ULTRASOUND-ASSISTED ZEIN EXTRACTION AND DETERMINATION IN SOME PATENTED MAIZE FLOURS

Zein, an alcohol soluble mixture of proteins with industrial applications, is the main storage protein found in the seeds of maize. Recently, a patent was awarded (RO128468-A2 dated June 28, 2013) for a process for producing corn meals each of them of different hardness, granulation and chemical composition. Since some of these maize flours are rich in starch and zein prolamin, whereas some other flours are rich in oil and non-zeinic proteins, both the extraction and determination of zeins should be investigated. Consequently, we proposed here the extraction of zein and determination in hard and normal corn meals. Besides, we characterized the extracted zeins by FTIR and UV-visible spectroscopy. Among the protein assays used to determine zein content of extracts, we found that biuret method is the most suitable procedure to follow the ultrasonic extraction of zein. Therefore, an adapted biuret micro-method was introduced herein and its feasibility and analytical parameters discussed. The alcoholic extracts proved to contain mostly alpha-zein.