Primjena blisko-infracrvene spektroskopije i briggs-rauscher reakcije u mjerenju polifenolnih spojeva

master's thesis

• Title (english): Application of near-infrared spectroscopy and briggs-rauscher reaction in measurement of polyphenolic compounds
• Author: Ivana Polović
• Mentor: Jasenka Gajdoš Kljusurić (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Process Engineering); (Laboratory for Measurement, Regulation and Automatisation); Zagreb
• Defense date and country: 2013-09-30, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Nutrition

Abstract

Voće i povrće je bogato polifenolima, glavnim izvorom antioksidansa u prehrani, a pripisuju im se brojni pozitivni učinci na zdravlje. Istraživanje je provedeno na sedam različitih namirnica. Cilj rada bio je uz standardne metode određivanja ukupnih fenola s Folin-Ciocalteu reagensom, koristiti i one metode koje se rijeđe koriste u analizi uzoraka bogatih polifenolima, a to su blisko-infracrvena spektroskopija i Briggs-Rauscherova reakcija. Ekstrakcija uzoraka provedena je metodom refluksa i u ultrazvučnoj kupelji. Primijenjeni su jednostavni regresijski modeli i korelacije, te multivarijatni alati kao što je analiza klastera, faktorska analiza te analiza glavnih komponenata kako bi se ispitale veze među promatranim podacima. Najveći udio ukupnih fenola određen je u ekstraktu goji (344 mg GAE/100g uzorka), a najmanji u vrganju (38 mg GAE/100g uzorka). Primjena blisko-infracrvene spektroskopije i Briggs-Rauscherove reakcije pokazala se vrlo uspješnom u mjerenju polifenolnih spojeva te je tako najveću vrijednost antioksidacijske aktivnosti pokazao goji (BRAI=3,63), a najmanju avokado (BRAI=0,03) dok se spektroskopijom mogao odrediti tzv. „otisak prsta“ fenolnih spojeva ispitivanih uzoraka, te navedene uzorke razdvojiti ovisno o načinu pripreme ekstrakta te sadržaju polifenolnih spojeva.

Abstract (english)

Fruits and vegetables are rich in polyphenols, which are the major source of antioxidants in the diet, awith a number of positive effects on human health. The aim of this study was to use the standard method for determining total phenols with Folin-Ciocalteu reagent and to use some methods that are rarely used in the analysis of samples rich in polyphenols, such as near-infrared spectroscopy and Briggs-Rauscher reaction. The mesurements were conducted on seven different samples. Extraction of the samples was conducted by reflux and in ultrasonic bath. The simple regression models and correlation were applied as well as multivariate tools such as cluster analysis, factor analysis and principal component analysis. The highest content of total phenols was determined in goji extract (344 mg GAE/100g sample), and the lowest in Boletus edulis (38 mg GAE/100g sample). Application of near-infrared spectroscopy and Briggs-Rauscher reaction proved to be very successful in measuring the polyphenolic compounds and thus the highest value of antioxidant activity showed goji (BRAI = 3.63), and the smallest avocado (BRAI = 0.03). Spectroscopy was helpful in detection of the so called "Fingerprint" of the phenolic compounds for tested samples allowing separation of these samples depending on the preparation and content of the polyphenols.

• Keywords: prehrana; antioksidansi; ukupni fenoli; BR reakcija; NIR spektroskopija
• Keywords (english): diet; antioxidant; total phenols; BR reaction; NIR spectroscopy
• Language: croatian
• URN:NBN: urn:nbn:hr:159:462380
• 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: Access restricted to students and staff of home institution
• Created on: 2017-05-05 11:53:12