Određivanje polifenolnih spojeva i antioksidativnog kapaciteta u kašama i kašastim sokovima drijenka (Cornus mas L.)

master's thesis

• Title (english): Determination of polyphenols and antioxidant capacity in cornelian cherry fruits and nectars (Cornus mas L.)
• Author: Silvija Prvčić
• Mentor: Verica Dragović-Uzelac (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Technology of Fruits and Vegetables Preservation and Processing); Zagreb
• Defense date and country: 2006-10-31, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Istraživanje je provedeno na plodovima dviju različitih sorata drijenka (“D1” I “D2”) te na njihovim kašastim sokovima. U ovom radu određen je fizikalno-kemijski sastav te su određivani bioaktivni spojevi, ukupni te pojedinačni fenolni spojevi. Ukupni fenolni spojevi određivani su spektrofotometrijski, a pojedinačne fenolne kiseline i flavan-3-oli primjenom HPLC metode uz UV-PDA detekciju. Antioksidativni kapacitet, plodova i kašastih sokova drijenka, određen je primjenom DPPH, FRAP i ABTS metoda. Ujedno je na uzorcima provedeno senzorsko određivanje primjenom kvantitativne deskriptivne analize. Obje sorte drijenka bogat su izvor fenolnih spojeva te prevladavaju fenolni spojevi iz skupine flavonoida. Iz skupine fenolnih kiselina u najvećoj koncentraciji određena je klorogenska kiselina, a u padajućem nizu slijede neindetificirani polifenol, kava kiselina, neoklorogenska kiselina, p-kumarinska kiselina, derivat hidroksicimetne kiseline te ferulinska kiselina. Značajnu skupinu fenolnih spojeva predstavlja skupina flavan-3-ola među kojima se ističu (+)-katehin i (-)-epikatehin. Najveće vrijednosti antioksidativnog kapaciteta određene su u kašama drijenka. Na temelju senzorske analize, kvantitativnom deskriptivnom metodom utvrđeno je da su sokovi drijenka dobrih senzorkih svojstava, a posebno sok s udjelom suhe tvari voća od 35 % u ukupnoj suhoj tvari gotovog proizvoda, koji je najbolje senzorski ocijenjen od strane ocjenjivača.

Abstract (english)

Two varieties (“D1” and “D2”) of cornelian cherry (Cornus mas L) fruits were analyzed and used for preparation of nectars. The aim of this study was to perform physical-chemical analysis and to determined bioactive compounds, the total and single polyphenols in cornelian cherry fruits and nectars. Total phenolic content was measured using the Folin-Ciocalteau method, whereas a HPLC method was used for the analysis of individual phenolic acids and flavan-3-ols. Three different methods (DPPH, FRAP and ABTS) were used to determined the antioxidant capacity. The aim was also to perform sensory evaluation by using the quntitative descripton analysis. The result showed the high concentration of total polyphenols in all investigated samples, especially in fresh cornelian cherry fruits (2695 mg/kg-“D1” and 3255 mg/kg-“D2”). From total polyphenols flavonoids were determinate in significant quantities. The phenolics acids, determined in investigated samples by HPLC method, in decreasing sequence are: chlorogenic acid, undefinable phenol, caffeic acid, neochlorogenic acid, p-coumaric acid, derivative of hydroxycinnamic acid ferulic acid. Flavan-3-ols ((-)-epicatechin and (+)-catechin) are significant group of polyphenols and they were also determined by HPLC method. Generally, this study showed the decrease of all phenolic compounds within processing of cornelian cherry fruits into nectars. According to DPPH, FRAP and ABTS method, all samples posses an evident antioxidant capacity. The quntitative descripton analysis confirmed that investigated cornelian cherry fruits is high quality, especially nectar which contained 35 % of dry matter fruits in total dry matter of nectar.

• Keywords: Cornus mas; drijenak; antioksidativni kapacitet; fenolni spojevi; HPLC metoda
• Keywords (english): Cornus mas; cornelian cherry; antioxidant activity; polyphenols; HPLC method
• Language: croatian
• URN:NBN: urn:nbn:hr:159:093822
• Study programme: Title: Food Technology; specializations in: Food Engineering; Course: Food Engineering; Study programme type: university; Study level: graduate; Academic / professional title: diplomirani inženjer prehrambene tehnologije; smjer prehrambeno inženjerstvo (diplomirani inženjer prehrambene tehnologije; smjer prehrambeno inženjerstvo)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-09-08 08:34:48