Optimization of Physical Sterilization Process Parameters for Dehydrated Fresh Noodles

It is of great significance to study change rule of bacterial colony content in dehydrated fresh noodles for prolonging shelf life of products and improving quality of pasta．Three groups of process parameters were selected, namely, temperature 70-90 °C, relative humidity 70%-90% and drying time 5-20 min, single factor test and orthogonal test were carried out on drying test bench to determine total number of bacterial colonies in noodle samples before and after sterilization according to national standards．Results showed that temperature, humidity and drying time were important parameters affecting bacterial colony content．When temperature was about 80 °C, effect of temperature on total number of colonies appeard a turning point．When temperature was between 70 °C and 80 °C, total number of colonies decreased sharply．When temperature was between 80 °C and 90 °C, total number of colonies changed slowly and total number of colonies remained at about 200 CFU/g．Total number of colonies decreased gradually with extension of relative humidity and drying time．The best technological parameters for physical sterilization of dehydrated fresh noodles were temperature 80 °C, humidity 85%, drying time 10 min, and total number of bacterial colonies of noodles prepared under this technological condition was maintained at 170 CFU/g．