Usage examples for Zein:

• Animals fed on the zein mixture died in a few days but the inexplicable thing was that when the missing tryptophan was added to the diet the animals lived a little longer but finally declined and died. "The Vitamine Manual" – Walter H. Eddy

• 1886. 10. Alaeddin and Zein ul Asnam. "The Life of Sir Richard Burton" – Thomas Wright