ZEIN BATCH EXTRACTION FROM DRY-MILLED CORN - CEREAL DISINTEGRATION BYDISSOLVING FLUID SHEAR

Corn particles were extracted in an agitated vessel with a 4:1 mass ra tio of 70% ethanol to corn for periods of 1-6 hr at ambient temperatur e. The extract solution was filtered and centrifuged to remove suspend ed particles after extraction and then diluted to 40% ethanol to preci pitate extracted solute. Measurements of the mass of suspended particl es separated by centrifugation indicate that mixing the corn particles with the ethanol dissolves and weakens the protein between cells and between starch granules within cells near the particles' surface. Unde r the conditions of this study, corn particles release starch granules more rapidly than the protein bodies dissolve, as indicated by analys is of the centrifuged particles. The diffusion coefficient for ethanol solution in corn was estimated and compared with a coefficent derived from a fit of the trend in the rate of release of fine particles from the milled corn. The diffusion coefficient of pure zein in a stagnant 70% ethanol solution was estimated from the measurement of weight los s by a ball of zein. Analysis of the ambient temperature protein extra ction rate indicates that 2-mm particles exhibit more convective mass transfer than 20-mu m particles.