Compositional and Functional Characteristics of Feta-Type Cheese Made from Micellar Casein Concentrate

Micellar casein concentrate (MCC) is a high protein ingredient (obtained by microfiltration of skim milk) with an elevated level of casein as a percentage of total protein (TP) compared to skim milk. It can be used as an ingredient in cheese making. Feta-type cheese is a brined soft cheese with a salty taste and acid flavor. We theorize that Feta-type cheese can be produced from MCC instead of milk, which can improve the efficiency of manufacture and allow for the removal of whey proteins before manufacturing Feta-type cheese. The objectives of this study were to develop a process of producing Feta-type cheese from MCC and to determine the optimum protein content in MCC to make Feta-type cheese. MCC solutions with 3% (MCC-3), 6% (MCC-6), and 9% (MCC-9) protein were prepared and standardized by mixing water, MCC powder, milk permeate, and cream to produce a solution with 14.7% total solids (TS) and 3.3% fat. Thermophilic cultures were added at a rate of 0.4% to MCC solutions and incubated at 35 °C for 3 h to get a pH of 6.1. Subsequently, calcium chloride and rennet were added to set the curd in 20 min at 35 °C. The curd was then cut into cubes, drained for 20 h followed by brining in 23% sodium chloride solutions for 24 h. Compositional analysis of MCC solutions and cheese was carried out. The yield, color, textural, and rheological measurements of Feta-type cheese were evaluated. Feta-type cheese was also made from whole milk as a control. This experiment was repeated three times. The yield and adjusted yield of Feta-type cheese increased from 19.0 to 54.8 and 21.4 to 56.5, respectively, with increasing the protein content in MCC from 3% to 9%. However, increasing the protein content in MCC did not show significant differences in the hardness (9.2–9.7 kg) of Feta-type cheese. The color of Feta-type cheese was less white with increasing the protein content in MCC. While the yellowish and greenish colors were high in Feta-type cheese made from MCC with 3% and 6% protein, no visible differences were found in the overall cheese color. The rheological characteristics were improved in Feta-type cheese made from MCC with 6% protein. We conclude that MCC with different levels of protein can be utilized in the manufacture of Feta-type cheese.

An experimental study on the determination of dispersion coefficient in layered soils

Dispersivity is a measurable parameter in soil porous media that is used for studying the transport of contaminants to groundwater. The value of this parameter depends on various factors, including the kind of porous media (homogeneous or heterogeneous), flow velocity, initial contaminant concentration, travel distance, and sampling method. A physical model with dimensions of 0.10 m in width, 0.80 m in height, and 1.10 m in length was constructed to investigate the effects of these parameters on the dispersivity value. The stratified soil consisted of three 20-cm-thick layers containing fine-grained, medium-grained, and coarse-grained soil. Sodium chloride solutions with electrical conductivity values of 10, 14, and 19 dS/m were used as the contaminants. Flow was forced through the layered heterogeneous soils at three discharge velocities of 17.58, 22.02, and 26.18 × 10−5 m/s. The point and mixed sampling methods were used. The results indicated that the soil dispersivity values in the layered heterogeneous soils and homogeneous soil were influenced by contaminant concentration, flow velocity, and travel distance. Moreover, the dispersivity values obtained by point sampling were lower than those obtained using the mixed sampling method, and the mean dispersivity value in the layered heterogeneous soils was lower than that of the homogeneous soil.

Relation between durability and mechanical properties on glass fiber reinforced slag-based geopolymer

This work seeks to improve the understanding of the durability of pure slag-based geopolymer composites containing glass fibers. Degradation by attack of saline mist, simulated by the salt-spray essay, was carried out for a period of 30 days. The test simulates the conditions found in the sea and nearby environments. The chamber works at relative humidity ∼97%, by nebulizing sodium chloride solutions with a concentration of 5% at 35 + 2 °C, solution pH between 6.5 and 7.2. After the cycle, the loss of mass and the compressive strength of the specimens were measured. The efflorescence formation in slag-based geopolymers is also assessed in this study to provide a better understanding of the effect of the synthesis parameters. It is noted that physical and chemical properties of geopolymers, and environmental exposure conditions can affect the rate of efflorescence formation. Besides the control set group, two different solutions to prevent efflorescence were tested, MgO and an efflorescence reduction agent from Sika®. The work aims to examine the effect of efflorescence formation on mechanical properties, through flexural and compressive strengths. A compromise between durability and mechanical properties was found for specimens enriched with 2% of efflorescence reduction agent.

Dissolution of iron in sodium chloride solution during alternating current polarization

Iron compounds are widely used in many industries and engineering, and even in medicine. The existing methods of obtaining iron compounds are multi-stage and complex. The purpose of this work is to obtain iron (II) hydroxide and oxide from metal waste under alternating current action using one and two half-cycles. For the first time, the electrochemical behavior of iron electrode was studied by electrolysis method during alternating current polarization of industrial frequency in sodium chloride solutions. The iron polarization was carried out in pair with titanium, while the current density on the iron electrode varied in the range of 200-1200 A/m2, and on the titanium is in the range of 20-100 kA/m2. It is established that in the anode half-cycle of alternating current, iron is oxidized to form divalent ions. At this moment, the titanium electrode is in the cathode half-cycle, hydrogen is released on it, hydroxyl ions are formed in the cathode space. In the solution, ions interact with iron (II) ions to produce iron hydroxide. At temperatures above 600C, iron (II) hydroxide is dehydrated with the production of iron (II) oxide. The electrolysis was carried out in two electrolyzers connected to each other in parallel with the immersion of pair of “titanium-iron” electrodes into each electrolyzer. The iron dissolution occurs simultaneously in two half-cycles of alternating current and this approach is proposed for the first time. The process productivity increases by more than 1.5 times.

Physiological quality of seeds and growth of seedlings of chickpea under salt stress

Salt stress is a condition that causes physiological changes in several species, the identifying cultivars tolerant to such conditions is essential to high salinity environments. The objective was to evaluate the physiological quality of seeds of chickpea cultivars to salt stress during germination and seedling growth. Two cultivars (‘BRS Cícero’ and ‘BRS Aleppo’) and five osmotic potentials simulated with sodium chloride solutions (0.0; -0.2; -0.4; -0.6 and -0.8 MPa), were evaluated by the test of germination speed index, mean germination time, epicotyl and primary root length, epicotyl and primary root fresh mass, epicotyl and the primary root dry mass of the seeds were evaluated. Significant interactions were found for all variables, indicating that there are cultivars with specific performance for a particular salt condition, and the simulated salt stress conditions negatively affected germination and seedling growth. Osmotic potentials of less than -0.4 MPa are harmful to the germination and growth of chickpea seedlings. The ‘BRS Cícero’ seeds showed a higher salt tolerance than ‘BRS Aleppo’. The cultivar BRS Aleppo has a longer epicotyl length compared to 'BRS Cícero' when subjected to the same conditions of salt stress.