ฉันรักการแปล4.conclusion
In this work, a recrasallization model describing separately growth and dissolution of the ice crystals during storage of ice cream was developed from a population balance equation coupled with an energy balance. The separate description of growth and dissolution of the ice crystals represents asignificant improvement over previus recrystallizayion models wich described growgh and dissolution using an aggregated rate coefficient and provided insight into how these two phenomena interact during long-term storage of ice cream. The model described accurately measure-ments of the average of ice crystals for two ice cream formulation stored for 104 day at temperatures brtween-5 and-18 c. simulation with the recrystallization model indicated that dissolution is the major phenomenon causing an increase of theaverage diameter of the crystals during the early stages ofstorage. After which both growth and dissolution occur at a decreasing rate fot the remaining of storage. Comparison of the average diameter for the two ice creams indicated that ice cream B. produced using carrageenan as the primary stabilizer. Provided a better preservation of the small diameter of the ice crystals than ice cream A. produced using locust bean gum as the primary stabilizer. Because the formlation of ice cream B reduced the growth
and the dissolution rates of the ice crystals compared to ice cream A.Finally.a sensitivity analysis was conducted and indicated that the acti-vation energy is the input parameter with the most significant impact on the recystalilzation model and that the impact of heat transfer parmeters is negligible because of the rapid change of the ice cream temperature with respect to the duration of storage.
Future work will concern the development a model for the description of recrystallization during stotage of ice cream at fluc-tuating storage temperatures. Instabiliti of the storage tempera-ture can accelerate recrystallization by alternately promoting growth and dissolution of the ice cream and can significantly affect the rheological and mechanical properties of the ice cream.A model coupling the population and energy balances with a description of the mechanical defomation of the ice cream will be developrd for an accurate represention of recyatallization in ice cream in the presence of fluctuating storage temperatures.