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Współczesne zastosowania związków powierzchniowo czynnych

Dywicki Paweł, Grabowska Ola, Chmurzyński Lech

Wiadomości Chemiczne

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2020

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[Z] 74, 5-6

391--409

EN

Surfactants have been known to mankind since the dawn of time. They have been used primarily as washing and cleaning agents. However, today they are used much more often in many fields of industry. This work focuses on two areas of surfactants use, the agriculture and the food industry due to the direct relationship between these two issues. In agriculture, surfactants play a number of important roles. One of the problems of modem agriculture is the low efficiency of spraying, associated with the low absorption of liquid utility for plants. This problem is solved by surfactants, as demonstrated by the example of glyphosate and the organosilicon compound Silwet® L-77. Nowadays, substitutes for conventional surfactants are being sought. Compounds produced by microorganisms are under great interest of scientists. It has been shown that they are characterized by the lower toxicity as well as high biodegradability, while maintaining the characteristics and properties of synthetic compounds. Directly related to the agriculture, the food industry also often uses surfactants. In the production and processing of food surfactants play the role of such compounds as emulsifiers, stabilizers, additives improving the texture of products and increasing the durability of products. Sorbitan esters, e.g. sorbitan monolaurate, their ethoxylated derivatives, e.g. Polysorbate 20, as well as sucrose esters, e.g. sucrose monostearate, are readily used for this purpose. Great emphasis is placed on the safety of compounds used in the food industry. As in the case of agriculture, biosurfactants and compounds of natural origin are tested for use in the food industry. Their use is not limited to being ingredients of products. They can play a biocidal, as well as a protecting role against surface colonization by microorganisms.

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Metody wyznaczania krytycznego stężenia micelarnego związków powierzchniowo czynnych

Grabowska Ola, Dywicki Paweł, Chmurzyński Lech

Wiadomości Chemiczne

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2020

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[Z] 74, 5-6

371--390

EN

Surface active agents, also known as surfactants, are a group of chemical compounds that are used in various products of the chemical industry. These compounds are components of medicines, detergents, motor oils and many others. The multitude of uses of surfactants makes it important to know their aggregation behaviour in solution. There are many methods used to analyse surfactants behaviour in liquid phase. The choice of a particular technique usually depends on the chemical structure of the surfactant. An example of a method that is used in studies of ionic surfactants is conductometry. This technique allows to study the dependence of specific conductivity on surfactant concentration, enabling determination of critical micellar concentration (CMC). Capillary electrophoresis is another example of the method used to determine the critical micellar concentration. It allows to make measurements in conditions where other methods fail, including conductometric method. Surfactant solutions differ in viscosity, which changes with the appearance of micelles in solution. Measurement of marker compound migration time through surfactant solutions of various concentrations allow to determine critical micellar concentration. Isothermal titration calorimetry (ITC) allows to study the thermal effects associated with the aggregation of surfactants into micelles. Based on the energy changes that occur during titration, the critical micellar concentration of surfactant can be precisely determined. ITC is very sensitive method, so basically it can be used to examine all types of surfactants. In addition, the ITC method allows to determine the thermodynamic parameters of the undergoing micellization process. The use of several measuring methods gives a more complete picture of the phenomena occurring in solutions. It allows to understand aggregation process more accurately. Therefore, CMC measurement are often made with the use of several complementary methods.

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Zastosowanie polikarboksylanowych związków kompleksowych w tworzeniu sieci metaloorganicznych typu MOF

Zych Dominika, Drzeżdżon Joanna, Jacewicz Dagmara, Chmurzyński Lech

Wiadomości Chemiczne

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2019

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[Z] 73, 5-6

401--423

EN

The first research on Coordination Polymers began at the beginning of the 20th century. Wider understanding of their structure has enabled the development of crystallography. Since then compounds, which belong to this group, have been the subject of broad-spectrum scientific research. A particular class of these compounds, known relatively recently, are Metal–Organic Frameworks (MOF). The MOF structure is based on negatively charged organic linkers, e.g. polycarboxylic anions connected to various metal cations or metal clusters. MOFs are mainly built up from metal cations: transition, alkaline earth, main groups of the periodic table, as well as rare earth metals. Moreover, organic ligands used in the construction of MOF materials should contain electron donors. A characteristic bond, that allows the formation of hybrids, through the interactions of nodes and bridges is the coordination bond. It allows to synthesize a three-dimensional framework structure. Modern synthesis leads to the generation of porous materials with a very large surface area of pores and unique properties. Considering their synthesis, crystalline structures and physicochemical properties of MOF, as well as broad MOFs applications including gas storage, separation, catalysts, luminescence, magnetism and others, it is reasonable to state that MOFs can be used in many areas, not only in science, but also in environmental protection and in industry, for example, energy industry, chemical and biochemical industry.

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Oznaczanie aktywności przeciwutleniającej metodami in-vitro

Malinowski Jacek, Drzeżdżon Joanna, Chmurzyński Lech, Jacewicz Dagmara

Wiadomości Chemiczne

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2019

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[Z] 73, 9-10

523--542

EN

In - vitro methods of determination of the antioxidant activity of complex compounds are very interesting and not fully investigated areas of knowledge from the borderline of chemistry and biology. Methods used for determination of the activity of antioxidant complex compounds are modified due to the conditions of the experiments in which they should be carried out, e.g. reactions at physiological pH. Civilization diseases, stress related to the fast pace of life and increasing requirements of our lives cause the formation of free radicals in our body, i.e. particles characterized by a high reactivity. The methods of determination of the antioxidant activity of complexes discussed in this work apply tests carried out in laboratory conditions - in - vitro.

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Metody in-vivo badania właściwości antyoksydacyjnych związków kompleksowych

Malinowski Jacek, Drzeżdżon Joanna, Chmurzyński Lech, Jacewicz Dagmara

Wiadomości Chemiczne

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2019

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[Z] 73, 7-8

523--538

EN

This article describes the in-vivo methods of studying the antioxidant properties of complex compounds. The reduced glutathione (GSH) method, which uses the reactivity of the reduced form of GSH with free radicals, is among the described methods. Further the in-vivo methods are based on the use of antioxidant enzymes such as glutathione peroxidase, glutathione S-transferase, superoxide dismutase, catalase. These types of enzymes occur naturally in the human body and they are responsible for the inactivation of free radicals, e. g. superoxide dismutase catalyzes the reaction of disproportionation of superoxide anion radical to water and oxygen. The next in-vivo methods described in this article use y-glutamyl transpeptidase and glutathione reductase, which are components of the antioxidant mechanism occurring in an organism. The last method described in this work relates to the lipid peroxidation, which is determined by the concentration of dimalonic aldehyde.

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Możliwości wykorzystania skórek z owoców w technologii przekąsek z pigwowca®

Kowalska Hanna, Masiarz Ewelina, Chmurzyński Lech

Postępy Techniki Przetwórstwa Spożywczego

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2019

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nr 2

72--79

PL

W artykule przedstawiono możliwości wykorzystania odpadu, jakimi są skórki pigwowca japońskiego, w celu wytworzenia przekąsek. Wykonano badania dotyczące zmian aktywności wody, masy i barwy przy zastosowaniu różnych metod suszenia, poprzedzonych odwadnianiem osmotycznym. Przeprowadzono również ocenę sensoryczną, którą przyjęto za wskaźnik atrakcyjności oraz jakości produktu. Wykazano, że rodzaj roztworu osmotycznego wpływa na barwę oraz smak końcowego produktu, zaś metoda suszenia wpływa na aktywność wody, twardość i wygląd zewnętrzny produktu. Poniższy artykuł stanowi praktyczne podejście dotyczące wykorzystania skórek jako pozostałości w procesie przetwarzania owoców w celu wytworzenia wartościowego produktu.

EN

The article presents the possibilities of using the waste as Japanese quince skins for the production of snacks. Changes in water activity, mass, colour using various drying methods preceded by osmotic dehydration were made in this study. A sensory evaluation was also carried out, which was adopted as an indicator of the attractiveness and quality of the product. The type of osmotic solution affects the colour and taste of the final product, while the method of drying affects the water activity, hardness and external appearance of the product. The following article is a practical approach regarding the use of skins as residues in the fruit processing process to produce a valuable product.