Browsing by Author "Yaqin, Wang"

Faba bean flour is a sustainable and relatively inexpensive way to make protein rich food in comparison with meat products, because it has high proteins content (rich in lysine (30%)) and considerable amounts of vitamins, minerals and dietary fibre. Even rough faba bean is widely cultivated and consumed, few data is available concerning the suitability to be fermented. The objective of this master’s thesis was to study the potential of sourdough fermentation of faba bean with selected lactic acid bacteria for in situ production of dextrans as texture forming components for various food applications. In this study, the growth and dextran formation by Leuconostoc and Weissella in faba bean sourdoughs were investigated. Eight lactic acid bacteria belonging to genera Leuconostoc and Weissella characterized for slime formation were used as starters for in situ formation of exopolysaccharides in faba bean flour. The growth of lactic acid bacteria, pH and acidity, and viscosity of different sourdoughs were analyzed. An enzyme assisted method and acid hydrolysis were used to analyze dextran content with further quantification by HPAEC-PAD. The amount of dextran formed by Leuc. pseudomesenteroides DSM 20193, Leuc. mesenteroides subsp mesenteroides LMG 7939, Leuc. Citreum DSM 5577, W. cibaria LMG 17699, and W. cibaria Sj1b varied from 1.86 to 4.22 g kg-1 (wet weight), which allows the possibilities to use dextran as alternatives for hydrocolloids in food applications. The synthesized dextran increased significantly viscosity of sourdoughs. After fermentation, the amount of raffinose family oligosaccharides (RFO) were decreased. The results of the sourdough fermented faba bean flours showed that Leuc. pseudomesenteroides DSM 20193 and Leuc. Mesenteroides subsp mesenteroides LMG 7939 were the most potential strains to produce dextrans and increase viscosity properties.