magistrsko delo
Mateja Stipič (Author), Polona Jamnik (Reviewer), Petra Terpinc (Mentor), Jasna Bertoncelj (Co-mentor)

Abstract

Namen magistrskega dela je bil ugotoviti vpliv fermentacije na vsebnost fenolnih spojin, antioksidativni potencial, vsebnost fitinske kisline in vsebnost prehranske vlaknine treh vrst psevdožit. Semena amaranta, kvinoje in ajde smo homogenizirali in fermentirali spontano, s pekovskim kvasom, z dodatkom neaktivnega komercialnega kislega testa in z mešano startersko kulturo LV1 pri izbranih pogojih (24 ali 48 h pri 20 °C oz. 30 °C). Fermentirane vzorce smo liofilizirali in iz njih pripravili metanolne ekstrakte. Fermentacija je vplivala na spremembo vseh analiziranih parametrov. Ti so se spreminjali odvisno od vrste psevdožita, načina in poteka fermentacije. Največji doprinos k vsebnosti fenolnih spojin (FS) in antioksidativnemu potencialu (AOP) amaranta in kvinoje je imela 48 h fermentacija pri 30 °C z dodatkom neaktivnega komercialnega kislega testa. Neodvisno od načina fermentacije smo pri ajdi zabeležili negativen učinek na FS in AOP. Spontana fermentacija, ki je trajala 48 h, je povzročila najbolj obsežno razgradnjo fitinske kisline (FK) pri vseh treh psevdožitih (vsaj 80 %), medtem ko je uporaba neaktivnega kislega testa pri optimalnih pogojih zmanjšala koncentracijo FK za dve tretjini ali več. Vsebnost netopne prehranske vlaknine se je v amarantu in kvinoji med fermentacijo praviloma povečala, v ajdi pa zmanjšala. Delež topne prehranske vlaknine smo v kvinoji in ajdi uspešno povečali zgolj z dodatkom neaktivnega kislega testa, pri različno fermentiranem amarantu smo povsod zabeležili negativen trend. Glede na analizirane parametre bi priporočili pripravo fermentiranih (48 h, 30 °C) psevdožit z dodatkom neaktivnega kislega testa.

Keywords

psevdožita;fermentacija;fenolne spojine;antioksidanti;fitinska kislina;prehranska vlaknina;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UL BF - Biotechnical Faculty
Publisher: [M. Stipič]
UDC: 633.1:664.654:641.1:613.2
COBISS: 79451907 Link will open in a new window
Views: 243
Downloads: 84
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Other data

Secondary language: English
Secondary title: ǂThe ǂimpact of fermentation on some important nutritional components of pseudocereals
Secondary abstract: The aim of the study was to determine the effect of fermentation on the phenolic compounds content, antioxidant potential, phytic acid content and dietary fibre content of three types of pseudocereals. Amaranth, quinoa and buckwheat seeds were homogenized and fermented spontaneously, with baker's yeast, with the addition of an inactive commercial sourdough and with a mixed starter culture LV1 under selected conditions (24 or 48 h at 20 °C and 30 °C, respectively). The fermented samples were lyophilized and methanolic extracts were prepared. Fermentation affected the change in all the parametres analysed. These varied depending on the type of pseudocereal, the method and the course of fermentation. The greatest contribution to the phenolic compound (PC) content and antioxidant potential (AOP) of amaranth and quinoa was obtained by fermentation at 30 °C for 48 h with the addition of an inactive commercial sourdough. Regardless of the fermentation method, a negative effect on PC and AOP was observed in buckwheat. Spontaneous fermentation for 48 h resulted in the most extensive degradation of phytic acid (PA) in all three pseudocereals (at least 80 %), while the use of sourdough at optimum conditions reduced the PA concentration by two thirds or more. The insoluble dietary fibre content generally increased in amaranth and quinoa during fermentation, but decreased in buckwheat. The soluble dietary fibre content of quinoa and buckwheat was successfully increased by the addition of sourdough alone, while a negative trend was observed in all cases with differently fermented amaranth. According to the parameters analysed, we would recommend the preparation of fermented (48 h, 30 °C) pseudocereals with the addition of an inactive sourdough.
Secondary keywords: pseudocereals;fermentation;phenolic compounds;antioxidants;phytic acid;dietary fibre;
Type (COBISS): Master's thesis/paper
Study programme: 0
Thesis comment: Univ. v Ljubljani, Biotehniška fak., Oddelek za živilstvo
Pages: XII, 73 f., [6] f. pril.
ID: 13620773