Dagmar Janáčová

Processing poultry feathers into keratin hydrolysate through alkaline-enzymatic hydrolysis

Poultry feathers make up for as much as 8.5% of chicken weight and represent a considerable amount of almost pure keratin waste which is not being adequately utilized at the present time. The present study dealt with the processing of poultry feathers through a two-stage alkaline-enzymatic hydrolysis. In the first stage, feathers were mixed with a 0.1 or 0.3% KOH water solution in a 1 : 50 ratio and were incubated at 70°C for 24 h. After adjusting pH to 9, the effects examined in the second processing stage on the amount of degraded feathers were those of proteolytic enzyme additions (1-5%), time (4-8 h) and temperature (50-70°C). Processing feathers in 0.3% KOH and hydrolysing for 8 h in the second stage at 70°C with a 5% dose of enzyme (relative to dry feathers weight) produced approx. 91% degradation. Keratin hydrolysate is distinct for its high nitrogen content and reasonable inorganic solids level. Two-stage technology of alkaline-enzymatic hydrolysing of poultry feathers in an environment of 0.3% KOH achieves high efficiency under quite mild reaction conditions (temperature not exceeding 70°C with pH in a mildly alkaline region), and is feasible from an economic viewpoint. Keratin hydrolysate can find particular application in packaging technology (films, foils and encapsulates).

Interactive software application for calculation of non-stationary heat conduction in a cylindrical body

In this paper we present software application used for the study of heat transfer problems that is a part of education of subject Process Engineering taught at the Tomas Bata University in Zlín. The application speeds up calculation of non‐stationary heat conduction and visualizes temperature distribution in the cylindrical body.

Physiological and GPS data fusion

The paper deals with fusion of physiological and GPS data acquired during cycling and their analysis using general methods of multichannel signal processing. Experimental data were acquired during 17 identical cycling routes each about 12 km long including more then 1100 segments of the length 60 s recorded with the varying sampling period. The proposed algorithm includes their initial analysis, de-nosing using selected digital filters, interpolation and resampling in the first stage followed by evaluation of the cross-correlation between the heart rate and the altitude gradient of positioning data recorded by the GPS system. Results obtained present (i) relation between the heart rate and the slope with the positive regression coefficient 6.04 and (ii) the heart rate and speed with the negative regression coefficient -1.67 over all segments analyzed.

Optimization of Protein Mixture Filtration

In this paper there is described filtering process for separating reaction mixture after enzymatic hydrolysis to process the chromium tanning waste [1]. Filtration process of this mixture is very complicated because it is case of mixture filtration with compressible cake. Successful process strongly depends on mathematical describing of filtration, calculating optimal values of pressure difference, specific resistant of filtration cake and temperature maintenance which is connected with viscosity change. The mathematic model of filtration with compressible cake we verified in laboratory conditions on special filtration device developed on our department. Industrial filtration differs from that in laboratory merely in the quantity of material being processed and in the necessity of processing it as cheaply as possible. In order to increase capacity while keeping filter dimensions not particularly large, the filter area per volume unit of plant gets increased as well as the difference between pressures before and behind the filtering screen or filter cake. A variety of different filter types are used and they depend on whether the particle content in liquid is low or high, whether the filter operates intermittently, semicontinuously or continuously, and on how the pressure difference is produced. Liquid flows through the cake and screen under the influence of a difference between pressures before the cake and behind the screen. We solved problems connected with filtration of reaction mixture after enzymatic hydrolysis.

Software for Control of Manipulator for Measuring Spatial Characteristics

This article deals with a way to control the very precise positioner for measuring spatial characteristics of detectors used in the security industry. There was used LabView software from National Instruments and the original library from the manufacturer of the manipulator.