Design and optimization of a new experimental blancher

The aim of this work was to optimize and test a new type of experimental blancher designed to carry out a wide range of processes, with the possibility to also use a combination of water and steam. This new type of blancher was developed in order to overcome many drawbacks of conventional blanching and drying methods, including low energy efficiency, long processing times, quality deterioration and environmental problems, through the use of a new system to control the blancher temperature. In particular this work focuses on the problem of optimizing the steeping process for blanching rice, using design of experiment techniques and analyzing the response to cooking of two varieties of rice. The first variety was simply polished while the second was parboiled, i.e. the latter variety of rice had previously been subjected to hydrothermal processing to gelatinize the starch. The study was also extended to find the optimal steeping conditions for blanching both the varieties. A fundamental requirement was to identify and analyze the optimal conditions for the independent variables, time and temperature, which come into play during the blanching process. To that end the statistical method of MultiSimplex optimization proved to be a valid tool.