ABSTRACT
Oxalate, a natural occurring substance, normally found in some plant parts and humans. The name oxalic acid (ethanedioic acid) which, now days called oxalate has been derived from the plant oxalis (wood sorrel). The most prominent form of oxalate, Calcium oxalate crystals, are extensive both in flowering monocotyledons and dicotyledons with shapes of Raphide, Styloid and Druse. Several forms of alkali and alkaline-earth oxalates like the sandstone whewellite, caoxite etc. are found in atmosphere, food, plants, fungi and other biological systems. As a mediator of Krebs citric acid cycle, the human body assimilate oxaloacetate which consequently hydrolyze to oxalate. Moreover, Oxalate salts, being badly soluble at intestinal pH are recognized to cut down calcium absorption resulting in diseases such as Rickets and Osteomalacia. Ingestion of 5–15 g of oxalic acid can be fatal to the humans. This chapter begins with an introduction to oxalate, its distribution in nature and the main sources that are the basis for its availability. It then covers myriad of tests: ion chromatography, gas chromatography, high-performance fluid chromatograph, enzymatic process, capillary electrophoresis and chemiluminescence. The effect of processing on oxalate via fermentation, baking, frying, boiling, soaking, germination, roasting and freezing are also presented.
