Fermented soymilk and soy and cow milk mixture, supplemented with orange peel fiber or Tremella flava fermented powder as prebiotics for high exopolysaccharide-producing Lactobacillus pentosus SLC 13

BACKGROUND: A high exopolysaccharide-producing Lactobacillus pentosus SLC 13 strain was isolated from mustard pickles and showed the characteristics of a probiotic. Orange peel fiber powder (OPFP) and Tremella flava fermented powder (TFP) were shown to be potential prebiotics for L. pentosus SLC 13. The present study aimed to further develop new symbiotic fermented lactic acid beverages using SLC 13 with different proportions of cow milk and soymilk as food substrates, as well as with OPFP or TFP as prebiotics. RESULTS: Acidification rate (soymilk groups, 3.02–4.37 mU min⁻¹; soymilk/milk mixture groups, 1.33–2.84 mU min⁻¹) and fermentation time (soymilk groups, 7.09–9.25 h; soymilk/milk mixture groups, 12.51–27.34 h) indicated that soymilk represents a suitable substrate for SLC 13-mediated fermentation. Moreover, OPFP and TFP induced a higher exopolysaccharide production of SLC 13 and a higher water holding capacity of fermented beverages. Sensory evaluations suggested that soymilk groups fermented with 10 g kg⁻¹ OPFP (SF-1.0P) and that with 5 g kg⁻¹ TFP (SF-0.5T) and also soymilk/milk mixture groups fermented with 5 g kg⁻¹ OPFP (HSMF-0.5P) and that with 10 g kg⁻¹ TFP (HSMF-1.0T) represent potential fermented drinks. Additionally, SF-1.0P and SF-0.5T products could be preserved for at least 21 days at 4 °C, with high viable cell counts (> 8.8 log₁₀ CFU mL⁻¹) and water holding capacity. CONCLUSION: In the present study, we developed SF-1.0P and SF-0.5T products as a new symbiotic fermented lactic acid beverages. However, in the future, consumer acceptability could be improved by properly regulating the ratio of sugar to acid or seasoning.