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Obrada plazmom je relativno novo područje istraživanja u prehrambenoj industriji. Glavni cilj ovog rada je utvrditi da li dolazi do redukcije broja mikroorganizama i lipidne oksidacije nakon tretmana plazmom, ribe Sparus aurata. Varijabilni ulazni parametri su protok plina argona (1, 1,5 i 2 L/min) i vrijeme tretiranja (5, 10 i 15 minuta). Za planiranje eksperimenta korišten je centralno kompozitni plan (CCD), te je provedeno i optimiranje procesa. Nakon tretmana došlo je do redukcije broja mikroorganizama (0,3-0,96 log CFU), najveće redukcije kod tretmana 5 minuta i protoka plina od 1,5 L/min. Kod analize oksidacije masti, došlo je do povećanja TBA vrijednosti osim kod tretmana pri 5 minuta i protoka 1 L/min. Najveći pad sposobnosti vezanja vode od 16% zabilježen je kod tretmana od 10 minuta i 1,5 L/min. Kod većine uzoraka L i h vrijednost se smanjila nakon tretmana, a s druge strane, došlo je do povečanja a, b i dC vrijednosti. Najveće promjene u teksturi su zabilježene kod tretmana od 10 min i 1 L/min od 46% za tvrdoću, 13% za elastičnost i 31% za rad u odnosu na netretirani uzorak. Plasma processing is a relatively new field of research in food processing. The main goal of this thesis is to determine if reduction of microorganisms and lipid oxidation occurs after plasma treatment of fish Sparus aurata. The changing input parameters were flow rate of the feeding Argon gas (1, 1,5 and 2 L/min) and duration of treatment (5, 10 and 15 minutes). Planning the experiment was done by using the central composite design (CCD), after which process optimisation was carried out. After the treatment, reduction of microorganisms was achieved (0,3-0,96 log CFU),, in the biggest extent for the treatment: 5 minutes and 1,5 L/min of gas flow. When analysing lipid oxidation, TBA value increased except for 5 minutes and 1 L/min treatment. For the water binding capacity the biggest drop of 16% was observed for 10 minutes and 1,5 L/min treatment. For most samples L and h value decreased after treatment, but on the other hand there has been an increase in a, b and dC value Changes in textural properties, in relation to untreated sample, were most significant in the treatment 10 minutes and 1 L/min, 46% for hardness, 13% for elasticity and 31% for work. |
