EconPapers    
Economics at your fingertips  
 

'GAB' generalised equation as a basis for sorption spectral analysis

Jiří Blahovec and Stavros Yanniotis
Additional contact information
Jiří Blahovec: Technology, Agricultural University of Athens, Athens, Greece
Stavros Yanniotis: Department of Food Science &

Czech Journal of Food Sciences, 2010, vol. 28, issue 5, 345-354

Abstract: The transformed sorption isotherm (represented by the ratio of water activity and moisture content (d.b.) versus water activity) was approximated by polynomials of 2nd-6th order. It is shown that the relative derivative of the transformed equation expresses the deviation of the sorption isotherm from the linear relationship between the moisture content and water activity either to the sorption isotherm of the Lagmuir's type (the positive relative derivative) or to the sorption isotherm of the solution type (the negative relative derivative). The relative derivative plotted versus water activity then serves as a spectral indicator of the prevailing sorption mechanism. Spectral analysis is applied to sorption isotherms of potato and wheat starches and some fruits and vegetables. For starches, the differences in the spectral indicator between resorption and desorption as well as the effect of starch processing (gelatinisation and hydrolysis) on spectral analysis are discussed. The role of spectral analysis in the assessment of the prevailing sorption mechanism (surface vs solution sorption) is demonstrated for fruits and vegetables.

Keywords: sorption; isotherm; GAB; food; approximation; polynomial; water; activity; spectrum (search for similar items in EconPapers)
Date: 2010
References: View complete reference list from CitEc
Citations:

Downloads: (external link)
http://cjfs.agriculturejournals.cz/doi/10.17221/146/2009-CJFS.html (text/html)
http://cjfs.agriculturejournals.cz/doi/10.17221/146/2009-CJFS.pdf (application/pdf)
free of charge

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:caa:jnlcjf:v:28:y:2010:i:5:id:146-2009-cjfs

DOI: 10.17221/146/2009-CJFS

Access Statistics for this article

Czech Journal of Food Sciences is currently edited by Ing. Zdeňka Náglová Ph.D.

More articles in Czech Journal of Food Sciences from Czech Academy of Agricultural Sciences
Bibliographic data for series maintained by Ivo Andrle ().

 
Page updated 2025-05-31
Handle: RePEc:caa:jnlcjf:v:28:y:2010:i:5:id:146-2009-cjfs