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The objective of this paper was to determine the influence of storage conditions on the quality of seeds in rapeseed cultivar Bristol and hybrid Triangl, namely on the oil and free fatty acids content, which are the two most important rapeseed quality parameters. The rapeseed seeds were stored in two conditions: in storage facility with controlled atmosphere (with temperature of 10 ｰC and relative air moisture approximately 70%) and in storage facility without atmosphere control (where the air temperature and moisture varied). During a nine-month storing period, the samples’ mass was monitored monthly while oil content, free fatty acids (FFA) content and seed moisture were determined before and after storing. Storing in conditions without atmosphere control showed that the samples’ mass was increasing during the first four months, in the following three months it was decreasing, and then stagnated until the end of the storing period. Samples stored in controlled atmosphere showed variations in mass, with minor oscillations during the whole storing period, which resulted in lower FFA content in comparison with the samples stored in facilities without atmosphere control. The oil content after storing in both facilities decreased, and FFA content rose in all samples. In conclusion; storing in controlled atmosphere gave better results in terms of rapeseed quality.

The purpose of this study was to define an impact of the cultivar, year and cultivation area of the standard Croatian winter wheat cultivars, Divana, Žitarka and Sana, on the bread-making quality. The bread-making quality of that standard wheat from the crop years 1998, 2000, 2002, 2004 and 2006, and from Zagreb and Osijek location was analyzed. Wheat from the cultivar tests cultivated under the same agro technological conditions was used for this testing. The tested winter wheat bread- making quality primarily depended on the genetic properties of cultivar. However, climatic changes occurring during the last 10 years, particularly the increase in temperatures and quantity of rainfalls at the period of the grain development, ripening and harvest, had a negative influence on the wheat bread-making quality. Even though the average values of tested quality factors were within the expected range, a significant dependence of the cultivar Divana bread-making quality upon the cultivation climate conditions was proven. Sana cultivar has proven to be the most stable, even though its bread-making quality was the lowest. For all three cultivars the bread- making quality has been decreasing in the last 10 years, although the quality of winter wheat from the Zagreb area was higher since the climate conditions were more favourable.

This paper examines the dimensions (length, width, and thickness) and some physical characteristics (density, volume, sphericity) of corn kernel grown at extensive and intensive agrotechnology levels. The research was conducted during three years (2002, 2003, and 2004) on hybrids ‘ Bc 4982’ , ‘ Bc 462’ , ‘ Bc Jumbo’ , ‘ Florencia’ , and ‘ Stefania’ , dried at four temperature levels (70°C, 90°C, 110°C, and 130°C). In order to determine the difference in dimensions, they were measured before drying as well. It was found that there were significant differences in corn kernel dimensions before and after drying process, as well as between samples exposed to different drying temperature levels.

In order to reach targets set by the EU in the 2003/30/EC Directive, in Republic of Croatia in the last years the emphasis was put on cultivation and treatment of rapeseed hybrids as the crucial raw material for biodiesel fuel production. Since in the Republic of Croatia such researches are in the very onset, the aim of this paper was to determine the yield of three rapeseed hybrids, ‘ Artus’ , ‘ Baldur’ and ‘ Titan’ , as well as to establish their properties aft er drying and storage, which are critical for biodiesel production. In this research, drying curves of three investigated hybrids’ seed were determined. Th e impact of drying temperature on oil content and on free fatty acids content was determined as well. It was found that Baldur hybrid had the highest oil content, followed by ‘ Titan’ , and ‘ Artus’ with somewhat lower oil content. Moreover, hybrid Artus had the lowest free fatty acid content, irrespective of the drying air temperature, while the free fatty acid content in hybrids ‘ Baldur’ and ‘ Titan’ was 30% higher. It was evident that the oil content and free fatty acid content are hybrid property of particular hybrids. Furthermore, the impact of storage conditions, hybrid type and temperature on rapeseed’ s oil content and free fatty acid content was determined. It was found that controlled storage conditions provided better quality of rapeseeds. Th e conclusion of this research is that the characteristics of rapeseed hybrids corroborate viability of sowing this crop and its usability as raw material for oil production, and thus, for biodiesel production.

In many European countries, residues from agricultural products represent a considerable potential for development of bio-energy industry. A significant part of these biomass materials come from the fruit-growing business, i.e., primary fruit production and fruit processing plants. The EU directives require that the disposal of such residues should be environmentally sustainable. The objective of this study was to determine proximate (moisture content, ash, fixed carbon, volatile matter), ultimate (carbon, hydrogen, nitrogen and sulphur) and energy values (higher, lower) of biomass, as well as the Croatian total energy potential generated after the pruning (pruned residues) and processing of plum fruit (stone). Five different plum varieties (Bistrica, Cacanska ljepotica, Cacanska rodna, President, and Stanley), most commonly grown in the territory of Croatia, were analyzed and compared. The analyzed data were compared with the norm CEN/TS 14961 (2005) for solid biofuels and the data from the relevant literature. Both types of investigated biomass proved to be highly valuable sources of energy ; and no significant difference between investigated plum varieties were found. Lower heating value, as one of the fundamental parameters of the biomass energy efficiency, averaged in the studied samples: 15.2 MJ kg-1 for plum pits and 17.12 MJ kg-1 for pruned biomass, which classifies plum biomass as a valuable energy raw material. Also, the calculations show that the potential production of the biomass available in Croatia could reach up to 292.13 MJ of renewable "green" energy annually.

Olive cake is by-product of olive oil production. This material cannot be stored in original condition for a long time because it has high water content and relatively high portion of oil that causes rapid deterioration. Thus it is necessary to investigate possible methods of remediation of such by-product, where utilization for energy generation presents a useful option. Several studies have been conducted on energy generation from olive cake, however not one that includes pelleting as a pre-treatment. Therefore, the aim of this paper was to determine the chemical composition of different cultivars of olive cake, to produce pellets, and determine their basic quality parameters. The pellets obtained from olive cake had mainly satisfactory results regarding their quality in comparison to standards for fuel pellets. It should be kept in mind that these standards are manly for wood pellets, and therefore some lower criteria could be applied for olive cake and such biomass. The highest amount of residual oil and the lowest amount of protein was found in cultivar ‘Buža’ and produced pellets had the smallest abrasion index (8.15%). Other cultivars had lower oil and higher protein content, and abrasion index higher than 10%. For these cultivars preparation of material (conditioning and/or binder adding) prior to pelleting is necessary. Higher heating value (HHV) and lower heating value (LHV) were not significantly influenced by different chemical composition of cultivars, thus attention should be paid on their influence on pelleting process.

The aim of this study was to investigate the water release from seeds of three rape hybrids, (‘Artus’, ‘Baldur’ and ‘Titan’), during the convection drying of the seeds at three different drying temperature (40, 60 and 80 °C). The drying was conducted in laboratory scale drier which can simulate the conditions of large drier. The air velocity in the drier was maintained at 1.0 m/s. Activation energy needed for starting the process of water release during the convective drying of oil seed rape seeds was also studied. According to the obtained values, the mathematical models (equations and curves) of kinematic drying were determined. By comparing the exponential equations and the constants of water release from seeds it was observed that drying of hybrid Artus was the slowest and the one of hybrid Titan the fastest. Results showed that there was a significant difference between all investigated hybrids in water release rate and that within the same drying conditions, hybrids showed different behaviour. Moreover, air temperature increase caused significant increase in water release from the seeds. The highest activation energy needed for starting the process of water release from the seeds had the hybrid Artus and the lowest one hybrid Titan. Due to this, it can be concluded that the activation energy was reversely proportional to the water release rate from the seeds.

Although grass Miscanthus × giganteus biomass is currently used mostly as a raw material for direct combustion, an increasing consideration is now given to its potential use in production of biogas, namely biomethane. Th e aim of this paper is to determine the yield of dry-matter (DM) and organic dry matter (oDM) from the crop Miscanthus × giganteus in three diff erent harvest times and at three diff erent locations, and, based on these values, to calculate the biomethane yield on the abandoned agricultural surfaces in Croatia. Th e investigations which were conducted for this purpose determined the average values of dry matter yield (24.77 t/ha) and organic dry matter yield (24.11 oDM/ha) as well as the biomethane yield of 5976 Nm3/ha. In relation to total natural gas consumption and percentage of the abandoned agricultural land, Croatia could replace between 1.6% to 4.8% of the consumed natural gas by introducing Miscanthus × giganteus grass on 5% to 15% of the abandoned agricultural lands in three of its counties (Sisačko-moslavačka, Karlovačka and Ličko- senjska).

Th is paper presents a mathematical model describing convective drying of corn kernels of different hybrids. The convective drying process was examined at four air temperatures (70, 90, 110 and 130º ; C) using hybrids ‘ Bc 462’ , ‘ Bc 4982’ , ‘ Bc Jumbo 48’ , ‘ Florencia’ and ‘ Stefania’ The drying process was able to be described by a model based on exponential equations. Activation energy necessary for the onset of the drying process, namely water activation in kernel, was determined using the Arrhenius equation. Results show that activation energy is in the ranges from 10.39 kJ/mol (hybrid Bc Jumbo 48) to 15.56 kJ/mol (hybrid Stefania). Data and analysis together indicate that the increase in energy necessary to induce the water release process from corn kernel is proportional to the increase in the activation energy of drying.