Today, researchers have developed new heat transfer fluids that have high thermal conductivity heat capacity, and low viscosity for food applications. Because the thermal conductivity of nanoparticles is higher than base fluids (water, ethylene glycol, and so on), Nanofluids (NFs) have high performance in heat transfer operations. In this study, the aim was to determine the effect of NFs used in heat transfer equipment on the heat transfer coefficient with Analysis of Covariance (ANCOVA) which is an optimization test. For heat transfer modeling of tomato juice, it was evaluated the effect of alumina content in NFs on Reynolds Number (Re) and overall heat transfer coefficient. For heat transfer modeling of milk, it was assessed the effect of carbon nanotube content in NFs on Peclet Number (Pe) and convective heat transfer coefficient. As a result, it was determined that Re and alumina content have crucial importance on heat transfer of tomato juice regarding their p-values. However, in milk production heat transfer, carbon nanotubes had no crucial importance.