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关键词： Agroindustrial residues   Thermochemical characterization   Combustion indexes   Gaseous emissions   Bioenergy potential  

摘要： Clean thermochemical conversion of lignocellulosic residues is particularly interesting for both bioenergy production and environmental protection. For this reason, the novelty of this study is to present tamarind residues (husks and seeds) from the tamarind fruit processing industry as new prospective feedstocks for bioenergy production considering their physicochemical properties, combustion performance indexes, and emission patterns. Characterization results confirmed the suitability of tamarind residues as raw materials for combustion with considerable energy contents (similar to 17.5 MJ kg(-1)), ash contents below 2.9 wt.%, and negligible sulfur (< 0.01 wt.%). High bulk (552.7-635.8 kg m(-3)) and bioenergy (9.1-10.4 GJ m(-3)) densities were found, indicating that the distribution and utilization of tamarind residues are significantly favored. Acceptable CO2, CO, and SO(2)emissions were found during the combustion of both residues. Elevated nitrogen concentrations (2.5-3.0 wt.%) were reported, implying higher NO(X)emissions (8.8-10.5 g kg(-1)), which require rigid control. The combustion performance indices suggest that tamarind residues have better properties for combustion than feedstocks commonly used as bioenergy sources. Tamarind residues thus appear to be promising renewable feedstocks for bioenergy because of their attractive properties, better combustion performance, and acceptable emission characteristics. This study conclusively indicates that tamarind residues are promising feedstocks for bioenergy and provides valuable insights to their future applications in commercial biomass boilers with controlled emissions.

关键词： Phaeophyceae   Polyphenols   Phlorotannins   Solid-phase extraction   Physicochemical properties   HPLC-MS   Redox potential   Acid-base properties   Antioxidant activity  

摘要： Brown algae of the Fucaceae family, collected in the western segment of the Arctic, contain a large number of polyphenolic compounds-phlorotannins-with a unique chemical nature, macromolecular structure, and physicochemical properties, exhibiting bioactive properties. The peculiarity of the biopolymers' properties and structure, which are an element of fundamental scientific research of the cycle, structure-functional nature-properties, determines the priority of the directions of use of polyphenols as effective biologically active pharmaceutical preparations. This work aims to develop methods for selective extraction of phlorotannins from the Arctic brown algaFucus vesiculosus, characterization of physicochemical properties, and biological activity of these compounds. The efficiency of solid-phase extraction (SPE) on a hydrophobic sorbent with grafted hexadecyl groups was shown for fractionation of the polyphenolic extract: active fractions were obtained, characterized by a high content of polyphenols (yield of polyphenols up to 98% relative to the content of these components in algae) with mass-average molecular weights of 21.4-35.8 kDa and oligomeric components in the mass range 374-994 Da. The IR spectra of the fractions were characterized, and the tendency of phlorotannins to form aggregates at high concentrations of the extract was shown. During hydrodynamic studies, a strong polyelectrolyte swelling of polyphenols (PP) was noted. The obtained polyphenolic fractions differ in physicochemical characteristics (acid-base and redox properties) and antioxidant activity.

关键词： Physicochemical analysis   Wastewater treatment plants   Wastewater effluent   Permissible limit  

摘要： Effluent from wastewater treatment plants (WWTPs) is one of the main sources of pollution that seriously affect the physicochemical parameters in water bodies. This occurs particularly when partially treated or untreated effluent is released to various aquatic ecosystems. This constitutes a potential danger to the general environment. To safeguard the lives of human, aquatic and other living organisms, regular monitoring of wastewater effluent to ascertain their compliance with both national and international regulatory limits for water quality improvement is very crucial. This research work was carried out using standard methods to evaluate ten physicochemical parameters from the effluent of two WWTPs in Cape Town, South Africa. Our findings were: temperatures (16.90-25.33 degrees C), pH (5.85-7.85), EC (923.00-1294.17 mu S/cm), TDS (590.72-828.27 mg/L), DO (1.30-5.50 mg/L), SO42- (3.23-163.18 mg/L), COD (23.70-898.58 mg/L), BOD (9.17-252.44 mg/L), Cl- (48.17-378.48 mg/L) and PO43- (0.10-11.32 mg/L). Temperature, pH and SO42- levels in the two WWTPs were within the recommended limit for wastewater discharge by the Department of Water Affairs and Forestry (DWAF), South Africa and the United State Environmental Protection Agency (USEPA). However, other parameters did not comply fully with both DWAF and USEPA standards. The result showed that effluents from these WWTPs are possible sources of pollution to the receiving water bodies and calls for enhancement of the WWTPs operations to ensure safe effluent discharge.

关键词： Double-pass extrusion-cooking   Citric acid   in vitro fermentation   Bran-water interaction   Chemical composition   Dietary fiber  

摘要： The potential of extrusion-cooking as a technique to change the physicochemical characteristics of wheat bran, and thereby its nutrition-related properties was investigated. It was investigated whether double-pass extrusion cooking or the addition of citric acid had a larger effect than single-pass extrusion-cooking alone. Double-pass extrusion-cooking resulted in the highest strong water-binding capacity (1.37 g/g dm), while acid extrusion cooking resulted in the lowest (0.66 g/g dm) due to hydrolysis of bran polymers that contribute to the microstructure. Double-pass and acid extrusion-cooking increased the amount of water-extractable arabinoxylan, the main dietary fiber constituent (from 0.62 % to 1.75 % and 3.11 % dm, respectively), and therefore also increased extract viscosity. An increased in vitro fermentation rate was observed for double-pass compared to single-pass extruded bran. More phytate was degraded and more ferulic acid released during double-pass extrusion-cooking as compared to acid and single-pass extrusion-cooking. In conclusion, double-pass and acid extrusion-cooking distinctly modify wheat bran physicochemical and nutrition-related properties.

关键词： Bambara groundnut   Dry fractionation   Plant protein gel   Protein functionality   Pulse proteins   Scaling model  

摘要： Plant proteins, and specifically those from legume crops, are increasingly recognised as sustainable and functional food ingredients. In this study, we expand on the knowledge of Bambara groundnut (Vigna subterranea (L.) Verdc.) [BGN] proteins, by characterising the composition, microstructure and rheological properties of BGN protein isolates obtained via wet extraction and protein-enriched fractions obtained via dry fractionation. The BGN protein isolates were compared in the context of the major storage protein, vicilin, as previously identified. Molecular weight analysis performed with gel electrophoresis and size-exclusion chromatography coupled to light-scattering, revealed some major bands (190 kDa) and elution patterns with molecular weights (205.6-274.1 kDa) corresponding to that of BGN vicilin, whilst the thermal denaturation temperature (Tp 91.1 degrees C, pH 7) of BGN protein isolates also coincided to that of the vicilin fraction. Furthermore, the concentration dependence of the elastic modulus G' of the BGN protein isolates, closely resembled that of BGN vicilin (both upon NaCl addition);suggesting that vicilin is the main component responsible for gelation. Confocal laser scanning and scanning electron micrographs revealed inhomogeneous aggregate structures, which implies that fractal scaling were better suited for description of the BGN protein isolate gel networks. Concerning the BGN protein-enriched fractions, both rotor and impact milling with air jet sieving and air classification, respectively, were successfully applied to separate these fractions from those high in starch;as evident from compositional analysis, particle size distributions and microscopic imaging. When considering sustainability aspects, dry fractionation could thus be a viable alternative for producing BGN protein-enriched fractions.

关键词： beta-Cyclodextrin   2-Hydroxypropyl-beta-cyclodextrin   Inclusion complexes   Non-complexes   Leishmanicidal activity  

摘要： The discovery of new drugs and dosage forms for the treatment of neglected tropical diseases, such as human and animal leishmaniasis, is gaining interest in the chemical, biological, pharmaceutical, and medical fields. Many pharmaceutical companies are exploring the use of old drugs to establishing new drug dosage forms and drug delivery systems, in particular for use in neglected diseases. The formation of complexes with cyclodextrins is widely used to improve the stability, solubility, and bioavailability of pharmaceutical drugs, as well as reduce both the toxicity and side effects of many of these drugs. The aim of this study was to characterize solid compounds obtained from the association between furazolidone (FZD) and beta-cyclodextrin (beta-CD) or hydroxypropyl-beta-cyclodextrin (HP-beta-CD). The solid compounds were prepared in molar ratios of 1:1 and 1:2 (drug:CD) by kneading and lyophilization. Molecular docking was used to predict the preferred relative orientation of FZD when bound in both studied cyclodextrins. The resulting solid compounds were qualitatively characterized by scanning electron microscopy (SEM), thermal analysis (DSC and TG/DTG), X-ray diffraction (XRD), Raman spectroscopy with image mapping (Raman mapping), and(13)C nuclear magnetic resonance spectroscopy (C-13 NMR) in the solid state. The cytotoxicity of the compounds against THP-1 macrophages and the 50% growth inhibition (IC50) againstLeishmania amazonensispromastigote forms were subsequently investigated using in vitro techniques. For all of the solid compounds obtained, the existence of an association between FZD and CD were confirmed by one or more characterization techniques (TG/DTG, DSC, SEM, XRD, RAMAN, and(13)C NMR), particularly by a significant decrease in the crystallinity of these materials and a reduction in the melting enthalpy associated with furazolidone thermal events. The formation of more effective interactions occurred in the compounds prepared by lyophilization, i

关键词： Steaming   Microwave processing   Oat beta-glucan   In vitro fermentation   Microbiota   Short-chain fatty acid  

摘要： This study aimed to compare the prebiotic effects of oat beta-glucan between steaming and microwave processing by high-throughput sequencing. The results showed that microwave-processed oat beta-glucan with lower average molecular weight (M-w) exhibited a more significant effect in promoting Lactobacillus and Bifidobacterium compared with steaming processed oat beta-glucan with higher M-w at the genus level. The overall microbial composition structure results indicated that the relative abundance of Escherichia-Shigella, Lactobacillus, Enterococcus, and Dialister exhibited significant differences between the samples (p < 0.05). Additionally, the shortchain fatty acid in microwave-processed oat beta-glucan fermentation slurries significantly increased (p < 0.05), and more butyrate was produced from microwave-processed oat beta-glucan, which may be attributed to the higher levels of Blautia and Dialister as butyrate-producers. These results suggest that microwave processing contributed to the degradation of oat beta-glucan and enhanced its prebiotic function.

关键词： Tea polyphenol   Whey protein   Physicochemical property   Antioxidant activity   Fresh-cut apple  

摘要： Effects of tea polyphenols (TP) incorporation on physicochemical and antioxidative properties of whey protein isolate (WPI) coating were studied. Two WPI coating solutions were prepared by heating WPI solutions (pH 8, 90 degrees C) for 30 min and then TP was incorporated. TP addition could increase the negative zeta potential of 5% solution. The surface hydrophobicity index of both solutions was increased and intrinsic fluorescence intensity decreased greatly after addition of TP. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2 '-azinobis (2 ethylbenzothiazoline-6-sulfonate) (ABTS) radical scavenging capacities of both solutions increased with increasing TP. Compared with apple pieces coated with whey protein only, those with TP containing whey protein coatings showed lower browning index and slight changes in weight loss during 24 h storage. Data indicated that TP could influence the physicochemical properties and improve the antioxidant activity of WPI coating solutions and can be used to retard the enzymatic browning of fruit during storage.

关键词： Apparent molar volume   Apparent molar compressibility   Streptomycin sulphate   Food acids   Viscosity B-coefficients  

摘要： Apparent molar volumes, apparent molar isentropic compressibilities and relative viscosities for streptomycin sulphate + aqueous [cosolute (L-ascorbic acid/citric acid)] solutions at different compositions of solute as also cosolute are determined from experimental set of densities, speeds of sound and viscosities collected at different temperatures. Infinite dilution values of apparent molar volumes and apparent molar isentropic compressibilities, using least-squares fittings of appropriate equations, are correlated in terms of solute-solute and solute-solvent interactions. The various parameters in relation to densities and speeds of sound are also evaluated. The viscosity data has been used to determine Falkenhagen coefficient A, viscosity B-coefficients and its transfer parameter. Solvation behaviour of streptomycin sulphate has also been computed. The absorption spectra for both systems have also been recorded with the help of UV-visible spectrophotometer. (c) 2020 Elsevier Ltd.

关键词： Bacterial biomass   Cell properties   Metabolic stress   Inverse gas chromatography   Xenobiotics  

摘要： In the efforts for the removal of hazardous materials from the environment biological processes are a valuable tool. Although much attention has been paid to the changes in bacteria at the omics level, another, physicalchemical perspective on the issue is essential, as little is known of microbial response to continuous exposition on harmful substances. This study provides in-depth characterization of the physical-chemical parameters of bacterial biomass after hydrocarbons exposure. To provide comparability of the harmful effects of chlorotoluenes and xylenes non-exposed and 12-months hydrocarbons exposed cells were analyzed, using the advanced spectrometric methods, inverse gas chromatography and low-temperature N2 sorption to evaluate acid-base as well as dispersive properties of the studied biomass. Presented results indicate P. fluorescens B01 cells strategy aimed at protecting the cell, thus lowering its' biodegradation efficiency as a result of metabolic stress. The outcome of the study was that prolonged exposure to pollutants might reduce the bioavailability of hydrocarbons to bacteria cells, and consequently decrease the effectiveness of decontamination of polluted sites by indigenous microorganisms.