Thermodynamic analysis on energy-exergy requirement and efficiency of serogroup C antigen production, farm to fork bread production and sourdough leavening

Efficient use of food and energy sources has gained great importance with increasing population, the increase of greenhouse gases and global warming. Hence, the yield of food and chemical processes with low energy consumption is intended to provide the energy efficient production systems. In context of this thesis; three biochemical processes were studied by kinetic and thermodynamic models. Thermodynamic models are investigated by first and second laws of thermodynamics. In the first study; kinetic and thermodynamic models are developed to relate substrate consumption, serogroup C antigen production and growth rate of Neisseria meningitidis, a meningitides causing bacterium for three cases: the uncontrolled; pH controlled and dissolved oxygen controlled cultivation. The model shows that maximum antigen production, minimum energy consumption, minimum entropy generation and exergy loss are obtained under stress conditions that N. meningitidis are exposed to. As the second study; energy and exergy efficiencies of the wheat and rye bread and hamburger bun making processes are assessed based on data from Turkey and Germany. Energy and exergy consumption, the cumulative degree of perfection (CDP) and CExC in each step in production of these various breads were calculated. Agriculture is the most significant step in bread production affecting all following steps. Hamburger bun production requires the maximum energy utilization due to the higher weight loss in baking. The rye bread production process requires the minimum energy utilization due to the lower energy input in the agriculture and higher efficiency in the flour production. The maximum exergy destructions occur during the milling and the baking steps. In the third study; the leavening process in sourdough is investigated in presence of various ratios of Saccharomyces cerevisiae and Lactobacillus plantarum in different temperatures in order to find out the maximum carbon dioxide production, expansion work and dough volume increase with optimum energy and exergy utilization.