Promjene sadržaja karotenoida i ukupne antioksidacijske aktivnosti zrna kukuruza u zimskim rokovima berbe

master's thesis

• Title (english): Changes of carotenoid content and total antioxidant activities of maize grain in winter harvesting period
• Author: Ivan Fureš
• Mentor: Kristina Kljak (mentor)
• Committee member: Kristina Kljak (predsjednik povjerenstva)
• Committee member: Darko Grbeša (član povjerenstva)
• Committee member: Zlatko Svečnjak (član povjerenstva)
• Granter: University of Zagreb; Faculty of Agriculture; (Animal Nutrition); Zagreb
• Defense date and country: 2018-07-17, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Agronomy

Abstract

Zbog nepovoljnih vremenskih uvjeta tijekom uobičajenog razdoblja berbe, kukuruz se ostavlja na polju te bere tijekom zimskih mjeseci. Međutim, prezimljavanje može negativno utjecati na kvalitetu zrna. Cilj ovog istraživanja je ispitati utjecaj roka zimske berbe na sadržaj karotenoida i ukupnu antioksidacijsku aktivnost zrna četiri Bc hibrida kukuruza (Bc 344, Bc 353, Bc 572 i Pajdaš). Zrno kukuruza istraživanih hibrida proizvedeno je na istom testnom polju u uvjetima intenzivne agrotehnike, a... More berba je provedena u listopadu 2015., uobičajenom roku berbe, te siječnju i ožujku 2016., tri i pet mjeseci nakon uobičajene berbe. Ukupni karotenoidi iz zrna su estrahirani heksanom i kvantificirani kao ekvivalent β-karotena spektrofotometrijskom metodom dok je antioksidacijska aktivnost cijelog zrna ispitana direktnom TEAC (eng. Trolox Equivalent Antioxidant Capacity) metodom. Istraživani hibridi (Bc 344, Bc 353, Bc 572 i Pajdaš; P<0,001) razlikovali su se u sadržaju karotenoida (23,67, 20,83, 23,07 i 24,00 μg/g) i antioksidacijskoj aktivnosti (14,59, 14,83, 15,36 i 15,09 mmol/kg). Nadalje, tijekom prezimljavanja opadao je sadržaj karotenoida (s 25,03 u uobičajenom roku berbe na 22,19 i 21,53 μg/g tri i pet mjeseci nakon) što upućuje na trošenje karotenoida u zaštiti zrna. Iako je u drugom roku berbe došlo do pada antioksidacijske aktivnosti (s 14,61 na 14,49 mmol/kg), u trećem roku ona raste (15,81 mmol/kg) što je najvjerojatnije rezultat otpuštanja vezanih fenola kao posljedica obrane zrna od mikroorganizama. Unatoč utvrđenom negativnom djelovanju prezimljavanja na sadržaj karotenoida i antioksidacijsku aktivnost, do većeg negativnog učinka nije došlo zbog blage zime tijekom promatranog razdoblja. Less

Abstract (english)

Adverse weather conditions during usual harvest period can cause leaving maize crops on field and harvesting during winter months. However, overwintering could have a negative effect on grain quality. The aim of this study was to investigate the effect of the winter harvest period on carotenoid content and total antioxidant activity of four grains of Bc hybrids of maize (Bc 344, Bc 353, Bc 572 and Pajdaš). Maize hybrid grains were produced in the same conditions on test field and harvested... More in October 2015, the usual harvest period, and in January and March 2016, three and five months after the usual harvest period. Total grain carotenoids were extracted with hexane and quantified as equivalents of β-carotene using spectrophotometric method while antioxidant activity of whole grains was tested using a direct TEAC (Trolox Equivalent Antioxidant Capacity) method. Tested hybrids (Bc 344, Bc 353, Bc 572 and Pajdaš; P<0,001) differentiated in carotenoid content (23,67, 20,83, 23,07 and 24,00 μg/g) and antioxidant activity (14,59, 14,83, 15,36 and 15,09 mmol/kg). Furthermore, carotenoid content decreased during overwintering period (from 25,03 in usual harvest period to 22,19 and 21,53 μg/g three and five months after) which implies carotenoid deterioration in grain protection. Although antioxidant activity decreased in second harvest period (from 14,61 to 14,49 mmol/kg), it increased in third harvest period (15,81 mmol/kg) which is most likely result of the release of bound phenolics during protection from microorganisms. Despite determined negative effect of overwintering on carotenoid content and antioxidant activity, more adverse impact did not occur because of mild winter during observed period. Less

• Keywords: kukuruz; karotenoidi; antioksidacijska aktivnost; rok berbe
• Keywords (english): maize; carotenoids; antioxidant activity; harvest period
• Language: croatian
• URN:NBN: urn:nbn:hr:204:853175
• 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: Open access
• Created on: 2018-07-23 09:47:00