Use of kefir-derived soy-adapted lactic acid bacteria for the preparation of a fermented soy drink with increased estrogenic activity

Phytoestrogens are a group of molecules deeply studied for their positive activities carried out on human health. These compounds are naturally present in plants belonging to the Fabaceae family, in particular soybeans. The aim of this study is to select safe food microorganism with the ability to ferment a soy drink resulting in increased estrogenic activity and improved functional properties. We used milk kefir granules, a dairy product with proven health-promoting properties, as starting inoculum. We were able to isolate four strains from the fermented soy product: Lactotoccus lactis K03, Leuconostc pseudomesenteroides K05, Leuconostc mesenteroides K09 and Lentilactobacillus kefiri K10.We have characterized the strains and demonstrated their ability to ferment the sugars naturally present in soybeans and to produce a creamy texture. The two strains belonging to the genus Leuconostoc have also been shown to effectively increase the estrogenic activity of the soybean drink.