Stabilnost napitka od lista masline tijekom skladištenja na sobnoj temperaturi

undergraduate thesis

• Title (english): The stability of olive leaf drink during storage at room temperature
• Author: Petra Lončarić
• 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: 2017-07-07, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Nutrition

Abstract

Cilj ovog rada je praćenje stabilnosti napitka od lista masline tijekom tromjesečnog skladištenja na sobnoj temperaturi određivanjem ukupnih fenola, antioksidacijske aktivnosti, boje, senzorskih svojstava te mikrobiološke kakvoće. Ukupni fenoli su određivani Folin – Ciocalteu metodom, a antioksidacijska aktivnost DPPH metodom. Boja se mjerila po CIELAB sustavu, a za određivanje senzorskih svojstava provedena je kvantitativna deskriptivna analiza. Udio ukupnih fenola u napitku kreće se od 0,276 mg GAE/mL do 0,186 mg GAE/mL, a tijekom skladištenja nije uočen jedinstveni trend promjena. Isto se odnosi i na antioksidacijsku aktivnost napitka samo se ona kretala u vrlo uskom rasponu od 0,144 – 0,149 μmol TAE/mL. Senzorska analiza ukazuje na vrlo male promjene senzorskih svojstava napitka. Skladištenjem se povećava ukupna razlika obojenosti. Mikrobiološka analiza je pokazala prisutnost aerobnih mezofilnih bakterija iznad dopuštene granice, ali stabilnost tijekom skladištenja.

Abstract (english)

The purpose of this work is to monitor the stability of olive leaf drink during three months storage at room temperature by determining total phenol content, antioxidant activity, color, sensory properties and microbiological quality. Total phenols were determinated by Folin – Ciocalteu method and antioxidant activity by DPPH method. The color was measured by the CIELAB system and quantitative descriptive analysis was used to evaluate the sensory properties. The percentage of total phenol in the drink ranges from 0,276 mg GAE/mL to 0,186 mg GAE/mL and no unique change trend has been observed during storage. The same applies to the antioxidant activity of drink only in a very narrow range of 0,144 – 0,149 μmol TAE/mL. Storage incereases the overall color difference. Microbiological analysis showed the presence of aerobic mesophilic bacteria above the allowed limit, but also the stability during storage.

• Keywords: antioksidacijska aktivnost; list masline; napitak; skladištenje; ukupni fenoli
• Keywords (english): antioxidant activity; total phenol content; drink; olive leaf; storage
• Language: croatian
• URN:NBN: urn:nbn:hr:159:777350
• Study programme: Title: Nutrition; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) nutricionizma (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) nutricionizma)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-07-10 12:31:06