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Sušenje je jedna od najstarijih metoda konzerviranja namirnica. Osim što produljuje rok trajanja proizvoda i usporava nepoželjne promjene, sušenjem se smanjuje volumen i težina proizvoda, što olakšava transport i skladištenje te smanjuje troškove. Međutim, postupci sušenja mogu dovesti do neželjenih promjena u strukturi, teksturi i izgledu hrane. Nove tehnike kao što je ultrazvuk visokog intenziteta se zbog svog djelovanja na staničnu strukturu tkiva voća i povrća sve više koriste kao metoda predobrade. Cilj ovog rada bio je pratiti i odrediti utjecaj različitih amplituda i trajanja predtretmana ultrazvukom visokog intenziteta, koristeći indirektni ultrazvučni postav, na vrijeme sušenja uzoraka muškatne bundeve, na boju i teksturu, te na potrošnju energije potrebne za sušenje. Najbolji učinak je postignut kod uzoraka koji su prije vakuum sušenja tretirani ultrazvukom amplitude 30 %, u trajanju od 45 min. Osim značajnog skraćenja vremena sušenja od 33 % i utroška energije od 26 %, navedeni uzorci očuvali su svoja teksturalna svojstva. Iako ΔE* vrijednosti boje nakon ultrazvukom potpomognutog sušenja variraju od uočljivih (3,0 – 6,0) do vrlo uočljivih (6,0 – 12,0) uspoređujući s referentnim, boja takvih uzoraka vizualno je prihvatljiva. Drying food is one of the oldest methods of food preservation. In addition to extending shelf life and slowing undesirable changes, drying reduces volume and weight of the product, making it easier to transport and store, thus reducing costs. However, drying methods can lead to negative changes in structure, texture and appearance of the food. New non-thermal technologies such as high-intensity ultrasound are increasingly used as pre-treatment methods due to their effects on the cellular matrix of fruits and vegetables. The aim of this study was to investigate the effects of high-intensity ultrasound treatment with different amplitudes and treatment times, using an indirect ultrasound device setup, on drying time, color, texture, and energy consumption required for drying. The best effect was obtained for the samples pre-treated with an amplitude of 30 % and a duration of 45 minutes and dried in vacuum. In addition to a significant reduction in drying time by 33 % and 26 % reduced energy consumption, the textural properties were also preserved in these samples. Although ΔE* color values after ultrasonic assisted drying vary from noticeable (3.0 - 6.0) to very noticeable (6.0 - 12.0) compared to the reference, color of such samples is visually acceptable. |
