HYBRID-DEPENDENT EFFECT OF LACTIC-ACID ON CORN STARCH YIELDS

The effect of lactic acid on starch yields of different corn hybrids w as determined by wet-milling 18 commercial corn hybrids at three level s of lactic acid. All 18 hybrid samples tested had higher starch yield s when lactic acid was added to the steep solution, although the magni tude of the increased starch yields varied between 2.9 and 12.0%. The optimal lactic acid concentration for maximum starch recovery was foun d to be between 0.55 and 1.67% lactic acid, by wet-milling nine of the same 18 corn hybrids with seven levels of added lactic acid. Between 0.83 and 1.67% lactic acid, the starch yields of eight of the nine hyb rids were constant (within +/-0.5%). Results showed that the average s tarch yield across all hybrids decreased with a lactic acid concentrat ion <0.55% and a lactic acid concentration >1.67%.