Enhancing Malva sylvestris extract properties through lactic acid bacteria fermentation: impact on phytochemical profile and bioactivity

This study investigates the fermentation of Malva sylvestris aerial parts using three lactic acid bacteria: Lactiplantibacillus plantarum 299V, Pediococcus acidilactici IRZ12B, and Lacticaseibacillus rhamnosus GG. The fermentation process resulted in a notable increase in microbial counts of LAB populations, production of organic acids, reduction of antinutritional factors such as tannins, and enhancement the bioavailability of some essential minerals. Post-fermentation analyses revealed a threefold increase in total phenolic content compared to the non-fermented extract. Antioxidant activity also showed a substantial enhancement, with L. plantarum 299V and P. acidilactici IRZ12B nearly doubling the DPPH inhibition percentage, while L. rhamnosus GG exhibited no improvement. Furthermore, antimicrobial activity varied among strains, with P. acidilactici IRZ12B and L. rhamnosus GG effectively inhibiting Y. enterocolitica growth, while all fermented samples significantly reduced S. enterica proliferation. These findings support the use of lactic acid bacteria fermentation as a bioprocess to improve the phytochemical profile of malva, with potential therapeutic applications. Furthermore, the optimized fermentation conditions could facilitate the incorporation of fermented malva as a functional ingredient in plant-based foods, aligning with the growing consumer demand for health-oriented products.