Soymilk modification by immobilized bacteria in a soft elastic tubular reactor's wall

Soybean products are an important food source, but there are issues related to their nutrition and waste accu-mulation. We developed an immobilized mixed strains system on agitated flasks and a soft elastic tubular reactor (SETR) to obtain a whole soymilk fermented product (without okara and hull removal). Our findings indicate that the mix of Lactobacillus plantarum/Bacillus subtilis subsp. Natto, immobilized in gellan/xanthan/PU foam mat lining the reactor, resulted in a product with a high protein hydrolysis degree (20%), degradation of the 7 S protein fraction, lower total reducing sugars (>70% reduction) and trypsin inhibitors (>80% reduction), and higher total phenolics (>200% increase). This is associated with lower flatulence, allergenicity, and higher nutrient availability and bioactivity. The SETR mixing profile, combined with the immobilization method used in this work, resulted in a stable continuous process and should be better explored as a bioprocess option for non-traditional media.

Automated summary

We developed an immobilized mixed strains system on agitated flasks and a soft elastic tubular reactor (SETR) to obtain a whole soymilk fermented product. The mix of Lactobacillus plantarum/Bacillus subtilis subsp. Natto, immobilized in gellan/xanthan/PU foam mat lining the reactor, resulted in a product with improved nutrition and reduced waste accumulation. This immobilization and SETR mixing method can be explored as a bioprocess option for non-traditional media.