<p>Suncokretova sačma ima manju zastupljenost u peletiranim sme&scaron;ama za<br />ishranu životinja od sojine sačme zbog većeg udela sirovih vlakana. Sirova<br />vlakna depresivno deluju na svarljivost obroka i proizvodne rezultate, a mogu<br />da imaju negativan uticaj na fizički kvalitet peleta. Pri peletiranju sme&scaron;a za<br />ishranu životinja u poslednje vreme značajna pažnja se posvećuje<br />funkcionalnim promenama makronutrijenata, jer se smatra da ove promene<br />pozitivno utiču na fizički kvalitet peleta. Razvojem modernih analitičkih tehnika,<br />posebno termalne analize, moguće je opisati promene na skrobu u procesu<br />peletiranja, nastale usled uticaja toplote i vlage. Sa druge strane, promene na<br />proteinskoj komponenti u procesu peletiranja nisu dovoljno obja&scaron;njene.<br />Najče&scaron;će se tumačenja svode na pretpostavke, bez obja&scaron;njenja o promenama<br />u veličini molekula proteina, kao i njihovoj koncentraciji. Inovativan pristup ove<br />doktorske disertacije je usmeren na opisivanje uticaja dodatka sojine i<br />suncokretovih sačmi različitog sadržaja proteina u sme&scaron;e na bazi kukuruza na<br />tehnolo&scaron;ke parametre procesa peletiranja, funkcionalne promene<br />makronutrijenata (želatinizaciju skroba i denaturaciju i degradaciju proteina) i<br />fizički kvalitet peleta. U okviru svake sme&scaron;e takođe je ispitivan uticaj procesnih<br />parametara, prečnika otvora sita mlina čekićara (2, 3 i 4 mm), vremena<br />produženog kondicioniranja parom (bez produženog kondicioniranja, 5 i 10<br />minuta) na fizički kvalitet peleta. Istraživanja su pokazala da temperatura<br />peletiranja, specifična potro&scaron;nja električne energije i udeo pra&scaron;ine u peletama<br />zavise od sirovinskog sastava sme&scaron;a, prečnika otvora sita mlina čekićara i<br />vremena zadržavanja u kondicioneru, pri čemu temperatura peletiranja i<br />specifična potro&scaron;nja električne energije rastu, a udeo pra&scaron;ine u peletama<br />opada sa porastom koncentracije proteina u sme&scaron;ama. Dokazano je i da<br />proces peletiranja utiče na funkcionalne promene makronutrijenata,<br />želatinizaciju skroba i strukturne promene na proteinima. Takođe je dokazano i<br />da za optimalno vreme zadržavanja materijala u kondicioneru, smanjenje<br />prečnika otvora sita mlina čekićara i povećanje sadržaja proteina u sme&scaron;ama<br />utiču na pobolj&scaron;anje fizičkog kvaliteta peleta, tj. tvrdoće peleta i stepena<br />otiranja peleta. Optimalni uslovi procesa peletiranja određeni su metodom<br />željene funkcije. Dat je predlog opsega procesnih parametara za dobijanje<br />peleta minimalnog stepena otiranja uz optimalnu specifičnu potro&scaron;nju<br />električne energije.<br />Istraživanja u ovoj doktorskoj disartaciji dala su doprinos novim saznanjima o<br />uticaju dodatka sačme različitog sadržaja proteina (37,3, 40,3 i 42,6 %) na<br />fizički kvalitet peleta. Kvalitet peleta sa dodatkom suncokretove sačme je<br />poređen sa kvalitetom peleta sa dodatom sojinom sačmom, kao i kvalitetom<br />peleta od čistog kukuruza, u cilju obja&scaron;njenja uticaja izvora i koncentracije<br />proteina. Ispitivanja su vr&scaron;ena ne samo za standardno vreme kondicioniranja,<br />nego uz primenu najsavremenijih postupaka termičke obrade hrane za<br />životinje, tj. uz upotrebu produženog kondicioniranja od 5 i 10 minuta.<br />Doprinos nauci je dat i time &scaron;to je pokazano da proces peletiranja utiče ne<br />samo na denaturaciju i degradaciju proteina, nego i na njihovo povezivanje.</p> / <p>Sunflower meal has a lesser presence in pelleted compound feed than<br />soybean meal due to a higher proportion of raw fiber. Raw fiber has<br />depressing effect on the digestibility and production results, and can have a<br />negative impact on the physical quality of the pellets. Lately, considerable<br />attention is paid to the functional changes of macronutrients in pelleting of<br />animal feed. It is believed that these changes have a positive impact on the<br />physical quality of the pellets. With the development of modern analytical<br />techniques, especially the thermal analysis, it is possible to describe the<br />changes of starch in pelleting process, caused by the impact of heat and<br />moisture. On the other hand, changes of the protein components in the<br />pelleting process are not sufficiently explained. The most common<br />interpretation is reduced to the presumption, with no explanation of changes in<br />the size of protein molecules, as well as in their concentration. The innovative<br />approach of this dissertation is focused on describing the effect of the addition<br />of soybean meal and sunflower meals, with different protein content, in<br />mixtures based on corn, on the technological parameters of the pelleting<br />process, functional changes of macronutrients (starch gelatinization, and<br />protein denaturation and degradation), and physical quality of the pellets.<br />Within each of the mixtures, the influence of process parameters, the diameter<br />of the hammer mill sieve openings (2, 3 and 4 mm), duration of long term<br />steam conditioning (without extended conditioning, 5 and 10 minutes) on the<br />physical quality of the pellets was also investigated. Studies have shown that<br />pelleting temperatures, the specific power consumption and the proportion of<br />dust in pellets were dependent of composition of the mixtures, the diameter of<br />the hammer mill sieve openings, and residence time in the conditioner.<br />Pelleting temperature and specific power consumption increased, and the<br />extent of fines in pellets decreased with increasing of concentration of protein<br />in the diets. Additionally, it is proved that pelleting process affects functional<br />changes of macronutrients, starch gelatinization and structural changes in<br />proteins. It is also proved that for the optimal retention time of material in<br />conditioner, decrease of diameter of the hammer mill sieve openings and<br />increase of protein content in the diets had positive effect on the physical<br />quality of pellets, i.e. pellet hardness and degree of abrasion of pellets. The<br />optimum process conditions in pelleting process were determined by the<br />method of desired function. A proposal has been made for setting the range of<br />process parameters for obtaining the minimum degree of abrasion of pellets,<br />with optimal specific energy consumption.<br />The research within this Ph.D. thesis contributed to the knowledge about the<br />effects of addition of sunflower meal with different protein content (37.3, 40.3<br />and 42.6 %) on the physical quality of the pellets. Quality of pelleted mixtures<br />with sunflower meal added were compared with the quality of pelleted mixtures<br />with soybean meal added and quality of pelleted corn, in order to explain the<br />effects of starch concentration, protein concentration and protein source.<br />Studies were performed not only for the standard time of conditioning, but with<br />the use of modern techniques for heat treatment of animal feed, i.e. with the<br />use of long term conditioning process for a 5 or 10 minutes. Additional<br />contribution to science has been given with showing that the pelleting process<br />causing not only the denaturation and degradation of proteins, but also<br />synthesis of proteins.</p>

<p>Apple pomace is a by-product of the industrial production of apple juice, amounting to approximately 20-30% of freshly processed apples. Several million tonnes of apple pomace is produced in the world annually. Fresh apple pomace is characterised by high sugar and moisture content, which makes it susceptible to microbial contamination, uncontrolled fermentation and spoiling. Despite increasingly stricter legal regulations in managing biodegradable waste, large quantities of apple pomace are still being disposed of at landfills, posing a serious environmental issue. Since apple pomace has a certain nutritive value, it seems necessary to consider possibilities for using it as animal feed.<br />The main goal of this research was to examine the possibility for using dried apple pomace as animal feed, i.e., as a raw material in the industrial production of animal feed. Accordingly, the nutritive value of dried apple pomace was examined, along with the process of pelleting, since pelleting is one of the most common technological procedures in the industrial production of animal feed.<br />The testing of the chemical composition of dried apple pomace, used to determine its nutritive value, included the analyses of the content of raw proteins, raw fats, raw fibres, ash, neutral detergent fibres (NDF), acid detergent lignin (ADL), lignin, total sugars, individual sugars &ndash; fructose, glucose and sucrose, essential amino-acids, vitamins and mineral elements. When compared with the majority of commonly used animal feeds, the dried apple pomace was found to contain large amounts of raw fibres and sugars and small amounts of proteins and fats.<br />In accordance with the determined nutritional composition of the dried apple pomace, concentrate mixtures for fattening pigs were prepared, after which a trial was performed to examine the effect of feeding the animals on the mixtures containing dried apple pomace in different concentrations on the production performance of the fattening pigs. The results of the feeding trial showed that adding 7% of dried apple pomace in the growing period and 10% in the finishing period had no negative effects on the animal health, production and meat yield.<br />In the next part of the research, the dried apple pomace was pressed into pellets, with three starting moisture contents in the unpelleted material &ndash; 10%, 13% and 16%. The examination of the produced pellets showed that they had very good physical quality in terms of the pellet durability index (PDI) and hardness. The value of PDI exceeded 99% for all three starting moisture contents. The bulk density of the pelleted dried apple pomace was nearly twice as large as it was before pelleting. Increasing the moisture content in the dried apple pomace from 13% to 16% resulted in lower temperatures and energy consumption in the process of pelleting.<br />The goal of the next part of the research was to examine the effect of adding apple pomace into the concentrate mixture models consisting of corn and sunflower meal on the physical quality of the obtained pellets, the specific electricity consumption of the pellet press and the temperature of the pellet press die. Three concentrate mixture models were prepared for the test, comprising 0%, 10% and 20% of dry apple pomace. The mixtures were conditioned by adding water to reach the moisture content of 13%, 15% and 17% and pelleted at three settings of the press die (8, 24 and 30 mm). Therefore, three parameters were varied at three levels, in a full factorial experimental design. The dependent variables (response variables) were: PDI, pellet hardness (H), dust content in the pellets, bulk density of the pellets, matrix temperature of the pellet press and the specific energy consumption of the pellet press. The results showed that adding dried apple pomace into the model concentrate mixtures led to a significant increase in pellet quality, especially in terms of increasing the PDI value and decreasing the dust content. The results of the analysis of standard scores (SS) showed that the optimum values for pellet quality, specific energy consumption and temperature of the press die were obtained for the model concentrate mixture containing 10% of dried apple pomace, using 30 mm press die and with 17% of the starting moisture content. Good results were also obtained for the model concentrate mixture containing 20% of dried apple pomace, using 24 mm press die and with 17% of the starting moisture content.<br />To define the effect of the concentration of dried apple pomace in the model mixtures, the press die thickness and the starting moisture content on the change of the response variables, the response surface methodology (RSM) was used. The analysis of variance (ANOVA) of the response models for each of the analysed quality parameters and pelleting processes, showed which of the process parameters (percentage of apple pomace in the concentrate model mixtures, press die thickness and starting moisture content) had statistically the biggest effect on creating the mathematical response models, presented in the form of the second order polynomial (SOP). The results of this research showed that the increase in the percentage of dried apple pomace, press die thickness and starting moisture content led to an increase in PDI value, hardness (H) and bulk density of the pellets and a decrease in the content of dust in the pellets. The increase in the share of apple pomace in the model mixtures and in the die thickness of the pellet press led to an increase in the specific energy consumption and die temperature. On the other hand, the increase in the starting moisture content led to a decrease in the specific energy consumption and die temperature.<br />In the last part of the research, on the basis of the determined nutritive value of the dried apple pomace the author made a calculation, in terms of optimising the concentrate mixtures containing dried apple pomace in the optimum amount for feeding particular species and categories of farm animals. The results suggest the way of practical utilization of dried apple pomace in feeding farm animals as well as in the industrial production of animal feed.</p>