Surfactant Sensors in Biotechnology; Part 1 – Electrochemical Sensors

An overview on electrochemical surfactant sensors is given with special attention to papers published since 1993. The importance of surfactants in modern biotechnology is stressed out. Electrochemical sensors are usually divided according to the measured physical quantity to potentiometric, amperometric, conductometric and impedimetric surfactant sensors. The last ones are very few. Potentiometric surfactant sensors are the most numerous due to their simplicity and versatility. They can be used either as end-point titration sensors or as direct EMF measurement sensors, in batch or flow-through mode. Some amperometric surfactant sensors are true biosensors that use microorganisms or living cells

CARNOSINE IN GENERAL

U radu se opisuju fizikalno-kemijska svojstva dipeptida karnozina koji se nalazi u značajnim količinama u mišićima pilića. Nastaje sintezom β-alanina i L-histidina uz djelovanje enzima karnozin sintetaze. Karnozin ispoljava značajnu pufersku ak¬tivnost, posebice pri mišićnoj aktivnosti kada dolazi do acidifikacije intracelularne sredine. Posjeduje antioksidativna svojstva radi hvatanja aktivnih kisikovih specija. U posljednje vrijeme karnozin se koristi u terapeutske namjene.The paper describes physical and chemical properties of dipeptide carnosine that is found in broiler muscles in significant amounts. It is created by a synthesis of β-alanine and L-histidine along with activity of carnosine synthetase enzyme. Carnosine exhibits significant buffering activity, especially in muscle activity with occurrence of intracellular acidification. It has antioxidative properties due to capturing active oxygen species. Recently, carnosine has been used for therapeutic purpose

Surfactant Sensors in Biotechnology; Part 2 – Non-Electrochemical Sensors

An overview on non-electrochemical surfactant sensors is given with special attention to work published since 1993. In the first part the importance of surfactants in modern biotechnology is stressed out and works on electrochemical surfactant sensors have been summarised. In this part the research of non-electrochemical surfactant sensors is reported, primarily optochemical and piezoelectric surfactant sensors. Papers investigating some specific interactions of potential interest for surfactant sensors are reported as well

Application of a New Functionalized MWCNTs for the Construction of Surfactant Potentiometric Sensors

The multi-walled carbon nanotubes (MWCNTs) were noncovalently functionalized with tetraoctadecylammonium tetraphenylborate (TODA-TPB) used as a sensing element and incorporated into a liquid PVC membrane of the new fast, low drift and sensitive potentiometric sensor (FCNSS) for anionic surfactants (ASs). The sensor exhibits a sub-Nernstian response for both dodecyl sulfate (DS) and dodecylbenzenesulfonate in H2O and in 10 mM Na2SO4. The lower limits of detection for DS and DBS in H2O were 1.5 · 10−7 and 2.0 · 10−7 M and in 10 mM Na2SO4, they were 2.0 · 10−7 M for both surfactants. The response time of the sensor varied between 8 and 12 s, depending on AS concentration and its signal drift was 2.1 mV/hour. The FCNSS exhibited excellent selectivity for DS against nearly all anions usually found in commercial products. It was successfully employed for end-point detection at potentiometric titrations of ASs in detergent products and effluents. This work is licensed under a Creative Commons Attribution 4.0 International License

EFFECT OF Β-ALANINE AND L-HISTIDINE ON CONCENTRATION OF CARNOSINE IN MUSCLE TISSUE AND OXIDATIVE STABILITY OF CHICKEN MEAT

This paper presents the results of two separate experiments, each involving 75 chickens of Cobb 500 provenience, divided into three experimental groups. During the last three weeks of fattening, chickens were fed finisher diets supplemented with amino acids β-alanine (0%, 0.5% and 1%) and L-histidine (0%, 0.3% and 0.5%) in different portions. After chickens have been slaughtered, 10 samples of breast tissue were taken from each group for carnosine content determination in muscle tissue and lipid oxidation expressed as TBARS. Analysis of THE results referring to carnosine concentration in breast muscle proved that supplementation of 0.5% L-histidine affected the carnosine concentration increase in breast muscles from 941.58 µg/g of tissue (H1) to 1186.06 µg/g of tissue (H3), while supplementation of 1% β-alanine influenced the increase in carnosine concentration from 756.15 µg/g of tissue (A1) to 911.01 µg/g of tissue (A3). Supplementation of amino acids did not have effects on TBARS values, but oxidation values decreased along with the supplementation of higher amounts of amino acids to diets, which was particularly expressed in samples stored for 60 days at -20°C. The experimental group H3 (0.5% L-histidine) exhibited 30.54% lower value of lipid oxidation than the control one H1 (0% L-histidine), while the group with 1% β-alanine (A3) had lipid oxidation value by 17.65% lower than the control group A1 (0% β-alanine)

Water for all : Proceedings of the 7th international scientific and professional conference Water for all

The 7th International Scientific and Professional Conference Water for all is organized to honour the World Water Day by the Josip Juraj Strossmayer University of Osijek, European Hygienic Engineering & Design Group (EHEDG), Danube Parks, Croatian Food Agency, Croatian Water, Faculty of Food Technology Osijek, Faculty of Agriculture in Osijek, Faculty of Civil Engineering Osijek, Josip Juraj Strossmayer University of Osijek Department of Biology, Josip Juraj Strossmayer University of Osijek Department of Chemistry, Nature Park “Kopački rit”, Osijek- Baranja County, Public Health Institute of the Osijek- Baranja County and „Vodovod-Osijek“ -water supply company in Osijek. The topic of World Water Day 2017 was "Wastewater" emphasizing the importance and influence of wastewater treatments on global environment. The international scientific and professional conference Water for all is a gathering of scientists and experts in the field of water management, including chemists, biologists, civil and agriculture engineers, with a goal to remind people about the significance of fresh water and to promote an interdisciplinary approach and sustainability for fresh water resource management. The Conference has been held since 2011. About 300 scientists and engineers submitted 95 abstracts to the 7th International Scientific and Professional Conference Water for all, out of which 33 was presented orally and 62 as posters. 47 full papers were accepted by the Scientific Committee. 38 full papers became the part of the this Proceedings while 9 papers were accepted for publication in Croatian Journal of Food Science and Technology and Electronic Journal of the Faculty of Civil Engineering Osijek - e-GFOS

Effect of Amino Acids on Growth Performance, Carcass Characteristics, Meat Quality, and Carnosine Concentration in Broiler Chickens

The aim of this research was to investigate the deposition of carnosine in broiler muscles by feeding treatments comprising β-alanine, L-histidine, and magnesium oxide in various concentrations. The research was carried out on 120 Cobb 500 broilers divided into four groups. From weeks four to six, broilers were fed finisher mixtures as follows: P1, control group; P2, 0.5% β-alanine + 0.24% MgO; P3, 0.25% L-histidine + 0.24% MgO; and P4, 0.20% β-alanine + 0.10% L-histidine + 0.24% MgO. This paper presents the weights of broilers and their carcasses, portions of main parts of carcasses, technological quality of breast muscles, and concentrations of carnosine in breast and thigh muscles. The following traits of muscle tissue quality were measured: initial and final pH value (45 min after slaughtering pH1, and 24 h after cooling pH2), drip loss, color (Minolta colorimeter, expressed as CIE L*, CIE a*, and CIE b* values), meat softness, and cooking loss. Data on relative concentration of protein carbonyl (nmol/mg protein) in the muscles of breasts and thighs and levels of thiobarbituric acid-reactive substances (TBARS) in fresh and frozen breasts muscles (nmol/mg of tissue) are presented. Statistical analysis proved that feeding treatments had an effect on the live weight of broilers in the 4th, 5th, and 6th weeks of fattening (P<0.05), as well as on the carcass quality at slaughter (P<0.05; except the portion of wings), pH1 value (P=0.035), CIE a* indicator (P=0.007), drip loss (P=0.002), and meat texture (P=0.008). Compared to the control group, synthesis and deposition of carnosine were increased in breast muscles in groups P2, P3, and P4 by 7.51%, 10.62%, and 62.93%, respectively, and in thigh muscles by 61.05%, 78.95%, and 89.52%, respectively. It was also confirmed that feeding treatments influenced the level of TBARS in frozen broiler breast muscles (P=0.014)

Determination of low levels of cyanide with a silver/silver sulphide wire electrode

A silver/silver sulphide electrode is prepred quickly by holding a cleaned silver wire in vapours from molten sulphur. In 1000-10 mg l-1 cyanide solutions, the electrode exhibits a linear E/log CCN function which becomes slightly sinusoidal for 10-0.1 mg l-1 cyanide. The average slope is slightl super-Nerstian (10 mV/decade concentration). The applicability of the electrode is demonstrated for the determinations of microgram quantities of water-soluble cyanide from the Prussian blue pigments which are constituents of externally applied cosmetics. The home-made electrode provides results agreing with those obtained with commercially available electrodes

Modelovanje i optimizovanje održivih karakteristika tenzidnog senzora za korišćenje pri analizi površinskih i otpadnih voda

The theoretical model of potentiometric titration curves of sodium dodecyl sulfate (anionic surfactant) was proposed and the response parameters of two surfactant sensors (commercial and self-made) were investigated. The both sensors were used to generate potentiometric experimental data, which were incorporated into the calculations using the mass and charge balance equations. The experimental data were compared with appropriate theoretical curves in which the sensor response parameters (sensor slope S, constant potential term Eo, potentiometric selectivity coefficient (K, pot i J), sensor's membrane parameter (solubility product constant KS, CatAn) and analyte properties (activity ai, concentration ci) were estimated and optimized with Solver (Excel).Predložen je teorijski model potenciometrijskih titracionih krivih natrijum-dodecil-sulfata (anjonski tenzid) i ispitane su odzivne karakteristike dva tenzidna senzora (komercijalnog i sopstvene konstrukcije). Oba senzora korišćena su za generisanje potenciometrijskih eksperimentalnih podataka, koji su upotrebljeni u izračunavanjima pomoću jednačina bilansa mase i naelektrisanja. Eksperimentalni podaci upoređeni su sa odgovarajućim teorijskim krivama u kojima su odzivni parametri senzora (nagib S, faktor konstantnog potencijala E0, potenciometrijski koeficijent selektivnosti K, pot i J), parametri membrane senzora (konstanta proizvoda rastvorljivosti KS,CatAn) i svojstva analita (aktivitet ai, koncentracija ci), određeni i optimizovani pomoću Solver aplikacije (Excel programski paket)