Effect of Lactic Acid on Protein Solubilization and Starch Yield in Corn Wet‐Mill Steeping: A Study of Hybrid Effects

Abstract

Cereal Chem. 79(2):257-260To better understand the role of lactic acid (LA) in corn wet-milling, steeping studies were performed on different yellow dent corn hybrids using four different solutions containing LA, sulfur dioxide (SO 2 ), a combination of LA and SO 2 , or no added chemicals. Although there was variation in protein solubilization among the hybrids, protein release was consistently higher when LA was included in the steepwater than when it was excluded (both with and without SO 2 ) . . Several groups have reported that starch recoveries are improved when steepwater contains LA. To explore the relationship between protein solubilization and starch yield as effected by LA, several yellow dent hybrids were steeped in 0.20% SO 2 and 0.50% LA-0.20% SO 2 solutions and milled to recover starch by a 100-g laboratory corn wet-milling procedure. In all instances, both starch yields and protein solubilization were enhanced in solutions containing LA. These results support the hypothesis that direct dissolution of the endosperm protein matrix by LA contributes to the improved starch recoveries.

Hydration kinetics of amaranth grain

“…According to Shandera, Packhurst, and Jackson (1995), lactic acid increased the rate of sulfur dioxide when it was added to the steeping solution. For that grain, Dailey (2002) has determined that such increase was due to protein solubilization present in corn grain with the consequent benefit on starch recovery. As we are interested in developing a wet-milling procedure for amaranth grain, future research will be directed towards establishing a correlation between water absorption increase, protein solubilization and starch recovery using SO 2 solutions with and without addition of lactic acid.…”

Enzymatic Milling Product Yield Comparison with Reduced Levels of Bromelain and Varying Levels of Sulfur Dioxide

“…The reduction of soakwater when compared with the conventional steepwater is due to the reduced soaking time and the solubilizing effects of the reducing agent (SO 2 ) and lactic acid (Dailey 2002). Dotted line represents average conventional corn wet-milling yield for germ using standard, highly reproducible, laboratory procedure.…”

Effect of a Cell‐Wall‐Degrading Enzyme Complex on Starch Recovery and Steeping Requirements of Sorghum and Maize

“…Wang et al (2000) found no significant differences in sorghum starch yield when grains were steeped with 0.2 or 0.3% SO 2 and lactic acid. Dailey (2002) suggested that, at increasing lactic acid concentrations, more protein from the endosperm matrix is solubilized and higher amounts of starch are recovered. Addition of increasing amounts of CWDE significantly increased starch yields in both types of grains.…”