Kinetika razgradnje karotenoida tijekom skladištenja zrna kukuruza različitih hibrida

master's thesis

• Title (english): Kinetics of carotenoid degradation during storage of different maize hybrids
• Author: Mirta Majerić Musa
• Mentor: Kristina Kljak (mentor)
• Committee member: Kristina Kljak (predsjednik povjerenstva)
• Committee member: Marija Duvnjak (član povjerenstva)
• Committee member: Zlatko Svečnjak (član povjerenstva)
• Granter: University of Zagreb; Faculty of Agriculture; (Animal Nutrition); Zagreb
• Defense date and country: 2021-09-28, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Agronomy

Abstract

U hranidbi životinja, karotenoidi su poželjni u obrocima zbog pigmentacijskih i antioksidacijskih svojstava te zbog funkcije provitamina A. Međutim, karotenoidi su nestabilni na visokoj temperaturi, svjetlu i zraku, te mljevenjem, najčešćim načinom obrade zrna kukuruza, dolazi do njihove pojačane razgradnje. Zbog toga je cilj ovog istraživanja bio istražiti kinetiku razgradnje karotenoida mljevenog zrna kukuruza tri hibrida (DKC 5182, Majstor i SY Zoan) na tri različite temperature skladištenja (-20, 4 i 25 °C) tijekom 90 dana. Uzorci mljevenog zrna uzorkovani su 0., 7., 14., 21., 28., 42., 56., 78. i 90. dana skladištenja a koncentracija luteina, zeaksantina, α- i β-kriptoksantina, i β-karotena u njima određena je HPLC metodom. Na temelju kinetike prvog reda, određeni su kinetički parametri – početna koncentracija pojedinog karotenoida u uzorku i brzina razgradnje (dan-1). Najzastupljeniji karotenoidi u istraživanim hibridima bili su lutein i zeaksantin, a β-karoten je imao najveći pad koncentracije nakon skladištenja 90 dana. Hibrid je imao značajan utjecaj na početnu koncentraciju karotenoida u zrnu istraživanih hibrida (P < 0,001), u skladu s genetički određenim svojstvom. Najviša brzina razgradnje svih pojedinačnih i ukupnih karotenoida je bila na sobnoj temperaturi (25 °C) dok je brzina razgradnje pri skladištenju na 4 °C bila slična ili niža od one pri skladištenju na -20 °C.

Abstract (english)

In animal nutrition, carotenoids are desirable in the diet because of their pigmenting and antioxidation properties and their function as pro-vitamin A. However, carotenoids are unstable under certain conditions such as high temperature, light and air, and after milling, the common way of processing maize grains, their losses increase. Therefore, the aim of this study was to investigate the kinetics of carotenoid degradation of milled maize from three hybrids (DKC 5182, Majstor and Zoan) at three different storage temperatures (-20, 4 and 25 °C) for 90 days. Samples of ground maize were taken after 0, 7, 14, 21, 28, 42, 56, 78 and 90 days of storage and the concentrations of lutein, zeaxanthin, α- and β-cryptoxanthin and β-carotene in the samples were determined by HPLC method. Based on the first-order kinetics, the kinetic parameters were determined - the initial concentration of the carotenoid in the sample and the rate of degradation (day-1). The most abundant carotenoids in the tested hybrids were lutein and zeaxanthin, and β-carotene had the greatest loss of initial concentration after 90 days of storage. The hybrid had a significant effect on the initial concentration of carotenoids in the grain of the tested hybrids (P < 0.001), which is consistent with genetic predisposition. The highest rate of degradation of all individual and total carotenoids was at a storage temperature of 25 °C, while the rate of degradation at a storage temperature of 4 °C was similar or lower than at a storage temperature of -20 °C.

• Keywords: karotenoidi; hibrid kukuruza; kinetika razgradnje; skladištenje; temperatura skladištenja
• Keywords (english): carotenoids; maize hybrids; kinetics of degradation; storage; storage temperature
• Language: croatian
• URN:NBN: urn:nbn:hr:204:190810
• Study programme: Title: Animal Nutrition and Feed Science; Study programme type: university; Study level: graduate; Academic / professional title: magistar/ magistra inženjer/inženjerka hranidbe životinja i hrane (magistar/ magistra inženjer/inženjerka hranidbe životinja i hrane)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to authenticated users
• Created on: 2021-12-07 08:28:06