Utjecaj tehnologije pulsirajućeg električnog polja na stabilnost fenolnih spojeva u sokovima od jagode tijekom skladištenja

master's thesis

• Title (english): The influence of pulsed electric field technology on polyphenols stability of strawberry juices during storage
• Author: Luka Batur
• Mentor: Danijela Bursać Kovačević (mentor)
• Committee member: Sven Karlović (predsjednik povjerenstva)
• 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: 2021-12-23, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Cilj ovog istraživanja bio je ispitati utjecaj tehnologije pulsirajućeg električnog polja (eng. Pulsed Electric Field, PEF) na udio topljive suhe tvari, pH vrijednost te stabilnost fenolnih spojeva u soku od jagode tijekom sedmodnevnog skladištenja pri 4 °C. Sok je pripremljen od jagode (Fragaria x ananassa Duch.) sorte 'Albion' i to plodova ubranih pri 75 % (Z1) i 100 % (Z2) zrelosti. Varirani parametri tretiranja uključivali su: (i) jakost električnog polja (40 i 50 kV), (ii) frekvenciju (100 i 200 Hz) i (ii) vrijeme tretiranja (3 i 6 min). Svi rezultati obrađeni su multifaktorskom analizom varijance (p ≤ 0,05). Svježi plodovi jagoda, kao i sokovi od jagode Z1 odlikovali su se manjom topljivom suhom tvari i pH vrijednošću, no i većim udjelom ukupnih fenola u usporedbi s istim uzorcima zrelosti Z2. Skladištenje je povoljno utjecalo na stabilnost polifenolnih spojeva, dok se od PEF procesnih parametara, jedino jakost električnog polja pokazala statistički signifikantnim utjecajem.

Abstract (english)

The aim of this study was to investigate the effects of Pulsed Electric Field technology on soluble solids content, pH and stability of polyphenols in strawberry juice during seven days of storage at 4 °C. Juice was prepared from strawberries (Fragaria x ananassa Duch.) cultivar 'Albion' whose fruits were harvested at 75 % (Z1) and 100 % (Z2) maturity. The treatment parameters were: (i) electric field strength (40 and 50 kV), (ii) frequency (100 and 200 Hz), and (ii) treatment time (3 and 6 min). All results were analysed using multifactorial analysis of variance (p≤0.05). Fresh strawberry fruits, as well as Z1 juices, were characterized by lower soluble solids and pH, but also by higher levels of total phenolics compared to the same samples with Z2 ripeness. Storage had a favourable effect on the stability of the polyphenolic compounds, while among the PEF process parameters only electric field strength showed a statistically significant effect.

• Keywords: PEF; polifenoli; sok od jagode; stupanj zrelosti
• Keywords (english): PEF; polyphenols; strawberry juice; ripeness stage
• Language: croatian
• URN:NBN: urn:nbn:hr:159:598235
• Study programme: Title: Nutrition; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra nutricionizma (magistar/magistra nutricionizma)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-01-31 13:17:54