Multiphasic and mixture lactic acid bacteria screening approach for the removal of antinutrients and off-flavors present in a pea, oat and potato blend

Abstract

• L. plantarum strains had a powerful phenolic acid metabolism machinery in vitro and in situ . • L. pseudomesenteroides provided the proteolytic system to degrade soy-based trypsin inhibitors. • Heterofermentative LAB were able to remove volatile off-flavors more efficiently. • Β-glucosidase activities in LAB in artificial media showed different performances than in situ . • Mixtures of LAB were effective at synergistically remove unwanted compounds in the POP blend. The antinutrients and off-flavors present in plant-based foods are some of the major organoleptic and consumer acceptance drawbacks considered when developing plant-based fermented dairy alternatives (PBFDA). Here, we investigated a combination of genotypical and phenotypical consecutive screening methods to find out the optimal single- and combination of lactic acid bacteria (LAB) strains based on volatile off-flavors, phenolic acids, saponins, and trypsin inhibitor degradation through the fermentation of a pea, oat, and potato (POP) blend. Lactiplantibacillus plantarum strains were the most optimal for the partial/complete degradation of p -coumaric (>98 %) and ferulic acid (10–20 %) compounds in the POP blend. Leuconostoc pseudomesenteroides strains, and their PII-type proteinases were demonstrated to be effective degrading trypsin inhibitors. Also, specific Leuconostoc mesenteroides and L. plantarum strains achieved higher degradation rates of plant saponins such as avenacoside A (10–40 % degradation) and soyasaponin B (55–75 % degradation) present, correlated with their β-glucosidase activity (30–50 U/mL). Strict heterofermentative LABs such as Leuconostoc spp. strains were significantly better at removing hexanal, pentanal, benzaldehyde, and nonanal up to 85 % after 6 h. Finally, 384 combinations of 2 and 3 LAB selected strains ( L. plantarum – L. mesenteroides – L. pseudomesenteroides ) were tested at different strain-ratios, which demonstrated synergistic effects at degrading ferulic acid to more than 80 %, increasing acidification rates, and producing higher concentrations of diacetyl and acetoin (up to 3.28 and 28.13 µg/g sample) when L. pseudomesenteroides 1993 was included in the mix. This study demonstrated the potential of using unconventional plant-adapted LAB strains as starter cultures for the elimination of multiple unwanted compounds for the development of higher quality PBFDA without the use of conventional dairy-based LAB isolates. Finally, the screening approach could be used for microbial screening purposes throughout the development of starter cultures for plant-based yogurts, cheese, and other non-dairy fermented products.

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