Abstract:

In order to explore the effect of addition of probiotics and probiotic exopolysaccharides (EPS) on properties of
soya yogurt, the physicochemical, sensory and texture properties of soya yogurt fermented by a traditional starter culture
combined with Bifidobacterium animalis subsp. lactis after addition of EPS produced by the probiotic strain were examined.
Changes in pH, water-holding capacity, apparent viscosity, EPS content and texture properties were determined during
fermentation and storage over 21 days. The results indicated that water-holding capacity, apparent viscosity and texture
properties of soya yogurt containing 0.3% EPS were significantly higher than those of the blank control (P < 0.05). The
addition of the EPS-producing bacterium had no effect on fermentation speed and gel properties of soya yogurt, but the EPS
(86 mg/L) produced during post-fermentation storage at 4 ℃ for 24 h led to a significant improvement in apparent viscosity
and texture properties (P < 0.05), while not significantly influencing water-holding capacity (P > 0.05). This study led us
to conclude that addition of EPS produced by Bifidobacterium animalis subsp. lactis was effective for improvement of gel
properties and quality of soya yogurt.

Key words: exopolysaccharides, Bifidobacterium, soya yogurt, texture properties