Enhanced growth of lactobacilli and bioconversion of isoflavones in biotin-supplemented soymilk by electroporation

Int J Food Sci Nutr. 2012 Aug;63(5):580-96. doi: 10.3109/09637486.2011.641940. Epub 2011 Dec 12.

Abstract

This study aimed at utilizing electroporation to further enhance the growth of lactobacilli and their isoflavone bioconversion activities in biotin-supplemented soymilk. Strains of lactobacilli were treated with different pulsed electric field strength (2.5, 5.0 and 7.5 kV/cm) for 3, 3.5 and 4 ms prior to inoculation and fermentation in biotin-soymilk at 37°C for 24 h. Electroporation triggered structural changes within the cellular membrane of lactobacilli that caused lipid peroxidation (p < 0.05) and alteration of membrane fluidity (p < 0.05). This was due to the application of electric potential difference across membrane that induced pores formation and subsequently increased membrane permeability. Reversible permeabilized cells resumed growth to >9 log CFU/ml after fermentation in biotin-soymilk (p < 0.05). Lactobacilli cells treated at electric field strength of 7.5 kV/cm for 3.5 ms also showed enhanced β-glucosidase activity (p < 0.05) compared to lower doses and control, leading to increased bioconversion of isoflavones glucosides to aglycones in biotin-soymilk (p < 0.05). Results from this study show that electroporation could be used to produce biotin-soymilk with increased bioactive aglycones.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biotin / metabolism*
  • Cell Membrane / ultrastructure*
  • Dietary Supplements
  • Electricity
  • Electroporation / methods*
  • Fermentation
  • Glucosides / metabolism
  • Isoflavones / metabolism*
  • Lactobacillus / growth & development*
  • Lactobacillus / metabolism
  • Lipid Peroxidation
  • Membrane Fluidity
  • Permeability
  • Probiotics*
  • Soy Foods / microbiology
  • Soy Milk / metabolism*
  • beta-Glucosidase / metabolism

Substances

  • Glucosides
  • Isoflavones
  • Biotin
  • beta-Glucosidase