»Zein is a prolamine derived from corn (Zea mays Linné[Fam.Gramineae]).
Packaging and storage
Preserve in tight containers.
Dissolve about 0.1g in 10ml of 0.1Nsodium hydroxide,and add a few drops of cupric sulfate TS.Warm in a water bath:a purple color develops.
To a test tube containing 25mg of Zein add 1mLof nitric acid.Agitate vigorously:the solution becomes light yellow.Further addition of about 10mLof 6Nammonium hydroxide produces an orange color.
It is insoluble in water,but 1g of it in 10mLof a mixture of isopropyl alcohol and water (85:15),at a temperature of about 37
,yields a clear to cloudy solution.
Microbial limits á61ñ
The total bacterial count does not exceed 1000cfu per g,and the tests for Salmonella
species and Escherichia coli
Loss on drying á731ñ
Dry it at 105
for 2hours:it loses not more than 8.0%of its weight.
Residue on ignition á281ñ:
not more than 2.0%.
Heavy metals,Method IIá231ñ:
Organic volatile impurities,Method IVá467ñ:
meets the requirements.
Proceed as directed under Nitrogen Determination,Method Iá461ñ
:the nitrogen content is not less than 13.1%and not more than 17.0%,on the dried basis.