ESTIMATION OF PHYSICAL-PROPERTIES OF FOAMED FOODS USING ENERGY-DISSIPATION IN SCRAPED-SURFACE HEAT-EXCHANGERS

A jacketed stirred column simulating a continuous scraped-surface heat exchanger under steady-state conditions was devised and used to produ ce foamed foods. The physical properties of these were assessed as a f unction of rotor speed, paddle diameter and gas/liquid ratio. Apparent viscosity of foamed food was calculated using a Newton number-Reynold s number experimental relation for the stirred column and power consum ption measurements. It was shown that the mean apparent viscosity was an inverse function of the density of the foamed food and of the rotat ion speed. Mean bubble diameter was correlated with the mixing conditi ons by a critical Weber number. For the starting material used the mea n bubble diameter reached a stationary value beyond a certain rotation speed. These results were explained theoretically.