Isolation, identification, and selection of strains as candidate probiotics and starters for fermentation of Swedish legumes.

BACKGROUND

The non-dairy sector is growing, fermented alternatives to dairy are sparse. Adapted starter cultures to substituting raw materials needs to be developed.

OBJECTIVE

Aims of this study were to isolate, identify, and phenotypically characterize lactic acid bacteria (LAB) that inhabit Swedish legumes, and assess properties necessary for selecting strains with the ability to ferment a bean beverage and with potential health beneficial properties.

DESIGN

Isolates of presumed LAB were obtained from legumes collected at Öland, Sweden. Strain diversity was assessed by repetitive polymerase chain reaction (rep-PCR). The strains were identified using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Species belonging to were predominant along with and closely related . Strains were tested for tolerance to low pH, phenol, and bile as well as their bile salt hydrolase (BSH) activity. In addition, strains were tested for antibiotic resistance, and strains for their ability to ferment a bean beverage.

RESULTS

From the 25 strains characterized, five were found resistant to low pH, bile, and phenol, suggesting that they can survive a passage through the gastrointestinal tract (GIT) and hence potentially exert beneficial effects in the host. These are suggested for further investigation on specific host-beneficial properties. Two of these, belonging to were able to ferment a bean beverage without any added nutrients, indicating that the strains are well adapted to the bean substrate. One of the P. strains were also able to markedly improve the reduction of phytate by the phytase-producing yeast strain TY1322 during co-fermentation as well as increase the final cell count of the yeast strain.

CONCLUSION

Strain isolation and characterization performed in this study aids in selecting starter cultures for legume fermentation. Nutritional properties can be improved by co-fermentation with yeast indicating that novel nutritious fermented non-dairy products could be developed.