Kinetics of Stone Fruit Drying
Kinetika sušenja koštičavog voća
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Author
Zivkovic, Milovan
Kosi, Franc
Keywords
low temperature dryingstone fruit
flow thermal measurements
draing kinetics
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Show full item recordAbstract
The results of the investigation of technical and technological parameters in
the low temperature drying processes of stone fruit (plum and apricot) under both
laboratory conditions and in a universal prototype dryer have been presented in the
paper. The measurements comprised flow and thermal measurement, technological and
kinetic drying parameters and energy consumption. Major emphasis has been on
temperature and relative humidity of the drying agents and humidity and temperature of
the drying material.
According to results, the preheating period has been found to be approx. 2-3 hours
being affected by the type of the material and the drying regime, i.e. by the state
of drying agents. Maximal plum drying rate has been after 2 h and amounted to about
1.15 kg w/kg d.b.h. In the case of apricot drying, maximal drying rate has been approx.
0.45 kgw/kg d.b.h. and was registered after 4 hours from the very beginning of the
drying process. In addition, the curve of apricot drying kinetics has been differed from
the curve of plum drying kinetics.
The quality of dry fruit under low temperature drying conditions has been found to
meet standard requirements primarily respecting sugar and acid loss and the fact that
there was no odour or contamination of fruit.
In addition to the technical solutions, the fruit drying process was found to be
affected by how the process itself is being managed the duration of which may be
shortened contributing to the quality of the products, energy production and profitability. U radu su prikazani rezultati istraživanja tehničko tehnoloških parametara
procesa niskotemperatuskog sušenja plodova koštičavog voća (šljiva i kajsija).
Eksperimentalna istraživanja sprovedena na laboratorijskoj instalaciji i na prototipskoj
univerzalnoj sušari namenjenoj za sušenje biljnih materijala, obuhvatila su
strujnotermička merenja, parametre kinetike procesa i tehnološke parametre sušenja.
Posebno su analizirani temperatura i relativna vlažnost agensa sušenja, vlažnost i
temperatura materijala za sušenje kao i brzina sušenja.
Rezultati pokazuju da period predgrevanja materijala iznosi od 2-3 h, što je
uslovljeno vrstom materijala i režimom sušenja tj. stanjem agensa sušenja. Maksimalna
brzina sušenja plodova šljive nastaje nakon 2 h i iznosi oko 1,15 kg w/kg s. m. h. Kod
sušenja plodova kajsija maksimalna brzina sušenja iznosi približno 0,45 kgw/kg s.m.h. i
pojavljuje se tek nakon 4 časa od početka procesa u čemu se razlikuje od brzine sušenje
plodova šljive za približno isti režim sušenja. Pored toga, kriva kinetike sušenja kajsija
ima drugačiji oblik u odnosu na krivu sušenja šljiva.
Ostvaren kvalitet obe vrste osušenih plodova sa navedenim niskotemperaturskim
režimima u velikoj meri odgovara standardima, pre svega u pogledu gubitka šećera i
kiselina, kao i odsustva bilo kakvih mirisa i zagađenosti plodova.
Dobijeni rezultati ukazuju da, pored tehničkih rešenja sistema za sušenje, na uspeh
procesa značajan uticaj ima i samo vođenje procesa čije se trajanje može redukovati.