RESIDENCE TIME DISTRIBUTION (RTD) CHARACTERISTICS OF MEAT AND CARROT CUBES IN STARCH SOLUTIONS IN A VERTICAL SCRAPED SURFACE HEAT-EXCHANGER(SSHE)

The residence time distribution (RTD) of meat and carrot cubes was eva luated in the vertical scraped surface heat exchanger of a pilot scale aseptic processing system using a full factorial design of experiment s employing flow rate (10, 15, 20 and 25 kg/min), particle size (meat cubes of size 10, 15 and 20 mm; and carrot cubes of size 6 and 13 mm) and concentration of the carrier fluid (4, 5 and 6% w/w starch) as fac tors. All factors influenced (P < 0.05) the fastest particle residence time (FPRT), the mean particle residence time (MPRT), standard deviat ion of the residence time distribution (SRTD) and their normalized ver sions. A generalized logistic model showed a reasonable fit for the ex perimental RTD under all test conditions (r(2) > 0.95). Analysis of va riance revealed that all test factors were responsive (P less than or equal to 0.05) to parameters associated with the model: the half conce ntration internal age (HRT and HNT), the particle accumulation rate (B ) and the upper limit particle concentration (U).