Sterilization of mixed seasoning powders comprises packing powders in nitrogen-substituted air, sealing and irradiating : Korea Energy Res. Inst. KR 9105283; 24 July 1991

Abstract

The increase in the use of twin-screw extruders for the production of directly expanded products can be attributed to the unique versatility of this machine and the products that may be produced with it. However, complex relationships between process inputs, system variables and unmeasurable product quality attributes make control of the process difficult. Understanding the effects of particular inputs on product properties will improve the general understanding of the fundamental phenomenon underlying the extrusion process. Using a system analysis approach, the effect of moisture and screw speed on percentage torque, specific mechanical energy (SME), product temperature and die pressure was determined. Corn meal was adjusted to 16%, 19% and 22% moisture and extruded at 200, 300 and 400 rev./min in an APV-Baker MPF 50, twin-screw extruder. Extrudates were characterized by their specific volume, longitudinal expansion index (LEI) and sectional expansion index (SEI). SME could be described as a linear combination of moisture and screw speed. Product temperature was highly correlated with SME regardless of whether changes in SME were a result of changes in moisture or screw speed. However, specific volume was found to be a function of both SME and moisture content. Longitudinal expansion was linearly correlated with SME alone, whereas radial expansion was not correlated with SME input. Based on these results, an algorithm for indirect control of specific volume was developed based on on-line measurement of SME and calculation of the actual in-barrel moisture content.