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A comparison of changes in the transformation of isoflavones in soymilk using varying concentrations of exogenous and probiotic-derived endogenous beta-glucosidases.
J Appl Microbiol. 2007 Sep; 103(3):601-12.JA

Abstract

AIMS

To compare endogenous and exogenous beta-glucosidases for the hydrolysis of the predominant isoflavone glucosides in soymilk in order to improve the biological activity.

METHODS AND RESULTS

beta-glucosidase activity of probiotic organisms, including Bifidobacterium animalis ssp. lactis Bb12, Lactobacillus acidophilus ATCC 4461 and Lactobacillus casei 2607 in soymilk, was evaluated and was related to the increase in the concentration of isoflavone aglycones during fermentation. The concentrations of isoflavone compounds in soymilk were monitored using a Varian model HPLC with an Amperometric electrochemical detector. The aglycone composition, also known as aglycone equivalent ratio, has been considered to be important for the delivery of health benefits of isoflavones, and was monitored during the fermentation of soymilk. Comparison of the hydrolytic effectiveness of both exogenous and endogenous enzyme during 4-h incubation in soymilk was conducted using the Otieno-Shah (O-S) index. Results showed that exogenous enzyme exhibited faster rate of isoflavone glucoside hydrolysis than that by endogenous enzyme. Highest O-S indices were obtained after 4, 3 and 2 h of incubation with enzyme solution having beta-glucosidase activity of 0.288 U ml(-1), 0.359 U ml(-1) and 0.575 U ml(-1), resulting into aglycone concentration increments of 5.87-, 6.07- and 5.94-fold, respectively. Conversely, aglycone concentration in the soymilk with B. animalis ssp. lactis Bb12, L. casei 2607 and L. acidophilus 4461 increased by 3.43-, 2.72- and 3.03-fold, respectively, after 4 h of fermentation at 37 degrees C. In addition, the O-S index of endogenous enzyme was much lower than that of the exogenous enzyme over the same 4-h incubation period. Optimum aglycone equivalent ratios coincided with highest O-S indices and highest aglycone concentrations in soymilk hydrolysed with exogenous enzyme. The same correlation of O-S indices and highest aglycone concentrations occurred for endogenous enzyme during the 24 h of fermentation.

CONCLUSIONS

Obtaining highest aglycone concentration and optimum aglycone equivalent ratio could provide a critical beginning point in clinical trials for the realization of unique health benefits of soy isoflavones.

SIGNIFICANCE AND IMPACT OF THE STUDY

Screening for beta-glucosidase activities of probiotics in soymilk and comparing their hydrolytic potentials with that of exogenous beta-glucosidase could find wide applications in the development of different aglycone-rich functional soy beverages.

Authors+Show Affiliations

School of Molecular Sciences, Victoria University, Werribee Campus, Melbourne, Victoria, Australia.No affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

17714393

Citation

Otieno, D O., and N P. Shah. "A Comparison of Changes in the Transformation of Isoflavones in Soymilk Using Varying Concentrations of Exogenous and Probiotic-derived Endogenous Beta-glucosidases." Journal of Applied Microbiology, vol. 103, no. 3, 2007, pp. 601-12.
Otieno DO, Shah NP. A comparison of changes in the transformation of isoflavones in soymilk using varying concentrations of exogenous and probiotic-derived endogenous beta-glucosidases. J Appl Microbiol. 2007;103(3):601-12.
Otieno, D. O., & Shah, N. P. (2007). A comparison of changes in the transformation of isoflavones in soymilk using varying concentrations of exogenous and probiotic-derived endogenous beta-glucosidases. Journal of Applied Microbiology, 103(3), 601-12.
Otieno DO, Shah NP. A Comparison of Changes in the Transformation of Isoflavones in Soymilk Using Varying Concentrations of Exogenous and Probiotic-derived Endogenous Beta-glucosidases. J Appl Microbiol. 2007;103(3):601-12. PubMed PMID: 17714393.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A comparison of changes in the transformation of isoflavones in soymilk using varying concentrations of exogenous and probiotic-derived endogenous beta-glucosidases. AU - Otieno,D O, AU - Shah,N P, PY - 2007/8/24/pubmed PY - 2007/12/28/medline PY - 2007/8/24/entrez SP - 601 EP - 12 JF - Journal of applied microbiology JO - J Appl Microbiol VL - 103 IS - 3 N2 - AIMS: To compare endogenous and exogenous beta-glucosidases for the hydrolysis of the predominant isoflavone glucosides in soymilk in order to improve the biological activity. METHODS AND RESULTS: beta-glucosidase activity of probiotic organisms, including Bifidobacterium animalis ssp. lactis Bb12, Lactobacillus acidophilus ATCC 4461 and Lactobacillus casei 2607 in soymilk, was evaluated and was related to the increase in the concentration of isoflavone aglycones during fermentation. The concentrations of isoflavone compounds in soymilk were monitored using a Varian model HPLC with an Amperometric electrochemical detector. The aglycone composition, also known as aglycone equivalent ratio, has been considered to be important for the delivery of health benefits of isoflavones, and was monitored during the fermentation of soymilk. Comparison of the hydrolytic effectiveness of both exogenous and endogenous enzyme during 4-h incubation in soymilk was conducted using the Otieno-Shah (O-S) index. Results showed that exogenous enzyme exhibited faster rate of isoflavone glucoside hydrolysis than that by endogenous enzyme. Highest O-S indices were obtained after 4, 3 and 2 h of incubation with enzyme solution having beta-glucosidase activity of 0.288 U ml(-1), 0.359 U ml(-1) and 0.575 U ml(-1), resulting into aglycone concentration increments of 5.87-, 6.07- and 5.94-fold, respectively. Conversely, aglycone concentration in the soymilk with B. animalis ssp. lactis Bb12, L. casei 2607 and L. acidophilus 4461 increased by 3.43-, 2.72- and 3.03-fold, respectively, after 4 h of fermentation at 37 degrees C. In addition, the O-S index of endogenous enzyme was much lower than that of the exogenous enzyme over the same 4-h incubation period. Optimum aglycone equivalent ratios coincided with highest O-S indices and highest aglycone concentrations in soymilk hydrolysed with exogenous enzyme. The same correlation of O-S indices and highest aglycone concentrations occurred for endogenous enzyme during the 24 h of fermentation. CONCLUSIONS: Obtaining highest aglycone concentration and optimum aglycone equivalent ratio could provide a critical beginning point in clinical trials for the realization of unique health benefits of soy isoflavones. SIGNIFICANCE AND IMPACT OF THE STUDY: Screening for beta-glucosidase activities of probiotics in soymilk and comparing their hydrolytic potentials with that of exogenous beta-glucosidase could find wide applications in the development of different aglycone-rich functional soy beverages. SN - 1364-5072 UR - https://www.unboundmedicine.com/medline/citation/17714393/A_comparison_of_changes_in_the_transformation_of_isoflavones_in_soymilk_using_varying_concentrations_of_exogenous_and_probiotic_derived_endogenous_beta_glucosidases_ L2 - https://doi.org/10.1111/j.1365-2672.2006.03245.x DB - PRIME DP - Unbound Medicine ER -