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关键词： Wettability   Water holding capacity   Biochar   Physical-chemical properties   Multiple regression analysis   Lignocellulose  

摘要： Nowadays, high attention is paid to the knowledge on wettability of biochar, which is still very complicated, since it is acknowledged that it can depend either on primary feedstock, pyrolysis conditions or on environmental factors. Until now, it is known that the main factor responsible for the production of hydrophobic biochar is aliphatic functional groups forming tar compounds which vapour only at a high temperature. High-temperature (> 500 degrees C) biochar types are considered as hydrophilic due to the effect of the release of pores from the tars. However, it is still not known what the relation between wettability of biochar and other physical-chemical properties of it is and, if it is possible, is there a need to predict wettability of biochar based on other available properties. The article focuses main attention on the determination of physical-chemical properties of biochar made of five different lignocellulosic feedstocks depending on the pyrolysis temperature (300-700 degrees C) and their relation with the water holding capacity and wettability of biochar using the multiple regression analysis. The results showed that 54% of variation of biochar wettability could be predicted by its average pore size and 77% of variation of biochar water holding capacity could be predicted according to its ash content. Relation of wettability of biochar with its average pore size can be explained by the physical capacity of biochar to adsorb water on its surface and internal pores as well as retention of water among its particles due to capillary forces.

关键词： Chaenomeles japonica   Drying   Polyphenols   5-HMF   Antioxidant capacity  

摘要： The aim of this study was to determine the effect of different drying methods - freeze drying, spray drying and vacuum drying (at 50, 70, 90 degrees C) - on the quality factors of Japanese quince polyphenol extract, including physical parameters, phenolic compounds, and in vitro biological activities (antioxidant, anti-diabetic, anti-obesity, and anticholinesterase). The highest content of bioactive compounds was observed in samples after freeze drying (total phenolic content - 912.7 g/kg dry weight [dw];flavan-3-ols - 467.3 g/kg dw). The anti-oxidant activity measured by Oxygen Radical Absorbance Capacity (ORAC) assay was the highest for samples vacuum dried at 70 degrees C (1455.5 mol Trolox/kg dw). Moreover, strong anti-diabetic properties were obtained after vacuum drying, and the samples subjected to freeze drying and spray drying showed the most favorable anti-cholinergic potential. Unfavorable changes in color, formation of 5-hydroxymethylfurfural (5-HMF) and degradation of phenolics were noted along with the increasing drying temperature in vacuum drying. For vac-uum drying, the most optimal temperature is 70 degrees C, as the final product obtained in this way is characterized by favorable physical properties, a beneficial content of biological compounds, a low concentration of undesirable 5-hydroxymethylfurfural and satisfactory biological properties.

关键词： Wheat straw   Nursery substrates   Lignocellulose   Enzyme   Fermentation  

摘要： To solve the central problems caused by traditional composting treatments, such as long-time consumption and poor regulation effects, this study used three fermentation methods and four enzymes to develop rapid and directional regulation methods to convert wheat straw into a suitable substrate. The results showed that the mixed anaerobic method led to better pH (4.39-5.75) and EC values (1.27-1.89 mS/cm) in the straw substrates, while the aerobic method retained more nutrients and increased lignin and cellulose contents by 5.07-8.04% and 1.52-3.32%. The cellulase mixed with hemicellulase or laccase treatments all increased the crystallinity by 0.45-7.23%. The TG/DTG results showed that all treatments decreased the initial straw glass transition temperature, particularly when using the mixed anaerobic method, with decreases of 10.63-25.48 degrees C. Overall, mixed anaerobic fermentation and multiple enzymes, including cellulase, have been suggested as alternative biological modification methods for straw substrates.

关键词： Mezam River water   Physico-chemical   Bacteriological analysis   Pollution   Bamenda Town  

摘要： The Mezam River and its tributaries constitute a prominent water source for domestic use and vegetable irrigation in Bamenda Town (North West Cameroon). The river flows through the city and is thus vulnerable to impairment by substances from point and non-point sources. This current research aims to assess the degree of pollution of the Mezam River water to ascertain its suitability for various uses. A total of 24 water samples were collected from six segments of the Mezam River basin in the dry and rainy seasons during the years 2015 and 2016 in view of physico-chemical and bacteriological analyses. In situ measurement of physical parameters was taken in the field. The data were analysed by multivariate statistical techniques (principal component analysis and factor analysis). The results revealed that the river water is slightly acidic (pH = 5.45-6.47) and ion concentration is low (41.67-237.00 mu S/cm). The water type is Ca-SO4 and Ca-Mg-(Cl + NO3) in the dry season and Ca-Mg-SO4 in the rainy season. High NO3- values (50 mg/l) are recorded at Nkimefueh. The Mezam River water is heavily polluted with indicator bacteria (0-500 CFU/100 ml) whose concentrations steadily increase from the reference point (YB) through sampling points in the city centre, suggesting the influence of human-induced activities. The population is urged to adopt a responsible behaviour towards waste disposal and refrain from disposing waste in water courses in order to safeguard the aquatic environment and also protect the health of the population.

关键词： Physicochemical   Antioxidant dietary fiber   Gluten-free   By-products  

摘要： Gluten-free producers face significant technical and nutritional challenges, technological challenges due to lack of gluten. Cantaloupe by-products (CB) contain dietary fiber-associated phenolic compounds in different proportions. This study examined a new gluten-free donut (GFD) supplemented with antioxidant dietary fiber made from cantaloupe by-products (ADF-CB). Using response surface methodology (RSM), the effect of ADF-CB incorporation level (5-20 g/100 g rice flour) at particle sizes (PS) (75-500 mu m) on pasting physicochemical and sensory properties of the experimental GFDs were investigated. The optimal conditions for producing high sensory scores to control were: 18 g/100 g rice flour at PS 438 mu m (T4);20 g/100 g rice flour at 288 mu m (T1) and 13 g/100 g rice flour at 500 mu m (T2). At these conditions, dietary fiber content increased by about fourfold higher than the control. Total phenolic content (TPC) increased by about ninefold higher than that of the control. Antioxidant properties exhibited as tested by IC50, which decrease by half-fold against the control. Oxygen radical absorbance capacity (ORAC) assay exhibited a significant increase by more than 8- folds higher than that of the control. Pasting properties values were increased as ADF-CB and PS increased except Setback viscosity (SBV). The use of ADF-CB with indicated PS to enhance the nutritional characteristics of GFD on an industrial scale as a health-promoting functional ingredient in gluten-free products.

关键词： wax remediation   chemical tracer   artificial intelligence   enhanced recovery   paraffin remediation   scale remediation   reservoir characterization   hydrate remediation   production chemistry   oilfield chemistry  

摘要： Seawater injection is widely used to improve oil recovery in offshore oil reservoirs. However, injecting seawater into reservoirs can cause many flow-assurance issues, such as scaling and reservoir souring, which are strongly related to the percentage of seawater breakthrough. Thermodynamic models have been developed to evaluate the effects of barite deposition on oil production, but the reservoir stripping effect has not been fully considered. In this study, a new model that incorporates both chemical reaction (barium and sulfate reaction) and physical reactions (ion adsorption/desorption) is developed to investigate the in-situ barite-deposition process. To the best of our knowledge, for the first time, ion adsorption/desorption is integrated by coupling the adsorption/desorption isotherm to the reservoir simulator. The barium and sulfate chemical reaction is modeled by incorporating the solubility product constant into the model. The model accuracy is verified through convergence rate tests and comparison with the coreflood experimental results. The simulation results of both barium and sulfate concentration profiles are greatly improved by integrating the ion adsorption/desorption process. The new physicochemical model is further used to investigate barite deposition under various scenarios. Simulation results indicate that most barite deposits are in the deep reservoir for the areal model. Barite that deposits in the reservoir before seawater breakthrough accounts for 45% of total barite deposition and the barite deposited during the seawater-breakthrough period makes up 54%, while the deposition during the tailing period, where the seawater fraction is larger than 95%, is negligible. For a homogeneous reservoir, the barite-deposition period at the near-wellbore area of the producer is between 30% and 65% of the seawater-breakthrough percentage, and heterogeneity leads to a broader deposition period. For vertical heterogeneous reservoirs, a considerable amount

关键词： shiitake mushroom   cold plasma   microstructural analysis   drying   nutritional attributes  

摘要： BACKGROUND Shiitake mushroom is one of the most popular delicious vegetables, although fresh shiitake mushroom has short shelf life as a result of biochemical degradation. Drying can prolong the shelf life of mushroom. Additionally, application of cold plasma pretreatments (CPT) before drying can preserve the product quality, processing costs and nutritional values. Therefore, we aimed to explore the effect of cold plasma pretreated hot-air drying at 50, 60 and 70 degrees C on the physicochemical characteristics, nutritional values and antioxidant activity of shiitake mushroom. RESULTS Scanning electron microscopy micrographs showed that CPT induced the surface modification of fresh shiitake (such as cellular disarrangement, cellular shrinkages, disruption or break down of cell walls, and intracellular spaces and cavities) and facilitate the rapid drying than control samples. Furthermore, CPT improved the powder qualities (bulk density, water retention and swelling index) and preserved higher nutritional attributes (sugars, vitamins, phenolic acids contents and antioxidant activity) compared to the control groups. CONCLUSION Conclusively, CPT could be a suitable alternative technique for improving drying characteristics and preserving nutritional attributes of agro-based products. (c) 2021 Society of Chemical Industry.

关键词： beta-Carotene   Trehalose   Microcapsule   Wet-milling   Physicochemical stability  

摘要： Solvent-free beta-carotene high loaded microcapsules formulated by octenyl succinic anhydride (OSA)-starch and trehalose were prepared by a combination of wet-milling and spray drying. The influence of different mass ratios of OSA-starch to trehalose on the particle size distribution, storage stability, hygroscopicity and redispersibility of beta-carotene microcapsules was investigated. The optimized microcapsules exhibited a small average diameter (228.2 nm) after rehydration with high encapsulation efficiency and loading capacity (99.06% and 10.32%, respectively). The phase separation in the OSA-starch and trehalose composite matrix was observed in the presence of trehalose at a high level, which was favorable for the prominent storage stability of beta-carotene (96.16% for 50 days). The half-life of rehydrated beta-carotene microcapsules was also extended by 2.23- and 1.25-folds during the thermal- and photo-degradation treatments. The crystallinity of beta-carotene microcapsules was largely reduced due to the enhanced hydrogen bonding interaction between OSA-starch and beta-carotene as analyzed by FTIR. SEM images showed that the morphology of beta-carotene microcapsules was regulated by the level of trehalose. Confocal Raman spectrum microscopy and hygroscopic variation jointly verified the entrapment of beta-carotene into a glassy matrix formed at a high level of trehalose. Moreover, a high level of trehalose could improve the spontaneous sinkability and dispersibility of beta-carotene microcapsules, which were completely rehydrated in less than 1 min.

关键词： Duck fat   Margarine   Quality characteristics   Oxidative stability  

摘要： Soybean oil (SBO) and fully hydrogenated soybean oil (FHSBO) have been used for margarine production. However, SBO-based margarine requires a considerable amount of trans fatty acid-containing FHSBO due to its low melting point. We aimed to reduce the FHSBO content in margarine by employing duck fat, which has a higher melting point than SBO. Margarines were prepared using different ratios of duck fat and reduced levels of SBO and FHSBO. Physicochemical, sensory, and oxidative properties of the margarines were evaluated. The quality characteristics of margarine improved when duck fat replaced SBO and FHSBO. Furthermore, the lipid oxidation parameters were lower in duck fat-added margarines than the control during storage at 60 degrees C for 28 days. The margarine containing 80% duck fat showed the best sensory properties. Collectively, duck fat can replace SBO in margarine while reducing the use of FHSBO and maintaining desirable physicochemical properties, oxidative stability, and sensory properties.

关键词： Meliponinae   Apis mellifera   Honey   Quality   QuEChERS   Pesticides  

摘要： This study evaluated the physicochemical parameters and the occurrence of pesticides in multi-flower honey produced by six species of Meliponinae and Apis mellifera and collected in different seasons, floral species and sites in southern Brazil. Meliponinae honey were found to exhibit higher moisture, free acidity and sucrose concentration and lower concentration of reducing sugars than the standard of Apis mellifera honey in Brazil. Regarding Apis mellifera honey, reducing sugars and sucrose did not comply with the legislation. The Principal Component Analysis (PCA) showed that most of the composition variability was defined by free acidity, moisture, soluble solids, fructose, glucose, and reducing sugars. Determination of pesticides was carried out by the citrate QuEChERS method and gas chromatography tandem mass spectrometry (GC-MS/MS). However, no pesticide residues at concentrations above the limit of quantification were found in the twenty honey samples. Results show that this region has the potential to produce honey.