The methods of raw materials and food products cutting used in practice were characterized by wire, ultrasonic, water and laser. The disadvantages, advantages and limitations of cutting methods were showed standard of such treatment techniques were indicated.

Leaves of White Mulberry (Morus alba L.) are a rich source of biologically active compounds. In recent years, this plant has become popular. It comes from China and has been used to treat various ailments for centuries. In Poland, the white mulberry has gained recognition thanks to the properties of lowering blood glucose levels, so willing to reach for it diabetics. The aim of the work was to determine the effect of brewing infusions from white mulberry leaves (Morus alba L.) on the content of polyphenolic compounds in them and antioxidant activity determined by the reduction of the free radical DPPH. The following tests show that the content of polyphenols expressed as gallic acid ranges between 48.61 mg·dm-3 ±0.03 to 152.63 mg·dm-3 ±0.02 depending on the initial temperature and brewing time. A similar relationship was found in the case of the flavonoid content determination where the values were determined at levels (24.39 mg·dm-3 ±0.03 to 123.14 mg·dm-3 ±0.15). In the case of the ability to reduce the antioxidant radical DPPH ranged from 48.91 to 94.05, the results obtained in the study confirm the high dependence of both time and brewing temperature on the content of phenolic compounds in herbal infusions.

A method of competence assessing of official control laboratories in the area of testing the homogeneity of feed products is presented. The 14 laboratories of veterinary hygiene and the reference laboratory (National Laboratory of Feedingstuffs) as an organ-izer took part in the performed proficiency test. 96 homogeneity tests were carried out, analyzing the content of key components in 180 primary samples. 576 investigation re-sults were obtained: chlorides- (156), calcium (156), zinc (132) and copper (132). The ob-tained data on the degree of mixing of compound feed (coefficients of variation) were lo-wer than 10% – the upper limit value included in the Instruction of the Chief Veterinary Officer. The authorized participating laboratories in the test were presented results of sat-isfactory quality (precision) and reliability confirming their competence to assess the de-gree of homogeneity of compound feed based on the analysis of macro- (Cl-, Ca) and micronutrients (Zn, Cu) as part of official control feedingstuffs. A revised homogeneity test instruction was developed in which the variability of the analytical method was taken into account.

The purpose of the work was to collect and compare the methods of estimating the cost of electromechanical equipment for small hydropower plants. To achieve the purpose of the work, the collected cost functions were transformed into a form that allows their comparison. Then, the theoretical cost of investment in electromechanical equipment for the six existing hydropower plants was calculated. The basic conclusion from the conducted research is that large differences in the results obtained using various methods do not allow their simple application in the case of planning a real investment in a small hydro power plant. Therefore, there is a need for extensive research based on national investments in small hydropower plants that would allow the development of models based on local data and the creation of a database on Polish case studies.

In this work, samples of humic acids (HA) extracted from six lake sediments were investigated. HA were isolated with method of two-stage successive extraction (A) – extraction with an neutral solution 0.1 mol L^-1 Na₄P₂O₇ and (B) – extraction with an alkaline solution 0.1 mol L^-1 NaOH). It is observed that HA-B are characterized by relatively higher H and O contents than it is observed in HA-A. Also the stable fraction of HA-B are characterized by higher oxidation degree than HA-A fraction loosely associated with mineral part. Analysis of optical parameters showed that the labile fractions of HA-A are characterized by a higher capacity to absorb the UV-VIS radiation than the stable HA-B, as indicated by higher specific absorbance coefficients z₂₈₀ and ₆₀₀. The results indicated that the HA-B extracted by alkaline solution are a more complex structure, larger molecular size and molecular weight and higher condensed of aromatic nuclei than HA-A separated by neutral pyrophosphate solution.