Usporedba sušenja buče u vakuum i kondukcijskoj sušari

master's thesis

• Title (english): Comparison of vacuum and conduction dried pumpkin
• Author: Monika Lasić
• Mentor: Mladen Brnčić (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Process Engineering); (Laboratory for Unit Operations); Zagreb
• Defense date and country: 2018-07-04, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Sušenje se ubraja među najstarije metode konzerviranja voća i povrća, a ujedno je i najprimjenjivaniji postupak produžavanja roka trajnosti. Vakuum sušenje povrća ili sušenje pri sniženim tlakom unaprijeđen je način sušenja budući da se istovremeno primjenjuje niža temperatura čime se smanjuje mogućnost toplinske razgradnje produkta. Primjenom vakuuma, sušenje povrća može se provesti pri nižim temperaturama sušenja u odnosu na konvencionalne postupke, čime se postiže očuvanje boje i teksturalnih svojstava. Cilj ovog rada je usporediti rezultate učinka vakuum sušenja uzoraka buče sa uzorcima buče podvrgnutih kondukcijskom sušenju pri atmosferskom tlaku. Vakuum sušenje provodilo se pri dvjema temperaturama (40 i 70˚C), dva tlaka (50 i 250 mbar) uz trajanje sušenja od 120, 180, 240 i 300 minuta. Primjenom apsolutnog tlaka od 50 mbar, uz nepromijenjenu temperaturu i vrijeme sušenja, postignuto je povećanje učinka sušenja od 99.94 %. Također primjenom apsolutnog tlaka od 50 mbara značajno je skraćeno vrijeme sušenja za 40% uz nepromijenjeni učinak sušenja. Dobiveni rezultati analize boje ukazuju da uzorci buče podvrgnuti vakuum postupku sušenja, uz primjenu nižih tlakova postižu značajno očuvanje boje od maksimalnih 70% (ΔE = 2,98).

Abstract (english)

Drying is the one of the oldest method of fruit and vegetables preservation, and it is also the most applied method of extending the duration. Vacuum drying or drying at reduced pressure improves the drying process as lower temperature is applied at the same time, thus reducing the possibility of thermal decomposition of the product. By applying a vacuum, drying of vegetables can be carried out at lower drying temperatures compared to conventional processes, thereby achieving preservation of color and texture properties. The aim of this work was to compare the results of the vacuum drying samples of pumpkin and compare with samples of conduction drying under atmospheric pressure. Vacuum drying was carried out at two temperatures (40 and 70 ˚C), two pressures (50 and 250 mbar) and four drying times (120, 180, 240 and 300 minutes). Applying an absolute pressure of 50 mbar, with unchanged temperature and drying time, resulted with a 99.94% increase in drying efficiency. Also, applying an absolute pressure of 50 with the same drying effect, drying time was significantly reduced by 40%. The results of the color analysis indicate that the samples subjected to a vacuum drying process, with the use of lower pressures resulted a significant color retention of up to 70% (ΔE = 2.98).

• Keywords: sušenje; buča; kondukcijsko sušenje; vakuum sušenje; tekstura; boja
• Keywords (english): drying; squash; vacuum drying; conduction drying; texture; colour
• Language: croatian
• URN:NBN: urn:nbn:hr:159:473893
• Study programme: Title: Food Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka prehrambenog inženjerstva (magistar/magistra inženjer/inženjerka prehrambenog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2019-12-04 12:26:58