Utjecaj procesa prerade bučine koštice na kemijska svojstva i antioksidacijsku aktivnost bučinog ulja

master's thesis

• Title (english): The influence of pumpkin seed processing on chemical properties and antioxidative activity of pumpkin seed oil
• Author: Antonija Bataljaku
• Mentor: Sandra Neđeral (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Oil and Fat Technology); Zagreb
• Defense date and country: 2010-12-01, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

U ovom radu istraživan je utjecaj različitih uvjeta procesa prerade dviju vrsta bučinih koštica na svojstva i antioksidacijsku aktivnost dobivenog bučinog ulja. Obične bučine koštice i koštice beskorke preradile su se u tri procesa s različitim stupnjevima toplinske obrade: prešanjem neprženog tijesta bučinih koštica uz hlađenje preše, prešanjem neprženog tijesta bučinih koštica i prešanjem prženog tijesta bučinih koštica. U proizvedenim bučinim uljima određeni su osnovni pokazatelji kakvoće ulja: peroksidni broj i slobodne masne kiseline, koji su pokazali dobru kvalitetu dobivenih ulja. Također, u dobivenim uljima istraživani su udjeli sterola, skvalena i tokoferola. Njihovi udjeli bili su viši u uljima iz obične koštice, a smanjivali su se povećanjem stupnja toplinske obrade. Određivanjem antioksidacijske aktivnosti kao % redukcije DPPH· utvrđeno je da najveću antioksidacijsku aktivnost imaju ulja dobivena prešanjem neprženog tijesta koštica uz hlađenje, te da postoji dobra korelacija između α-tokoferola i antioksidacijske aktivnosti ispitivanih uzoraka bučinog ulja. Rezultati PCA analize (eng. Principal component analysis) potvrdili su primjećene razlike u svojstvima dobivenih ulja.

Abstract (english)

This study researched the influence of two different pumpkin seed types on the properties and antioxidative activity of the produced pumpkin seed oil. Ordinary pumpkin seed and naked pumpkin seed were processed through three treatments with different degrees of thermal treatment: with and without roasting of pumpkin seed paste and without roasting of pumpkin seed paste combined with press cooling. In the produced pumpkin seed oils basic quality parameters, peroxide value and free fatty acid content were determined and have shown a good quality of produced oil. Processing conditions had a significant influence on pumpkin seed oil properties. The best process yield was obtained by pressing the seed paste without roasting. Sterol composition and squalene content, using gas chromatography, and tocopherol content, using HPLC method, were also researched. Increasing the degree of thermal treatment caused a decrease in their content. Determination of the antioxidative activity as a percentage of DPPH· radicals reduction has shown that oils produced by pressing the unroasted seed paste, had the highest antioxidative activity. The high correlation coefficient (R=0,848) shows good correlation between tocopherol content and antioxidative activity of tested oils. The results of PCA analysis (principal component analysis) have confirmed differences in the properties of the obtained oils.

• Keywords: bučine koštice; bučino ulje; prešanje; bioaktivni sastojci; antioksidacijska aktivnost
• Keywords (english): pumpkin seed; pumpkin seed oil; pressing; bioactive compounds; antioxidative activity
• Language: croatian
• URN:NBN: urn:nbn:hr:159:003165
• 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: 2017-08-28 10:26:46