In the last decade, the demand for edible niche oils has increased. Therefore, the aim of this study was to characterize the seeds hemp (Cannabis sativa L.) varieties: ‘Finola’ (FIN-314)’, ‘Earlina 8FC’, and ‘Secuieni Jubileu’, and cold and hot pressed oils were prepared from each seed. The seeds were examined for moisture content, granulometric distribution, bulk density, and fat content. Seeds were pressed without and with preconditioning (60 °C), and oil yield and pressing time were recorded. The oil was filtered through cellulose membranes. Oil–water content, oil color, fatty acid profile, and sterol content were studied. From the study conducted, there are significant differences in the parameters of oil recovery and its quality compared to ‘Finola’ seed oil, which is widely reported in the literature. ‘Finola’ oil yield was the lowest, with an average of 79% compared to ‘Earlina’ (82%) and ‘S. Jubileu’ (84%). All oil samples contained a comparable amount of sterols, with campesterol (0.32 mg/g), β-sitosterol (1.3 mg/g) and Δ5-avenasterol (0.15 mg/g) predominating. From the organoleptic evaluation, it was evident that both varieties hemp oils and marc (‘Earlina’ and ‘S. Jubileu’) were not bitter like the “Finola” oil and marc. More detailed studies in this direction have to be undertaken.

The aim of this study was to perform a comparative analysis of the unit gas emission value in the exhaust of a dual fuel diesel engine. The results of the effects of a diesel engine’s applications in biogas plants and the method for calculating mass gas emissions per unit of produced electricity are shown. The test was performed using a two-cylinder, naturally aspirated, liquid-cooled diesel engine. The diesel engine powered a generator connected to the grid. The engine was fed with liquid fuels—waste cooking oil methyl ester (UCOME) and diesel fuel (DF)—and with a gas fuel, biogas (BG). The engine ran at a constant rotational speed (2000 rpm ± 30 rpm) with variable load. The gas analyzer measured the amount of CO, NO, NO₂, and PM (particulate matter) in exhaust gas. This gas content share was then converted to mass per engine generated energy unit. This experiment showed the effect of BG introduced to the intake manifold on fuel combustion, as well as an increase in CO and NO₂ emission and decrease in NO and PM. In terms of dependence of exhaust emissions on the type of liquid fuel used, the use of UCOME as opposed to diesel fuel resulted in PM reduction and increase of NO emissions.

Unrefined vegetable oils from niche oilseeds are now sought after by consumers because of their unique nutritional properties and taste qualities. The color and flavor intensity of niche oils is a big problem, and their refining is not industrially feasible due to the small production scale. The study undertaken aimed analyze the effect of changing the amount of phytosterols (PSs) after the bleaching process of hemp oils of the ‘Finola’, ‘Earlina 8FC’ and ‘Secuieni Jubileu’ varieties. Cold-pressed (C) and hot-pressed (H) crude vegetable oils were bleached with selected bleaching earth (BE) at two concentrations. The post-process BE was extracted with methanol. The amount of PSs in the crude oils and the extract after washing the BE with methanol was analyzed by GC (gas chromatography). The study shows that the bleaching process did not significantly affect the depletion of PSs in the oils. Trace amounts of PSs remain on the BE and, due to methanol extraction, can be extracted from the oil. The conclusion of the performed research is that the bleaching of hemp oil does not cause depletion of the oil, and it significantly improves organoleptic properties. The oil bleaching process results in an oil loss of less than 2% by weight of the bleached oil, while the loss depends on the type of BE used. The study shows that the loss of phytosterols after the bleaching process averages 2.69 ± 0.69%, and depends on the type of BE used and the oil extracted from different varieties of hemp seeds.

The negative effect of liquid and gaseous fuel combustion is toxic gases (i.e., carbon and nitrogen oxides NO_x) and particulate matter (PM) formation. The content of harmful and toxic components of exhaust gases is strongly dependent on the quality and type of burnt fuel. Experimental research is required to verify the use of current technical and technological solutions for the production of electricity on farms, using various types of conventional fuels and biofuels. The aim of the current research was to comprehensively verify the use of commonly available fuels and biofuels without adapting the internal combustion engine. Gaseous fuels—propane-butane mixture (LPG), compressed natural gas (CNG) and biogas (BG)—were added to liquid fuels—methyl esters of higher fatty acids (RME) and diesel fuel (DF)—in six different power configurations to evaluate the effect on the emission of toxic gases: carbon monoxide (CO), nitric oxide (NO), nitric dioxide (NO₂) and particulate matter (PM), and the efficiency of fuel conversion. The use of RME in various configurations with gaseous fuels increased the emission of oxides and reduced the emission of PM. Increasing the share of LPG and CNG significantly increased the level of NO emissions. The use of gaseous fuels reduced the efficiency of the generator, particularly in the case of co-firing with DF. For medium and high loads, the lowest decrease in efficiency was recorded for the RME configuration with BG. Taking into account the compromise between individual emissions and the configuration of RME with BG, the most advantageous approach is to use it in power generators.

Stored vegetable oil undergoes numerous processes, i.e., oxidation, hydrolysis, and thermal polymerization. As a result, its quality and organoleptic parameters deteriorate. The content of natural chlorophyll and carotenoid pigments determines the color of rapeseed oil. Almost imperceptible changes in the color of the oil may indicate the deterioration of its quality. Therefore, vegetable oils must be stored in the appropriate conditions to protect them against unfavorable factors leading to deterioration. This publication examines and describes the influence of storage temperature, type of packaging (clear glass, colored glass, PET), and presence of an oxygen-free atmosphere on the quality of stored cold-pressed rapeseed oil for three and six months. Changes in the following parameters were verified: the content of chlorophyll and carotenoid pigments, oil color (measured by the CIE Lab method), acid value, and radical scavenging activity (%RSA) by the ABTS (diammonium 2,2′-azinobis[3-ethyl-2,3-dihydrobenzothiazole-6-sulphonate) method. The decrease in the content of natural dyes was 7 to 87% after three months, depending on storage conditions, and after six months, from 12 to 97%. To determine which factors were responsible for the change in the physicochemical properties of the oil during storage, a principal component analysis (PCA) was performed.

According to the EU Directive, the so-called RED II, there is increasing significance for biofuels produced from biomass with low indirect land use change (ILUC) risk. Such an alternative and sustainable feedstock could be microalgae, among others, used for biodiesel production. This is due to the high lipid content of their cells and their potential ability to accumulate significant amounts of carbon dioxide in their biomass, which has a positive effect on the carbon footprint of the product. The aim of this study was to determine the effect of adding algal biodiesel to conventional diesel fuel on selected performance parameters of a diesel engine, taking into account the composition of the emitted exhaust gas. Energy-related engine performance parameters such as power, hourly and specific fuel consumption, engine thermal efficiency, and indicated efficiency were determined. No significant differences were found in the energy parameters of engine operation with the fuels tested. In terms of carbon monoxide and NOx emissions, at the highest engine torque, more favorable parameters were obtained for fuel with biodiesel produced from rapeseed oil (B/RME). Under the same conditions, carbon dioxide emissions for the fuel with the addition of biodiesel from microalgae (B/Algae) were 8.1% lower.