Utjecaj kriomljevenja na veličinu čestica i bioaktivne spojeve posija prosa

master's thesis

• Title (english): The influence of cryomilling on the particle size and the bioactive compounds of the millet bran
• Author: Matea Habuš
• Mentor: Nikolina Čukelj Mustač (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Cereal Chemistry and Technology); Zagreb
• Defense date and country: 2018-06-19, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

U ovom radu ispitan je utjecaj vremena i načina mljevenja na raspodjelu veličine čestica, sadržaj ukupnih polifenola, kao i slobodne antioksidanse posija prosa. Mljevenje je provodeno u kugličnom mlinu bez i uz kriogeno hlađenje, odnosno primjenu tekućeg dušika (N2). Posije prosa mljevene su 2, 4, 8 i 12 minuta, uz frekvenciju od 30 Hz. Sadržaj ukupnih fenolnih spojeva određen je Folin-Ciocalteu metodom, a antioksidacijska aktivnost ABTS, DPPH i FRAP metodama. Rezultati pokazuju kako oba načina mljevenja dovode do smanjenja veličine čestica, međutim niti vrijeme niti način mljevenja nisu utjecali na količinu slobodnih ukupnih fenolnih spojeva, kao niti DPPH antioksidacijsku aktivnost. U slučaju ABTS i FRAP metoda, najviša antioksidacijska aktivnost izmjerena je u uzorcima mljevenima uz kriogeno hlađenje 4 minute, ali su te vrijednosti usporedive s uzorcima mljevenima 4 minute bez kriogenog hlađenja. U slučaju FRAP metode, ako nije primjenjeno kriogeno hlađenje, antioksidacijska aktivnost je dodatno rasla s vremenom mljevenja.

Abstract (english)

This study explored the effect of time and grinding conditions on the particle size distribution, content of the total polyphenols, as well as the free antioxidants of the millet bran. The milling was conducted in a ball mill without and with cryogenic cooling, i.e. the application of liquid nitrogen (N2). Millet bran was milled for 2, 4, 8 and 12 minutes at a frequency of 30 Hz. The total phenolic content was determined by the Folin-Ciocalte method and antioxidant activity by ABTS, DPPH and FRAP methods. The results show that both grinding modes reduced particle size, however, neither time nor grinding mode influenced the amount of free total phenolic compounds or DPPH antioxidant activity. In the case of ABTS and FRAP methods, the highest antioxidant activity was measured in samples milled with cryogenic cooling for 4 minutes but these values were comparable to samples milled for 4 minutes without cryogenic cooling.

• Keywords: posije; proso; kriomljevenje; polifenoli; antioksidacijski kapacitet
• Keywords (english): bran; millet; cryomilling; polyphenols; antioxidant capacity
• Language: croatian
• URN:NBN: urn:nbn:hr:159:049745
• Study programme: Title: Food Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka prehrambenog inženjerstva (magistar/magistra inženjer/inženjerka prehrambenog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-11-21 14:21:11