb color, and greater overall acceptability. The optimal combination had no adverse impact on the volatile organic compounds (VOCs) of frozen dough bread. In terms of the functional properties of bread, the water-holding capacity (WHC), oil-holding capacity (OHC), and swelling capacity (SWC) of dietary fiber in frozen dough bread decreased in the presence of the optimal combination, whereas the glucose adsorption capacity (GAC) did not affect them. Correspondingly, the in vitro digestive glucose release was not significantly different between the control group and the optimal combination group after frozen storage. CONCLUSION: The optimal combination could improve the quality attributes and functional properties of whole wheat bread baked from frozen dough effectively, thereby increasing consumption. © 2023 Society of Chemical Industry.

Effects of phosphorous precursors and speciation on reducing bioavailability of heavy metal in paddy soil by engineered biochars.

Ammonium phosphate (AP), phosphoric acid (PC), and potassium phosphate (TKP) were used for the modification of biochar for enhanced heavy metal passivation in soil. The effect of various phosphorus (P) precursors on adsorption-related properties, P speciation distribution pattern, and the passivation mechanism was investigated by BET, FTIR, XRD, XPS, and 31P NMR analysis. The mobility and bio-availability of cadmium (Cd) were studied by extraction experiments, and the P release kinetics was also determined. Results showed that the immobilization efficiency of Cd (II) by biochars followed the order: TKP-BC > PC-BC > AP-BC > BC, and TKP-BC reduced available Cd content by 81% treated with 2% addition. The P speciation shows a significant effect on the P-enriched biochars' passivation performance, especially orthophosphate, which is essential for the immobilization of Cd2+ by forming phosphate precipitation. Pyrophosphate and orthophosphate monoester in AP-BC and PC-BC can promote Cd2+ passivation via the formation of P-Cd complexes or organometallic chelates. It is also shown that PC-BC has the lowest P release rate while TKP-BC has the highest percentage of P (15.50%) remaining in the biochar. The results may contribute to the development of modified biochar for soil remediation based on P-related technologies.

Mechanism of biomass activation and ammonia modification for nitrogen-doped porous carbon materials.

The effect of chemical activation and NH3 modification on activated carbons (ACs) was explored via two contrasting bamboo pyrolysis strategies involving either two steps (activation followed by nitrogen doping in NH3 atmosphere) or one step (activation in NH3 atmosphere) with several chemical activating reagents (KOH, K2CO3, and KOH + K2CO3). The ACs produced by the two-step method showed relatively smaller specific surface areas (∼90% micropores) and lower nitrogen contents. From the one-step method, the ACs had larger pore diameters with about 90% small mesopores (2-3.5 nm). Due to a promotion effect with the KOH + K2CO3 combination, the AC attained the greatest surface area (2417 m2 g-1) and highest nitrogen content (3.89 wt%), endowing the highest capacitance (175 F g-1). The balance between surface area and nitrogen content recommends KOH + K2CO3 activation via the one-step method as the best choice for achieving both greener production process and better pore structure.

Influence of Biochar Addition on Nitrogen Transformation during Copyrolysis of Algae and Lignocellulosic Biomass.

Algae are extremely promising sustainable feedstock for fuels and chemicals, while they contain high nitrogen content, which may cause some serious nitrogen emission during algae pyrolysis utilization. In this study, we proposed a feasible method to control the nitrogen emission during algae pyrolysis by introducing lignocellulosic biomass and biochar addition. Nitrogen transformation mechanism was investigated through quantitative analysis of N-species in the pyrolysis products. Results showed that copyrolysis of algae and lignocellulosic biomass greatly increased nitrogen in solid char with large amount of NH3 and HCN releasing (∼20 wt %), while nitrogen in bio-oil decreased largely. With biochar addition, NH3, HCN, and N-containing intermediates (amines/amides and nitriles) reacted with higher active O-species (O-C═O, -OH, and -COOH) in biochar addition, and formed large amounts of amine/amide-N, pyridinic-N, pyrrolic-N, and quaternary-N on the surface of biochar addition, which led to most nitrogen being enriched in char product and biochar addition (over 75 wt %) at the expense of amines/amides, nitriles, and N-containing gas (only 3 wt % NH3 and HCN emission; decrease of 85%). These results demonstrated that biochar addition showed a positive influence on fixation of N-species during thermochemical conversion of algae and could convert nitrogen to valuable N-doped biochar materials.

Influence of NH3 concentration on biomass nitrogen-enriched pyrolysis.

In this study, nitrogen was used to replace oxygen through biomass N-enriched pyrolysis in a fixed-bed reactor to obtain N-containing chemicals and N-doped biochar. Influence of NH3 concentration on the formation mechanism of N-species and electrochemical performance of N-doped biochar was investigated in depth. Results showed that increasing NH3 concentration promoted bio-oil and gas generation, and increased H2, CH4 and CO yield at the diminishing of CO2. Simultaneously, bio-oil showed lower oxygen content with non-methoxy phenols and N-heterocyclics as the main components, and the maximums were 57.73% and 16.21% at 80 vol% NH3 concentration, respectively. With regard to solid N-doped biochar, nitrogen content (4.85 wt%), N-containing groups and specific surface area (369.59 m2/g) increased greatly, and excellent electrochemical property (120 F/g) was shown with NH3 concentration increasing. However, NH3 conversion efficiency decreased gradually with NH3 increasing, and 40 vol% may be the optimum NH3 concentration for biomass N-enriched pyrolysis.

Co-pyrolysis of lignocellulosic biomass and microalgae: Products characteristics and interaction effect.

Co-pyrolysis of biomass has a potential to change the quality of pyrolytic bio-oil. In this work, co-pyrolysis of bamboo, a typical lignocellulosic biomass, and Nannochloropsis sp. (NS), a microalgae, was carried out in a fixed bed reactor at a range of mixing ratio of NS and bamboo, to find out whether the quality of pyrolytic bio-oil was improved. A significant improvement on bio-oil after co-pyrolysis of bamboo and NS was observed that bio-oil yield increased up to 66.63wt% (at 1:1) and the content of long-chain fatty acids in bio-oil also dramatically increased (the maximum up to 50.92% (13.57wt%) at 1:1) whereas acetic acid, O-containing species, and N-containing compounds decreased greatly. Nitrogen transformation mechanism during co-pyrolysis also was explored. Results showed that nitrogen in microalgae preferred to transform into solid char and gas phase during co-pyrolysis, while more pyrrolic-N and quaternary-N generated with diminishing protein-N and pyridinic-N in char.

Transformation of Nitrogen and Evolution of N-Containing Species during Algae Pyrolysis.

Transformation and evolution mechanisms of nitrogen during algae pyrolysis were investigated in depth with exploration of N-containing products under variant temperature. Results indicated nitrogen in algae is mainly in the form of protein-N (∼90%) with some inorganic-N. At 400-600 °C, protein-N in algae cracked first with algae pyrolysis and formed pyridinic-N, pyrrolic-N, and quaternary-N in char. The content of protein-N decreased significantly, while that of pyrrolic-N and quaternary-N increased gradually with temperature increasing. Pyridinic-N and pyrrolic-N formation was due to deamination or dehydrogenation of amino acids; subsequently, some pyridinic-N converted to quaternary-N. Increasing temperature decreased amides content greatly while increased that of nitriles and N-heterocyclic compounds (pyridines, pyrroles, and indoles) in bio-oil. Amides were formed through NH3 reacting with fatty acids, that underwent dehydration to form nitriles. Besides, NH3 and HCN yields increased gradually. NH3 resulted from ammonia-N, labile amino acids and amides decomposition, while HCN came from nitrile decomposition. At 700-800 °C, evolution trend of N-containing products was similar to that at 400-600 °C. While N-heterocyclic compounds in bio-oil mainly came from pyrifinic-N, pyrrolic-N, and quaternary-N decomposition. Moreover, cracking of pyridinic-N and pyrrolic-N produced HCN and NH3. A mechanism of nitrogen transformation during algae pyrolysis is proposed based on amino acids decomposition.

[The safety and outcome of patients with acute myocardial infarction transferred for primary angioplasty].

OBJECTIVE: To evaluate the safety and outcome of patients with acute myocardial infarction (AMI) transferred for primary percutaneous coronary intervention (PCI). METHODS: Data from patients with ST elevation AMI urgently transferred from first admitted hospitals to our cath-lab to receive primary PCI were analyzed. According to time intervals from symptom onset to transfer, the patients were divided into early transfer (< 6 h, n = 26), delayed transfer (6 - 24 h, n = 39) and late transfer (24 h to 1 week, n = 18) group. The major cardiac events during transfer periods and one month after PCI were obtained and echocardiogram and left ventricular systolic functions were compared among groups. RESULTS: There was no serious cardiac event during transfer period and all 83 patients received primary PCI with a mean transfer-to-balloon time about 180 minutes. Success rate of PCI was 92.3% in early transfer group, 89.7% in delayed transfer group, and 94.4% in late transfer group (P > 0.05). At one month follow-up after PCI, 0, 10.3% and 16.7% of patients developed heart failure in early, delayed transfer and late transfer group respectively (P > 0.05 vs. early), the LVEF of early transfer group (53.2% +/- 9.7%) was also significantly higher than delayed transfer group (48.6% +/- 8.2%, P < 0.05) and late transfer group (43.1% +/- 10.3%, P < 0.01). CONCLUSIONS: Transfer patients with AMI for primary PCI is safe in the observed time intervals during acute phase. Early transferred patients are associated with better outcome at 1 month post PCI compared to delayed and late transferred AMI patients.