doctoral thesis
The effect of process conditions and method of solid-liquid extraction on extractability of phenolic compounds from grape seeds

Ana Bucić-Kojić (2008)
Josip Juraj Strossmayer University of Osijek
FACULTY OF FOOD TECHNOLOGY
Department of Process Engineering
Sub-department of Unit Operations
Metadata
TitleUtjecaj procesnih uvjeta i načina kruto-tekuće ekstrakcije na ekstraktibilnost fenolnih tvari iz sjemenki grožđa
AuthorAna Bucić-Kojić
Mentor(s)Srećko Tomas
Abstract
U radu se istraživao utjecaj omjera-kruto-tekuće (10, 20, 30 i 40 mL/g), otapala (vode, te 50, 70 i 96%-tnog etanola), vremena (10-200 minuta) te veličine čestica (> 0,63 mm; 0,63 - 0,4 mm; 0,4 - 0,16 mm i < 0,16 mm) na prinos ekstrakcije ukupnih fenola iz sjemenki grožđa, kao i utjecaj temperature (25, 40, 50, 60, 70 i 80 °C) na kinetiku ekstrakcije ukupnih i individualnih fenolnih tvari. Istraživao se i utjecaj različitih načina ekstrakcije (ekstrakcija uz zagrijavanje u vodenoj kupelji s tresilicom, ekstrakcija na univerzalnom sustavu za ekstrakciju, kombinacija ekstrakcije superkritičnim fluidima i ekstrakcije otapalom) na ekstraktibilnost fenolnih tvari, antioksidacijsku aktivnost i boju ekstrakata. Prijenos fenolnih tvari tijekom kruto-tekuće ekstrakcije odvijao se difuzijom, a određene vrijednosti koeficijenata efektivne difuzije ukupnih (0,2 - 1,96·10-10 m2/min) i individualnih fenolnih tvari (0,02 - 0,69·10-10 m2/min) povećavale su se s porastom temperature ekstrakcije. Svi ispitani eksponencijalni matematički modeli (modificirani Fickov II, modificirani Henderson-Pabisov i Pageov model) te neeksponencijalni Pelegov model bili su prikladni za opisivanje kinetike kruto-tekuće ekstrakcije, međutim, na osnovi više statističkih pokazatelja Pageov model je pokazao najbolja slaganja eksperimentalnih i modelom predviđenih podataka. Ekstrakcijom u vodenoj kupelji, najveći prinos ukupnih fenolnih tvari ostvaren je ekstrakcijom iz čestica manjih od 0,63 mm pri omjeru kruto-tekuće 40 mL/g i temperaturi 80 °C pomoću 50% -tnog etanola u trajanju 200 minuta, dok je za iste uvjete ekstrakcija na univerzalnom sustavu za ekstrakciju dala veći prinos fenolnih tvari od 6 do 35 %. Oduljavanje sjemenki grožđa pod različitim procesnim uvjetima superkritične ekstrakcije (tlakovi: 300 i 450 bara i temperature 40 i 60 °C) imalo je pozitivan utjecaj na ekstraktibilnost fenolnih tvari tijekom ekstrakcije otapalom, kao i na antioksidacijsku aktivnost dobivenih ekstrakata. Procesni uvjeti i način kruto-tekuće ekstrakcije utjecali su na antioksidacijsku aktivnost i boju ekstrakta. Utvrđena je visoka korelacija između antioksidacijske aktivnosti ekstrakata sjemenki grožđa i masenog udjela individualnih fenolnih spojeva te ukupnih fenolnih tvari kao i postojanje povezanosti boje ekstrakata i masenog udjela fenolnih tvari u ekstraktima.
Keywordsextraction phenolic compounds grape seed kinetics modeling antioxidant activity
Parallel title (English)The effect of process conditions and method of solid-liquid extraction on extractability of phenolic compounds from grape seeds
Committee MembersVišnja Katalinić (committee chairperson)
GranterJosip Juraj Strossmayer University of Osijek
FACULTY OF FOOD TECHNOLOGY
Lower level organizational unitsDepartment of Process Engineering
Sub-department of Unit Operations
PlaceOsijek
StateCroatia
Scientific field, discipline, subdisciplineBIOTECHNICAL SCIENCES
Food Technology
Engineering
UDK66
APPLIED SCIENCES. MEDICINE. TECHNOLOGY
Chemical technology. Chemical and related industries
633/635
APPLIED SCIENCES. MEDICINE. TECHNOLOGY
Horticulture. Fruit growing. Viticulture. Gardening
Study programme typeuniversity
Study levelpostgraduate
Study programmeFood Engineering
Academic title abbreviationdr. sc.
Genredoctoral thesis
Language Croatian
Defense date2008-12-11
Parallel abstract (English)
This study was aimed to investigate the influence of solvent (water and aqueous ethanol: 50, 70 and 96%), solid-liquid ratio (10, 20, 30 and 40 mL/g), extraction time (10-200 minutes) and particle size (> 0.63mm, 0.63 - 0.4 mm, 0.4 - 0.16 mm and < 0.16 mm) on yield of solid-liquid extraction as well as influence of temperature (25, 40, 50, 60, 70 and 80 °C) on extraction kinetics of total and individual phenolic compounds. The effect of extraction method (water bath extraction, universal extraction system, combined supercritical fluid extraction and water bath extraction) on phenolic extractability, antioxidant activity and colour of extract was also investigated. The main mechanism of mass transfer during solid-liquid extraction was diffusion. The values of effective diffusion coefficient for total (0.2 - 1.96·10-10 m2/min) and individual (0.02 - 0.69·10-10 m2/min) phenolic compound increased with extraction temperature. All examined exponential mathematical models (modified Fick II, modified Henderson-Pabis and Page) and non-exponential model proposed by Peleg were suitable for describing extraction kinetics. However, Page model showed the best accordance between experimental and model predicted data which was confirmed by several relevant statistical criteria. The highest phenolic yield was obtained from grape seed particle lower than 0.63 mm during 200 minutes of extraction in water bath at 80 °C and solid-liquid ratio 40 mL/g by using 50% aqueous ethanol. Results obtained by universal extraction system were higher in average 6 - 35% in relation to water bath extraction. Oil elimination from grape seed under different regimes of supercritical fluid extraction (300 and 450 bar; 40 and 60 °C) had the positive effect on phenolic extractability by conventional solid-liquid extraction and on antioxidant activity of extracts. The influence of process parameters and extraction method on antioxidant activity and colour of extract was observed. Antioxidant activity of grape seed extracts was strongly correlated with total and individual phenolic content. Relationship between phenolic content and colour of extracts was observed.
Parallel keywords (Croatian)ekstrakcija fenolne tvari sjemenke grožđa antioksidacijska aktivnost
Extent151 str.; 30 cm
Versionaccepted version
Resource typetext
Access conditionAccess restricted to students and staff of home institution
Terms of usehttp://rightsstatements.org/vocab/InC/1.0/
Noteaccepted version
URN:NBNhttps://urn.nsk.hr/urn:nbn:hr:109:551901
CommitterIvana Šuvak