master's thesis
Influence of sugar addition and pH on pigment stability in red beet frozen puree

Sandra Rak (2009)
Josip Juraj Strossmayer University of Osijek
FACULTY OF FOOD TECHNOLOGY
Department of Food Technologies
Sub-department of Fruits and Vegetables Technology
Metadata
TitleUtjecaj dodatka različitih šećera i pH na stabilnost pigmenata u zamrznutoj kaši cikle
AuthorSandra Rak
Mentor(s)Nela Nedić Tiban (thesis advisor)
Abstract
Cilj ovog rada bio je utvrditi utjecaj različitih šećera (glukoze, fruktoze i saharoze) u masenim udjelima od 3, 5 i 7 %, i pH vrijednosti 3 i 5 (podešavanje dodatkom askorbinske i limunske kiseline) na stabilnost pigmenata betalaina u kaši cikle prije zamrzavanja, te nakon jednog i šest mjeseci skladištenja pri -18 °C. Zamrzavanje je provedeno kriogenom tekućinom (tekućim dušikom) kako bi proizvod bio zamrznut u najkraćem mogućem vremenu. Takoder je ispitivan utjecaj dodatka glukoze, fruktoze i saharoze kao i različitog pH, 3 i 5 na boju i antioksidativnu aktivnost kaše cikle tijekom skladištenja pri -18 °C. Za proučavanje termičkih svojstava uzoraka kaše cikle korištena je diferencijalna motridbena kalorimetrija, uz određivanje entalpije taljenja (H), početne (To) i temperature vrha krivulje taljenja (Tp). Rezultati su pokazali najveću stabilnost betacijana u uzorcima s dodatkom askorbinske i limunske kiseline (pH 3 i 5), a najmanju stabilnost u uzorcima s dodatkom šećera glukoze (3, 5 i 7 %). Najveća ukupna promjena boje (E) bila je u uzorcima s dodatkom glukoze, a najmanja u uzorcima s dodatkom saharoze i fruktoze. Povećanjem udjela suhe tvari u uzorcima snižavala se je i entalpija taljenja (H). Entalpija taljenja je u uzorcima s dodatkom šećera bila manja što je koncentracija šećera bila veća, dok su uzorci cikle s dodatkom kiselina imali približno jednake vrijednosti entalpije taljenja (u rasponu od 238,54 do 247,45 Jg-1). Udio nesmrzljive vode u uzorcima nije se značajnije mijenjao dodatkom šećera (glukoze, fruktoze i saharoze) i kiselina (limunske i askorbinske; pH 3 i 5).
Keywordsred beet betacyans freezing melting enthalpy
Parallel title (English)Influence of sugar addition and pH on pigment stability in red beet frozen puree
Committee MembersVlasta Piližota
Nela Nedić Tiban
Drago Šubarić
Mirela Kopjar
GranterJosip Juraj Strossmayer University of Osijek
FACULTY OF FOOD TECHNOLOGY
Lower level organizational unitsDepartment of Food Technologies
Sub-department of Fruits and Vegetables Technology
PlaceOsijek
StateCroatia
Scientific field, discipline, subdisciplineBIOTECHNICAL SCIENCES
Food Technology
Engineering
Study programme typeuniversity
Study levelgraduate
Study programmeFood Technology and Process Engineering
Academic title abbreviationdipl. ing.
Genremaster's thesis
Language Croatian
Defense date2009-07-24
Parallel abstract (English)
In this work, the influence of different sugars (glucose, fructose and sucrose) in mass fraction of 3, 5 and 7%, and pH, with the addition of ascorbic and citric acid (3 and 5) on betalain pigment stability of red beet puree before freezing, after one and six months of storage at -18 °C, was investigated. Freezing was carried out with cryogenic liquid (liquid nitrogen) in order that the product was frozen in the shortest time. The influence of addition of glucose, fructose and sucrose and different pH, 3 and 5 on colour and antioxidant activity of red beet puree during storage at -18 ° C also is observed. For the study of thermal properties of samples red beet puree the differential scanning calorimetry is used, with the determination of enthalpy of melting (H), onset (To) and melting peak temperatures (Tp). The results showed the highest stability of betacyans in samples with addition of ascorbic and citric acid (pH 3 and 5) and lowest stability of betacyans in the samples with the addition of sugar glucose (3, 5 and 7 %). The highest colour change (E) had samples with the addition of glucose, and the lowest colour change had samples with the addition of sucrose and fructose. With increasing dry matter content in samples, enthalpy of melting was decreased. Enthalpies of melting in the samples with the addition of sugars decreased as the concentration of sugars were higher, while the samples with the addition of acids had nearly equal values of enthalpy of melting (from 238.54 to 247.45 Jg-1). The fraction of unfrozen water in samples did not significantly change with the addition of sugars (glucose, fructose and sucrose) and acids (citric and ascorbic; pH 3 and 5).
Parallel keywords (Croatian)cikla betacijani zamrzavanje taljenje entalpija
Resource typetext
Access conditionAccess restricted to students and staff of home institution
Terms of usehttp://rightsstatements.org/vocab/InC/1.0/
URN:NBNhttps://urn.nsk.hr/urn:nbn:hr:109:432241
CommitterSanda Hasenay