Kvaliteta rakije loze proizvedene pri različitim uvjetima fermentacije od sorte grožđa Izabela

master's thesis

• Title (english): Quality of spirit loza produced in different fermentation conditions out of grapes of Isabella variety
• Author: Nevenka Banović
• Mentor: Jasna Mrvčić (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Fermentation and Yeast Technology); Zagreb
• Defense date and country: 2016-07-25, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Loza je voćna rakija koja se proizvodi destilacijom prefermentirane komine grožđa. Cilj ovog rada bio je odrediti kvalitetu rakije loze dobivene destilacijom iz prefermentirane komine grožđa sorte Izabela, dobivene alkoholnim fermentacijama vođenim spontano i dirigirano uz inokulaciju s kvascem Saccharomyces cerevisiae pri temperaturama 20°C i 30°C. Destilacije su provedene u šaržnom laboratorijskom kotlu uz presijecanje frakcija u kojima je zatim određena koncentracija 16 spojeva sekundarne arome primjenom plinskog kromatografa s plamenoionizacijskim detektorom (GC-FID). Rezultati su pokazali da je za dobivanje kvalitetnije rakije poželjno fermentaciju voditi pri nižoj temperaturi uz inokulaciju selekcioniranim kvascem Saccharomyces cerevisiae. Odvajanje 1% volumena prefermentirane komine u prvijenac te presijecanje drugog, glavnog toka destilata pri koncentraciji etanola na izlazu od 40%, pokazalo se kao dobra tehnika destilacije koja rezultira optimalnim koncentracijama hlapivih spojeva u destilatu, a koncentracija metanola, spoja koji se u vinu ove sorte nalazi u povišenim koncentracijama, u sve četiri proizvedene loze nalazi se unutar koncentracija propisanih Pravilnikom o jakim alkoholnim pićima.

Abstract (english)

Loza is a fruit spirit produced by distillation of fermented grape marc. The aim of this study was to determine the quality of loza produced by distillation of fermented grapes of Isabella variety. Alcoholic fermentations were conducted spontaneously and controlled by the inoculation with yeast Saccharomyces cerevisiae at temperatures of 20°C and 30°C. Distillations were carried out in batch laboratory distilling copper. The concentration of 16 secondary aroma compounds were determined in obtained distillates using a gas chromatograph with flame ionization detection (GC-FID). Fermentation carried out at lower temperature with inoculation by the selected yeast Saccharomyces cerevisiae resulted in spirit with better quality. Separation of 1% of fermented grape marc and cutting off the distillate main flow at 40% ethanol, proved to be a good distillation technique. This technique ensured optimal concentrations of volatile compounds in the distillate. Furthermore, concentrations of methanol, a compound that is found in high concentrations in wine of this grape variety, in all four produced batches of loza were within the limits prescribed by regulations.

• Keywords: kvaliteta; loza; kvasac; destilacija; spojevi arome
• Keywords (english): quality; spirit loza; yeast; distillation; aroma compounds
• Language: croatian
• URN:NBN: urn:nbn:hr:159:301309
• 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: Open access
• Created on: 2017-04-26 12:22:24