<p>U radu se na osnovu eksperimentalnih podataka analizira konvektivno sušenje jedne sorte<br />jabuke u laboratorijskoj šaržnoj kondenzacionoj sušari vlastite konstrukcije. Istražuju se uticaj<br />procesnih parametara na kinetiku sušenja i kvalitet sušenih proizvoda. U tu svrhu izabrana je široko<br />rasprostranjena sorta „crveni delišes“, rezana na kolutove, početne relativne vlage oko 87% sušena na<br />konačnu oko 7,5 - 8,5 %.<br />Relevantnost pojedinih faktora i njihov uticaj na vreme trajanja procesa i parametre kvaliteta<br />sušenih proizvoda određivani su metodom planiranog eksperimenta.<br />Cilj primene procedure faktorskih planova eksperimrenta je dobijanje matematičkih modela i<br />grafičkih prikaza uticaja procesnih parametara na promenu merenog svojstva.<br />Temperatura vazduha menjala se od 40 do 600C, uz brzinu strujanja od 1 do 2 m/s i relativnu<br />vlažnost vazduha od 55 do 75%. Utvrđene su krive kinetike sušenja a kvalitet sušenih jabuka ispitan<br />je instrumentalnom analizom i ocenom potrošača o prihvatljivosti proizvoda. Dobijeni su sušeni<br />proizvodi visokog kvaliteta. Regresionom analizom eksperimentalnih podataka dobijeni su<br />matematički modeli koji opisuju zavisnost izlaznih veličina od procesnih parametara koji definišu<br />režim sušenja. Izlazne veličine koje se prate (odzivi) i označavaju stanje sistema su: vreme trajanja<br />procesa sušenja, sadržaj ukupnih kiselina izražene kao jabučna i sadržaj ukupnih šećera.<br />Na osnovu matematičkog modela provešće se detaljna parametarska analiza istraživanog<br />procesa, uticaj pojedine ulazne veličine na sam proces i omogućiti predviđanje svojstava sušenog<br />proizvoda u različitim kombinacijama procesnih parametara.<br />Rezultati istraživanja potvrđuju da se povećanjem temperature i smanjenjem relativne<br />vlažnosti agensa sušenja (vazduha) značajno smanjuje vreme procesa sušenja kolutova jabuke. Na<br />sadržaj ukupnih kiselina dobijen je značajan uticaj brzine srujanja vazduha, interakcije brzine<br />strujanja i temperature, temperature i relativne vlažnosti vazduha.<br />Očekujemo da će rezultati ovih istraživanja proizvesti dovoljno dobre matematičke modele<br />za dobijanje kvalitetnih sušenih proizvoda koji će se moći primeniti kao osnova za optimizaciju i<br />upravljanje procesima sušenja u poluindustrijskim i industrijskim razmerama.<br />Značaj predloženog istraživanja je, uz očekivani naučni doprinos, dobijanje sušenih<br />proizvoda ciljanih svojstava, uvažavajući kriterijum očuvanja kvaliteta, očuvanja energije i zaštite<br />okoline.</p> / <p>The thesis analyzes, on the basis of experimental data, convective drying of a sort of apple in<br />a laboratory batch condensation drying plant designed especially for the laboratory researches. The<br />influence of process parameters on drying kinetics and quality of dried products is examined. For this<br />purpose a widespread sort of apple called „Red Delicious“ is chosen. It is cut into slices with the<br />starting and final moisture being about 87% and 7,5-8,5%, respectively.<br />The relevance of certain factors and their effect on the duration of the process and parameters<br />of the quality of dried products is determined by the method of planned experiment.<br />The procedure of factor plans of the experiment is applied in order to obtain mathematical<br />models and graphical illustrations of the influences of process parameters on the change of measured<br />characteristic.<br />Air temperature varies from 40 to 60ºC, while the flow speed is from 1 to 2 m/s and relative<br />moisture of air is in the range from 55 to 75%. The curves of drying speed are identified and the<br />quality of dried apples is tested by instrumental analysis and consumers’ evaluation on the product<br />acceptability. The obtained dried products are of high quality. Regression analysis of experimental<br />data results in mathematical models describing dependance of output values on process parameters<br />which define drying mode. Output values (responses) which are monitored and which represent the<br />state of the system are: duration of drying process, content of total acids expressed as malic acid and<br />content of total sugars.<br />On the basis of mathematical model, a detailed parameter analysis of the process is carried<br />out as well as the influence of individual input value on the process itself and it will provide the<br />prediction of characteristics of dried products in various combinations of process parameters.<br />Research results confirm that the increase of temperature and decrease of relative moisture of<br />drying agents (air) significantly reduce the process of drying apple slices. The content of total acids is<br />significantly influenced by the speeds of air flow, interaction of flow speed and temperature,<br />temperature and relative air moisture.<br />The results of the research work are expected to produce mathematical models which are<br />good enough to achieve high quality dried products which can be applied as a basis for optimization<br />and control of drying processes in semi-industrial and industrial scopes.<br />In addition to expected scientific achievement, the presented research is significant for<br />obtaining dried products having defined qualities with regard to criteria of quality preservation,<br />energy conservation and environment protection.</p>
| Identifer | oai:union.ndltd.org:uns.ac.rs/oai:CRISUNS:(BISIS)89542 |
| Date | 25 September 2014 |
| Creators | Karić Marina |
| Contributors | Brkić Miladin, Janić Todor, Đaković Damir |
| Publisher | Univerzitet u Novom Sadu, Poljoprivredni fakultet u Novom Sadu, University of Novi Sad, Faculty of Agriculture at Novi Sad |
| Source Sets | University of Novi Sad |
| Language | Serbian |
| Detected Language | English |
| Type | PhD thesis |
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