сряда, 28 октомври 2009 г.
вторник, 27 октомври 2009 г.
New sensor allowing continuous water activity measurement of submerged or solid-subs
Article
New sensor allowing continuous water activity measurement of submerged or solid-substrate fermentations
P. Gervais
Département de Biologie Physico-Chimique - E. N. S. B. A. N. A.-C. U. M., 21100 Dijon, France
setDOI("ADOI=10.1002/bit.260330304")
Abstract
Water activity of the substrate is an important and acute factor for growth as well as for metabolic production of microorganisms or for biocatalyst systems. A sensor has been designed in order to control this parameter on-line during submerged and solid-substrate fermentations. This sterilizable sensor allows the measurement of the relative humidity of the atmosphere in a small chamber by means of a capacitive element separated from the medium by a thin ethylenepolytetrafluoride membrane. For high aw values (>0.90) a sequential circulation of a dried gas prevents the sensor saturation. Measurements are rapid and accurate, and control of the water activity of a fermentation medium has been carried out for 5 days using this sensor.
Accepted: 12 January 1988
Digital Object Identifier (DOI)10.1002/bit.260330304 About DOI
Wiley InterScience :: JOURNALS :: Biotechnology and Bioengineering
New sensor allowing continuous water activity measurement of submerged or solid-substrate fermentations
P. Gervais
Département de Biologie Physico-Chimique - E. N. S. B. A. N. A.-C. U. M., 21100 Dijon, France
setDOI("ADOI=10.1002/bit.260330304")
Abstract
Water activity of the substrate is an important and acute factor for growth as well as for metabolic production of microorganisms or for biocatalyst systems. A sensor has been designed in order to control this parameter on-line during submerged and solid-substrate fermentations. This sterilizable sensor allows the measurement of the relative humidity of the atmosphere in a small chamber by means of a capacitive element separated from the medium by a thin ethylenepolytetrafluoride membrane. For high aw values (>0.90) a sequential circulation of a dried gas prevents the sensor saturation. Measurements are rapid and accurate, and control of the water activity of a fermentation medium has been carried out for 5 days using this sensor.
Accepted: 12 January 1988
Digital Object Identifier (DOI)10.1002/bit.260330304 About DOI
Wiley InterScience :: JOURNALS :: Biotechnology and Bioengineering
сряда, 21 октомври 2009 г.
Влияние на водната активност и рН върху образуването на микотоксини в хлебни изделия
The effect of water activity and pH on the production of mycotoxins by fungi growing on a bread analogue
Letters in Applied Microbiology
Volume 3 Issue 6, Pages 123 - 125
Published Online: 28 Jun 2008
MARGARET PATTERSON 1 , 2 A. P. DAMOGLOU 1 , 2
1 Department of Agricultural and Food Bacteriology, Queen's University of Belfast and Agricultural 2 Food Bacteriology Research Division, Department of Agriculture for Northern Ireland, Newforge Lane, Belfast BT9 5PX, Northern Ireland
Copyright 1986 The Society for Applied Microbiology
ABSTRACT
Mycotoxin production by various toxigenic fungi, growing on a bread analogue, was investigated at various water activities (aw) and pH combinations. Citrinin, ochratoxin A and sterigmatocystin could be detected at aw > 0·80, while patulin was only observed at aw= 0·95. These results show that some toxins may be produced at lower water activities than have been reported on synthetic media and suggest that, where possible, natural substrates should be used to investigate factors affect-ing mycotoxin production in foodstuffs.
Електронен превод:
ABSTRACT Изследвано е натрупването на Микотоксин от различни токсични гъби в хлебни изделия при различни комбинации на активност на водата (AW) и рН. Citrinin, охратоксин А и sterigmatocystin биха могли да бъдат открити в AW> 0,80, докато патулин се наблюдават само при AW = 0,95. Тези резултати показват, че някои токсини могат да се образуват и при по-ниска водна активност, отколкото е било докладвано при различни изкуствени хранителни среди.
Received 11 July 1986 and accepted 17 September 1986
Източник: http://www3.interscience.wiley.com/journal/119850870/abstract
Letters in Applied Microbiology
Volume 3 Issue 6, Pages 123 - 125
Published Online: 28 Jun 2008
MARGARET PATTERSON 1 , 2 A. P. DAMOGLOU 1 , 2
1 Department of Agricultural and Food Bacteriology, Queen's University of Belfast and Agricultural 2 Food Bacteriology Research Division, Department of Agriculture for Northern Ireland, Newforge Lane, Belfast BT9 5PX, Northern Ireland
Copyright 1986 The Society for Applied Microbiology
ABSTRACT
Mycotoxin production by various toxigenic fungi, growing on a bread analogue, was investigated at various water activities (aw) and pH combinations. Citrinin, ochratoxin A and sterigmatocystin could be detected at aw > 0·80, while patulin was only observed at aw= 0·95. These results show that some toxins may be produced at lower water activities than have been reported on synthetic media and suggest that, where possible, natural substrates should be used to investigate factors affect-ing mycotoxin production in foodstuffs.
Електронен превод:
ABSTRACT Изследвано е натрупването на Микотоксин от различни токсични гъби в хлебни изделия при различни комбинации на активност на водата (AW) и рН. Citrinin, охратоксин А и sterigmatocystin биха могли да бъдат открити в AW> 0,80, докато патулин се наблюдават само при AW = 0,95. Тези резултати показват, че някои токсини могат да се образуват и при по-ниска водна активност, отколкото е било докладвано при различни изкуствени хранителни среди.
Received 11 July 1986 and accepted 17 September 1986
Източник: http://www3.interscience.wiley.com/journal/119850870/abstract
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