SMALL SCALE STEAM INJECTION COOKER FOR CORN MEAL.
ABSTRACT Acontinuous laboratory cooker for 0.2 kg/min of ground corn {Zea Mays) was developed and evaluated. Pure corn starch and corn meal were used as feedstocks. Solids concentrations from 10 to 25% were examined. The feedstocks were hydrolyzed with alphaamylase at temperatures from 100° to 125 °C, and saccharified at 60 °C with amyloglucosidase. Slurry samples were analyzed for total reducing sugars (TRS). The results were analyzed using a response surface technique. The dependent variables were: (a) material efficiency, the fraction of starch converted to TRS, (b) conversion ratio, the ratio of TRS in the output supernatant to the input solids concentration, and (c) energy ratio, the ratio of the higher heating value of TRS produced to electrical and steam energy used in the process. The operation of the cooker was limited to 18% corn meal solids due to plugging of the viscous product. In order to operate at a conversion ratio greater than 70% it was necessary to operate the cooker at 105 °C for pure starch and 125 °C for corn meal. This resulted in material efficiency in excess of 90% for both feed stocks.