Abstract
The current research studied the properties of stirred yogurt, its composition, texture, rheology, and
morphology, after fortification with varying levels of oat powder. Yogurt samples were prepared with
1%, 2%, 3% and 5% added oat powder and tested at multiple time points. The chemical analysis of
these samples showed increases in total solids, dietary fibre and ash with increasing levels of oat
powder, while the concentration of protein decreased due to dilution. oat supplementation did not
influence the fermentation process or the rate at which it occurred, as there were no differences in pH
between control and oat fortified yogurts. The textural analysis of the yogurts showed significant
decreases in hardness and improvements in cohesiveness with increasing amounts of oat powder used
in the formulation. Significant increases in water holding capacity (WHC) of the yogurt occurred with
the addition of oat powder; this will result in greater moisture retention and reduction of syneresis. The
results from FT-IR spectroscopy were consistent with these findings and suggested an embedding of
polysaccharides within the yogurt matrix without altering the milk proteins. Viscosity showed non-
linear behavior; thus, yogurt samples supplemented with high oat fiber concentration (5%) regained
their flowability by virtue of polysaccharide networks. Consequently, oat powder fortification at 3-5%
concentration could be an interesting approach in designing high fiber-added functional yogurt
products having better composition and characteristics.
morphology, after fortification with varying levels of oat powder. Yogurt samples were prepared with
1%, 2%, 3% and 5% added oat powder and tested at multiple time points. The chemical analysis of
these samples showed increases in total solids, dietary fibre and ash with increasing levels of oat
powder, while the concentration of protein decreased due to dilution. oat supplementation did not
influence the fermentation process or the rate at which it occurred, as there were no differences in pH
between control and oat fortified yogurts. The textural analysis of the yogurts showed significant
decreases in hardness and improvements in cohesiveness with increasing amounts of oat powder used
in the formulation. Significant increases in water holding capacity (WHC) of the yogurt occurred with
the addition of oat powder; this will result in greater moisture retention and reduction of syneresis. The
results from FT-IR spectroscopy were consistent with these findings and suggested an embedding of
polysaccharides within the yogurt matrix without altering the milk proteins. Viscosity showed non-
linear behavior; thus, yogurt samples supplemented with high oat fiber concentration (5%) regained
their flowability by virtue of polysaccharide networks. Consequently, oat powder fortification at 3-5%
concentration could be an interesting approach in designing high fiber-added functional yogurt
products having better composition and characteristics.
Keywords
fiber
FTIR.
oat-fortified yogurt
Viscosity