Određivanje stabilnosti soka mandarine tijekom skladištenja

master's thesis

• Title (english): Determination of stability of mandarin juice during storage
• Author: Gabrijela Petrušić
• Mentor: Branka Levaj (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Technology of Fruits and Vegetables Preservation and Processing); Zagreb
• Defense date and country: 2015-09-30, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

U soku od mandarina, proizvedenom od mješavine kasnih sorti, ubranih na području doline Neretve u prosincu 2014. godine, skladištenom na temperaturama -18 ˚C, +4 ˚C i +20 ˚C, u intervalima od 21 dan u trajanju od 90 dana, određivani su fizikalno-kemijski parametri (pH, ukupna kiselost i topljiva suha tvar), parametri boje, ukupna razlika obojenosti, ukupni karotenoidi, senzorska svojstva i mikrobiološka stabilnost. Također je provedena analiza soka prije i nakon pasterizacije. Promjene ukupnih karotenoioda praćene su pomoću spektrofotometrijske metode i promjene boje određivanjem Lab parametara boje primjenom kolorimetra. Senzorsko ocjenjivanje je provedeno kvantitativnom deskriptivnom analizom. Mikrobiološka stabilnost praćena je određivanjem ukupnog broja mikroorganizama. Na temelju dobivenih rezultata, primijećeno je da pasterizacija utječe na blago povećanje vrijednosti fizikalno-kemijskih parametara, smanjenje parametara boje i količine ukupnih karotenoida. Rezultati su pokazali da temperatura i vrijeme skladištenja utječu samo na promjene senzorskih svojstava soka, te da je optimalna temperatura skladištenja +4 ˚C. Mikrobiološko ispitivanje je pokazalo zdravstvenu ispravnost svih uzoraka.

Abstract (english)

The mandarin juice, produced from a mixture of late varieties harvested in the area of the Neretva valley in december 2014, stored at -18 ˚C, + 4 ˚C and +20 ˚C, at intervals of 21 days to 90 days were determined physical-chemical parameters (pH, total acidity and soluble solids), color parameters, The total difference of coloration, total carotenoids, sensory properties and microbiological stability. The juice was analyzed before and after pasteurization. Changes in total carotenoids were monitored using colorimetric methods and changes in color determing Lab color parameters using the colorimeter. Sensory evaluation was conducted by quantitative descriptive analysis. The microbiological stability was monitored by determing the total number of microorganisms. Based on results, it was noted that pasteurization affects the slight increase in the value of physical-chemical parameters, color parameters and reduce the quantity of total carotenoids. Results showed that the temperature and storage time only affect the organoleptic characteristics of the juice, and that the optimum storage temperature is + 4 ˚C. Microbiological testing has demonstrated health safety of all samples.

• Keywords: mandarina; sok; fizikalno kemijska svojstva; senzorska svojstva; ukupni karotenoidi; boja; zdravstvena ispravnost
• Keywords (english): mandarin; juice; physical-chemical parameters; sensory properties; total carotenoids; color; health safety
• Language: croatian
• URN:NBN: urn:nbn:hr:159:251370
• 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: 2017-04-28 12:29:43