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Article: A comparison of changes in the transformation of isoflavones in soymilk using varying concentrations of exogenous and probiotic-derived endogenous β-glucosidases

TitleA comparison of changes in the transformation of isoflavones in soymilk using varying concentrations of exogenous and probiotic-derived endogenous β-glucosidases
Authors
KeywordsAglycone equivalent ratio
Aglycone increment quotient
Glucoside reduction quotient
Isoflavone transformation
Otieno-Shah index
Issue Date2007
PublisherBlackwell Publishing Ltd. The Journal's web site is located at http://www.blackwellpublishing.com/journals/JAM
Citation
Journal Of Applied Microbiology, 2007, v. 103 n. 3, p. 601-612 How to Cite?
AbstractAims: To compare endogenous and exogenous β-glucosidases for the hydrolysis of the predominant isoflavone glucosides in soymilk in order to improve the biological activity. Methods and Results: β-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 β-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°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 β-glucosidase activities of probiotics in soymilk and comparing their hydrolytic potentials with that of exogenous β-glucosidase could find wide applications in the development of different aglycone-rich functional soy beverages. © 2007 The Authors.
Persistent Identifierhttp://hdl.handle.net/10722/144412
ISSN
2015 Impact Factor: 2.156
2015 SCImago Journal Rankings: 0.921
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorOtieno, DOen_HK
dc.contributor.authorShah, NPen_HK
dc.date.accessioned2012-01-20T09:01:54Z-
dc.date.available2012-01-20T09:01:54Z-
dc.date.issued2007en_HK
dc.identifier.citationJournal Of Applied Microbiology, 2007, v. 103 n. 3, p. 601-612en_HK
dc.identifier.issn1364-5072en_HK
dc.identifier.urihttp://hdl.handle.net/10722/144412-
dc.description.abstractAims: To compare endogenous and exogenous β-glucosidases for the hydrolysis of the predominant isoflavone glucosides in soymilk in order to improve the biological activity. Methods and Results: β-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 β-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°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 β-glucosidase activities of probiotics in soymilk and comparing their hydrolytic potentials with that of exogenous β-glucosidase could find wide applications in the development of different aglycone-rich functional soy beverages. © 2007 The Authors.en_HK
dc.languageengen_US
dc.publisherBlackwell Publishing Ltd. The Journal's web site is located at http://www.blackwellpublishing.com/journals/JAMen_HK
dc.relation.ispartofJournal of Applied Microbiologyen_HK
dc.subjectAglycone equivalent ratioen_HK
dc.subjectAglycone increment quotienten_HK
dc.subjectGlucoside reduction quotienten_HK
dc.subjectIsoflavone transformationen_HK
dc.subjectOtieno-Shah indexen_HK
dc.titleA comparison of changes in the transformation of isoflavones in soymilk using varying concentrations of exogenous and probiotic-derived endogenous β-glucosidasesen_HK
dc.typeArticleen_HK
dc.identifier.emailShah, NP: npshah@hku.hken_HK
dc.identifier.authorityShah, NP=rp01571en_HK
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1111/j.1365-2672.2006.03245.xen_HK
dc.identifier.pmid17714393-
dc.identifier.scopuseid_2-s2.0-34547867380en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-34547867380&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume103en_HK
dc.identifier.issue3en_HK
dc.identifier.spage601en_HK
dc.identifier.epage612en_HK
dc.identifier.eissn1365-2672-
dc.identifier.isiWOS:000249267400011-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridOtieno, DO=12242657400en_HK
dc.identifier.scopusauthoridShah, NP=7401823907en_HK
dc.identifier.citeulike1558676-

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