Corn steeping:: influence of time and lactic acid on isolation and thermal properties of starch

A semi-dent corn hybrid was laboratory batch-steeped at 52 degreesC in a sulfur dioxide solution (2500 ppm) and sulfur dioxide solution with lactic acid (2500 ppm SO2 + 0.5% v/v lactic acid) for various time intervals. Starch was laboratory wet milled and gelatinization characteristics were analyzed by differential scanning calorimeter (DSC). Starch isolated from corn steeped in SO2 solution alone had higher peak temperatures and narrower gelatinization range as the steeping time increased. This demonstrated that the wet milling process anneals corn starch during the isolation procedure. Such an effect was less pronounced when starch was milled from corn steeped with lactic acid. Higher starch yields were obtained from corn steeped in sulfur dioxide solution with lactic acid. (C) 2001 Elsevier Science Ltd. All rights reserved.