β-Glucosidase activity and bioconversion of isoflavones during fermentation of soymilk.
BACKGROUND
Lactobacillus rhamnosus C6 strain showed higher β-glucosidase activity as well as biotransformation of isoflavones from glycones (daidzin and genistin) to aglycones (daidzein and genistein) in soymilk. However, L. rhamnosus C2 and Lactobacillus casei NCDC297 also exhibited similar activity during soymilk fermentation. These three strains can be selected for the development of functional fermented soy foods enriched with aglycone forms of isoflavones, such as soy yoghurt, soy cheese, soy beverages and soy dahi.


RESULTS
The study determined β-glucosidase activity of probiotic Lactobacillus cultures for bioconversion of isoflavones to aglycones in fermenting soymilk medium. Soymilk was fermented with six strains (L. rhamnosus C6 and C2, L. rhamnosus NCDC19 and NCDC24 and L. casei NCDC17 and NCDC297) at 37 °C for 12 h. The highest β-glucosidase activity and isoflavone bioconversion after 12 h occurred by L. rhamnosus C6 culture during fermentation in soymilk. Increased isoflavone aglycone content in fermented soymilk is likely to improve the biological functionality of soymilk (e.g. antioxidant activity, alleviation of hormonal disorders in postmenopausal women, etc.).


CONCLUSIONS
Lactobacillus rhamnosus C6 culture can be used for the development of functional fermented soy-based products.
Dairy Microbiology Department, S.M.C. College of Dairy Science, Anand Agricultural University, Anand, 388110, (Gujarat), India.
Subrota
S
Hati
Shilpa
S
Vij
Brij Pal
BP
Singh
Surajit
S
Mandal
D005285:Fermentation; D055951:Functional Food; D006801:Humans; D007529:Isoflavones / Q000378:metabolism*; D007778:Lactobacillus / Q000201:enzymology* / Q000378:metabolism; D007780:Lacticaseibacillus casei / Q000201:enzymology / Q000378:metabolism; D052201:Lacticaseibacillus rhamnosus / Q000201:enzymology / Q000378:metabolism; D019936:Probiotics / Q000378:metabolism; D041942:Soy Milk / Q000378:metabolism*; D001617:beta-Glucosidase / Q000378:metabolism*
D007529:Isoflavones; C040641:genistin; C013908:daidzin; D001617:beta-Glucosidase
aglycones; daidzein; fermentation; genistein; glucosidase; isoflavones; soy