Tom 22 (2018): Zeszyt 4 (December 2018)

The aim of this study was to determine the effect of ultrasound waves on mechanical properties of organic bread. Mixed grain bread baked at a local bakery according to its original recipe was the material subjected to testing. Prior to baking, the dough was sonicated at frequencies of 20 kHz and 40 kHz for 3 minutes, and at a frequency of 100 kHz for 3 minutes and 6 minutes. The mechanical properties of the bread (compression test, penetration test and TPA) were examined after 24 h, 48 h and 72 h following the baking process. The maximum work obtained in the compression test after 24 h following the baking ranged from 616 N to 668 N. On the next day following the baking, the maximum work value ranged from 750 N to 898 N, while after 72 hours, it ranged from 988 N to 1135 N. In the penetration test, the following results were obtained: after 24 hours, the force value ranged from 2.71 N to 3.17 N; after 48 hours following the baking, it ranged from 4.90 N to 6.35 N; and after 72 hours following the baking, from 3.98 N to 6.88 N. As regards elasticity, the obtained results fell within the following ranges: after 24 hours following the baking, from 0.53 to 0.58; after 48 hours following the baking, from 0.43 to 0.55; and after 72 hours following the baking, from 0.40 to 0.45. Gumminess measured after 24 hours following the baking ranged from 8.75 N to 18.71 N; after 48 hours, from 10.83 N to 15.48 N; and after 72 hours, the gumminess values ranged from 15.57 N to 19.06 N. As regards chewiness, the following results were obtained: after 24 hours following the baking, from 8.00 N to 17.59 N; after 48 hours following the baking, from 9.77 N to 13.87 N; and after 72 hours following the baking, from 12.56 N to 16.85 N. The frequencies and durations of sonication applied changed no mechanical properties of the tested bread.

The methods currently used to assess orchard infestation are time-consuming and do not take into account non-adult forms of mites, due to their small size. Advance in digital imaging technology, however, has resulted in the discovery of a more viable method to enable a fast and reliable assessment of orchard infestation. Digital images of infected apple leaves were made and examined for the presence of European red mites and two-spotted spider mites. As well as adult mites, non-adult European red mite forms were also encountered. After extracting all objects considered as mites from the image, imaging software was then used to assess their dimension and shape parameters. Length, width, area, and equivalent diameter were different for all three observed mite groups: adult female European red mites, possible non-adult European red mites and adult two-spotted spider mites. Differences in circularity and elongation were found in adult two-spotted spider mites and various forms of European red mites, while the perimeter was similar in adult European red mites and two-spotted spider mites, and different in the non-adult forms of European red mites. However, as the ranges of 95% prediction intervals for these features overlap, a combination of at least two features as well as employing statistical procedures may greatly increase the probability of appropriate classification of the observed objects as different mites.

The objective of the paper is to determine the size of human and objectified labour in selected specialist vegetable farms. The paper covered studies carried out in the area of southern Poland in 50 organic vegetable farms. Based on the detailed studies, the size and structure of work, and energy inputs used in the production process were determined. The highest inputs of labour per a unit of the production area and 1 tonne of a product were incurred in production of Cucurbita vegetables – 1883.1 and 547.74 man-hour, while the lowest of Solanacea vegetables – 342.8 and 7.11 man-hour. From among all analysed groups of plants, the highest energy inputs were incurred in cultivation of root and onion vegetables and they were three times higher than in traditional farms. Contrary, the lowest inputs were incurred in cultivation of brassica and Solanaceae vegetables.

The objective of the paper was to determine the level of circumferential stress in a wall of an open milk tank and to assess the tank wall degree of utilization according to the FKM Guideline calculation algorithm − Analytical Strength Assessment of Components, Made of Steel Cast Iron and Aluminium Materials in Mechanical Engineering. (German: FKM – Forschungskuratorium für Maschinenbau). The stress level in the tank wall was determined based on analytical calculations and numerical method using the FEA – Finite Elements Analysis. Numerical calculations were made in FEMAP with NX NASTRAN Solver (NASTRAN – NASA Structure Analysis). Similar stress values were found using two independent calculation methods. The difference between obtained stress values does not exceed 2%. Based on the FKM algorithm, the safety factor j_ges = 1.4 and static capacity of the tank wall a_sk = 19.7% were calculated.

In recent years, a dynamic development of brewing has been observed. Increasingly, production of malt and beer takes place even in smaller industrial factories, breweries restaurants or at home. Extraction is a process applied in a variety of industries, including food production, as a way of extracting specific ingredients from their mixtures. As a result of this process, not only sugars, proteins, fats, enzymes, vitamins, colorants, fragrances and flavors, but also malt and hop extracts are being isolated. In the process of mashing, in which the malt ingredients are being extracted, many biochemical, physical and chemical changes take place. The aim of the study was to analyze the effect of the degree of fragmentation of pilsner type malt on the amount of extract obtained and the pH of the mash. It has been observed that the degree of malt fragmentation has a significant effect on the content of the extract in the mash: the more fragmented malt, the more malt extract in mash produced using the malt. It has also been found that the pH of the mash increases with the average particle size of malt.

This paper reports the effect of the parboiling time on dehulled kernel out-turns (DKO) of African breadfruit seeds, and the most recent effort to upgrade an existing dehuller and its performance. Two common and readily available varieties – Treculia var. africana and var. inverse were used in the study. The seeds were parboiled for 0 (control), 2, 5, 8, 11 and 14 minutes and then dehulled. The result revealed that the parboiling time had a significant effect on the DKO of the two varieties of the seed. The DKO increased from 0 to 5 min of the treatment, after which it decreased considerably up to 14 min of the parboiling time. The obtained data were used to develop a non-linear quadratic regression model to predict the DKO as a function of the parboiling time. The performance evaluation of the breadfruit seeds dehuller revealed that it was significantly influenced by the variety.

Two tests were carried out to measure the standard flat fan nozzles wear during a specific period of an accelerated wear procedure. The first test aimed at getting 10% increase in the flow rate compared to the nominal flow rate, which is the threshold to replace the nozzles according to the nozzles testing standards. The second test was to wear the nozzles intensively (100 hours of accelerated wear), which represents the use of nozzles beyond the allowed threshold. The results showed that the flow rate reached 1.31 l·min⁻¹ (equal to 10% increase) for the tested nozzles after 35 hours of the wear test. For the second test, the 10% increase of the flow rate was reached after approximately 30 hours. The wear rate reached 27.5% at the end of the test and this is 2.7 times more than the standardized threshold.

The article analyzes the current state of production of second generation biofuels in the world and evaluates the possibility of launching such production in Ukraine. The work is topical due to the fact that liquid biofuels can replace a certain share of motor fuels consumed in Ukraine, thus contributing to the strengthening of the country’s energy independence. The purpose of the study is to assess feasibility of a project on the production of second generation bioethanol in Ukraine; the task is to carry out a preliminary feasibility study for such a project. The analysis of the study of pure co-substrate fermentation and as a supplement for cattle manure proves that the maximum biogas yield obtained using alcohol stillage in a ratio of 40-80% increased compared to fermentation of pure cattle manure. The use of pure bards compared to the bard and the slurry mixture increases the maximum yield of biogas. It was found that the biogas obtained from the use of alcohol stillage is a high con-sumption of biogas with the methane content of between 70 and 78%.

Efficient increase in the content of available forms of elements in soil depends not only on their total content introduced to soil material, but also on the technology of its application. Technology consists of techniques and date of application as well as agronomic practices aimed at maintaining proper conditions for element transformations. The method of application of waste elemental sulfur and ground phosphate rock was assessed. Doses of 20 and 40 mg S as well as 40 and 80 mg P·kg⁻¹d.m. were added to medium soil; 30 and 60 mg S as well as 60 and 120 mg P·kg⁻¹d.m. were added to heavy soil. The soil samples were collected on the day of application of materials and after 15, 30, 60 and 90 days. The soil pH value decreased during the incubation. An increase in available sulfur content was observed in both soils after elemental sulfur application; the sulfur content in the medium soil depended on the dose of waste. The soils with the addition of a double dose of ground phosphate rock had the highest content of available phosphorus.

The aim of the research was to determine the selected properties of packaging materials applicable for vacuum and modified atmosphere packaging. Six samples of multilayer films with different composition were tested to evaluate the thickness, basic weight, density and the mechanical properties in elongation and puncture tests. Zwick/Roell apparatus equipped with elongation jaws and a puncture pin was used in the experiments. The tensile modulus, tensile strength, elongation at tensile strength, stress at break and work at break were investigated with the elongation test, whereas the breaking force, puncture work and extension at break were evaluated with the puncture test. The obtained results allow conclusion that the thickness and basic weight of the packaging films used in the vacuum system was higher comparing with the MAP system. Analyzing the results of the elongation modulus and stress at break it was reported that the materials used for food packaging in the MAP system were characterized with better properties, whereas elongation at the tensile strength was higher for films applied in the vacuum system, except for a film with a metalized layer. The highest resistance for puncture was evaluated for OPET/PE film used in MAP packaging. The extension at break under the puncture test was higher for films dedicated for vacuum packaging suggesting their better resistance for the mechanical damage by a thin pin. Several correlations between physical and mechanical properties of multilayer films were found.