Browsing by Author "Karhu, Simo"

The primary objective of this thesis was to observe the effect of fermentation of oat and faba bean flour mixture on oat β-glucan. The secondary objective was to define how fermentation conditions affect β-glucan content, pH, total titratable acidity (TTA) and viscosity in oat-faba bean matrix utilizing experimental design and response surface methodology (RSM). As fermentation is a part of manufacturing process of plant-based yoghurt alternatives, this thesis observed the fermentation process in detail to define its effect on β-glucan. The flour mixture consisted of whole grain oat flour, oat bran concentrate, faba bean flour, faba bean protein isolate and water. This mixture was fermented with a commercial yoghurt starter, consisting of Bifidobacterium sbsp., Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus paracasei and Streptococcus thermophilus species. Studied fermentation condition factors were time (7 h, 12.5 h, 18 h), temperature (30 °C, 37.5 °C, 45 °C) and inoculum ratio (0.01 %, 0.1 %, 1% w/w). The relationship between the factors and responses were analyzed with the Central Composite Face-centered (CCF) design and response surface modelling. In all tested fermentation conditions, no significant decrease in β-glucan content was observed. However, relationships between fermentation condition factors and other responses were obtained. All factors had decreasing effect on pH and increasing effect on TTA. All factors contributed to viscosity, but temperature was significantly more effective than others, having positive, non-linear effect.