Provider: - Institution: Josip Juraj Strossmayer University of Osijek. FACULTY OF FOOD TECHNOLOGY. Department of Process Engineering. Sub-department of Process Design and Construction Materials. - ...Data provided by Europeana Collections- Provedeno je optimiranje i modeliranje procesa sušenja voća i povrća na osnovi praćenja kinetike
sušenja i pokazatelja o očuvanju nutritivnih i organoleptičkih svojstava. Kinetika sušenja odabranih
uzoraka voća i povrća determinirana je kontinuiranim praćenjem: promjene mase uzoraka,
temperaturnog profila materijala i medija za sušenje, te profila vlage. Istraživanje je provedeno
primjenom termogravimetrijske tehnike s laboratorijskim uređajima koji su u svrhu ovog
istraživanja posebno nadograđeni i opremljeni: tunelski sušionik (TD), vakuum sušionik (VK),
infracrveni sušionik (IC), te sušionik za sušenje s fluidiziranim slojem (FBD). U svrhu ubrzavanja
kinetike sušenja, sprečavanja enzimske aktivnosti kao i neenzimskih promjena tijekom procesa
sušenja, primijenjeni su različiti fizikalno-kemijski postupci prethodne obrade uzoraka, te su ovisno
o metodi sušenja predložena odgovarajuća rješenja. Za procjenu pojedine metode, te za praćenje
utjecaja procesnih parametara na svojstva osušenih uzoraka, primijenjene su standardne analitičke
metode termogravimetrija, rehidratacija, kolorimetrija, volumetrija, te tekućinska kromatografija
visokog učinka (HPLC). Modeliranjem eksperimentalnih podataka promjene vlažnosti za uzorke
marelice i jabuke sušene u tunelskom sušioniku pri različitim temperaturama sušenja (50 °C, 60 °C,
70 °C i 80 °C) i brzinama strujanja zraka (1,4 m s-1; 2,1 m s-1; 2,8 m s-1) utvrđeno je da najbolje
slaganje s eksperimentalnim podacima daje Midilli i Kucukov model. Izrađeni su i novi
poluempirijski modeli koji mogu poslužiti za simuliranje kinetike sušenja uzoraka marelice i
jabuke unutar granica ispitanih procesnih parametara, temperature i brzine strujanja zraka. Ispitan
je utjecaj temperature sušenja i različitih metoda sušenja na sadržaj β-karotena u uzorcima mrkve.
Najmanja degradacija β – karotena izmjerena je u neobrađenim uzorcima mrkve koji su sušeni u
tunelskom sušioniku pri temperaturi sušenja 70 °C i brzini strujanja zraka 2,8 m s-1. Najveći
rehidratacijski omjer izmjeren je kod uzoraka marelice koje su sušene u tunelskom sušioniku pri
temperaturi 80 °C i brzini strujanja zraka 1,4 m s-1. Najbolji rezultati (visoka vrijednost
rehidratacijskog omjera i najmanja ukupna promjena boje) dobiveni su u slučaju sušenja uzoraka
jabuke u tunelskom sušioniku (TD) pri temperaturi sušenja 50 °C, te kod sušenja uzoraka mrkve i
peršina u tunelskom sušioniku (TD) pri temperaturi sušenja 60 °C i brzini strujanja zraka od 2,8 m
s-1. Dobivena je i ovisnost utjecaja različitih postupaka prethodne obrade na kinetiku sušenja i
parametre kvalitete osušenih proizvoda.- The influence of the process parameters on the drying kinetics of different food products, fruits
and vegetables, using different dryers was investigated. The dehydration kinetics of samples was
determined by continues recording of mass changes, temperature profile of material and drying
media as well as moisture profile using computer process control. To speed up the dehydration
kinetics, and to eliminate the enzymatic browning activity as well as non enzymatic changes during
dehydration process different physical and chemical procedures of samples pre-treatment were
applied, depending on method used, related technical solutions were proposed. Evaluation of each
method and the influence of the process parameters on the properties of dried materials were
performed using standard analytical methods: thermo-gravimetric, rehydration, colorimetric,
volumetric and high pressure liquid chromatography – HPLC. The changes in colour and volume
as well as rehydration rate (reconstitution characteristic) for each of the drying methods were
studied. After defining the optimal drying process parameters, different pre-treatment methods
were investigated. The existing mathematical models (thin-layer equations) were tested and new
semi-empirical models that describe drying processes of fruits and vegetables using different driers
were defined.
When modelling the experimental data for apricot and apple samples which were dried in the
tunnel dryer at drying temperatures of 50 °C, 60 °C, 70 °C and 80 °C and air flow velocities of 1,4
m s-1; 2,1 m s-1 and 2,8 m s-1, Midilli–Kucuk model proved to be the best and showed a good
agreement with the experimental data. A new semi-empirical models were developed for the
simulation of apricot and apple drying at temperature range 50–80 °C and velocity range 1,4–2,8 m
s-1 of drying air. Furthermore, the influence of the drying temperature and drying methods on the
content of the main nutritive components was studied. The degradation of β – carotene was the
smallest when non-treated carrot samples were dried in the tunnel dryer (TD) at temperature of 70
°C and at airflow velocities of 2,8 m s-1. The highest rehydration ratio was observed when apricot
samples were dried at temperature of 80 °C and airflow velocities of 1,4 m s-1. The best results
(good rehydration ratio and colour) were achieved when apple samples were dried in the tunnel
dryer (TD) at temperature of 50 °C. As for carrot and parsley root samples, the best results were
achieved when drying in the tunnel dryer (TD) at temperature of 60 °C and airflow velocities of 2,8
m s-1. The influence of the different sample pre-treatment procedures on the drying kinetics and the
properties of dried materials was determined.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
