Chemical Technology

EFFECT OF VARIOUS CARBOHYDRATE ADDITIVES ON PEROXIDE FORMATION IN FAT FOR CONFECTIONERY PRODUCTION

V. Vītola — 2017-08-22

A lot of ingredients used for food may have their own antioxidant activity. For this reason, it is necessary to explore the effect of natural antioxidants and non-specific antioxidants of some confectionery ingredients for the stabilization of food products against the formation of peroxides.

The aim of the study was to verify the effect of some carbohydrates in preventing the formation of peroxides in fat for the confectionery production and to prove that the quality and shelf-life of confectionery products are affected by ingredients used in the compositions of confectionery products and by compounds that are formed in their interaction.

Butter was used as the basic ingredient to study the fat stability. The effect of carbohydrates used in confectionery and their interaction with butter was examined, and the peroxides were determined. The effect of vanillin in facilitating or preventing the above-mentioned interaction was also determined.

Peroxides were determined by means of the standard LVS EN ISO 3960:2010.

It was established that practically all carbohydrates decreased the formation of peroxides in the samples. The quantity of peroxides in butter with 30 % of sucrose was by 10.7 % lower, with 30 % of glucose – by 41.3 % lower comparing to butter without additives after the samples had been stored for 30 days at 28 ± 2°C. The most effective after 30 days of storage was sorbitol which decreased the formation of peroxides by 65.3 %. The same activity was also established for vanillin. Its antioxidant activity was similar to the activity of sugars, and therefore their summary activity reduces in confectionery products. It is established that the activity of sugars is quite temporary, and with increasing the quantity of peroxides in the product it decreases or completely disappears.

DOI: http://dx.doi.org/10.5755/j01.ct.68.1.18879

PROPERTIES OF CATIONIC STARCHES OBTAINED BY REACTIVE EXTRUSION

J. Bendoraitienė — 2017-08-22

Two different methods, namely chemical and physical modification in the Druvather® reactor DVT5 and Krauss Maffei twin-screw extruder ZE25R x 40D UTXi were used to prepare cationically modified starches, and the properties of those were compared. The reactive extrusion process consisted of two stages. In the first one, the mixture of reaction components at the molar ratio starch : 2,3-epoxypropyltrimethyl-ammonium chloride : NaOH : H₂O = 1 : 0.125 : 0.04 : 3.5 was obtained. In the second one, the derived mixture was extruded by using a twin-screw extruder. The extrusion temperature varied from 20 to 140 °C, the screw speed was 50 rpm, and the mixture feed rate was about 1.5 kg/h. Four different samples of extruded cationic starches were obtained. The main characteristics such as the degree of substitution of cationic groups (DS), reaction efficiency, particle size and the polydispersity index were determined and compared with those of a non-extruded control sample of cationic starch of similar DS. Also, the parameters well defining the behavior of samples in water, such as the swelling power (SP) and the solubility index (SOL) at 75 °C were determined for extruded and control samples. It was established that the properties of extruded and non-extruded cationic starches were different. The following observations can be drawn with respect to the obtained data: the particle size of the extruded samples is much lower and the SP values are 7–13 times lower than those of the control sample; the SOL values of the extruded samples are twice as high, reaching 76–92 %, and even might be higher.

DOI: http://dx.doi.org/10.5755/j01.ct.68.1.18876

SYNTHESIS AND ANTIBACTERIAL PROPERTIES OF N,N-DISUBSTITUTED β-AMINO ACIDS CONTAINING FUNCTIONALIZED THIAZOLE FRAGMENT IN THE STRUCTURE

E. Urbonavičiūtė — 2017-08-22

Aminothiazoles were synthesized from the thioureido acid and halo carbonyl compounds by the Hantzsch method. The bromination of thiazolone, performed in acetic acid at 30 °C, gave the expected product 3-[(5,5-dibromo-4-oxo-4,5-dihydrothiazol-2-yl)(4-methoxyphenyl)amino]propanoic acid. The methylene group in the five-membered heterocyclic ring easily participates in condensation reactions with carbaldehydes. All these reactions were carried out in a mixture of water and 2-propanol in the presence of sodium carbonate. The formed sodium salts were converted into acids by acidifying the reaction mixture with acetic acid to pH 6. The 3-[{5-[4-{[2-[(2-carboxyethyl)-(4-methoxyphenyl)amino]-4-oxo-1,3-thiazol-5(4H)-ylidene]methyl}phenyl)methylidene]-4-oxo-4,5-dihydro-1,3-thiazol-2-yl]-(4-methoxyphenyl)-amino]propanoic acid was obtained analogously to the above-mentioned method, only instead of carbaldehyde using dialdehyde terephthalaldehyde.

The synthesized compounds 1-13 were evaluated for their antibacterial activity against the Xanthomonas campestris, Rhizobium radiobacter and Escherichia coli strains by the agar diffusion technique. Their activities were compared with those of the known antibacterial agent ampicillin (control C). The evaluation was performed at the Laboratory of Biotechnology of the Department of Organic Chemistry (Kaunas University of Technology). The growth of bacteria and the antibacterial activity were determined by using the Luria-Bertani (LB) nutrition media. The following concentrations of solutions in dimethyl sulfoxide were prepared: 1000, 500, 250, 125, 50 and 25 μg/ml. The prepared test-samples were incubated at 37 °C for 48 h. The effectiveness of the compounds was determined by measuring the zones of inhibition on a bacterial culture.

The test cultures of E. coli appeared not to be sensitive to any concentration of the tested compounds. Nine of the thirteen compounds were inactive against the Xanthomonas campestris bacterium strain, and only four of them – the condensed aminothiazole derivative 3-[(4-methoxyphenyl)-(4,5,6,7-tetrahydrobenzothiazol-2-yl)amino]propanoic acid (4) and thiazolone derivatives 3-[(5,5-dibromo-4-oxo-4,5-dihydrothiazol-2-yl)(4-methoxyphenyl)amino]propanoic acid (6), (Z)-3-[(5-(4-bromobenzylidene)-4-oxo-4,5-dihydrothiazol-2-yl)(4- methoxyphenyl)amino]propanoic acid (8), and (Z)-3-[(5-(4-chlorobenzylidene)-4-oxo-4,5-dihydro-thiazol-2-yl)(4- methoxyphenyl)amino]propanoic acid (9) at a concentration of 1000 μg/ml inhibited the growth of the X. campestris strain. It should be noted that compound 9 (at the same concentration) was also active against the Rh. radiobacter bacterium strain.

Hence, the results revealed the most effective compound – (Z)-3-[(5-(4-chlorobenzylidene)-4-oxo-4,5-dihydrothiazol-2-yl)(4-methoxyphenyl)amino]propanoic acid (9), which inhibited the growth of the Xanthomonas campestris and Rhizobium radiobacter bacteria strains.

DOI: http://dx.doi.org/10.5755/j01.ct.68.1.18877

BACTERIA OF THE GENUS BACILLUS AS A METHOD OF DIRECTED MODIFICATION OF POLYCAPROAMIDE FIBERS

Y. Komarovskaya — 2017-08-22

In this paper, studies are presented that indicate the feasibility and effectiveness of the use of the genus Bacillus microorganisms for the directional modification of physicomechanical properties (strength, nominal stretching) of polycaproamide fibers and the production of high-strength polymer-matrix composites. Bacteria of the genus Bacillus can affect the structure of the surface of the fibers by increasing the nanoroughness and the amorphous layer. It is possible to use Bacillus brevis, Bacillus subtilis, Bacillus mesentericus and others strains to improve the consumer characteristics by the direct biodegradation of polycaproamide fibers.

DOI: http://dx.doi.org/10.5755/j01.ct.68.1.18878

VERIFICATION OF AVAILABLE GLASS MECHANICAL PROPERTIES AGAINST RECOMMENDATION BY THE DRAFT EUROCODE DESIGN PRACTICE

L. Sable — 2017-08-22

Glass as a structural material has strongly evolved in modern architecture. Wide windows, glass facades and even load-bearing structures make buildings appear transparent and more integrated in the surrounding environment. According to the ongoing effort by the European Committee for Electrotechnical Standardisation, only recently the notice “Eurocode on glass in construction” has been issued. This will make applicable the binding design practice in the EU starting from the next decade. This design practice will include, among others, the required properties of material and products, application fields, respective failure potential and failure consequences, safety and reliability approaches, principles of design, design and calculation rules for primary members, joints, connections and supports. This standard will be binding in all European countries, therefore, until then every member state should adapt these guidelines in order to make safe design practices for glass structures. At present, in Latvia there is no enforced regulation for glass-bearing structural design and a scattered view on the mechanical properties of the available glass applied for load-carrying designs.

In the present verification study, laboratory testings were performed to characterise glass mechanical properties such as stiffness and bending strength of the set of specimens provided by national distributers. For this reason, a series of samples has been tested by a 4-point bending with two different geometrical settings 360 ´ 1100 mm (EN 1228-3) and short beam tests of 50 ´ 200 mm. The current research has shown that compared with the Eurocode reference values, these test results show a lower strength of the internally available raw glass panels. The cause should be merged with edge grinding technology and studied in more detail in the further analysis.

DOI: http://dx.doi.org/10.5755/j01.ct.68.1.18872

ACCUMULATION OF RESIDUAL ENERGY OF AN EXPERIMENTAL STOVE AFTER BURNING

C. Stone — 2017-08-22

Engineers, architects and designers increasingly rely on mathematical constructs incorporated into civil engineering programs to explain physical and mechanical phenomena. A low thermal diffusivity represents a material’s ability to slow down the rate of heat transfer due to heat absorption and storage, so that high thermal masses are desirable. The thermal inertia of the earth structures in general is an under-researched topic, especially regarding their unique ability to delay and attenuate temperature responses. The paper uses a high temperature difference example, in the form of an experimental stove, to highlight the benefits of a thermal mass. Countries such as Austria, the Czech Republic and Slovakia are known for their ornate historical masonry stoves that grace many stately houses, castles and palaces. They were stoked once or twice daily and radiated heat constantly during the winter months. This guild developed and thrived until the advent of modern HVAC systems in the 20th century. The paper sets out to monitor the temperature difference produced by stoking and firing a simplified experimental stove and analyses the decrease in temperature until it approaches a fixed room temperature. Temperature and heat flux are then observed to determine the total residual heat energy after burning, and the results are discussed in the conclusion. Inspired by these sound principles, based on lessons from the vernacular building traditions that have been used for centuries, the output of this work could be used in future to design an appropriate amount of the thermal mass to maximize thermal efficiency in fireplaces and stoves and as a precedent for a synergetic combination of the thermal mass and renewable energy sources.

DOI: http://dx.doi.org/10.5755/j01.ct.68.1.15006

APPLICATION OF ION-EXCHANGE RESINS FOR REMOVING SULPHATE IONS FROM ACIDIC SOLUTIONS

M. Holub — 2017-08-22

The removal of sulphate ions from different types of wastewater is an environmental challenge faced by several industrial sectors such as the mining, petrochemical or metallurgical industry. Most of the current existing options are inefficient and economically unviable, particularly for acid mine drainage (AMD), where the low pH and high concentrations of heavy metals and sulphates are limiting for these processes. This work is focused on ion-exchange as one of the most common treatment methods for AMD treatment.

Ion-exchange represents a very powerful technology where one or more undesirable contaminants are removed from the aqueous environment by exchange with another substance. The ideal ion-exchange solution for sulphate reduction is one that combines both anionic and cationic resins. The paper presents the results from ion-exchange experiments by the synthetic ion-exchange resin and the AMBERLITE MB20 for SO₄^2– removal from a model solution.

The efficiency of the AMBERLITE MB20 resin for SO₄^2– removal from the model solution H₂SO₄ was higher than of the PUROLITE MB400, and its efficiency decreased with increasing the concentration of sulphates from 86.6 % for the concentration 100 mg/L to 66.9 % for the concertation 1000 mg/L.

DOI: http://dx.doi.org/10.5755/j01.ct.68.1.15004

THE INFLUENCE OF THE SILICA/SODIUM RATIO ON THE FLY ASH GEOPOLYMER BINDER

V. Bocullo — 2017-08-22

This article investigates the properties of a geopolymer, an alternative binding material to the ordinary Portland cement (OPC), and their dependence on different SiO₂/Na₂O ratios in the system. To make the geopolymer polish coal burning fly ash consisting mainly of amorphous SiO₂ and Al₂O₃, it was activated with a NaOH solution. While many researches have been done on the Si/Al ratio influence, not many studies have examined the activator solution influence on geopolymer properties. Samples were made with 8 different mix compositions with the SiO₂/Na₂O ratio varying within 0.8–3.1. The samples were tested for compressive strength after 7, 14 and 28 days of curing. The mineral composition of each set mix was examined with XRD. Samples with the SiO₂/Na₂O ratio equal to 2.0 showed the highest compressive strength. The XRD of these samples showed the presence of low-crystallinity hydrosodalite and a small amount of mullite and quartz. The acceptable strength was shown by samples with the SiO₂/Na₂O ratio in the range of 1.5–2.5. Samples with the ratio beyond this range failed to produce enough of the necessary binding agents.

DOI: http://dx.doi.org/10.5755/j01.ct.68.1.18873

MANUFACTURING OF LIQUID COMPOUND FERTILIZERS FROM WASTE POTASSIUM DIHYDROGEN PHOSPHATE PRODUCTION

K. Jančaitienė — 2017-08-22

In the production of many products in various industries, especially chemical, the positive aspect is the creation and use of a waste-free technology. It has been found that the content of a liquid phase after interaction between NH₄H₂PO₄ and KCl (the molar ratio of the starting materials was 0.8 : 0.2) depends on the conversion temperatures. The chemical composition of the liquid phase can vary from 1.19 to 1.45 % of N, from 14.96 to 26.55 % of K₂O, from 1.06 to 2.55 % of P₂O₅ and from 13.42 to 13.71 % of Cl. The other properties of the solutions, such as pH, density and viscosity, are almost independent of temperature and meet the requirements for liquid compound fertilizers. This means that it is possible to produce a liquid fertilizer 4–5–15 grade in the post-crystallization of potassium dihydrogen phosphate remaining solution (when the molar ratio of the starting materials is 0.8 : 0.2) by adding 6 % of CO(NH₂)₂ wherein the crystallization temperature is 15 °C. It has been discovered that the liquid fertilizers 4–5–15 grade are efficient and give a bigger yield of plants. It increased the test plate dry weight by 78.2 %, the ash content by 41.6 % and the height of the plants by 31.2 %.

DOI: http://dx.doi.org/10.5755/j01.ct.68.1.18874

APPLICATION OF SURFACE COMPLEXATION AND ION EXCHANGE MODELLING FOR THE ESTIMATION OF BENTONITE SORPTION CAPACITY ON SELECTED RADIONUCLIDES UNDER POSSIBLE GEOLOGICAL DISPOSAL CONDITIONS IN LITHUANIA

V. Vaitkevičienė — 2017-08-22

Designing a repository for radioactive waste as a multi-barrier system with predefined multiple safety functions provides for the protection of people and environment from the harmful effect of the ionising radiation of radionuclides once released from high-level radioactive waste. The multi-barrier system is comprised of the engineered barrier system (EBS) and its surrounding natural environment. Because of the high retention capacity for the radionuclides, various forms of bentonite are usually considered as a part of the EBS in the design of radioactive waste repositories. Laboratory batch experiments with natural sediments illustrate that the sorption (and K_d values) is sensitive to aqueous chemical conditions, including the pH and the dissolved carbonate concentration as well as the mineralogy and surface area of the bentonite buffer. The cations considered for the study were chosen as covering a representative range of cations behaviour: from a weakly sorbed cation Cs(I) to moderately sorbed cation the Ni(II) and strongly sorbed cation, Eu(III). In this study, a potential retardation of sorbing radionuclides (Cs, Ni, Eu) as a function of aqueous chemical conditions in the groundwater of the Lithuanian crystalline basement contacting the bentonite material was estimated for the first time. The ion exchange and surface complexation models (SPNE/CE) and the computer program PHREEQC (USA) were applied for modelling the interaction within the radionuclide/water/bentonite system. The modelling of the K_d values under different pH conditions and a given partial pressure of carbon dioxide in the gas phase were performed. The highest value of K_d in the pCO₂ open system and the strongest sorption dependence on pCO₂ was estimated for Eu(I) among radionuclides being studied. There was estimated only a slight change in K_d values with respect to the temperature.

DOI: http://dx.doi.org/10.5755/j01.ct.68.1.18875