Wheat bran is a by-product of wheat flour production used as a nutritious and economic feed ingredient, but since it possesses several anti-nutritional factors that entrap nutrients and interfere ...with digestion and absorption, its application is limited. The utilization of organic-rich wastes for the production of value-added products and nutritional improvement of food is a means to an end – sustainability. Here we propose addressing these challenges via fermentation by Bacillus sp. TMF–2, a strain that produces several enzymes and simultaneously, wheat bran of higher nutritional quality. Following solid-state fermentation, the soluble phenolic content of wheat bran nearly triplicated compared to the raw bran. The total proportion of polyphenols along with the antioxidant capacity and free radical scavenging rate were significantly improved, particularly the ability to reduce Fe3+ increased by 10-fold. Additionally, the activity of hydrolytic enzymes: amylase, cellulase, pectinase, mannanase, protease, and phytase increased during fermentation, whereas the level of anti-nutrient, phytic acid decreased. Among all produced enzymes, there is a special emphasis on the protease prone to degrade gluten thus resulting in gluten-free wheat bran. The results of this research could contribute to a beneficial procedure for the natural modification of wheat bran, which further augments the health benefits and utilization of wheat bran.
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•Wheat bran is a good substrate for production of hydrolytic enzymes by Bacillus sp. TMF–2.•Fermented wheat bran consists high amount of polyphenols with abudant bioactivity.•Multienzyme complex of Bacillus sp. TMF–2 revealed potential towards anti-nutritional factors reduction.•Gluten-free wheat bran was obtained.
The development of a novel process for the production of xylooligosaccharides (XOS) based on the 4R concept is made possible by the integration of numerous techniques, especially enzymatic ...modification together with the physical pretreatment of renewable materials. This study aims to integrate the use of agricultural wastes for the production of xylanase by a new strain of
sp. and value-added products, XOS.
For the production of xylanase, a solid-state fermentation was performed using wheat bran as substrate. To obtain the most active crude extract of xylanase, the time frame of cultivation was first adjusted. Then, the downstream process for xylanase purification was developed by combining different membrane separation units with size exclusion chromatography. Further characterisation included determination of the optimal pH and temperature, determination of the molecular mass of the purified xylanase and analysis of kinetic parameters. Subsequently, the hydrolytic ability of the partially purified xylanase in the hydrolysis of alkali-extracted hemicellulose from soybean hulls was investigated.
Our results show that
produced extracellular xylanase at a yield of 21 U/g during solid-state fermentation. Using two ultrafiltration membranes of 10 and 3 kDa in combination with size exclusion chromatography, a yield of 49 % and 13-fold purification of xylanase was achieved. The purified xylanase (35 kDa) cleaved linear bonds β-(1→4) in beechwood xylan at a maximum rate of 0.64 μmol/(min·mg) and a Michaelis constant of 44 mg/mL. At pH=6 and 45 °C, the purified xylanase showed its maximum activity. The xylanase produced showed a high ability to hydrolyse the hemicellulose fraction isolated from soybean hulls, as confirmed by thin-layer chromatography. In the hydrothermally pretreated hemicellulose hydrolysate, the content of XOS with different degrees of polymerisation was detected, while in the non-pretreated hemicellulose hydrolysate, the content of xylotriose and glucose was confirmed.
Future research focusing on the creation of new enzymatic pathways for use in processes to convert renewable materials into value-added products can draw on our findings.
The possibility to utilize Alcalase to hydrolyze soft wheat flour (SWF) containing high concentration of solids (i.e. starch) and the effect of its presence was investigated. At a degree of ...hydrolysis of 23.49% ± 0.64%, sample prepared as 15% (w/w) showed greatest reduction in gliadin content, resulting in 9.42 ± 1.5 ppm of gluten, tested by competitive ELISA test. SDS‐PAGE electrophoresis confirmed the differences in gliadin content for all of the prepared wheat flour hydrolysates (WFHs). All WFHs had improved radical‐scavenging (>60%), metal‐ion chelating (>80%) and techno‐functional properties after enzymatic hydrolysis compared to SWF. FTIR spectra confirmed structural changes in the Amide I (1,700–1,600 cm−1) region. Changes in total zeta‐potential and average particle size were observed. The hydrolysis reaction was facilitated by the increase of the solids content since it interferes with the aggregation of gluten proteins, therefore less available water was proven beneficial for the enzymatic reaction.
Novelty impact statement
Gluten originating from soft wheat flour can be efficiently hydrolyzed by endo‐protease Alcalase (DH ~24%), without introducing steps that include the extraction and isolation of gluten. By preparing the wheat flour hydrolysates, the significant reduction of adverse allergenicity of wheat flour has been achieved; gluten content was less than 10 ppm. Improvement of techno‐functional properties, zeta‐potential and particle size distribution, as well as antioxidant potential of soft wheat flour was observed upon enzymatic hydrolysis for all samples.
•Vanadium modified olivine was synthesized by gel combustion technique.•In situ formed carbon enabled the conductivity of 2×10−2Scm−2.•High rate capability in aqueous LiNO3 solution was achieved.•The ...capacity of 35mAhg−1 was measured at the rate of 100C in aqueous electrolyte.•Stable capacity of 91mAhg−1 was evidenced in aqueous electrolyte upon 190 cycles.
The nitrate-(glycine+malonic acid)-assisted gel-combustion process, followed by a heat treatment at 750°C under reductive atmosphere, was used as a fast and effective way to synthesize vanadium doped olivine incorporated in carbon matrix, of general formula LiFe(1−x)VxPO4/C. The two-phased Rietveld refinement confirmed that vanadium incorporation into olivine structure was complete. The heating under reduction atmosphere caused the formation of iron phosphide to some extent, the concentration was determined by Rietveld analysis. The capacity and rate capability of these composites were tested by both cyclic voltammetry and galvanostatic cycling. Specifically, the average discharging capacities of the composite with x=0.055, determined in an saturated aqueous LiNO3 solution equilibrated with air, at the rates of 1, 10 and 100C, amounted to 91, 73 and 35mAhg−1, respectively, with no perceivable capacity fade.
Lipase B from Candida antarctica was immobilized by adsorption onto laboratory prepared metakaolin. This support has great potential for enzyme immobilization since it has good mechanical ...characteristics and thermal stability and it is easily obtained from naturally abundant raw kaolin, as presented in this paper. Immobilization process was studied as a function of pH, ionic strength and protein concentration in terms of immobilization and activity yield. It was shown that immobilization occurred via the Langmuir model, and that electrostatic forces were major, but not exclusive contributor for the binding process. The optimum conditions were achieved in 10mM acetic buffer pH5. Biocatalyst obtained under optimum conditions was further successfully used in the synthesis of lipophilic antioxidants, where conversion yields as high as 100% were achieved.
•Immobilization of lipase B from Candida antarctica on metakaolin is achieved.•Adsorption of lipase on metakaolin occurs via Langmuir model.•The obtained biocatalyst was successfully used in in the synthesis of lipophilic antioxidants (conversion yield of 100%).
In this study, we assessed the effects of microwave irradiation of wheat gluten proteins as a pretreatment performed in a microwave reactor that could accurately control process parameters as a ...function of power and temperature, as well as comparing it with conventional heat treatment. The aim was to identify suitable combinations of partial enzymatic hydrolysis and microwave pretreatment parameters to produce gluten hydrolysates with reduced allergenicity and conserved techno-functional features for food application. FTIR analysis, and total and reactive SH group contents confirmed that the microwave-controlled heating can significantly change the secondary structure and conformation of gluten protein. The microwave treatment had the largest effect at 200 W and 100 °C, at which the content of gluten has been reduced by about 2.5-fold. The microwave pretreatment also accelerated the enzymatic hydrolysis of gluten, changing the kinetic profile. The apparent hydrolysis rate constants (k2) were 1.00, 3.68, 3.48, 4.64 and 4.17 min−1 for untreated gluten, and those pretreated with microwave power of 200, 400, 600 and 800 W, respectively. Compared to the heat treatment, it appeared that microwave specific non-thermal effects had a significant influence on the gluten structure and allergenicity and, in combination with the enzymatic hydrolysis, ultimately yielded protein hydrolysates with enhanced antioxidant and functional properties.
The key parameters related to cathode materials for commercial use are a high specific capacity, good cycling stability, capacity retention at high current rates, as well as the simplicity of the ...synthesis process. This study presents a facile synthesis of a composite cathode material, Li₂FeSiO₄ with carbon, under extreme conditions: rapid heating, short dwell at 750 °C and subsequent quenching. The water-soluble polymer methylcellulose was used both as an excellent dispersing agent and a carbon source that pyrolytically degrades to carbon, thereby enabling the homogeneous deployment of the precursor compounds and the control of the Li₂FeSiO₄ particle growth from the earliest stage of processing. X-ray powder diffraction reveals the formation of Li₂FeSiO₄ nanocrystallites with a monoclinic structure in the P2₁/n space group (#14). The composite’s electrochemical performance as a cathode material in Li-ion batteries was examined. The influence of the amount of methylcellulose on the microstructural, morphological, conductive, and electrochemical properties of the obtained powders has been discussed. It has been shown that the overall electrochemical performance is improved with an increase of carbon content, through both the decrease of the mean particle diameter and the increase of electrical conductivity.
The nitrate-(glycine + malonic acid)-assisted gel-combustion process, followed by a heat treatment at 750 degreesC under reductive atmosphere, was used as a fast and effective way to synthesize ...vanadium doped olivine incorporated in carbon matrix, of general formula LiFe sub((1-x))V sub(x)PO sub(4)/C. The two-phased Rietveld refinement confirmed that vanadium incorporation into olivine structure was complete. The heating under reduction atmosphere caused the formation of iron phosphide to some extent, the concentration was determined by Rietveld analysis. The capacity and rate capability of these composites were tested by both cyclic voltammetry and galvanostatic cycling. Specifically, the average discharging capacities of the composite with x = 0.055, determined in an saturated aqueous LiNO sub(3) solution equilibrated with air, at the rates of 1, 10 and 100 C, amounted to 91, 73 and 35 mAh g super(-1), respectively, with no perceivable capacity fade.
LiCr0.15Mn1.85O4 spinel has been successfully synthesized by glycine-nitrate method (GNM). The presence of pure spinel phase was confirmed by long term XRPD measurements and the Rietveld structural ...refinement. Lattice parameter was estimated to be 8.2338A. Average particle size of prepared powder material is below 500nm. The BET surface area is 9.6m2 g-1. As a cathode material for lithium batteries LiCr0.15Mn1.85O4 shows initial discharge capacity of 110mA h g-1 and capacity retention of 83% after 50 cycles.
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