How we can determine the presence of oxalate ion in guava fruit at different stage of ripening?

Question

experiments which includes titration; readings; some information about guava fruit at different stage of ripening

Answer 1

It might be difficult to find publications about this very special subject.

This article compares stored guava fruits and says:

"The levels of ammonium oxalate soluble pectin (OSP) were minimal in fruits of both the Groups."

http://www.actahort.org/members/showpdf?...

Biochemistry of fruit ripening of guava

http://lib.bioinfo.pl/pmid:15354790

"Details of the constituents of the fruit of Psidium guajava"

http://www.google.de/search?hl=de&q=%28P...

General info guava fruit:

http://209.85.135.104/search?q=cache:Gwd...

Here are some links to articles dealing with determination of soluble oxalates in plant material:

This publication: "Determination of oxalate in foodstuffs with arylamine glass-bound oxalate oxidase and peroxidase."

lists different methods ( incl. cons ) and explains the enzymatic colorimetric one

http://www.ias.ac.in/currsci/aug102001/2...

Determination of Oxalate in Forage .by Reverse-Phase High Pressure Liquid Chromatography:

http://jds.fass.org/cgi/reprint/73/2/474...

Simple capillary electrophoretic determination of soluble oxalate

http://www.ophsource.org/periodicals/oph...

"Results indicate that any nitrate and

soluble oxalate are removed by extraction into the cooking water"

http://pubs.acs.org/cgi-bin/abstract.cgi...

Under "Oxalate Measurements" you find seeds "analyzed for soluble oxalate levels using an oxalate diagnostic kit "

http://www.pubmedcentral.nih.gov/article...

The enzymatic method seems to be the most popular one.

Hope it helps a bit!