A simple method to determine the water activity of ethanol-containing samples
Data(s) |
20/01/1999
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Resumo |
The water activity (a(w)) of microbial substrates, biological samples, and foods and drinks is usually determined by direct measurement of the equilibrium relative humidity above a sample. However, these materials can contain ethanol, which disrupts the operation of humidity sensors. Previously, an indirect and problematic technique based on freezing-point depression measurements was needed to calculate the a(w) when ethanol was present. We now describe a rapid and accurate method to determine the a(w) of ethanol-containing samples at ambient temperatures. Disruption of sensor measurements was minimized by using a newly developed, alcohol-resistant humidity sensor fitted with an alcohol filter. Linear equations were derived from a(w) measurements of standard ethanol-water mixtures, and from Norrish's equation, to correct sensor measurements. To our knowledge, this is the first time that electronic sensors have been used to determine the a(w) of ethanol- containing samples. |
Identificador |
http://dx.doi.org/10.1002/(SICI)1097-0290(19990120)62:2<242::AID-BIT15>3.0.CO;2-R |
Idioma(s) |
eng |
Direitos |
info:eu-repo/semantics/restrictedAccess |
Fonte |
Hallsworth , J E & Nomura , Y 1999 , ' A simple method to determine the water activity of ethanol-containing samples ' Biotechnology and Bioengineering , vol 62 , no. 2 , pp. 242-245 . DOI: 10.1002/(SICI)1097-0290(19990120)62:2<242::AID-BIT15>3.0.CO;2-R |
Palavras-Chave | #Electronic humidity sensors #Ethanol #Freezing-point depression #Osmotic stress #Saccharomyces cerevisiae #Water activity measurement #/dk/atira/pure/subjectarea/asjc/1300/1305 #Biotechnology #/dk/atira/pure/subjectarea/asjc/2400/2404 #Microbiology |
Tipo |
article |