Usporedba udjela polifenola i antioksidacijskog kapaciteta tijekom ubrzanog i prirodnog starenja piva

undergraduate thesis

• Title (english): Comparison of polyphenols content and antioxidative properties in forced and naturally aged beers
• Author: Iva Patron
• Mentor: Sunčica Beluhan (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Biochemical Engineering); (Laboratory for Biochemical Engineering, Industrial Microbiology and Malting and Brewing Technology); Zagreb
• Defense date and country: 2012-06-29, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Pivo je dobar izvor polifenola koji potječu iz ječmenog slada i hmelja. Zahvaljujući svom antioksidaciijskom kapacitetu i niskom udjelu alkohola (između 3 i 8 %), pivo može poboljšati antioksidacijsku aktivnost plazme, smanjiti rizik od srčanih i krvožilnih bolesti i to bez popratnih negativnih učinaka visokih doza alkohola. Pivo je nestabilan proizvod u kojem se događa niz kemijskih, fizikalnih i senzoričkih promjena tijekom roka trajanja. Ovaj rad prikazuje procjenu oksidativnog profila dva različita tipa hrvatskih piva podvrgnutih ubrzanom postupku starenja (6 dana pri 42 oC) i prirodnom starenju (4 mjeseca pri sobnoj temperaturi). Primjenjeni testovi su bili: određivanje udjela polifenola, sposobnost vezanja slobodnih radikala (DPPH), redukcijska snaga i određivanje stabilnosti boje piva. Rezultati dobiveni tijekom ubrzanog starenja piva su pokazali da se nije dogodila promjena udjela ukupnih polifenolai antioksidacijskog kapaciteta. Piva koja su prirodno starila imala su smanjeni udjel polifenola i antioksidacijskog kapaciteta. Za održavanje stablinosti boje piva preporučeno je skladištenje piva bez prisustva kisika pri niskim temperaturama.

Abstract (english)

Beer can be considered a good source of polyphenols derived both from barley malt and hop. Due to its antioxidant capacity and low alcohol content (between 3 and 8%), it is able to improve plasma antioxidant activity, reducing the risk of cardiovascular diseases, without the negative effects of high doses of alcohol. Beer is an unstable product that is involved in a series of chemical, physical and sensorial transformations during its shelf life. This study evaluated the oxidative profile of two different types of Croatian beer submitted to a forced aging process (6 days at 42 oC) and natural aging (4 months at room temperature). The applied tests were: total polyphenol content, free radical scavenging ability (DPPH), reducing power and beer colour stability. Results showed no changes in total polyphenol content or antioxidant capacity during forced aging. Beers aged naturally showed a decrease in their polyphenol content and antioxidant capacity. Beer storage in the absence of oxygen and at low temperature is recommended so as to minimize beer color instability.

• Keywords: pivo; polifenoli; antioksidacijski kapacitet; starenje; skladištenje
• Keywords (english): Beer; polyphenols; antioxidant capacity; aging; storage
• Language: croatian
• URN:NBN: urn:nbn:hr:159:452422
• Study programme: Title: Biotechnology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-05-15 09:30:23