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  • Author or Editor: P. Dvořák x
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Parallel extraction (coextraction) of several elements is a phenomenon in technological processes where extraction is applied as a separation method. On the basis of the stability constants, it is possible to derive simple expressions for the prediction of effects of a complexing agent. The proposed mathematical model, the validity of which was verified by comparison with experimental data, proved to be a suitable approximation of real systems. From the technological point of view, the method presented enables to simulate the purification process of a macrocomponent according to the known dependences DMi,Ma=f(c Ma o ).

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Authors: J. Pokorná, P. R. Venskutonis, V. Kraujalyte, P. Kraujalis, P. Dvořák, B. Tremlová, V. Kopřiva and M. Ošťádalová

Coffee beans contain a large amount of antioxidants, which are subjected to various changes during roasting. In this study, antioxidant potential of raw and roasted to different degree (light, medium, dark) C. arabica and C. robusta coffee beans was evaluated by the four antioxidant assay methods, TPC, FRAP, TEAC, and DPPH˙.

The obtained results revealed significant differences between the coffee types, roasting degree, and antioxidant activity assessment methods. FRAP and TPC appeared to be the most appropriate methods for revealing the differences in antioxidant potential of different coffee types and the effects of roasting. The results obtained by these methods were in good correlation. ABTS and DPPH? methods are not enough sensitive for the determination of roasting degrees.

In general, based on statistical data evaluation, antioxidant activity is more dependent on the coffee type than on the degree of roasting, however, the selection of analytical method may also be significant.

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Authors: P Szablics, K Orbán, S Szabó, M Dvorák, M Ungvári, S Béres, AH Molnár, Z Pintér, K Kupai, A Pósa and Cs Varga


The quality and function of movements undergo deterioration due to weight gain. Aerobic training normalizes body weight, improves the health status, and in addition, it is expected to improve the dynamics of movements. The aims of this study were to prove the beneficial effects of recreational physical activities on the movements.


Participants were divided into five different age categories: second childhood, adolescence, mature age I, mature age II, and aging. Squatting and vertical jumping of the participants were measured at the beginning and at the end of a 5-month training program. These movements simulated ordinary daily movements. Changes in the body were determined by InBody230. APAS 3D system was used for movement analysis.


The results showed significant improvements in body weight, fat mass, muscle mass, fat mass–body weight ratio, muscle mass–body weight ratio, body mass index, body fat percentage, and waist–hip ratio. During jumping, the lifting and sinking of the center of gravity’s (CG) position and its velocity and acceleration were improved. In case of squatting, the results showed significant improvements in the velocity and acceleration of dynamical characteristics of the CG. Other correlations were observed between changes in body composition and the dynamics of movements.


The research proved that recreational training optimized body composition and improved the characteristics of CG’s dynamics. The study suggests considerable connection between body composition and the characteristics of the movements’ dynamics. From this point of view, our training program was the most effective in the working age groups.

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