Air Blast Freezing of Lime Juice: Effect of Processing Parameters

Abstract

This research characterized the effects of air velocity and lime juice layer thickness on freezing time. In the experiment, the air velocity of the freezer and the thickness of the lime juice layer were set to be 4-12 m sec^-1 and 4-10 mm, respectively. The temperatures of the lime juice were measured from 15°C until it reached -20°C and were continuously recorded during each test. The experimental freezing time curves showed a decreased freezing rate period. In addition, the mathematical model of freezing time was fit to a set of the experimental sample data, which was characterized by 6 different regression models. The results showed that the freezing times increased when decreasing air velocity. Moreover, increasing the lime juice layer thickness would also increase the freezing time of lime juice in which occurred mostly in S-2 stage. With the air velocity exceeding 8 m/s and the lime juice layer thickness less than 8 mm, the experiment gave the best operating condition for the freezing time of lime juice in this freezing process. The Model (6) was found to satisfactorily describe the curves freezing time of lime juice with R² of 0.9656.