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关键词： Physicochemical properties  

摘要： The aim of this study was to evaluate the influence of temperature on drying kinetics and the physicochemical properties of whey powder. The whey foam was prepared and dried at 40, 50, 60, 70, and 80 degrees C. The moisture ratio (MR) was calculated. Mathematical models were fitted to the MR data. The effective moisture diffusivity (D-eff) and the activation energy were calculated. The samples were characterized in terms of moisture, water binding capacity (WBC), protein, and color. The optimal treatment was determined by the desirability function. The Midilli model was the most appropriate to represent the drying of the whey. Higher drying air temperatures resulted in shorter drying times and higher D-eff, in addition to lower moisture, WBC, brightness and hue, and greater chromaticity. The protein content was not influenced by the drying temperature. The temperature of 60 degrees C was the best for drying the whey in a foam mat. Practical applications Whey is a by-product generated by cheese production and represents about 90% of the volume of milk. This by-product still has a rich nutritional composition and can be incorporated into other products to add value. The whey can be subjected to drying processes, generating a powdered product with greater chemical stability and long shelf life. Alternative methods that contribute to reducing process costs have been increasingly used, such as foam mat drying. This process requires few technological resources, low operating cost, and allows the use of lower temperatures.

关键词： Concentration (process)  

摘要： An innovative refractance window (RW) concentrator was developed and used to concentrate milk samples at temperatures of 50-70 degrees C and pressures of 0.4-0.8 bar. Optimum process conditions were found through response surface methodology to compare RW at optimal conditions with the conventional concentration (CC). Also, the effects of process parameters and their interactions on the RW process and product specifications were analyzed. According to the results, optimal RW conditions were a pressure of 0.4 bar and a temperature of 69.1 degrees C. Besides, the energy efficiency and overall heat transfer coefficient of RW at optimal conditions were higher than those of CC by 125.2% and 15.3%, respectively. Compared to CC, RW reduced the concentration-time by 60.8% and minimized the changes in the chemical composition and color of the milk. RW process was found to be a time- and energy-saving concentration technique that can produce concentrated milk with improved quality. Practical applications Alternative concentration techniques that can reduce energy consumption and processing time while guaranteeing the quality retention of the product might be considered by the food industry. The innovative RW milk concentration method that was developed in the present study showed to be a promising time- and energy- saving concentration technique. This method was able to retain the quality characteristics of milk during the concentration process. Also, the optimization information provided in the present study can be used for developing upscaled units that can be used for the commercial concentration process of milk.

关键词： Minerals  

摘要： The present study focused on monitoring the physico-chemical parameters, microbiological quality, minerals, and antioxidant potential of colostrum samples collected from buffaloes (n = 20) until 10th milking (twice-daily milking) after partum. Solids not fat (SNF), fat (%), protein (%), and ash (%) decreased with time, while pH gradually increased. There was a significant (p < .05) effect regarding milking after partum on all the investigated minerals, that is, Ca, Mg, Na, K, Fe, and Zn. Regarding Trolox equivalent antioxidant capacity (TEAC), the maximum value (107.05 mg/100g Trolox equivalent (TE)) was observed in buffalo colostrum in the first milking of the postpartum period. Similarly, the maximum value (39.66 mg/100g gallic acid equivalent (GAE)) of total phenolics (TP) was also observed in the colostrum of 1st milking after partum. As indicated, it may be concluded that buffalo colostrum collected during the first 2 days after parturition might be a rich source of nutrients and antioxidant agents. Practical applications In the present study, the contents of fat (%), protein (%), ash (%), and solids not fat (%) were high in colostrum at the beginning of the postpartum period. Similarly, high levels of minerals and improved antioxidant potential were observed in colostrum until 4th postpartum milking. Therefore, it may be suggested that buffalo colostrum collected during the first 2 days of the postpartum period could fortify human organism due to its health benefits as a result of the presence of increased quantities of bioactive compounds.

关键词： Casein  

摘要： Besides deionised water, tap or softened water could be used as diafiltration media for separation and purification of the casein fraction from milk by means of membrane technology. The effect of compositional differences on key properties of casein micelles was investigated with these media and simulated milk serum as reference at laboratory scale under conditions mimicking typical industrially applied diafiltration processes. Evaluation of zeta-potential, particle size distribution, voluminosity as well as casein and calcium composition revealed marked differences of micellar attributes at temperatures of 10 and 50 degrees C depending mainly on the medium hardness. While tap water induced a slight micellar contraction, dehardened water types differently fostered a swelling that was followed by partial disintegration over contact time especially at 50 degrees C. Results demonstrate that water composition impacts micellar properties in typical DF conditions, which can, in consequence, be crucial for processing efficiency and product functionality of obtained casein products. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Polysaccharides  

摘要： To select a suitable drying pretreatment method to obtain biologically active polysaccharides with a required function, fresh Osmunda japonica Thunb. was subjected to natural drying (ND), hot air drying (HD), and vacuum freeze-drying (FD) treatments. After pretreatment, the O. japonica Thunb. polysaccharides (OPs) were extracted and denoted ND-OP, HD-OP, and FD-OP. The chemical composition, physicochemical characteristics, and antioxidant activities of the OPs were analyzed. The drying method substantially influenced the OPs. HD-OP had the highest yield (4.88%) and uronic acid content (9.17%) and the lowest molecular weight (252.54 kDa). Moreover, based on the correlation analysis, the high uronic acid content, low molecular weight, and unique monosaccharide composition may be closely related to the stronger antioxidant activity of HD-OP. The above results indicate that HD is the best method for the industrial production of high-quality OPs. Practical applications The picking period of O. japonica Thunb. is short and it should be processed in time after harvesting. By choosing a suitable drying pretreatment method, we can obtain bioactive polysaccharides with desired functions, and we hope to have good application prospects in medicine, cosmetics, food, and other fields. This can also transform OPs into products with added economic value.

关键词： Bentonite   Lime   Loess   Physical-chemical properties   Rheology   Stabilization  

摘要： Loess is a collapsible soil;when it collapses, it can cause significant damage to structures built on it. Improvement in the stability and strength performance of loess is necessary to meet engineering needs. In the present study, the effects on the physical-chemical and rheological characteristics of Ghardaia loess of adding bentonite and lime (southern Algeria) were examined. Rheological characterization of suspensions was implemented to assess the mechanical sensitivity of the bonds and the structural inter-particle resistance to both the chemical effect and mechanical impact. By analyzing the viscosity results and the evolution of the rheological parameters, the improvements needed in terms of the resistance characteristics of the loess-bentonite and loess-lime mixtures were evaluated and confirmed. The loess physical sensitivity was examined through grain-size distribution and plasticity properties. The pH and electrical conductivity of the mixtures were also used to explore structural modifications. Physical test results showed that introduction of the additives changed the loess texture and improved the plasticity of mixtures. Chemical examination (via change in pH and electrical conductivity) revealed the structural changes in the mixtures studied. Rheological test results showed that increasing concentrations of bentonite and lime improves the mechanical strength and increased the yield stress, consistency, and viscosity of the suspensions. The creation of cement interactions between mixture particles explained the increase in those parameters. Hydration, agglomeration, and inter-particle flocculation induced by the additives promoted these interactions. The experimental results led to the conclusion that bentonite and lime may represent an effective means to improve the performance in terms of preventing loess collapse and to increase its resistance to mechanical impact. The results presented in the present study may provide a geotechnical and rheological

关键词： Yield stress  

摘要： The impacts of stirring and homogenisation processes on the physicochemical and sensory character-istics of stirred yoghurt produced from fresh, refrigerated and frozen/thawed sheep milk were studied. Yoghurt from frozen/thawed milk was more sensitive to post acidification and had a higher Casson yield stress than yoghurt from fresh milk. The main differences caused by stirring and homogenisation were observed in NIR backscattering and in rheological parameters of yoghurt from refrigerated and frozen/ thawed milk (Casson yield stress reduced and Casson consistency index increased). These modifications, however, were not able to improve the low scores of sensory evaluation of yoghurt from frozen/thawed milk, probably penalised by their worst textures. Results suggest that sheep milk cold preservation, mainly freezing/thawing, negatively affects the characteristics of yoghurt;although some improvements in physicochemical parameters are observed after stirring and homogenisation, these were not enough to avoid poor sensory evaluation of the samples. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Buckwheat   Gel   Bran   Physicochemical   Pasting   Digestibility  

摘要： This study investigated the effects of different levels of buckwheat bran inclusion onto the physicochemical, pasting properties and in vitro starch digestibility of buckwheat flour gels. Total phenolic content and antioxidant activities (DPPH radical-scavenging activity and ferric reducing/antioxidant power) were also measured. Total starch content per 100 g of gel ranged from 64.45 to 75.66, and the percentage of resistant starch ranged from 1.36% to 1.75%, while protein ranged from 12.07% to 12.93%. The results showed that the amount of bran addition decreased total starch and slightly reduced protein content, but increased resistant starch content. The level of bran addition increased the total phenolic content and antioxidant activity of the gels, while it reduced the blood sugar response. As the bran levels increased, the glucose released decreased (95.17, 84.08, 69.80, 60.23 mg glucose/g sample, respectively). The results showed that the bran of buckwheat (a pseudocereal) has nutritional value and can be used in the development of buckwheat products.

关键词： adsorption   capacitive deionization   coagulation   flocculation   flotation   ion exchange   oxidation   wastewater treatment  

摘要： By summarizing 187 relevant research articles published in 2019, the review is focused on the research progress of physicochemical processes for wastewater treatment. This review divides into two sections, physical processes and chemical processes. The physical processes section includes three sub-sections, that is, adsorption, granular filtration, and dissolved air flotation, whereas the chemical processes section has five sub-sections, that is, coagulation/flocculation, advanced oxidation processes, electrochemical, capacitive deionization, and ion exchange. Practitioner points Totally 187 research articles on wastewater treatment have been reviewed and discussed. The review has two major sections with eight sub-topics.

关键词： Muscocho Pluton   Granodiorite   Abitibi Subprovince   Syntectonic magmatism   Physico-chemical parameters   intrusion-related gold systems (IRGS)  

摘要： The Muscocho Pluton is one of a number of syntectonic Neoarchean granodiorite intrusions formed during the main deformation phase in the Abitibi Subprovince that lead to stabilization of the Superior craton. Such magma locally are associated with magmatic-hydrothermal styles of mineralization, interpreted by some works to reflect intrusion-related gold systems (IRGS). Determining whether magmas can transport enough Au to fertilize the upper crust during this tectonomagmatic interval requires insights into physico-chemical parameters such as pressure, temperature, and oxygen fugacity (integral O-2). The integral O-2 parameter is particularly important because it affects S-speciation and S-solubility, which correlates with Au-solubility in magmas. Retrieving such parameters from the metamorphosed, locally hydrothermally altered, and generally deformed Neoarchean rocks is particularly challenging. As such, this contribution uses fresh to altered granodiorites of the Muscocho Pluton, a 16 km diameter granodiorite intrusion spatially associated with polymetallic mineralization, to evaluate whether physico-chemical parameters can be retrieved from ancient altered rocks based on amphibole, apatite, and zircon chemistry. This study also has implications for the origins of the Muscocho Pluton, which ascended slowly toward the upper crust as a single pulse of evolved magma and became emplaced at about 12 km depth. The magma had an integral O-2 above the Ni/NiO solid oxygen buffer (NNO + 1), which is not considered optimal for Au transportation. The magma also formed a deep intrusion unable to provide magmatic fluids to trigger an efficient hydrothermal system. This study provides the basis for a systematic evaluation of the physico-chemical conditions within which syntectonic magmas evolved in the upper crust. Knowledge of these physico-chemical conditions are necessary to better constrain the IRGS metallogenic model.