Solid state fermentation to obtain vegetable products bio-enriched with isoflavone aglycones using lactic cultures

Area of Science:

• Food Science and Technology
• Microbiology
• Biotechnology

Background:

• Soybean isoflavones (IS) offer health benefits, but their bioavailability is limited.
• Lactic acid bacteria with β-glucosidase activity can convert IS to their active aglycone form.
• Solid-state fermentation (SSF) is a promising technique for producing bioactive compounds.

Purpose of the Study:

• To investigate the use of SSF with Lactobacillus rhamnosus CRL 981 on soybean paste.
• To evaluate the effect of sucrose addition on bacterial growth and IS conversion.
• To assess the production of bioactive compounds and nutritional characteristics.

Main Methods:

• Solid-state fermentation of soybean paste using Lactobacillus rhamnosus CRL 981.
• Analysis of bacterial growth (pH, cell count), sugar consumption, organic acid production, and β-glucosidase activity.
• Monitoring of isoflavone (IS) conversion and free amino acid content.

Main Results:

• L. rhamnosus CRL 981 demonstrated β-glucosidase activity, achieving complete IS hydrolysis within 12 hours.
• No significant differences in bacterial growth or pH were observed with or without sucrose.
• Higher lactic acid production was noted in soybean paste without sucrose.
• The fermentation process increased free amino acid content.

Conclusions:

• SSF using L. rhamnosus CRL 981 is an effective method for bio-enriching soybean paste with active IS.
• The process yields a soybean product with enhanced nutritional properties and bioavailability of isoflavones.
• Sucrose addition did not significantly impact bacterial performance but influenced organic acid profiles.